Commit Graph

4761 Commits

Author SHA1 Message Date
Jeremy Fitzhardinge 64141da587 vmalloc: eagerly clear ptes on vunmap
On stock 2.6.37-rc4, running:

  # mount lilith:/export /mnt/lilith
  # find  /mnt/lilith/ -type f -print0 | xargs -0 file

crashes the machine fairly quickly under Xen.  Often it results in oops
messages, but the couple of times I tried just now, it just hung quietly
and made Xen print some rude messages:

    (XEN) mm.c:2389:d80 Bad type (saw 7400000000000001 != exp
    3000000000000000) for mfn 1d7058 (pfn 18fa7)
    (XEN) mm.c:964:d80 Attempt to create linear p.t. with write perms
    (XEN) mm.c:2389:d80 Bad type (saw 7400000000000010 != exp
    1000000000000000) for mfn 1d2e04 (pfn 1d1fb)
    (XEN) mm.c:2965:d80 Error while pinning mfn 1d2e04

Which means the domain tried to map a pagetable page RW, which would
allow it to map arbitrary memory, so Xen stopped it.  This is because
vm_unmap_ram() left some pages mapped in the vmalloc area after NFS had
finished with them, and those pages got recycled as pagetable pages
while still having these RW aliases.

Removing those mappings immediately removes the Xen-visible aliases, and
so it has no problem with those pages being reused as pagetable pages.
Deferring the TLB flush doesn't upset Xen because it can flush the TLB
itself as needed to maintain its invariants.

When unmapping a region in the vmalloc space, clear the ptes
immediately.  There's no point in deferring this because there's no
amortization benefit.

The TLBs are left dirty, and they are flushed lazily to amortize the
cost of the IPIs.

This specific motivation for this patch is an oops-causing regression
since 2.6.36 when using NFS under Xen, triggered by the NFS client's use
of vm_map_ram() introduced in 56e4ebf877 ("NFS: readdir with vmapped
pages") .  XFS also uses vm_map_ram() and could cause similar problems.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Bryan Schumaker <bjschuma@netapp.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Alex Elder <aelder@sgi.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-12-02 14:51:15 -08:00
Wu Fengguang e172662d11 vmstat: fix dirty threshold ordering
The nr_dirty_[background_]threshold fields are misplaced before the
numa_* fields, and users will read strange values.

This is the right order.  Before patch, nr_dirty_background_threshold
will read as 0 (the value from numa_miss).

	numa_hit 128501
	numa_miss 0
	numa_foreign 0
	numa_interleave 7388
	numa_local 128501
	numa_other 0
	nr_dirty_threshold 144291
	nr_dirty_background_threshold 72145

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Michael Rubin <mrubin@google.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-12-02 14:51:14 -08:00
Zeng Zhaoming 55cfaa3cbd mm/mempolicy.c: add rcu read lock to protect pid structure
find_task_by_vpid() should be protected by rcu_read_lock(), to prevent
free_pid() reclaiming pid.

Signed-off-by: Zeng Zhaoming <zengzm.kernel@gmail.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-12-02 14:51:14 -08:00
Dean Nelson 1f64d69c7a mm/hugetlb.c: avoid double unlock_page() in hugetlb_fault()
Have hugetlb_fault() call unlock_page(page) only if it had previously
called lock_page(page).

Setting CONFIG_DEBUG_VM=y and then running the libhugetlbfs test suite,
resulted in the tripping of VM_BUG_ON(!PageLocked(page)) in
unlock_page() having been called by hugetlb_fault() when page ==
pagecache_page.  This patch remedied the problem.

Signed-off-by: Dean Nelson <dnelson@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-12-02 14:51:14 -08:00
Linus Torvalds 6072d13c42 Call the filesystem back whenever a page is removed from the page cache
NFS needs to be able to release objects that are stored in the page
cache once the page itself is no longer visible from the page cache.

This patch adds a callback to the address space operations that allows
filesystems to perform page cleanups once the page has been removed
from the page cache.

Original patch by: Linus Torvalds <torvalds@linux-foundation.org>
[trondmy: cover the cases of invalidate_inode_pages2() and
          truncate_inode_pages()]
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2010-12-02 09:55:21 -05:00
Jesper Juhl fa9f90be74 Kill off a bunch of warning: ‘inline’ is not at beginning of declaration
These warnings are spewed during a build of a 'allnoconfig' kernel
(especially the ones from u64_stats_sync.h show up a lot) when building
with -Wextra (which I often do)..
They are
  a) annoying
  b) easy to get rid of.
This patch kills them off.

include/linux/u64_stats_sync.h:70:1: warning: ‘inline’ is not at beginning of declaration
include/linux/u64_stats_sync.h:77:1: warning: ‘inline’ is not at beginning of declaration
include/linux/u64_stats_sync.h:84:1: warning: ‘inline’ is not at beginning of declaration
include/linux/u64_stats_sync.h:96:1: warning: ‘inline’ is not at beginning of declaration
include/linux/u64_stats_sync.h:115:1: warning: ‘inline’ is not at beginning of declaration
include/linux/u64_stats_sync.h:127:1: warning: ‘inline’ is not at beginning of declaration
kernel/time.c:241:1: warning: ‘inline’ is not at beginning of declaration
kernel/time.c:257:1: warning: ‘inline’ is not at beginning of declaration
kernel/perf_event.c:4513:1: warning: ‘inline’ is not at beginning of declaration
mm/page_alloc.c:4012:1: warning: ‘inline’ is not at beginning of declaration

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2010-11-28 23:08:04 +01:00
Steven Rostedt 85beb5869a tracing/slab: Move kmalloc tracepoint out of inline code
The tracepoint for kmalloc is in the slab inlined code which causes
every instance of kmalloc to have the tracepoint.

This patch moves the tracepoint out of the inline code to the
slab C file, which removes a large number of inlined trace
points.

  objdump -dr vmlinux.slab| grep 'jmpq.*<trace_kmalloc' |wc -l
213
  objdump -dr vmlinux.slab.patched| grep 'jmpq.*<trace_kmalloc' |wc -l
1

This also has a nice impact on size.

   text	   data	    bss	    dec	    hex	filename
7023060	2121564	2482432	11627056	 b16a30	vmlinux.slab
6970579	2109772	2482432	11562783	 b06f1f	vmlinux.slab.patched

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2010-11-28 21:16:28 +02:00
Jens Axboe f30195c502 Merge branch 'cleanup-bd_claim' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/misc into for-2.6.38/core 2010-11-27 19:49:18 +01:00
David Sterba 5f0af70a25 mm: remove call to find_vma in pagewalk for non-hugetlbfs
Commit d33b9f45 ("mm: hugetlb: fix hugepage memory leak in
walk_page_range()") introduces a check if a vma is a hugetlbfs one and
later in 5dc37642 ("mm hugetlb: add hugepage support to pagemap") it is
moved under #ifdef CONFIG_HUGETLB_PAGE but a needless find_vma call is
left behind and its result is not used anywhere else in the function.

The side-effect of caching vma for @addr inside walk->mm is neither
utilized in walk_page_range() nor in called functions.

Signed-off-by: David Sterba <dsterba@suse.cz>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Matt Mackall <mpm@selenic.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-11-25 06:50:46 +09:00
KAMEZAWA Hiroyuki e9959f0f37 mm/page_alloc.c: fix build_all_zonelist() where percpu_alloc() is wrongly called under stop_machine_run()
During memory hotplug, build_allzonelists() may be called under
stop_machine_run().  In this function, setup_zone_pageset() is called.
But it's bug because it will do page allocation under stop_machine_run().

Here is a report from Alok Kataria.

  BUG: sleeping function called from invalid context at kernel/mutex.c:94
  in_atomic(): 0, irqs_disabled(): 1, pid: 4, name: migration/0
  Pid: 4, comm: migration/0 Not tainted 2.6.35.6-45.fc14.x86_64 #1
  Call Trace:
   [<ffffffff8103d12b>] __might_sleep+0xeb/0xf0
   [<ffffffff81468245>] mutex_lock+0x24/0x50
   [<ffffffff8110eaa6>] pcpu_alloc+0x6d/0x7ee
   [<ffffffff81048888>] ? load_balance+0xbe/0x60e
   [<ffffffff8103a1b3>] ? rt_se_boosted+0x21/0x2f
   [<ffffffff8103e1cf>] ? dequeue_rt_stack+0x18b/0x1ed
   [<ffffffff8110f237>] __alloc_percpu+0x10/0x12
   [<ffffffff81465e22>] setup_zone_pageset+0x38/0xbe
   [<ffffffff810d6d81>] ? build_zonelists_node.clone.58+0x79/0x8c
   [<ffffffff81452539>] __build_all_zonelists+0x419/0x46c
   [<ffffffff8108ef01>] ? cpu_stopper_thread+0xb2/0x198
   [<ffffffff8108f075>] stop_machine_cpu_stop+0x8e/0xc5
   [<ffffffff8108efe7>] ? stop_machine_cpu_stop+0x0/0xc5
   [<ffffffff8108ef57>] cpu_stopper_thread+0x108/0x198
   [<ffffffff81467a37>] ? schedule+0x5b2/0x5cc
   [<ffffffff8108ee4f>] ? cpu_stopper_thread+0x0/0x198
   [<ffffffff81065f29>] kthread+0x7f/0x87
   [<ffffffff8100aae4>] kernel_thread_helper+0x4/0x10
   [<ffffffff81065eaa>] ? kthread+0x0/0x87
   [<ffffffff8100aae0>] ? kernel_thread_helper+0x0/0x10
  Built 5 zonelists in Node order, mobility grouping on.  Total pages: 289456
  Policy zone: Normal

This patch tries to fix the issue by moving setup_zone_pageset() out from
stop_machine_run(). It's obviously not necessary to be called under
stop_machine_run().

[akpm@linux-foundation.org: remove unneeded local]
Reported-by: Alok Kataria <akataria@vmware.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Petr Vandrovec <petr@vmware.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-11-25 06:50:45 +09:00
Michal Hocko a42c390cfa cgroups: make swap accounting default behavior configurable
Swap accounting can be configured by CONFIG_CGROUP_MEM_RES_CTLR_SWAP
configuration option and then it is turned on by default.  There is a boot
option (noswapaccount) which can disable this feature.

This makes it hard for distributors to enable the configuration option as
this feature leads to a bigger memory consumption and this is a no-go for
general purpose distribution kernel.  On the other hand swap accounting
may be very usuful for some workloads.

This patch adds a new configuration option which controls the default
behavior (CGROUP_MEM_RES_CTLR_SWAP_ENABLED).  If the option is selected
then the feature is turned on by default.

It also adds a new boot parameter swapaccount[=1|0] which enhances the
original noswapaccount parameter semantic by means of enable/disable logic
(defaults to 1 if no value is provided to be still consistent with
noswapaccount).

The default behavior is unchanged (if CONFIG_CGROUP_MEM_RES_CTLR_SWAP is
enabled then CONFIG_CGROUP_MEM_RES_CTLR_SWAP_ENABLED is enabled as well)

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-11-25 06:50:45 +09:00
Daisuke Nishimura b1dd693e5b memcg: avoid deadlock between move charge and try_charge()
__mem_cgroup_try_charge() can be called under down_write(&mmap_sem)(e.g.
mlock does it). This means it can cause deadlock if it races with move charge:

Ex.1)
                move charge             |        try charge
  --------------------------------------+------------------------------
    mem_cgroup_can_attach()             |  down_write(&mmap_sem)
      mc.moving_task = current          |    ..
      mem_cgroup_precharge_mc()         |  __mem_cgroup_try_charge()
        mem_cgroup_count_precharge()    |    prepare_to_wait()
          down_read(&mmap_sem)          |    if (mc.moving_task)
          -> cannot aquire the lock     |    -> true
                                        |      schedule()

Ex.2)
                move charge             |        try charge
  --------------------------------------+------------------------------
    mem_cgroup_can_attach()             |
      mc.moving_task = current          |
      mem_cgroup_precharge_mc()         |
        mem_cgroup_count_precharge()    |
          down_read(&mmap_sem)          |
          ..                            |
          up_read(&mmap_sem)            |
                                        |  down_write(&mmap_sem)
    mem_cgroup_move_task()              |    ..
      mem_cgroup_move_charge()          |  __mem_cgroup_try_charge()
        down_read(&mmap_sem)            |    prepare_to_wait()
        -> cannot aquire the lock       |    if (mc.moving_task)
                                        |    -> true
                                        |      schedule()

To avoid this deadlock, we do all the move charge works (both can_attach() and
attach()) under one mmap_sem section.
And after this patch, we set/clear mc.moving_task outside mc.lock, because we
use the lock only to check mc.from/to.

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-11-25 06:50:44 +09:00
Kirill A. Shutemov 112bc2e120 memcg: fix false positive VM_BUG on non-SMP
Fix this:

  kernel BUG at mm/memcontrol.c:2155!
  invalid opcode: 0000 [#1]
  last sysfs file:

  Pid: 18, comm: sh Not tainted 2.6.37-rc3 #3 /Bochs
  EIP: 0060:[<c10731b2>] EFLAGS: 00000246 CPU: 0
  EIP is at mem_cgroup_move_account+0xe2/0xf0
  EAX: 00000004 EBX: c6f931d4 ECX: c681c300 EDX: c681c000
  ESI: c681c300 EDI: ffffffea EBP: c681c000 ESP: c46f3e30
   DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068
  Process sh (pid: 18, ti=c46f2000 task=c6826e60 task.ti=c46f2000)
  Stack:
   00000155 c681c000 0805f000 c46ee180 c46f3e5c c7058820 c1074d37 00000000
   08060000 c46db9a0 c46ec080 c7058820 0805f000 08060000 c46f3e98 c1074c50
   c106c75e c46f3e98 c46ec080 08060000 0805ffff c46db9a0 c46f3e98 c46e0340
  Call Trace:
   [<c1074d37>] ? mem_cgroup_move_charge_pte_range+0xe7/0x130
   [<c1074c50>] ? mem_cgroup_move_charge_pte_range+0x0/0x130
   [<c106c75e>] ? walk_page_range+0xee/0x1d0
   [<c10725d6>] ? mem_cgroup_move_task+0x66/0x90
   [<c1074c50>] ? mem_cgroup_move_charge_pte_range+0x0/0x130
   [<c1072570>] ? mem_cgroup_move_task+0x0/0x90
   [<c1042616>] ? cgroup_attach_task+0x136/0x200
   [<c1042878>] ? cgroup_tasks_write+0x48/0xc0
   [<c1041e9e>] ? cgroup_file_write+0xde/0x220
   [<c101398d>] ? do_page_fault+0x17d/0x3f0
   [<c108a79d>] ? alloc_fd+0x2d/0xd0
   [<c1041dc0>] ? cgroup_file_write+0x0/0x220
   [<c1077ba2>] ? vfs_write+0x92/0xc0
   [<c1077c81>] ? sys_write+0x41/0x70
   [<c1140e3d>] ? syscall_call+0x7/0xb
  Code: 03 00 74 09 8b 44 24 04 e8 1c f1 ff ff 89 73 04 8d 86 b0 00 00 00 b9 01 00 00 00 89 da 31 ff e8 65 f5 ff ff e9 4d ff ff ff 0f 0b <0f> 0b 0f 0b 0f 0b 90 8d b4 26 00 00 00 00 83 ec 10 8b 0d f4 e3
  EIP: [<c10731b2>] mem_cgroup_move_account+0xe2/0xf0 SS:ESP 0068:c46f3e30
  ---[ end trace 7daa1582159b6532 ]---

lock_page_cgroup and unlock_page_cgroup are implemented using
bit_spinlock.  bit_spinlock doesn't touch the bit if we are on non-SMP
machine, so we can't use the bit to check whether the lock was taken.

Let's introduce is_page_cgroup_locked based on bit_spin_is_locked instead
of PageCgroupLocked to fix it.

[akpm@linux-foundation.org: s/is_page_cgroup_locked/page_is_cgroup_locked/]
Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujtisu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-11-25 06:50:40 +09:00
Steven J. Magnani 04c3496152 nommu: yield CPU while disposing VM
Depending on processor speed, page size, and the amount of memory a
process is allowed to amass, cleanup of a large VM may freeze the system
for many seconds.  This can result in a watchdog timeout.

Make sure other tasks receive some service when cleaning up large VMs.

Signed-off-by: Steven J. Magnani <steve@digidescorp.com>
Cc: Greg Ungerer <gerg@snapgear.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-11-25 06:50:38 +09:00
Linus Torvalds 2744b8889c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6:
  slub: Fix slub_lock down/up imbalance
2010-11-14 13:06:37 -08:00
Pavel Emelyanov 68cee4f118 slub: Fix slub_lock down/up imbalance
There are two places, that do not release the slub_lock.

Respective bugs were introduced by sysfs changes ab4d5ed5 (slub: Enable
sysfs support for !CONFIG_SLUB_DEBUG) and 2bce6485 ( slub: Allow removal
of slab caches during boot).

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2010-11-14 16:53:11 +02:00
Tejun Heo e525fd89d3 block: make blkdev_get/put() handle exclusive access
Over time, block layer has accumulated a set of APIs dealing with bdev
open, close, claim and release.

* blkdev_get/put() are the primary open and close functions.

* bd_claim/release() deal with exclusive open.

* open/close_bdev_exclusive() are combination of open and claim and
  the other way around, respectively.

* bd_link/unlink_disk_holder() to create and remove holder/slave
  symlinks.

* open_by_devnum() wraps bdget() + blkdev_get().

The interface is a bit confusing and the decoupling of open and claim
makes it impossible to properly guarantee exclusive access as
in-kernel open + claim sequence can disturb the existing exclusive
open even before the block layer knows the current open if for another
exclusive access.  Reorganize the interface such that,

* blkdev_get() is extended to include exclusive access management.
  @holder argument is added and, if is @FMODE_EXCL specified, it will
  gain exclusive access atomically w.r.t. other exclusive accesses.

* blkdev_put() is similarly extended.  It now takes @mode argument and
  if @FMODE_EXCL is set, it releases an exclusive access.  Also, when
  the last exclusive claim is released, the holder/slave symlinks are
  removed automatically.

* bd_claim/release() and close_bdev_exclusive() are no longer
  necessary and either made static or removed.

* bd_link_disk_holder() remains the same but bd_unlink_disk_holder()
  is no longer necessary and removed.

* open_bdev_exclusive() becomes a simple wrapper around lookup_bdev()
  and blkdev_get().  It also has an unexpected extra bdev_read_only()
  test which probably should be moved into blkdev_get().

* open_by_devnum() is modified to take @holder argument and pass it to
  blkdev_get().

Most of bdev open/close operations are unified into blkdev_get/put()
and most exclusive accesses are tested atomically at the open time (as
it should).  This cleans up code and removes some, both valid and
invalid, but unnecessary all the same, corner cases.

open_bdev_exclusive() and open_by_devnum() can use further cleanup -
rename to blkdev_get_by_path() and blkdev_get_by_devt() and drop
special features.  Well, let's leave them for another day.

Most conversions are straight-forward.  drbd conversion is a bit more
involved as there was some reordering, but the logic should stay the
same.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Neil Brown <neilb@suse.de>
Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Peter Osterlund <petero2@telia.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <joel.becker@oracle.com>
Cc: Alex Elder <aelder@sgi.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: dm-devel@redhat.com
Cc: drbd-dev@lists.linbit.com
Cc: Leo Chen <leochen@broadcom.com>
Cc: Scott Branden <sbranden@broadcom.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Cc: Joern Engel <joern@logfs.org>
Cc: reiserfs-devel@vger.kernel.org
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
2010-11-13 11:55:17 +01:00
Nick Piggin 27d20fddc8 radix-tree: fix RCU bug
Salman Qazi describes the following radix-tree bug:

In the following case, we get can get a deadlock:

0.  The radix tree contains two items, one has the index 0.
1.  The reader (in this case find_get_pages) takes the rcu_read_lock.
2.  The reader acquires slot(s) for item(s) including the index 0 item.
3.  The non-zero index item is deleted, and as a consequence the other item is
    moved to the root of the tree. The place where it used to be is queued for
    deletion after the readers finish.
3b. The zero item is deleted, removing it from the direct slot, it remains in
    the rcu-delayed indirect node.
4.  The reader looks at the index 0 slot, and finds that the page has 0 ref
    count
5.  The reader looks at it again, hoping that the item will either be freed or
    the ref count will increase. This never happens, as the slot it is looking
    at will never be updated. Also, this slot can never be reclaimed because
    the reader is holding rcu_read_lock and is in an infinite loop.

The fix is to re-use the same "indirect" pointer case that requires a slot
lookup retry into a general "retry the lookup" bit.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Reported-by: Salman Qazi <sqazi@google.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-11-12 07:55:32 -08:00
Shaohua Li 1dce071e18 vmscan: avoid setting zone congested if no page dirty
nr_dirty and nr_congested are increased only when the page is dirty.  So
if all pages are clean, both them will be zero.  In this case, we should
not mark the zone congested.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-11-12 07:55:31 -08:00
Dave Hansen 8d056cb965 mm/vfs: revalidate page->mapping in do_generic_file_read()
70 hours into some stress tests of a 2.6.32-based enterprise kernel, we
ran into a NULL dereference in here:

	int block_is_partially_uptodate(struct page *page, read_descriptor_t *desc,
	                                        unsigned long from)
	{
---->		struct inode *inode = page->mapping->host;

It looks like page->mapping was the culprit.  (xmon trace is below).
After closer examination, I realized that do_generic_file_read() does a
find_get_page(), and eventually locks the page before calling
block_is_partially_uptodate().  However, it doesn't revalidate the
page->mapping after the page is locked.  So, there's a small window
between the find_get_page() and ->is_partially_uptodate() where the page
could get truncated and page->mapping cleared.

We _have_ a reference, so it can't get reclaimed, but it certainly
can be truncated.

I think the correct thing is to check page->mapping after the
trylock_page(), and jump out if it got truncated.  This patch has been
running in the test environment for a month or so now, and we have not
seen this bug pop up again.

xmon info:

  1f:mon> e
  cpu 0x1f: Vector: 300 (Data Access) at [c0000002ae36f770]
      pc: c0000000001e7a6c: .block_is_partially_uptodate+0xc/0x100
      lr: c000000000142944: .generic_file_aio_read+0x1e4/0x770
      sp: c0000002ae36f9f0
     msr: 8000000000009032
     dar: 0
   dsisr: 40000000
    current = 0xc000000378f99e30
    paca    = 0xc000000000f66300
      pid   = 21946, comm = bash
  1f:mon> r
  R00 = 0025c0500000006d   R16 = 0000000000000000
  R01 = c0000002ae36f9f0   R17 = c000000362cd3af0
  R02 = c000000000e8cd80   R18 = ffffffffffffffff
  R03 = c0000000031d0f88   R19 = 0000000000000001
  R04 = c0000002ae36fa68   R20 = c0000003bb97b8a0
  R05 = 0000000000000000   R21 = c0000002ae36fa68
  R06 = 0000000000000000   R22 = 0000000000000000
  R07 = 0000000000000001   R23 = c0000002ae36fbb0
  R08 = 0000000000000002   R24 = 0000000000000000
  R09 = 0000000000000000   R25 = c000000362cd3a80
  R10 = 0000000000000000   R26 = 0000000000000002
  R11 = c0000000001e7b60   R27 = 0000000000000000
  R12 = 0000000042000484   R28 = 0000000000000001
  R13 = c000000000f66300   R29 = c0000003bb97b9b8
  R14 = 0000000000000001   R30 = c000000000e28a08
  R15 = 000000000000ffff   R31 = c0000000031d0f88
  pc  = c0000000001e7a6c .block_is_partially_uptodate+0xc/0x100
  lr  = c000000000142944 .generic_file_aio_read+0x1e4/0x770
  msr = 8000000000009032   cr  = 22000488
  ctr = c0000000001e7a60   xer = 0000000020000000   trap =  300
  dar = 0000000000000000   dsisr = 40000000
  1f:mon> t
  [link register   ] c000000000142944 .generic_file_aio_read+0x1e4/0x770
  [c0000002ae36f9f0] c000000000142a14 .generic_file_aio_read+0x2b4/0x770 (unreliable)
  [c0000002ae36fb40] c0000000001b03e4 .do_sync_read+0xd4/0x160
  [c0000002ae36fce0] c0000000001b153c .vfs_read+0xec/0x1f0
  [c0000002ae36fd80] c0000000001b1768 .SyS_read+0x58/0xb0
  [c0000002ae36fe30] c00000000000852c syscall_exit+0x0/0x40
  --- Exception: c00 (System Call) at 00000080a840bc54
  SP (fffca15df30) is in userspace
  1f:mon> di c0000000001e7a6c
  c0000000001e7a6c  e9290000      ld      r9,0(r9)
  c0000000001e7a70  418200c0      beq     c0000000001e7b30        # .block_is_partially_uptodate+0xd0/0x100
  c0000000001e7a74  e9440008      ld      r10,8(r4)
  c0000000001e7a78  78a80020      clrldi  r8,r5,32
  c0000000001e7a7c  3c000001      lis     r0,1
  c0000000001e7a80  812900a8      lwz     r9,168(r9)
  c0000000001e7a84  39600001      li      r11,1
  c0000000001e7a88  7c080050      subf    r0,r8,r0
  c0000000001e7a8c  7f805040      cmplw   cr7,r0,r10
  c0000000001e7a90  7d6b4830      slw     r11,r11,r9
  c0000000001e7a94  796b0020      clrldi  r11,r11,32
  c0000000001e7a98  419d00a8      bgt     cr7,c0000000001e7b40    # .block_is_partially_uptodate+0xe0/0x100
  c0000000001e7a9c  7fa55840      cmpld   cr7,r5,r11
  c0000000001e7aa0  7d004214      add     r8,r0,r8
  c0000000001e7aa4  79080020      clrldi  r8,r8,32
  c0000000001e7aa8  419c0078      blt     cr7,c0000000001e7b20    # .block_is_partially_uptodate+0xc0/0x100

Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: <arunabal@in.ibm.com>
Cc: <sbest@us.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-11-12 07:55:31 -08:00
Dan Carpenter d2e61b8dc9 memcg: null dereference on allocation failure
The original code had a null dereference if alloc_percpu() failed.  This
was introduced in commit 711d3d2c9b ("memcg: cpu hotplug aware percpu
count updates")

Signed-off-by: Dan Carpenter <error27@gmail.com>
Reviewed-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-11-12 07:55:31 -08:00
Pekka Enberg 63bfd7384b perf_events: Fix perf_counter_mmap() hook in mprotect()
As pointed out by Linus, commit dab5855 ("perf_counter: Add mmap event hooks to
mprotect()") is fundamentally wrong as mprotect_fixup() can free 'vma' due to
merging. Fix the problem by moving perf_event_mmap() hook to
mprotect_fixup().

Note: there's another successful return path from mprotect_fixup() if old
flags equal to new flags. We don't, however, need to call
perf_event_mmap() there because 'perf' already knows the VMA is
executable.

Reported-by: Dave Jones <davej@redhat.com>
Analyzed-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>
Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-11-09 10:19:38 -08:00
Pavel Emelyanov 98072e4d97 slub: Fix slub_lock down/up imbalance
There are two places, that do not release the slub_lock.

Respective bugs were introduced by sysfs changes ab4d5ed5 (slub: Enable
sysfs support for !CONFIG_SLUB_DEBUG) and 2bce6485 ( slub: Allow removal
of slab caches during boot).

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2010-11-06 09:04:33 +02:00
Richard Kennedy 4a92379bdf slub tracing: move trace calls out of always inlined functions to reduce kernel code size
Having the trace calls defined in the always inlined kmalloc functions
in include/linux/slub_def.h causes a lot of code duplication as the
trace functions get instantiated for each kamalloc call site. This can
simply be removed by pushing the trace calls down into the functions in
slub.c.

On my x86_64 built this patch shrinks the code size of the kernel by
approx 36K and also shrinks the code size of many modules -- too many to
list here ;)

size vmlinux (2.6.36) reports
       text        data     bss     dec     hex filename
    5410611	 743172	 828928	6982711	 6a8c37	vmlinux
    5373738	 744244	 828928	6946910	 6a005e	vmlinux + patch

The resulting kernel has had some testing & kmalloc trace still seems to
work.

This patch
- moves trace_kmalloc out of the inlined kmalloc() and pushes it down
into kmem_cache_alloc_trace() so this it only get instantiated once.

- rename kmem_cache_alloc_notrace()  to kmem_cache_alloc_trace() to
indicate that now is does have tracing. (maybe this would better being
called something like kmalloc_kmem_cache ?)

- adds a new function kmalloc_order() to handle allocation and tracing
of large allocations of page order.

- removes tracing from the inlined kmalloc_large() replacing them with a
call to kmalloc_order();

- move tracing out of inlined kmalloc_node() and pushing it down into
kmem_cache_alloc_node_trace

- rename kmem_cache_alloc_node_notrace() to
kmem_cache_alloc_node_trace()

- removes the include of trace/events/kmem.h from slub_def.h.

v2
- keep kmalloc_order_trace inline when !CONFIG_TRACE

Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2010-11-06 09:04:33 +02:00
Wu Fengguang ff8b16d7e1 vmstat: fix offset calculation on void*
Fix regression introduced by commit 79da826aee ("writeback: report
dirty thresholds in /proc/vmstat").

The incorrect pointer arithmetic can result in problems like this:

  BUG: unable to handle kernel paging request at 07c06d16
  IP: [<c050c336>] strnlen+0x6/0x20
  Call Trace:
   [<c050a249>] ? string+0x39/0xe0
   [<c042be6b>] ? __wake_up_common+0x4b/0x80
   [<c050afcc>] ? vsnprintf+0x1ec/0x380
   [<c04b380e>] ? seq_printf+0x2e/0x60
   [<c04829a6>] ? vmstat_show+0x26/0x30
   [<c04b3bb6>] ? seq_read+0xa6/0x380
   [<c04b3b10>] ? seq_read+0x0/0x380
   [<c04d5d2f>] ? proc_reg_read+0x5f/0x90
   [<c049c4a1>] ? vfs_read+0xa1/0x140
   [<c04d5cd0>] ? proc_reg_read+0x0/0x90
   [<c049c981>] ? sys_read+0x41/0x70
   [<c0402bd0>] ? sysenter_do_call+0x12/0x26

Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Michael Rubin <mrubin@google.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-11-03 14:39:58 -04:00
Michel Lespinasse d88c0922fa Release page reference during page fault retry
This slipped by when unifying the filemap and swap versions of
lock_page_or_retry()...

Signed-off-by: Michel Lespinasse <walken@google.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-11-02 17:02:31 -04:00
Uwe Kleine-König b595076a18 tree-wide: fix comment/printk typos
"gadget", "through", "command", "maintain", "maintain", "controller", "address",
"between", "initiali[zs]e", "instead", "function", "select", "already",
"equal", "access", "management", "hierarchy", "registration", "interest",
"relative", "memory", "offset", "already",

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2010-11-01 15:38:34 -04:00
Al Viro 120a795da0 audit mmap
Normal syscall audit doesn't catch 5th argument of syscall.  It also
doesn't catch the contents of userland structures pointed to be
syscall argument, so for both old and new mmap(2) ABI it doesn't
record the descriptor we are mapping.  For old one it also misses
flags.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-10-30 08:45:43 -04:00
Al Viro 3c26ff6e49 convert get_sb_nodev() users
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-10-29 04:16:31 -04:00
Eric Dumazet 800416f799 numa: fix slab_node(MPOL_BIND)
When a node contains only HighMem memory, slab_node(MPOL_BIND)
dereferences a NULL pointer.

[ This code seems to go back all the way to commit 19770b32609b: "mm:
  filter based on a nodemask as well as a gfp_mask".  Which was back in
  April 2008, and it got merged into 2.6.26.  - Linus ]

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <cl@linux.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-28 10:04:30 -07:00
Linus Torvalds bdab225015 Merge git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-2.6-mn10300
* git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-2.6-mn10300: (44 commits)
  MN10300: Save frame pointer in thread_info struct rather than global var
  MN10300: Change "Matsushita" to "Panasonic".
  MN10300: Create a defconfig for the ASB2364 board
  MN10300: Update the ASB2303 defconfig
  MN10300: ASB2364: Add support for SMSC911X and SMC911X
  MN10300: ASB2364: Handle the IRQ multiplexer in the FPGA
  MN10300: Generic time support
  MN10300: Specify an ELF HWCAP flag for MN10300 Atomic Operations Unit support
  MN10300: Map userspace atomic op regs as a vmalloc page
  MN10300: And Panasonic AM34 subarch and implement SMP
  MN10300: Delete idle_timestamp from irq_cpustat_t
  MN10300: Make various interrupt priority settings configurable
  MN10300: Optimise do_csum()
  MN10300: Implement atomic ops using atomic ops unit
  MN10300: Make the FPU operate in non-lazy mode under SMP
  MN10300: SMP TLB flushing
  MN10300: Use the [ID]PTEL2 registers rather than [ID]PTEL for TLB control
  MN10300: Make the use of PIDR to mark TLB entries controllable
  MN10300: Rename __flush_tlb*() to local_flush_tlb*()
  MN10300: AM34 erratum requires MMUCTR read and write on exception entry
  ...
2010-10-27 18:53:26 -07:00
Miklos Szeredi 0be8557bcd fuse: use release_pages()
Replace iterated page_cache_release() with release_pages(), which is
faster and shorter.

Needs release_pages() to be exported to modules.

Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-27 18:03:17 -07:00
KAMEZAWA Hiroyuki 26174efd42 memcg: generic filestat update interface
This patch extracts the core logic from mem_cgroup_update_file_mapped() as
mem_cgroup_update_file_stat() and adds a wrapper.

As a planned future update, memory cgroup has to count dirty pages to
implement dirty_ratio/limit.  And more, the number of dirty pages is
required to kick flusher thread to start writeback.  (Now, no kick.)

This patch is preparation for it and makes other statistics implementation
clearer.  Just a clean up.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Reviewed-by: Greg Thelen <gthelen@google.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-27 18:03:10 -07:00
KAMEZAWA Hiroyuki 1489ebad8b memcg: cpu hotplug aware quick acount_move detection
An event counter MEM_CGROUP_ON_MOVE is used for quick check whether file
stat update can be done in async manner or not.  Now, it use percpu
counter and for_each_possible_cpu to update.

This patch replaces for_each_possible_cpu to for_each_online_cpu and adds
necessary synchronization logic at CPU HOTPLUG.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-27 18:03:09 -07:00
KAMEZAWA Hiroyuki 711d3d2c9b memcg: cpu hotplug aware percpu count updates
Now, memcgroup's per cpu coutner uses for_each_possible_cpu() to get the
value.  It's better to use for_each_online_cpu() and a cpu hotplug
handler.

This patch only handles statistics counter.  MEM_CGROUP_ON_MOVE will be
handled in another patch.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-27 18:03:09 -07:00
KAMEZAWA Hiroyuki 7d74b06f24 memcg: use for_each_mem_cgroup
In memory cgroup management, we sometimes have to walk through
subhierarchy of cgroup to gather informaiton, or lock something, etc.

Now, to do that, mem_cgroup_walk_tree() function is provided.  It calls
given callback function per cgroup found.  But the bad thing is that it
has to pass a fixed style function and argument, "void*" and it adds much
type casting to memcontrol.c.

To make the code clean, this patch replaces walk_tree() with

  for_each_mem_cgroup_tree(iter, root)

An iterator style call.  The good point is that iterator call doesn't have
to assume what kind of function is called under it.  A bad point is that
it may cause reference-count leak if a caller use "break" from the loop by
mistake.

I think the benefit is larger.  The modified code seems straigtforward and
easy to read because we don't have misterious callbacks and pointer cast.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-27 18:03:09 -07:00
KAMEZAWA Hiroyuki 32047e2a85 memcg: avoid lock in updating file_mapped (Was fix race in file_mapped accouting flag management
At accounting file events per memory cgroup, we need to find memory cgroup
via page_cgroup->mem_cgroup.  Now, we use lock_page_cgroup() for guarantee
pc->mem_cgroup is not overwritten while we make use of it.

But, considering the context which page-cgroup for files are accessed,
we can use alternative light-weight mutual execusion in the most case.

At handling file-caches, the only race we have to take care of is "moving"
account, IOW, overwriting page_cgroup->mem_cgroup.  (See comment in the
patch)

Unlike charge/uncharge, "move" happens not so frequently. It happens only when
rmdir() and task-moving (with a special settings.)
This patch adds a race-checker for file-cache-status accounting v.s. account
moving. The new per-cpu-per-memcg counter MEM_CGROUP_ON_MOVE is added.
The routine for account move
  1. Increment it before start moving
  2. Call synchronize_rcu()
  3. Decrement it after the end of moving.
By this, file-status-counting routine can check it needs to call
lock_page_cgroup(). In most case, I doesn't need to call it.

Following is a perf data of a process which mmap()/munmap 32MB of file cache
in a minute.

Before patch:
    28.25%     mmap  mmap               [.] main
    22.64%     mmap  [kernel.kallsyms]  [k] page_fault
     9.96%     mmap  [kernel.kallsyms]  [k] mem_cgroup_update_file_mapped
     3.67%     mmap  [kernel.kallsyms]  [k] filemap_fault
     3.50%     mmap  [kernel.kallsyms]  [k] unmap_vmas
     2.99%     mmap  [kernel.kallsyms]  [k] __do_fault
     2.76%     mmap  [kernel.kallsyms]  [k] find_get_page

After patch:
    30.00%     mmap  mmap               [.] main
    23.78%     mmap  [kernel.kallsyms]  [k] page_fault
     5.52%     mmap  [kernel.kallsyms]  [k] mem_cgroup_update_file_mapped
     3.81%     mmap  [kernel.kallsyms]  [k] unmap_vmas
     3.26%     mmap  [kernel.kallsyms]  [k] find_get_page
     3.18%     mmap  [kernel.kallsyms]  [k] __do_fault
     3.03%     mmap  [kernel.kallsyms]  [k] filemap_fault
     2.40%     mmap  [kernel.kallsyms]  [k] handle_mm_fault
     2.40%     mmap  [kernel.kallsyms]  [k] do_page_fault

This patch reduces memcg's cost to some extent.
(mem_cgroup_update_file_mapped is called by both of map/unmap)

Note: It seems some more improvements are required..but no idea.
      maybe removing set/unset flag is required.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Greg Thelen <gthelen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-27 18:03:09 -07:00
KAMEZAWA Hiroyuki 0c270f8f99 memcg: fix race in file_mapped accouting flag management
Presently memory cgroup accounts file-mapped by counter and flag.  counter
is working in the same way with zone_stat but FileMapped flag only exists
in memcg (for helping move_account).

This flag can be updated wrongly in a case.  Assume CPU0 and CPU1 and a
thread mapping a page on CPU0, another thread unmapping it on CPU1.

    CPU0                   		CPU1
				rmv rmap (mapcount 1->0)
   add rmap (mapcount 0->1)
   lock_page_cgroup()
   memcg counter+1		(some delay)
   set MAPPED FLAG.
   unlock_page_cgroup()
				lock_page_cgroup()
				memcg counter-1
				clear MAPPED flag

In the above sequence counter is properly updated but FLAG is not.  This
means that representing a state by a flag which is maintained by counter
needs some special care.

To handle this, when clearing a flag, this patch check mapcount directly
and clear the flag only when mapcount == 0.  (if mapcount >0, someone will
make it to zero later and flag will be cleared.)

Reverse case, dec-after-inc cannot be a problem because page_table_lock()
works well for it.  (IOW, to make above sequence, 2 processes should touch
the same page at once with map/unmap.)

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Greg Thelen <gthelen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-27 18:03:09 -07:00
Peter Zijlstra a8e23a2918 mm,x86: fix kmap_atomic_push vs ioremap_32.c
It appears i386 uses kmap_atomic infrastructure regardless of
CONFIG_HIGHMEM which results in a compile error when highmem is disabled.

Cure this by providing the needed few bits for both CONFIG_HIGHMEM and
CONFIG_X86_32.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reported-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-27 18:03:05 -07:00
David Howells 7c7fcf762e MN10300: Save frame pointer in thread_info struct rather than global var
Save the current exception frame pointer in the thread_info struct rather than
in a global variable as the latter makes SMP tricky, especially when preemption
is also enabled.

This also replaces __frame with current_frame() and rearranges header file
inclusions to make it all compile.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Akira Takeuchi <takeuchi.akr@jp.panasonic.com>
2010-10-27 17:29:01 +01:00
Linus Torvalds 426e1f5cec Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (52 commits)
  split invalidate_inodes()
  fs: skip I_FREEING inodes in writeback_sb_inodes
  fs: fold invalidate_list into invalidate_inodes
  fs: do not drop inode_lock in dispose_list
  fs: inode split IO and LRU lists
  fs: switch bdev inode bdi's correctly
  fs: fix buffer invalidation in invalidate_list
  fsnotify: use dget_parent
  smbfs: use dget_parent
  exportfs: use dget_parent
  fs: use RCU read side protection in d_validate
  fs: clean up dentry lru modification
  fs: split __shrink_dcache_sb
  fs: improve DCACHE_REFERENCED usage
  fs: use percpu counter for nr_dentry and nr_dentry_unused
  fs: simplify __d_free
  fs: take dcache_lock inside __d_path
  fs: do not assign default i_ino in new_inode
  fs: introduce a per-cpu last_ino allocator
  new helper: ihold()
  ...
2010-10-26 17:58:44 -07:00
Peter Zijlstra 766f916419 kernel: remove PF_FLUSHER
PF_FLUSHER is only ever set, not tested, remove it.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:15 -07:00
Jan Beulich 3ecb01df32 use clear_page()/copy_page() in favor of memset()/memcpy() on whole pages
After all that's what they are intended for.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:13 -07:00
Hagen Paul Pfeifer 732eacc054 replace nested max/min macros with {max,min}3 macro
Use the new {max,min}3 macros to save some cycles and bytes on the stack.
This patch substitutes trivial nested macros with their counterpart.

Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net>
Cc: Joe Perches <joe@perches.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Roland Dreier <rolandd@cisco.com>
Cc: Sean Hefty <sean.hefty@intel.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:12 -07:00
Bob Liu f3ab2636c5 mm: do_migrate_range: reduce list_empty() check
Simple code for reducing list_empty(&source) check.

Signed-off-by: Bob Liu <lliubbo@gmail.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:11 -07:00
Bob Liu 809c444977 mm: do_migrate_range: exit loop if not_managed is true
If not_managed is true all pages will be putback to lru, so break the loop
earlier to skip other pages isolate.

Signed-off-by: Bob Liu <lliubbo@gmail.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:11 -07:00
Bob Liu f6a3607e5f mm: page_isolation: codeclean fix comment and rm unneeded val init
__test_page_isolated_in_pageblock() returns 1 if all pages in the range
are isolated, so fix the comment.  Variable `pfn' will be initialised in
the following loop so remove it.

Signed-off-by: Bob Liu <lliubbo@gmail.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:11 -07:00
KAMEZAWA Hiroyuki 572438f9b5 mm: fix is_mem_section_removable() page_order BUG_ON check
page_order() is called by memory hotplug's user interface to check the
section is removable or not.  (is_mem_section_removable())

It calls page_order() withoug holding zone->lock.
So, even if the caller does

	if (PageBuddy(page))
		ret = page_order(page) ...
The caller may hit BUG_ON().

For fixing this, there are 2 choices.
  1. add zone->lock.
  2. remove BUG_ON().

is_mem_section_removable() is used for some "advice" and doesn't need to
be 100% accurate.  This is_removable() can be called via user program..
We don't want to take this important lock for long by user's request.  So,
this patch removes BUG_ON().

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Wu Fengguang <fengguang.wu@intel.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:11 -07:00
Dean Nelson 44e2aa937e mm/hugetlb.c: add missing spin_lock() to hugetlb_cow()
Add missing spin_lock() of the page_table_lock before an error return in
hugetlb_cow(). Callers of hugtelb_cow() expect it to be held upon return.

Signed-off-by: Dean Nelson <dnelson@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:11 -07:00
Gleb Natapov 70384dc6dc mm: fix error reporting in move_pages() syscall
The vma returned by find_vma does not necessarily include the target
address.  If this happens the code tries to follow a page outside of any
vma and returns ENOENT instead of EFAULT.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:11 -07:00
Kay Sievers 66d7dd518a /proc/swaps: support polling
System management wants to subscribe to changes in swap configuration.
Make /proc/swaps pollable like /proc/mounts.

[akpm@linux-foundation.org: document proc_poll_event]
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Acked-by: Greg KH <greg@kroah.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:11 -07:00
Dave Young e1ca7788de mm: add vzalloc() and vzalloc_node() helpers
Add vzalloc() and vzalloc_node() to encapsulate the
vmalloc-then-memset-zero operation.

Use __GFP_ZERO to zero fill the allocated memory.

Signed-off-by: Dave Young <hidave.darkstar@gmail.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Acked-by: Greg Ungerer <gerg@snapgear.com>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:10 -07:00
Andrew Morton 7bbc0905ea mm/memory_hotplug.c: make scan_lru_pages() static
Reported-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:10 -07:00
Namhyung Kim 36deb0be31 vmstat: include compaction.h when CONFIG_COMPACTION
This removes following warning from sparse:

 mm/vmstat.c:466:5: warning: symbol 'fragmentation_index' was not declared. Should it be static?

[akpm@linux-foundation.org: move the include to top-of-file]
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:10 -07:00
Namhyung Kim e199b5d1fe vmalloc: annotate lock context change on s_start/stop()
s_start() and s_stop() grab/release vmlist_lock but were missing proper
annotations.  Add them.

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:10 -07:00
Namhyung Kim 170168d0a3 vmalloc: rename temporary variable in __insert_vmap_area()
Rename redundant 'tmp' to fix following sparse warnings:

 mm/vmalloc.c:296:34: warning: symbol 'tmp' shadows an earlier one
 mm/vmalloc.c:293:24: originally declared here

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:10 -07:00
Namhyung Kim e574b5fd20 rmap: make anon_vma_chain_free() static
Make anon_vma_chain_free() static.  It is called only in rmap.c and the
corresponding alloc function is already static.

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:10 -07:00
Namhyung Kim e9a81a821d rmap: wrap page_check_address() using __cond_lock()
The page_check_address() conditionally grabs *@ptlp in case of returning
non-NULL.  Rename and wrap it using __cond_lock() removes following
warnings from sparse:

 mm/rmap.c:472:9: warning: context imbalance in 'page_mapped_in_vma' - unexpected unlock
 mm/rmap.c:524:9: warning: context imbalance in 'page_referenced_one' - unexpected unlock
 mm/rmap.c:706:9: warning: context imbalance in 'page_mkclean_one' - unexpected unlock
 mm/rmap.c:1066:9: warning: context imbalance in 'try_to_unmap_one' - unexpected unlock

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:09 -07:00
Namhyung Kim ea4525b600 rmap: annotate lock context change on page_[un]lock_anon_vma()
The page_lock_anon_vma() conditionally grabs RCU and anon_vma lock but
page_unlock_anon_vma() releases them unconditionally.  This leads sparse
to complain about context imbalance.  Annotate them.

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:09 -07:00
Namhyung Kim 1b36ba815b mm: wrap follow_pte() using __cond_lock()
The follow_pte() conditionally grabs *@ptlp in case of returning 0.
Rename and wrap it using __cond_lock() removes following warnings:

 mm/memory.c:2337:9: warning: context imbalance in 'do_wp_page' - unexpected unlock
 mm/memory.c:3142:19: warning: context imbalance in 'handle_mm_fault' - different lock contexts for basic block

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:09 -07:00
Namhyung Kim e6219ec819 mm: add lock release annotation on do_wp_page()
The do_wp_page() releases @ptl but was missing proper annotation.  Add it.
 This removes following warnings from sparse:

 mm/memory.c:2337:9: warning: context imbalance in 'do_wp_page' - unexpected unlock
 mm/memory.c:3142:19: warning: context imbalance in 'handle_mm_fault' - different lock contexts for basic block

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:09 -07:00
Namhyung Kim 25ca1d6c02 mm: wrap get_locked_pte() using __cond_lock()
The get_locked_pte() conditionally grabs 'ptl' in case of returning
non-NULL.  This leads sparse to complain about context imbalance.  Rename
and wrap it using __cond_lock() to make sparse happy.

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:09 -07:00
Namhyung Kim e6223a3b19 mm: add casts to/from gfp_t in gfp_to_alloc_flags()
This removes following warning from sparse:

 mm/page_alloc.c:1934:9: warning: restricted gfp_t degrades to integer

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:09 -07:00
Namhyung Kim 0116651c85 mm: remove temporary variable on generic_file_direct_write()
'end' shadows earlier one and is not necessary at all.  Remove it and use
'pos' instead.  This removes following sparse warnings:

 mm/filemap.c:2180:24: warning: symbol 'end' shadows an earlier one
 mm/filemap.c:2132:25: originally declared here

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:09 -07:00
Michel Lespinasse d065bd810b mm: retry page fault when blocking on disk transfer
This change reduces mmap_sem hold times that are caused by waiting for
disk transfers when accessing file mapped VMAs.

It introduces the VM_FAULT_ALLOW_RETRY flag, which indicates that the call
site wants mmap_sem to be released if blocking on a pending disk transfer.
In that case, filemap_fault() returns the VM_FAULT_RETRY status bit and
do_page_fault() will then re-acquire mmap_sem and retry the page fault.

It is expected that the retry will hit the same page which will now be
cached, and thus it will complete with a low mmap_sem hold time.

Tests:

- microbenchmark: thread A mmaps a large file and does random read accesses
  to the mmaped area - achieves about 55 iterations/s. Thread B does
  mmap/munmap in a loop at a separate location - achieves 55 iterations/s
  before, 15000 iterations/s after.

- We are seeing related effects in some applications in house, which show
  significant performance regressions when running without this change.

[akpm@linux-foundation.org: fix warning & crash]
Signed-off-by: Michel Lespinasse <walken@google.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Reviewed-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Ying Han <yinghan@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: "H. Peter Anvin" <hpa@zytor.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:09 -07:00
Michel Lespinasse b522c94da5 mm: filemap_fault: unique path for locking page
Introduce a single location where filemap_fault() locks the desired page.
There used to be two such places, depending if the initial find_get_page()
was successful or not.

Signed-off-by: Michel Lespinasse <walken@google.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Reviewed-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Ying Han <yinghan@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:09 -07:00
Dima Zavin ea05c8444e mm: add a might_sleep_if() to dma_pool_alloc()
Buggy drivers (e.g.  fsl_udc) could call dma_pool_alloc from atomic
context with GFP_KERNEL.  In most instances, the first pool_alloc_page
call would succeed and the sleeping functions would never be called.  This
allowed the buggy drivers to slip through the cracks.

Add a might_sleep_if() checking for __GFP_WAIT in flags.

Signed-off-by: Dima Zavin <dima@android.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:08 -07:00
Peter Zijlstra ece0e2b640 mm: remove pte_*map_nested()
Since we no longer need to provide KM_type, the whole pte_*map_nested()
API is now redundant, remove it.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Miller <davem@davemloft.net>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:08 -07:00
Peter Zijlstra 3e4d3af501 mm: stack based kmap_atomic()
Keep the current interface but ignore the KM_type and use a stack based
approach.

The advantage is that we get rid of crappy code like:

	#define __KM_PTE			\
		(in_nmi() ? KM_NMI_PTE : 	\
		 in_irq() ? KM_IRQ_PTE :	\
		 KM_PTE0)

and in general can stop worrying about what context we're in and what kmap
slots might be appropriate for that.

The downside is that FRV kmap_atomic() gets more expensive.

For now we use a CPP trick suggested by Andrew:

  #define kmap_atomic(page, args...) __kmap_atomic(page)

to avoid having to touch all kmap_atomic() users in a single patch.

[ not compiled on:
  - mn10300: the arch doesn't actually build with highmem to begin with ]

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix up drivers/gpu/drm/i915/intel_overlay.c]
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Miller <davem@davemloft.net>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dave Airlie <airlied@linux.ie>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:08 -07:00
KOSAKI Motohiro 2e30244a7c vmscan,tmpfs: treat used once pages on tmpfs as used once
When a page has PG_referenced, shrink_page_list() discards it only if it
is not dirty.  This rule works fine if the backing filesystem is a regular
one.  PG_dirty is a good signal that the page was used recently because
the flusher threads clean pages periodically.  In addition, page writeback
is costlier than simple page discard.

However, when a page is on tmpfs this heuristic doesn't work because
flusher threads don't write back tmpfs pages.  Consequently tmpfs pages
always rotate around the lru twice at least and adds unnecessary lru
churn.  Simple tmpfs streaming io shouldn't cause large anonymous page
swap-out.

Remove this unncessary reclaim bonus of tmpfs pages.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:08 -07:00
Wu Fengguang 4cbec4c8b9 writeback: remove the internal 5% low bound on dirty_ratio
The dirty_ratio was silently limited in global_dirty_limits() to >= 5%.
This is not a user expected behavior.  And it's inconsistent with
calc_period_shift(), which uses the plain vm_dirty_ratio value.

Let's remove the internal bound.

At the same time, fix balance_dirty_pages() to work with the
dirty_thresh=0 case.  This allows applications to proceed when
dirty+writeback pages are all cleaned.

And ">" fits with the name "exceeded" better than ">=" does.  Neil thinks
it is an aesthetic improvement as well as a functional one :)

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Jan Kara <jack@suse.cz>
Proposed-by: Con Kolivas <kernel@kolivas.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Neil Brown <neilb@suse.de>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Michael Rubin <mrubin@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:08 -07:00
Mel Gorman 0e093d9976 writeback: do not sleep on the congestion queue if there are no congested BDIs or if significant congestion is not being encountered in the current zone
If congestion_wait() is called with no BDI congested, the caller will
sleep for the full timeout and this may be an unnecessary sleep.  This
patch adds a wait_iff_congested() that checks congestion and only sleeps
if a BDI is congested else, it calls cond_resched() to ensure the caller
is not hogging the CPU longer than its quota but otherwise will not sleep.

This is aimed at reducing some of the major desktop stalls reported during
IO.  For example, while kswapd is operating, it calls congestion_wait()
but it could just have been reclaiming clean page cache pages with no
congestion.  Without this patch, it would sleep for a full timeout but
after this patch, it'll just call schedule() if it has been on the CPU too
long.  Similar logic applies to direct reclaimers that are not making
enough progress.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:07 -07:00
KOSAKI Motohiro 08fc468f4e vmscan: isolate_lru_pages(): stop neighbour search if neighbour cannot be isolated
isolate_lru_pages() does not just isolate LRU tail pages, but also
isolates neighbour pages of the eviction page.  The neighbour search does
not stop even if neighbours cannot be isolated which is excessive as the
lumpy reclaim will no longer result in a successful higher order
allocation.  This patch stops the PFN neighbour pages if an isolation
fails and moves on to the next block.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Wu Fengguang <fengguang.wu@intel.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:07 -07:00
KOSAKI Motohiro 4718505216 vmscan: remove dead code in shrink_inactive_list()
After synchrounous lumpy reclaim, the page_list is guaranteed to not have
active pages as page activation in shrink_page_list() disables lumpy
reclaim.  Remove the dead code.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:07 -07:00
KOSAKI Motohiro 7d3579e8e6 vmscan: narrow the scenarios in whcih lumpy reclaim uses synchrounous reclaim
shrink_page_list() can decide to give up reclaiming a page under a
number of conditions such as

  1. trylock_page() failure
  2. page is unevictable
  3. zone reclaim and page is mapped
  4. PageWriteback() is true
  5. page is swapbacked and swap is full
  6. add_to_swap() failure
  7. page is dirty and gfpmask don't have GFP_IO, GFP_FS
  8. page is pinned
  9. IO queue is congested
 10. pageout() start IO, but not finished

With lumpy reclaim, failures result in entering synchronous lumpy reclaim
but this can be unnecessary.  In cases (2), (3), (5), (6), (7) and (8),
there is no point retrying.  This patch causes lumpy reclaim to abort when
it is known it will fail.

Case (9) is more interesting. current behavior is,
  1. start shrink_page_list(async)
  2. found queue_congested()
  3. skip pageout write
  4. still start shrink_page_list(sync)
  5. wait on a lot of pages
  6. again, found queue_congested()
  7. give up pageout write again

So, it's useless time wasting.  However, just skipping page reclaim is
also notgood as x86 allocating a huge page needs 512 pages for example.
It can have more dirty pages than queue congestion threshold (~=128).

After this patch, pageout() behaves as follows;

 - If order > PAGE_ALLOC_COSTLY_ORDER
	Ignore queue congestion always.
 - If order <= PAGE_ALLOC_COSTLY_ORDER
	skip write page and disable lumpy reclaim.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:07 -07:00
KOSAKI Motohiro bc57e00f5e vmscan: synchronous lumpy reclaim should not call congestion_wait()
congestion_wait() means "wait until queue congestion is cleared".
However, synchronous lumpy reclaim does not need this congestion_wait() as
shrink_page_list(PAGEOUT_IO_SYNC) uses wait_on_page_writeback() and it
provides the necessary waiting.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Wu Fengguang <fengguang.wu@intel.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:07 -07:00
Mel Gorman 52bb919866 writeback: account for time spent congestion_waited
There is strong evidence to indicate a lot of time is being spent in
congestion_wait(), some of it unnecessarily.  This patch adds a tracepoint
for congestion_wait to record when congestion_wait() was called, how long
the timeout was for and how long it actually slept.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:07 -07:00
Mel Gorman e11da5b4fd tracing, vmscan: add trace events for LRU list shrinking
There have been numerous reports of stalls that pointed at the problem
being somewhere in the VM.  There are multiple roots to the problems which
means dealing with any of the root problems in isolation is tricky to
justify on their own and they would still need integration testing.  This
patch series puts together two different patch sets which in combination
should tackle some of the root causes of latency problems being reported.

Patch 1 adds a tracepoint for shrink_inactive_list.  For this series, the
most important results is being able to calculate the scanning/reclaim
ratio as a measure of the amount of work being done by page reclaim.

Patch 2 accounts for time spent in congestion_wait.

Patches 3-6 were originally developed by Kosaki Motohiro but reworked for
this series.  It has been noted that lumpy reclaim is far too aggressive
and trashes the system somewhat.  As SLUB uses high-order allocations, a
large cost incurred by lumpy reclaim will be noticeable.  It was also
reported during transparent hugepage support testing that lumpy reclaim
was trashing the system and these patches should mitigate that problem
without disabling lumpy reclaim.

Patch 7 adds wait_iff_congested() and replaces some callers of
congestion_wait().  wait_iff_congested() only sleeps if there is a BDI
that is currently congested.  Patch 8 notes that any BDI being congested
is not necessarily a problem because there could be multiple BDIs of
varying speeds and numberous zones.  It attempts to track when a zone
being reclaimed contains many pages backed by a congested BDI and if so,
reclaimers wait on the congestion queue.

I ran a number of tests with monitoring on X86, X86-64 and PPC64. Each
machine had 3G of RAM and the CPUs were

X86:    Intel P4 2-core
X86-64: AMD Phenom 4-core
PPC64:  PPC970MP

Each used a single disk and the onboard IO controller.  Dirty ratio was
left at 20.  I'm just going to report for X86-64 and PPC64 in a vague
attempt to keep this report short.  Four kernels were tested each based on
v2.6.36-rc4

traceonly-v2r2:     Patches 1 and 2 to instrument vmscan reclaims and congestion_wait
lowlumpy-v2r3:      Patches 1-6 to test if lumpy reclaim is better
waitcongest-v2r3:   Patches 1-7 to only wait on congestion
waitwriteback-v2r4: Patches 1-8 to detect when a zone is congested

nocongest-v1r5: Patches 1-3 for testing wait_iff_congestion
nodirect-v1r5:  Patches 1-10 to disable filesystem writeback for better IO

The tests run were as follows

kernbench
	compile-based benchmark. Smoke test performance

sysbench
	OLTP read-only benchmark. Will be re-run in the future as read-write

micro-mapped-file-stream
	This is a micro-benchmark from Johannes Weiner that accesses a
	large sparse-file through mmap(). It was configured to run in only
	single-CPU mode but can be indicative of how well page reclaim
	identifies suitable pages.

stress-highalloc
	Tries to allocate huge pages under heavy load.

kernbench, iozone and sysbench did not report any performance regression
on any machine.  sysbench did pressure the system lightly and there was
reclaim activity but there were no difference of major interest between
the kernels.

X86-64 micro-mapped-file-stream

                                      traceonly-v2r2           lowlumpy-v2r3        waitcongest-v2r3     waitwriteback-v2r4
pgalloc_dma                       1639.00 (   0.00%)       667.00 (-145.73%)      1167.00 ( -40.45%)       578.00 (-183.56%)
pgalloc_dma32                  2842410.00 (   0.00%)   2842626.00 (   0.01%)   2843043.00 (   0.02%)   2843014.00 (   0.02%)
pgalloc_normal                       0.00 (   0.00%)         0.00 (   0.00%)         0.00 (   0.00%)         0.00 (   0.00%)
pgsteal_dma                        729.00 (   0.00%)        85.00 (-757.65%)       609.00 ( -19.70%)       125.00 (-483.20%)
pgsteal_dma32                  2338721.00 (   0.00%)   2447354.00 (   4.44%)   2429536.00 (   3.74%)   2436772.00 (   4.02%)
pgsteal_normal                       0.00 (   0.00%)         0.00 (   0.00%)         0.00 (   0.00%)         0.00 (   0.00%)
pgscan_kswapd_dma                 1469.00 (   0.00%)       532.00 (-176.13%)      1078.00 ( -36.27%)       220.00 (-567.73%)
pgscan_kswapd_dma32            4597713.00 (   0.00%)   4503597.00 (  -2.09%)   4295673.00 (  -7.03%)   3891686.00 ( -18.14%)
pgscan_kswapd_normal                 0.00 (   0.00%)         0.00 (   0.00%)         0.00 (   0.00%)         0.00 (   0.00%)
pgscan_direct_dma                   71.00 (   0.00%)       134.00 (  47.01%)       243.00 (  70.78%)       352.00 (  79.83%)
pgscan_direct_dma32             305820.00 (   0.00%)    280204.00 (  -9.14%)    600518.00 (  49.07%)    957485.00 (  68.06%)
pgscan_direct_normal                 0.00 (   0.00%)         0.00 (   0.00%)         0.00 (   0.00%)         0.00 (   0.00%)
pageoutrun                       16296.00 (   0.00%)     21254.00 (  23.33%)     18447.00 (  11.66%)     20067.00 (  18.79%)
allocstall                         443.00 (   0.00%)       273.00 ( -62.27%)       513.00 (  13.65%)      1568.00 (  71.75%)

These are based on the raw figures taken from /proc/vmstat.  It's a rough
measure of reclaim activity.  Note that allocstall counts are higher
because we are entering direct reclaim more often as a result of not
sleeping in congestion.  In itself, it's not necessarily a bad thing.
It's easier to get a view of what happened from the vmscan tracepoint
report.

FTrace Reclaim Statistics: vmscan

                                traceonly-v2r2   lowlumpy-v2r3 waitcongest-v2r3 waitwriteback-v2r4
Direct reclaims                                443        273        513       1568
Direct reclaim pages scanned                305968     280402     600825     957933
Direct reclaim pages reclaimed               43503      19005      30327     117191
Direct reclaim write file async I/O              0          0          0          0
Direct reclaim write anon async I/O              0          3          4         12
Direct reclaim write file sync I/O               0          0          0          0
Direct reclaim write anon sync I/O               0          0          0          0
Wake kswapd requests                        187649     132338     191695     267701
Kswapd wakeups                                   3          1          4          1
Kswapd pages scanned                       4599269    4454162    4296815    3891906
Kswapd pages reclaimed                     2295947    2428434    2399818    2319706
Kswapd reclaim write file async I/O              1          0          1          1
Kswapd reclaim write anon async I/O             59        187         41        222
Kswapd reclaim write file sync I/O               0          0          0          0
Kswapd reclaim write anon sync I/O               0          0          0          0
Time stalled direct reclaim (seconds)         4.34       2.52       6.63       2.96
Time kswapd awake (seconds)                  11.15      10.25      11.01      10.19

Total pages scanned                        4905237   4734564   4897640   4849839
Total pages reclaimed                      2339450   2447439   2430145   2436897
%age total pages scanned/reclaimed          47.69%    51.69%    49.62%    50.25%
%age total pages scanned/written             0.00%     0.00%     0.00%     0.00%
%age  file pages scanned/written             0.00%     0.00%     0.00%     0.00%
Percentage Time Spent Direct Reclaim        29.23%    19.02%    38.48%    20.25%
Percentage Time kswapd Awake                78.58%    78.85%    76.83%    79.86%

What is interesting here for nocongest in particular is that while direct
reclaim scans more pages, the overall number of pages scanned remains the
same and the ratio of pages scanned to pages reclaimed is more or less the
same.  In other words, while we are sleeping less, reclaim is not doing
more work and as direct reclaim and kswapd is awake for less time, it
would appear to be doing less work.

FTrace Reclaim Statistics: congestion_wait
Direct number congest     waited                87        196         64          0
Direct time   congest     waited            4604ms     4732ms     5420ms        0ms
Direct full   congest     waited                72        145         53          0
Direct number conditional waited                 0          0        324       1315
Direct time   conditional waited               0ms        0ms        0ms        0ms
Direct full   conditional waited                 0          0          0          0
KSwapd number congest     waited                20         10         15          7
KSwapd time   congest     waited            1264ms      536ms      884ms      284ms
KSwapd full   congest     waited                10          4          6          2
KSwapd number conditional waited                 0          0          0          0
KSwapd time   conditional waited               0ms        0ms        0ms        0ms
KSwapd full   conditional waited                 0          0          0          0

The vanilla kernel spent 8 seconds asleep in direct reclaim and no time at
all asleep with the patches.

MMTests Statistics: duration
User/Sys Time Running Test (seconds)         10.51     10.73      10.6     11.66
Total Elapsed Time (seconds)                 14.19     13.00     14.33     12.76

Overall, the tests completed faster. It is interesting to note that backing off further
when a zone is congested and not just a BDI was more efficient overall.

PPC64 micro-mapped-file-stream
pgalloc_dma                    3024660.00 (   0.00%)   3027185.00 (   0.08%)   3025845.00 (   0.04%)   3026281.00 (   0.05%)
pgalloc_normal                       0.00 (   0.00%)         0.00 (   0.00%)         0.00 (   0.00%)         0.00 (   0.00%)
pgsteal_dma                    2508073.00 (   0.00%)   2565351.00 (   2.23%)   2463577.00 (  -1.81%)   2532263.00 (   0.96%)
pgsteal_normal                       0.00 (   0.00%)         0.00 (   0.00%)         0.00 (   0.00%)         0.00 (   0.00%)
pgscan_kswapd_dma              4601307.00 (   0.00%)   4128076.00 ( -11.46%)   3912317.00 ( -17.61%)   3377165.00 ( -36.25%)
pgscan_kswapd_normal                 0.00 (   0.00%)         0.00 (   0.00%)         0.00 (   0.00%)         0.00 (   0.00%)
pgscan_direct_dma               629825.00 (   0.00%)    971622.00 (  35.18%)   1063938.00 (  40.80%)   1711935.00 (  63.21%)
pgscan_direct_normal                 0.00 (   0.00%)         0.00 (   0.00%)         0.00 (   0.00%)         0.00 (   0.00%)
pageoutrun                       27776.00 (   0.00%)     20458.00 ( -35.77%)     18763.00 ( -48.04%)     18157.00 ( -52.98%)
allocstall                         977.00 (   0.00%)      2751.00 (  64.49%)      2098.00 (  53.43%)      5136.00 (  80.98%)

Similar trends to x86-64. allocstalls are up but it's not necessarily bad.

FTrace Reclaim Statistics: vmscan
Direct reclaims                                977       2709       2098       5136
Direct reclaim pages scanned                629825     963814    1063938    1711935
Direct reclaim pages reclaimed               75550     242538     150904     387647
Direct reclaim write file async I/O              0          0          0          2
Direct reclaim write anon async I/O              0         10          0          4
Direct reclaim write file sync I/O               0          0          0          0
Direct reclaim write anon sync I/O               0          0          0          0
Wake kswapd requests                        392119    1201712     571935     571921
Kswapd wakeups                                   3          2          3          3
Kswapd pages scanned                       4601307    4128076    3912317    3377165
Kswapd pages reclaimed                     2432523    2318797    2312673    2144616
Kswapd reclaim write file async I/O             20          1          1          1
Kswapd reclaim write anon async I/O             57        132         11        121
Kswapd reclaim write file sync I/O               0          0          0          0
Kswapd reclaim write anon sync I/O               0          0          0          0
Time stalled direct reclaim (seconds)         6.19       7.30      13.04      10.88
Time kswapd awake (seconds)                  21.73      26.51      25.55      23.90

Total pages scanned                        5231132   5091890   4976255   5089100
Total pages reclaimed                      2508073   2561335   2463577   2532263
%age total pages scanned/reclaimed          47.95%    50.30%    49.51%    49.76%
%age total pages scanned/written             0.00%     0.00%     0.00%     0.00%
%age  file pages scanned/written             0.00%     0.00%     0.00%     0.00%
Percentage Time Spent Direct Reclaim        18.89%    20.65%    32.65%    27.65%
Percentage Time kswapd Awake                72.39%    80.68%    78.21%    77.40%

Again, a similar trend that the congestion_wait changes mean that direct
reclaim scans more pages but the overall number of pages scanned while
slightly reduced, are very similar.  The ratio of scanning/reclaimed
remains roughly similar.  The downside is that kswapd and direct reclaim
was awake longer and for a larger percentage of the overall workload.
It's possible there were big differences in the amount of time spent
reclaiming slab pages between the different kernels which is plausible
considering that the micro tests runs after fsmark and sysbench.

Trace Reclaim Statistics: congestion_wait
Direct number congest     waited               845       1312        104          0
Direct time   congest     waited           19416ms    26560ms     7544ms        0ms
Direct full   congest     waited               745       1105         72          0
Direct number conditional waited                 0          0       1322       2935
Direct time   conditional waited               0ms        0ms       12ms      312ms
Direct full   conditional waited                 0          0          0          3
KSwapd number congest     waited                39        102         75         63
KSwapd time   congest     waited            2484ms     6760ms     5756ms     3716ms
KSwapd full   congest     waited                20         48         46         25
KSwapd number conditional waited                 0          0          0          0
KSwapd time   conditional waited               0ms        0ms        0ms        0ms
KSwapd full   conditional waited                 0          0          0          0

The vanilla kernel spent 20 seconds asleep in direct reclaim and only
312ms asleep with the patches.  The time kswapd spent congest waited was
also reduced by a large factor.

MMTests Statistics: duration
ser/Sys Time Running Test (seconds)         26.58     28.05      26.9     28.47
Total Elapsed Time (seconds)                 30.02     32.86     32.67     30.88

With all patches applies, the completion times are very similar.

X86-64 STRESS-HIGHALLOC
                traceonly-v2r2     lowlumpy-v2r3  waitcongest-v2r3waitwriteback-v2r4
Pass 1          82.00 ( 0.00%)    84.00 ( 2.00%)    85.00 ( 3.00%)    85.00 ( 3.00%)
Pass 2          90.00 ( 0.00%)    87.00 (-3.00%)    88.00 (-2.00%)    89.00 (-1.00%)
At Rest         92.00 ( 0.00%)    90.00 (-2.00%)    90.00 (-2.00%)    91.00 (-1.00%)

Success figures across the board are broadly similar.

                traceonly-v2r2     lowlumpy-v2r3  waitcongest-v2r3waitwriteback-v2r4
Direct reclaims                               1045        944        886        887
Direct reclaim pages scanned                135091     119604     109382     101019
Direct reclaim pages reclaimed               88599      47535      47863      46671
Direct reclaim write file async I/O            494        283        465        280
Direct reclaim write anon async I/O          29357      13710      16656      13462
Direct reclaim write file sync I/O             154          2          2          3
Direct reclaim write anon sync I/O           14594        571        509        561
Wake kswapd requests                          7491        933        872        892
Kswapd wakeups                                 814        778        731        780
Kswapd pages scanned                       7290822   15341158   11916436   13703442
Kswapd pages reclaimed                     3587336    3142496    3094392    3187151
Kswapd reclaim write file async I/O          91975      32317      28022      29628
Kswapd reclaim write anon async I/O        1992022     789307     829745     849769
Kswapd reclaim write file sync I/O               0          0          0          0
Kswapd reclaim write anon sync I/O               0          0          0          0
Time stalled direct reclaim (seconds)      4588.93    2467.16    2495.41    2547.07
Time kswapd awake (seconds)                2497.66    1020.16    1098.06    1176.82

Total pages scanned                        7425913  15460762  12025818  13804461
Total pages reclaimed                      3675935   3190031   3142255   3233822
%age total pages scanned/reclaimed          49.50%    20.63%    26.13%    23.43%
%age total pages scanned/written            28.66%     5.41%     7.28%     6.47%
%age  file pages scanned/written             1.25%     0.21%     0.24%     0.22%
Percentage Time Spent Direct Reclaim        57.33%    42.15%    42.41%    42.99%
Percentage Time kswapd Awake                43.56%    27.87%    29.76%    31.25%

Scanned/reclaimed ratios again look good with big improvements in
efficiency.  The Scanned/written ratios also look much improved.  With a
better scanned/written ration, there is an expectation that IO would be
more efficient and indeed, the time spent in direct reclaim is much
reduced by the full series and kswapd spends a little less time awake.

Overall, indications here are that allocations were happening much faster
and this can be seen with a graph of the latency figures as the
allocations were taking place
http://www.csn.ul.ie/~mel/postings/vmscanreduce-20101509/highalloc-interlatency-hydra-mean.ps

FTrace Reclaim Statistics: congestion_wait
Direct number congest     waited              1333        204        169          4
Direct time   congest     waited           78896ms     8288ms     7260ms      200ms
Direct full   congest     waited               756         92         69          2
Direct number conditional waited                 0          0         26        186
Direct time   conditional waited               0ms        0ms        0ms     2504ms
Direct full   conditional waited                 0          0          0         25
KSwapd number congest     waited                 4        395        227        282
KSwapd time   congest     waited             384ms    25136ms    10508ms    18380ms
KSwapd full   congest     waited                 3        232         98        176
KSwapd number conditional waited                 0          0          0          0
KSwapd time   conditional waited               0ms        0ms        0ms        0ms
KSwapd full   conditional waited                 0          0          0          0
KSwapd full   conditional waited               318          0        312          9

Overall, the time spent speeping is reduced.  kswapd is still hitting
congestion_wait() but that is because there are callers remaining where it
wasn't clear in advance if they should be changed to wait_iff_congested()
or not.  Overall the sleep imes are reduced though - from 79ish seconds to
about 19.

MMTests Statistics: duration
User/Sys Time Running Test (seconds)       3415.43   3386.65   3388.39    3377.5
Total Elapsed Time (seconds)               5733.48   3660.33   3689.41   3765.39

With the full series, the time to complete the tests are reduced by 30%

PPC64 STRESS-HIGHALLOC
                traceonly-v2r2     lowlumpy-v2r3  waitcongest-v2r3waitwriteback-v2r4
Pass 1          17.00 ( 0.00%)    34.00 (17.00%)    38.00 (21.00%)    43.00 (26.00%)
Pass 2          25.00 ( 0.00%)    37.00 (12.00%)    42.00 (17.00%)    46.00 (21.00%)
At Rest         49.00 ( 0.00%)    43.00 (-6.00%)    45.00 (-4.00%)    51.00 ( 2.00%)

Success rates there are *way* up particularly considering that the 16MB
huge pages on PPC64 mean that it's always much harder to allocate them.

FTrace Reclaim Statistics: vmscan
              stress-highalloc  stress-highalloc  stress-highalloc  stress-highalloc
                traceonly-v2r2     lowlumpy-v2r3  waitcongest-v2r3waitwriteback-v2r4
Direct reclaims                                499        505        564        509
Direct reclaim pages scanned                223478      41898      51818      45605
Direct reclaim pages reclaimed              137730      21148      27161      23455
Direct reclaim write file async I/O            399        136        162        136
Direct reclaim write anon async I/O          46977       2865       4686       3998
Direct reclaim write file sync I/O              29          0          1          3
Direct reclaim write anon sync I/O           31023        159        237        239
Wake kswapd requests                           420        351        360        326
Kswapd wakeups                                 185        294        249        277
Kswapd pages scanned                      15703488   16392500   17821724   17598737
Kswapd pages reclaimed                     5808466    2908858    3139386    3145435
Kswapd reclaim write file async I/O         159938      18400      18717      13473
Kswapd reclaim write anon async I/O        3467554     228957     322799     234278
Kswapd reclaim write file sync I/O               0          0          0          0
Kswapd reclaim write anon sync I/O               0          0          0          0
Time stalled direct reclaim (seconds)      9665.35    1707.81    2374.32    1871.23
Time kswapd awake (seconds)                9401.21    1367.86    1951.75    1328.88

Total pages scanned                       15926966  16434398  17873542  17644342
Total pages reclaimed                      5946196   2930006   3166547   3168890
%age total pages scanned/reclaimed          37.33%    17.83%    17.72%    17.96%
%age total pages scanned/written            23.27%     1.52%     1.94%     1.43%
%age  file pages scanned/written             1.01%     0.11%     0.11%     0.08%
Percentage Time Spent Direct Reclaim        44.55%    35.10%    41.42%    36.91%
Percentage Time kswapd Awake                86.71%    43.58%    52.67%    41.14%

While the scanning rates are slightly up, the scanned/reclaimed and
scanned/written figures are much improved.  The time spent in direct
reclaim and with kswapd are massively reduced, mostly by the lowlumpy
patches.

FTrace Reclaim Statistics: congestion_wait
Direct number congest     waited               725        303        126          3
Direct time   congest     waited           45524ms     9180ms     5936ms      300ms
Direct full   congest     waited               487        190         52          3
Direct number conditional waited                 0          0        200        301
Direct time   conditional waited               0ms        0ms        0ms     1904ms
Direct full   conditional waited                 0          0          0         19
KSwapd number congest     waited                 0          2         23          4
KSwapd time   congest     waited               0ms      200ms      420ms      404ms
KSwapd full   congest     waited                 0          2          2          4
KSwapd number conditional waited                 0          0          0          0
KSwapd time   conditional waited               0ms        0ms        0ms        0ms
KSwapd full   conditional waited                 0          0          0          0

Not as dramatic a story here but the time spent asleep is reduced and we
can still see what wait_iff_congested is going to sleep when necessary.

MMTests Statistics: duration
User/Sys Time Running Test (seconds)      12028.09   3157.17   3357.79   3199.16
Total Elapsed Time (seconds)              10842.07   3138.72   3705.54   3229.85

The time to complete this test goes way down.  With the full series, we
are allocating over twice the number of huge pages in 30% of the time and
there is a corresponding impact on the allocation latency graph available
at.

http://www.csn.ul.ie/~mel/postings/vmscanreduce-20101509/highalloc-interlatency-powyah-mean.ps

This patch:

Add a trace event for shrink_inactive_list() and updates the sample
postprocessing script appropriately.  It can be used to determine how many
pages were reclaimed and for non-lumpy reclaim where exactly the pages
were reclaimed from.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:07 -07:00
Shaohua Li 66d9a986cd vmscan: delete dead code
`priority' cannot be negative here.  And the comment is obsolete.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:07 -07:00
Michael Rubin 79da826aee writeback: report dirty thresholds in /proc/vmstat
The kernel already exposes the user desired thresholds in /proc/sys/vm
with dirty_background_ratio and background_ratio.  But the kernel may
alter the number requested without giving the user any indication that is
the case.

Knowing the actual ratios the kernel is honoring can help app developers
understand how their buffered IO will be sent to the disk.

        $ grep threshold /proc/vmstat
        nr_dirty_threshold 409111
        nr_dirty_background_threshold 818223

Signed-off-by: Michael Rubin <mrubin@google.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:06 -07:00
Michael Rubin ea941f0e2a writeback: add nr_dirtied and nr_written to /proc/vmstat
To help developers and applications gain visibility into writeback
behaviour adding two entries to vm_stat_items and /proc/vmstat.  This will
allow us to track the "written" and "dirtied" counts.

   # grep nr_dirtied /proc/vmstat
   nr_dirtied 3747
   # grep nr_written /proc/vmstat
   nr_written 3618

Signed-off-by: Michael Rubin <mrubin@google.com>
Reviewed-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:06 -07:00
Michael Rubin f629d1c9bd mm: add account_page_writeback()
To help developers and applications gain visibility into writeback
behaviour this patch adds two counters to /proc/vmstat.

  # grep nr_dirtied /proc/vmstat
  nr_dirtied 3747
  # grep nr_written /proc/vmstat
  nr_written 3618

These entries allow user apps to understand writeback behaviour over time
and learn how it is impacting their performance.  Currently there is no
way to inspect dirty and writeback speed over time.  It's not possible for
nr_dirty/nr_writeback.

These entries are necessary to give visibility into writeback behaviour.
We have /proc/diskstats which lets us understand the io in the block
layer.  We have blktrace for more in depth understanding.  We have
e2fsprogs and debugsfs to give insight into the file systems behaviour,
but we don't offer our users the ability understand what writeback is
doing.  There is no way to know how active it is over the whole system, if
it's falling behind or to quantify it's efforts.  With these values
exported users can easily see how much data applications are sending
through writeback and also at what rates writeback is processing this
data.  Comparing the rates of change between the two allow developers to
see when writeback is not able to keep up with incoming traffic and the
rate of dirty memory being sent to the IO back end.  This allows folks to
understand their io workloads and track kernel issues.  Non kernel
engineers at Google often use these counters to solve puzzling performance
problems.

Patch #4 adds a pernode vmstat file with nr_dirtied and nr_written

Patch #5 add writeback thresholds to /proc/vmstat

Currently these values are in debugfs. But they should be promoted to
/proc since they are useful for developers who are writing databases
and file servers and are not debugging the kernel.

The output is as below:

 # grep threshold /proc/vmstat
 nr_pages_dirty_threshold 409111
 nr_pages_dirty_background_threshold 818223

This patch:

This allows code outside of the mm core to safely manipulate page
writeback state and not worry about the other accounting.  Not using these
routines means that some code will lose track of the accounting and we get
bugs.

Modify nilfs2 to use interface.

Signed-off-by: Michael Rubin <mrubin@google.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp>
Cc: Jiro SEKIBA <jir@unicus.jp>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:06 -07:00
Vasiliy Kulikov 0def08e3ac mm/mempolicy.c: check return code of check_range
Function check_range may return ERR_PTR(...). Check for it.

Signed-off-by: Vasiliy Kulikov <segooon@gmail.com>
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:06 -07:00
Minchan Kim 74e3f3c339 vmscan: prevent background aging of anon page in no swap system
Ying Han reported that backing aging of anon pages in no swap system
causes unnecessary TLB flush.

When I sent a patch(69c8548175), I wanted this patch but Rik pointed out
and allowed aging of anon pages to give a chance to promote from inactive
to active LRU.

It has a two problem.

1) non-swap system

Never make sense to age anon pages.

2) swap configured but still doesn't swapon

It doesn't make sense to age anon pages until swap-on time.  But it's
arguable.  If we have aged anon pages by swapon, VM have moved anon pages
from active to inactive.  And in the time swapon by admin, the VM can't
reclaim hot pages so we can protect hot pages swapout.

But let's think about it.  When does swap-on happen?  It depends on admin.
 we can't expect it.  Nonetheless, we have done aging of anon pages to
protect hot pages swapout.  It means we lost run time overhead when below
high watermark but gain hot page swap-[in/out] overhead when VM decide
swapout.  Is it true?  Let's think more detail.  We don't promote anon
pages in case of non-swap system.  So even though VM does aging of anon
pages, the pages would be in inactive LRU for a long time.  It means many
of pages in there would mark access bit again.  So access bit hot/code
separation would be pointless.

This patch prevents unnecessary anon pages demotion in not-yet-swapon and
non-configured swap system.  Even, in non-configuared swap system
inactive_anon_is_low can be compiled out.

It could make side effect that hot anon pages could swap out when admin
does swap on.  But I think sooner or later it would be steady state.  So
it's not a big problem.

We could lose someting but gain more thing(TLB flush and unnecessary
function call to demote anon pages).

Signed-off-by: Ying Han <yinghan@google.com>
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:06 -07:00
KAMEZAWA Hiroyuki 49ac825587 memory hotplug: unify is_removable and offline detection code
Now, sysfs interface of memory hotplug shows whether the section is
removable or not.  But it checks only migrateype of pages and doesn't
check details of cluster of pages.

Next, memory hotplug's set_migratetype_isolate() has the same kind of
check, too.

This patch adds the function __count_unmovable_pages() and makes above 2
checks to use the same logic.  Then, is_removable and hotremove code uses
the same logic.  No changes in the hotremove logic itself.

TODO: need to find a way to check RECLAMABLE. But, considering bit,
      calling shrink_slab() against a range before starting memory hotremove
      sounds better. If so, this patch's logic doesn't need to be changed.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reported-by: Michal Hocko <mhocko@suse.cz>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:06 -07:00
KAMEZAWA Hiroyuki 4b20477f58 memory hotplug: fix notifier's return value check
Even if notifier cannot find any pages, it doesn't mean no pages are
available...And, if there are no notifiers registered, this condition will
be always true and memory hotplug will show -EBUSY.

This is a bug but not critical.

In most case, a pageblock which will be offlined is MIGRATE_MOVABLE This
"notifier" is called only when the pageblock is _not_ MIGRATE_MOVABLE.
But if not MIGRATE_MOVABLE, it's common case that memory hotplug will
fail.  So, no one notice this bug.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:06 -07:00
Minchan Kim cf608ac19c mm: compaction: fix COMPACTPAGEFAILED counting
Presently update_nr_listpages() doesn't have a role.  That's because lists
passed is always empty just after calling migrate_pages.  The
migrate_pages cleans up page list which have failed to migrate before
returning by aaa994b3.

 [PATCH] page migration: handle freeing of pages in migrate_pages()

 Do not leave pages on the lists passed to migrate_pages().  Seems that we will
 not need any postprocessing of pages.  This will simplify the handling of
 pages by the callers of migrate_pages().

At that time, we thought we don't need any postprocessing of pages.  But
the situation is changed.  The compaction need to know the number of
failed to migrate for COMPACTPAGEFAILED stat

This patch makes new rule for caller of migrate_pages to call
putback_lru_pages.  So caller need to clean up the lists so it has a
chance to postprocess the pages.  [suggested by Christoph Lameter]

Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andi Kleen <andi@firstfloor.org>
Reviewed-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Wu Fengguang <fengguang.wu@intel.com>
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:06 -07:00
Thadeu Lima de Souza Cascardo e4455abb50 mm: only build per-node scan_unevictable functions when NUMA is enabled
Non-NUMA systems do never create these files anyway, since they are only
created by driver subsystem when NUMA is configured.

[akpm@linux-foundation.org: cleanup]
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:05 -07:00
Wu Fengguang 1b430beee5 writeback: remove nonblocking/encountered_congestion references
This removes more dead code that was somehow missed by commit 0d99519efe
(writeback: remove unused nonblocking and congestion checks).  There are
no behavior change except for the removal of two entries from one of the
ext4 tracing interface.

The nonblocking checks in ->writepages are no longer used because the
flusher now prefer to block on get_request_wait() than to skip inodes on
IO congestion.  The latter will lead to more seeky IO.

The nonblocking checks in ->writepage are no longer used because it's
redundant with the WB_SYNC_NONE check.

We no long set ->nonblocking in VM page out and page migration, because
a) it's effectively redundant with WB_SYNC_NONE in current code
b) it's old semantic of "Don't get stuck on request queues" is mis-behavior:
   that would skip some dirty inodes on congestion and page out others, which
   is unfair in terms of LRU age.

Inspired by Christoph Hellwig. Thanks!

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: David Howells <dhowells@redhat.com>
Cc: Sage Weil <sage@newdream.net>
Cc: Steve French <sfrench@samba.org>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:05 -07:00
David Rientjes 1e99bad0d9 oom: kill all threads sharing oom killed task's mm
It's necessary to kill all threads that share an oom killed task's mm if
the goal is to lead to future memory freeing.

This patch reintroduces the code removed in 8c5cd6f3 (oom: oom_kill
doesn't kill vfork parent (or child)) since it is obsoleted.

It's now guaranteed that any task passed to oom_kill_task() does not share
an mm with any thread that is unkillable.  Thus, we're safe to issue a
SIGKILL to any thread sharing the same mm.

This is especially necessary to solve an mm->mmap_sem livelock issue
whereas an oom killed thread must acquire the lock in the exit path while
another thread is holding it in the page allocator while trying to
allocate memory itself (and will preempt the oom killer since a task was
already killed).  Since tasks with pending fatal signals are now granted
access to memory reserves, the thread holding the lock may quickly
allocate and release the lock so that the oom killed task may exit.

This mainly is for threads that are cloned with CLONE_VM but not
CLONE_THREAD, so they are in a different thread group.  Non-NPTL threads
exist in the wild and this change is necessary to prevent the livelock in
such cases.  We care more about preventing the livelock than incurring the
additional tasklist in the oom killer when a task has been killed.
Systems that are sufficiently large to not want the tasklist scan in the
oom killer in the first place already have the option of enabling
/proc/sys/vm/oom_kill_allocating_task, which was designed specifically for
that purpose.

This code had existed in the oom killer for over eight years dating back
to the 2.4 kernel.

[akpm@linux-foundation.org: add nice comment]
Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Ying Han <yinghan@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:05 -07:00
David Rientjes e18641e19a oom: avoid killing a task if a thread sharing its mm cannot be killed
The oom killer's goal is to kill a memory-hogging task so that it may
exit, free its memory, and allow the current context to allocate the
memory that triggered it in the first place.  Thus, killing a task is
pointless if other threads sharing its mm cannot be killed because of its
/proc/pid/oom_adj or /proc/pid/oom_score_adj value.

This patch checks whether any other thread sharing p->mm has an
oom_score_adj of OOM_SCORE_ADJ_MIN.  If so, the thread cannot be killed
and oom_badness(p) returns 0, meaning it's unkillable.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Ying Han <yinghan@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:05 -07:00
Mel Gorman b7f50cfa36 mm, page-allocator: do not check the state of a non-existant buddy during free
There is a bug in commit 6dda9d55 ("page allocator: reduce fragmentation
in buddy allocator by adding buddies that are merging to the tail of the
free lists") that means a buddy at order MAX_ORDER is checked for merging.
 A page of this order never exists so at times, an effectively random
piece of memory is being checked.

Alan Curry has reported that this is causing memory corruption in
userspace data on a PPC32 platform (http://lkml.org/lkml/2010/10/9/32).
It is not clear why this is happening.  It could be a cache coherency
problem where pages mapped in both user and kernel space are getting
different cache lines due to the bad read from kernel space
(http://lkml.org/lkml/2010/10/13/179).  It could also be that there are
some special registers being io-remapped at the end of the memmap array
and that a read has special meaning on them.  Compiler bugs have been
ruled out because the assembly before and after the patch looks relatively
harmless.

This patch fixes the problem by ensuring we are not reading a possibly
invalid location of memory.  It's not clear why the read causes corruption
but one way or the other it is a buggy read.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Cc: Corrado Zoccolo <czoccolo@gmail.com>
Reported-by: Alan Curry <pacman@kosh.dhis.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:03 -07:00
KAMEZAWA Hiroyuki f8f72ad539 mm: fix return value of scan_lru_pages in memory unplug
scan_lru_pages returns pfn. So, it's type should be "unsigned long"
not "int".

Note: I guess this has been work until now because memory hotplug tester's
      machine has not very big memory....
      physical address < 32bit << PAGE_SHIFT.

Reported-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:03 -07:00
Linus Torvalds f1ebdd60cc Merge branch 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6
* 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6: (22 commits)
  Add _addr_lsb field to ia64 siginfo
  Fix migration.c compilation on s390
  HWPOISON: Remove retry loop for try_to_unmap
  HWPOISON: Turn addr_valid from bitfield into char
  HWPOISON: Disable DEBUG by default
  HWPOISON: Convert pr_debugs to pr_info
  HWPOISON: Improve comments in memory-failure.c
  x86: HWPOISON: Report correct address granuality for huge hwpoison faults
  Encode huge page size for VM_FAULT_HWPOISON errors
  Fix build error with !CONFIG_MIGRATION
  hugepage: move is_hugepage_on_freelist inside ifdef to avoid warning
  Clean up __page_set_anon_rmap
  HWPOISON, hugetlb: fix unpoison for hugepage
  HWPOISON, hugetlb: soft offlining for hugepage
  HWPOSION, hugetlb: recover from free hugepage error when !MF_COUNT_INCREASED
  hugetlb: move refcounting in hugepage allocation inside hugetlb_lock
  HWPOISON, hugetlb: add free check to dequeue_hwpoison_huge_page()
  hugetlb: hugepage migration core
  hugetlb: redefine hugepage copy functions
  hugetlb: add allocate function for hugepage migration
  ...
2010-10-26 10:13:10 -07:00
Nick Piggin 7ccf19a804 fs: inode split IO and LRU lists
The use of the same inode list structure (inode->i_list) for two
different list constructs with different lifecycles and purposes
makes it impossible to separate the locking of the different
operations. Therefore, to enable the separation of the locking of
the writeback and reclaim lists, split the inode->i_list into two
separate lists dedicated to their specific tracking functions.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-10-25 21:26:15 -04:00
Christoph Hellwig 85fe4025c6 fs: do not assign default i_ino in new_inode
Instead of always assigning an increasing inode number in new_inode
move the call to assign it into those callers that actually need it.
For now callers that need it is estimated conservatively, that is
the call is added to all filesystems that do not assign an i_ino
by themselves.  For a few more filesystems we can avoid assigning
any inode number given that they aren't user visible, and for others
it could be done lazily when an inode number is actually needed,
but that's left for later patches.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-10-25 21:26:11 -04:00
Al Viro 7de9c6ee3e new helper: ihold()
Clones an existing reference to inode; caller must already hold one.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-10-25 21:26:11 -04:00
Al Viro 1d3382cbf0 new helper: inode_unhashed()
note: for race-free uses you inode_lock held

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-10-25 21:24:15 -04:00
Martin Schwidefsky e2b8d7af0e [S390] add support for nonquiescing sske
Improve performance of the sske operation by using the nonquiescing
variant if the affected page has no mappings established. On machines
with no support for the new sske variant the mask bit will be ignored.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-10-25 16:10:15 +02:00
Linus Torvalds 229aebb873 Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (39 commits)
  Update broken web addresses in arch directory.
  Update broken web addresses in the kernel.
  Revert "drivers/usb: Remove unnecessary return's from void functions" for musb gadget
  Revert "Fix typo: configuation => configuration" partially
  ida: document IDA_BITMAP_LONGS calculation
  ext2: fix a typo on comment in ext2/inode.c
  drivers/scsi: Remove unnecessary casts of private_data
  drivers/s390: Remove unnecessary casts of private_data
  net/sunrpc/rpc_pipe.c: Remove unnecessary casts of private_data
  drivers/infiniband: Remove unnecessary casts of private_data
  drivers/gpu/drm: Remove unnecessary casts of private_data
  kernel/pm_qos_params.c: Remove unnecessary casts of private_data
  fs/ecryptfs: Remove unnecessary casts of private_data
  fs/seq_file.c: Remove unnecessary casts of private_data
  arm: uengine.c: remove C99 comments
  arm: scoop.c: remove C99 comments
  Fix typo configue => configure in comments
  Fix typo: configuation => configuration
  Fix typo interrest[ing|ed] => interest[ing|ed]
  Fix various typos of valid in comments
  ...

Fix up trivial conflicts in:
	drivers/char/ipmi/ipmi_si_intf.c
	drivers/usb/gadget/rndis.c
	net/irda/irnet/irnet_ppp.c
2010-10-24 13:41:39 -07:00
Linus Torvalds 76c39e4fef Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6: (27 commits)
  SLUB: Fix memory hotplug with !NUMA
  slub: Move functions to reduce #ifdefs
  slub: Enable sysfs support for !CONFIG_SLUB_DEBUG
  SLUB: Optimize slab_free() debug check
  slub: Move NUMA-related functions under CONFIG_NUMA
  slub: Add lock release annotation
  slub: Fix signedness warnings
  slub: extract common code to remove objects from partial list without locking
  SLUB: Pass active and inactive redzone flags instead of boolean to debug functions
  slub: reduce differences between SMP and NUMA
  Revert "Slub: UP bandaid"
  percpu: clear memory allocated with the km allocator
  percpu: use percpu allocator on UP too
  percpu: reduce PCPU_MIN_UNIT_SIZE to 32k
  vmalloc: pcpu_get/free_vm_areas() aren't needed on UP
  SLUB: Fix merged slab cache names
  Slub: UP bandaid
  slub: fix SLUB_RESILIENCY_TEST for dynamic kmalloc caches
  slub: Fix up missing kmalloc_cache -> kmem_cache_node case for memoryhotplug
  slub: Add dummy functions for the !SLUB_DEBUG case
  ...
2010-10-24 12:47:55 -07:00
Linus Torvalds 1765a1fe5d Merge branch 'kvm-updates/2.6.37' of git://git.kernel.org/pub/scm/virt/kvm/kvm
* 'kvm-updates/2.6.37' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (321 commits)
  KVM: Drop CONFIG_DMAR dependency around kvm_iommu_map_pages
  KVM: Fix signature of kvm_iommu_map_pages stub
  KVM: MCE: Send SRAR SIGBUS directly
  KVM: MCE: Add MCG_SER_P into KVM_MCE_CAP_SUPPORTED
  KVM: fix typo in copyright notice
  KVM: Disable interrupts around get_kernel_ns()
  KVM: MMU: Avoid sign extension in mmu_alloc_direct_roots() pae root address
  KVM: MMU: move access code parsing to FNAME(walk_addr) function
  KVM: MMU: audit: check whether have unsync sps after root sync
  KVM: MMU: audit: introduce audit_printk to cleanup audit code
  KVM: MMU: audit: unregister audit tracepoints before module unloaded
  KVM: MMU: audit: fix vcpu's spte walking
  KVM: MMU: set access bit for direct mapping
  KVM: MMU: cleanup for error mask set while walk guest page table
  KVM: MMU: update 'root_hpa' out of loop in PAE shadow path
  KVM: x86 emulator: Eliminate compilation warning in x86_decode_insn()
  KVM: x86: Fix constant type in kvm_get_time_scale
  KVM: VMX: Add AX to list of registers clobbered by guest switch
  KVM guest: Move a printk that's using the clock before it's ready
  KVM: x86: TSC catchup mode
  ...
2010-10-24 12:47:25 -07:00
Pekka Enberg 6d4121f6c2 Merge branch 'master' into for-linus
Conflicts:
	include/linux/percpu.h
	mm/percpu.c
2010-10-24 19:57:05 +03:00
Xiao Guangrong 45888a0c6e export __get_user_pages_fast() function
This function is used by KVM to pin process's page in the atomic context.

Define the 'weak' function to avoid other architecture not support it

Acked-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2010-10-24 10:51:24 +02:00
Linus Torvalds 0fc0531e0a Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
  percpu: update comments to reflect that percpu allocations are always zero-filled
  percpu: Optimize __get_cpu_var()
  x86, percpu: Optimize this_cpu_ptr
  percpu: clear memory allocated with the km allocator
  percpu: fix build breakage on s390 and cleanup build configuration tests
  percpu: use percpu allocator on UP too
  percpu: reduce PCPU_MIN_UNIT_SIZE to 32k
  vmalloc: pcpu_get/free_vm_areas() aren't needed on UP

Fixed up trivial conflicts in include/linux/percpu.h
2010-10-22 17:31:36 -07:00
Linus Torvalds 91b745016c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: remove in_workqueue_context()
  workqueue: Clarify that schedule_on_each_cpu is synchronous
  memory_hotplug: drop spurious calls to flush_scheduled_work()
  shpchp: update workqueue usage
  pciehp: update workqueue usage
  isdn/eicon: don't call flush_scheduled_work() from diva_os_remove_soft_isr()
  workqueue: add and use WQ_MEM_RECLAIM flag
  workqueue: fix HIGHPRI handling in keep_working()
  workqueue: add queue_work and activate_work trace points
  workqueue: prepare for more tracepoints
  workqueue: implement flush[_delayed]_work_sync()
  workqueue: factor out start_flush_work()
  workqueue: cleanup flush/cancel functions
  workqueue: implement alloc_ordered_workqueue()

Fix up trivial conflict in fs/gfs2/main.c as per Tejun
2010-10-22 17:13:10 -07:00
Linus Torvalds a2887097f2 Merge branch 'for-2.6.37/barrier' of git://git.kernel.dk/linux-2.6-block
* 'for-2.6.37/barrier' of git://git.kernel.dk/linux-2.6-block: (46 commits)
  xen-blkfront: disable barrier/flush write support
  Added blk-lib.c and blk-barrier.c was renamed to blk-flush.c
  block: remove BLKDEV_IFL_WAIT
  aic7xxx_old: removed unused 'req' variable
  block: remove the BH_Eopnotsupp flag
  block: remove the BLKDEV_IFL_BARRIER flag
  block: remove the WRITE_BARRIER flag
  swap: do not send discards as barriers
  fat: do not send discards as barriers
  ext4: do not send discards as barriers
  jbd2: replace barriers with explicit flush / FUA usage
  jbd2: Modify ASYNC_COMMIT code to not rely on queue draining on barrier
  jbd: replace barriers with explicit flush / FUA usage
  nilfs2: replace barriers with explicit flush / FUA usage
  reiserfs: replace barriers with explicit flush / FUA usage
  gfs2: replace barriers with explicit flush / FUA usage
  btrfs: replace barriers with explicit flush / FUA usage
  xfs: replace barriers with explicit flush / FUA usage
  block: pass gfp_mask and flags to sb_issue_discard
  dm: convey that all flushes are processed as empty
  ...
2010-10-22 17:07:18 -07:00
Andi Kleen 46e387bbd8 Merge branch 'hwpoison-hugepages' into hwpoison
Conflicts:
	mm/memory-failure.c
2010-10-22 17:40:48 +02:00
Andi Kleen e9d08567ef Merge branch 'hwpoison-cleanups' into hwpoison 2010-10-22 17:40:11 +02:00
Linus Torvalds 3044100e58 Merge branch 'core-memblock-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-memblock-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (74 commits)
  x86-64: Only set max_pfn_mapped to 512 MiB if we enter via head_64.S
  xen: Cope with unmapped pages when initializing kernel pagetable
  memblock, bootmem: Round pfn properly for memory and reserved regions
  memblock: Annotate memblock functions with __init_memblock
  memblock: Allow memblock_init to be called early
  memblock/arm: Fix memblock_region_is_memory() typo
  x86, memblock: Remove __memblock_x86_find_in_range_size()
  memblock: Fix wraparound in find_region()
  x86-32, memblock: Make add_highpages honor early reserved ranges
  x86, memblock: Fix crashkernel allocation
  arm, memblock: Fix the sparsemem build
  memblock: Fix section mismatch warnings
  powerpc, memblock: Fix memblock API change fallout
  memblock, microblaze: Fix memblock API change fallout
  x86: Remove old bootmem code
  x86, memblock: Use memblock_memory_size()/memblock_free_memory_size() to get correct dma_reserve
  x86: Remove not used early_res code
  x86, memblock: Replace e820_/_early string with memblock_
  x86: Use memblock to replace early_res
  x86, memblock: Use memblock_debug to control debug message print out
  ...

Fix up trivial conflicts in arch/x86/kernel/setup.c and kernel/Makefile
2010-10-21 18:52:11 -07:00
Linus Torvalds c3b86a2942 Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86-32, percpu: Correct the ordering of the percpu readmostly section
  x86, mm: Enable ARCH_DMA_ADDR_T_64BIT with X86_64 || HIGHMEM64G
  x86: Spread tlb flush vector between nodes
  percpu: Introduce a read-mostly percpu API
  x86, mm: Fix incorrect data type in vmalloc_sync_all()
  x86, mm: Hold mm->page_table_lock while doing vmalloc_sync
  x86, mm: Fix bogus whitespace in sync_global_pgds()
  x86-32: Fix sparse warning for the __PHYSICAL_MASK calculation
  x86, mm: Add RESERVE_BRK_ARRAY() helper
  mm, x86: Saving vmcore with non-lazy freeing of vmas
  x86, kdump: Change copy_oldmem_page() to use cached addressing
  x86, mm: fix uninitialized addr in kernel_physical_mapping_init()
  x86, kmemcheck: Remove double test
  x86, mm: Make spurious_fault check explicitly check the PRESENT bit
  x86-64, mem: Update all PGDs for direct mapping and vmemmap mapping changes
  x86, mm: Separate x86_64 vmalloc_sync_all() into separate functions
  x86, mm: Avoid unnecessary TLB flush
2010-10-21 13:47:29 -07:00
Tejun Heo 10ccd84695 memory_hotplug: drop spurious calls to flush_scheduled_work()
lru_add_drain_all() uses schedule_on_each_cpu() which is synchronous.
There is no reason to call flush_scheduled_work() after
lru_add_drain_all().  Drop the spurious calls.

This is to prepare for the deprecation and removal of
flush_scheduled_work().

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
2010-10-19 11:08:41 +02:00
Jens Axboe fa251f8990 Merge branch 'v2.6.36-rc8' into for-2.6.37/barrier
Conflicts:
	block/blk-core.c
	drivers/block/loop.c
	mm/swapfile.c

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-10-19 09:13:04 +02:00
H. Peter Anvin 8e4029ee35 Merge branch 'x86/urgent' into core/memblock
Reason for merge:

Forward-port urgent change to arch/x86/mm/srat_64.c to the memblock tree.

Resolved Conflicts:
	arch/x86/mm/srat_64.c

Originally-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2010-10-11 17:05:11 -07:00
Yinghai Lu cd79481d27 memblock: Annotate memblock functions with __init_memblock
Stephen found

WARNING: mm/built-in.o(.text+0x25ab8): Section mismatch in reference from the function memblock_find_base() to the function .init.text:memblock_find_region()
The function memblock_find_base() references
the function __init memblock_find_region().
This is often because memblock_find_base lacks a __init
annotation or the annotation of memblock_find_region is wrong.

So let memblock_find_region() to use __init_memblock instead of __init
directly.

Also fix one function that did not have __init* to be __init_memblock.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <4CB366B1.40405@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2010-10-11 16:00:52 -07:00
Jeremy Fitzhardinge 236260b90d memblock: Allow memblock_init to be called early
The Xen setup code needs to call memblock_x86_reserve_range() very early,
so allow it to initialize the memblock subsystem before doing so.  The
second memblock_init() is ignored.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
LKML-Reference: <4CACFDAD.3090900@goop.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2010-10-11 15:59:01 -07:00
Andi Kleen 3ef8fd7f72 Fix migration.c compilation on s390
31bit s390 doesn't have huge pages and failed with:

> mm/migrate.c: In function 'remove_migration_pte':
> mm/migrate.c:143:3: error: implicit declaration of function 'pte_mkhuge'
> mm/migrate.c:143:7: error: incompatible types when assigning to type 'pte_t' from type 'int'

Put that code into a ifdef.

Reported by Heiko Carstens

Signed-off-by: Andi Kleen <ak@linux.intel.com>
2010-10-11 16:57:39 +02:00
Andi Kleen a08c80ebb6 HWPOISON: Remove retry loop for try_to_unmap
We don't reply in other temporary failure cases and there were no
reports of replies happening. I think the original reason it was
added was also just an early bug, not an observation of the race.

So remove the loop for now, but keep a warning message.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
2010-10-08 09:33:01 +02:00
Andi Kleen 9033ae1640 HWPOISON: Turn addr_valid from bitfield into char
The addr_valid flag is the only flag in "to_kill" and it's slightly more
efficient to have it as char instead of a bitfield.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
2010-10-08 09:33:01 +02:00
Andi Kleen 898e70d1e5 HWPOISON: Disable DEBUG by default
Now that only a few obscure messages are left as pr_debug disable
outputting of pr_debug in memory-failure.c by default.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
2010-10-08 09:33:00 +02:00
Andi Kleen fb46e73520 HWPOISON: Convert pr_debugs to pr_info
Convert a lot of pr_debugs in memory-failure.c that are generally useful
to pr_info. It's reasonable to print at least one message why
offlining succeeded or failed by default.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
2010-10-08 09:33:00 +02:00
Andi Kleen 1c80b990a3 HWPOISON: Improve comments in memory-failure.c
Clean up and improve the overview comment in memory-failure.c

Tidy some grammar issues in other comments.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
2010-10-08 09:33:00 +02:00
Andi Kleen aa50d3a7aa Encode huge page size for VM_FAULT_HWPOISON errors
This fixes a problem introduced with the hugetlb hwpoison handling

The user space SIGBUS signalling wants to know the size of the hugepage
that caused a HWPOISON fault.

Unfortunately the architecture page fault handlers do not have easy
access to the struct page.

Pass the information out in the fault error code instead.

I added a separate VM_FAULT_HWPOISON_LARGE bit for this case and encode
the hpage index in some free upper bits of the fault code. The small
page hwpoison keeps stays with the VM_FAULT_HWPOISON name to minimize
changes.

Also add code to hugetlb.h to convert that index into a page shift.

Will be used in a further patch.

Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: fengguang.wu@intel.com
Signed-off-by: Andi Kleen <ak@linux.intel.com>
2010-10-08 09:32:46 +02:00
Andi Kleen d5bd910696 hugepage: move is_hugepage_on_freelist inside ifdef to avoid warning
Fixes warning reported by Stephen Rothwell

mm/hugetlb.c:2950: warning: 'is_hugepage_on_freelist' defined but not used

for the !CONFIG_MEMORY_FAILURE case.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
2010-10-08 09:32:46 +02:00
Andi Kleen 4e1c19750a Clean up __page_set_anon_rmap
Linus asked for a cleanup of __page_set_anon_rmap to make
it look more like the cleaner huge pages version.

Factor out the duplicated PageAnon check into a single check
at the beginning of the function.

Remove obsolete comments and rewrite them into standard English.

No functional changes.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
2010-10-08 09:32:46 +02:00
Naoya Horiguchi 6a90181c7b HWPOISON, hugetlb: fix unpoison for hugepage
Currently unpoisoning hugepages doesn't work correctly because
clearing PG_HWPoison is done outside if (TestClearPageHWPoison).
This patch fixes it.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
2010-10-08 09:32:45 +02:00
Naoya Horiguchi d950b95882 HWPOISON, hugetlb: soft offlining for hugepage
This patch extends soft offlining framework to support hugepage.
When memory corrected errors occur repeatedly on a hugepage,
we can choose to stop using it by migrating data onto another hugepage
and disabling the original (maybe half-broken) one.

ChangeLog since v4:
- branch soft_offline_page() for hugepage

ChangeLog since v3:
- remove comment about "ToDo: hugepage soft-offline"

ChangeLog since v2:
- move refcount handling into isolate_lru_page()

ChangeLog since v1:
- add double check in isolating hwpoisoned hugepage
- define free/non-free checker for hugepage
- postpone calling put_page() for hugepage in soft_offline_page()

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
2010-10-08 09:32:45 +02:00
Naoya Horiguchi 8c6c2ecb44 HWPOSION, hugetlb: recover from free hugepage error when !MF_COUNT_INCREASED
Currently error recovery for free hugepage works only for MF_COUNT_INCREASED.
This patch enables !MF_COUNT_INCREASED case.

Free hugepages can be handled directly by alloc_huge_page() and
dequeue_hwpoisoned_huge_page(), and both of them are protected
by hugetlb_lock, so there is no race between them.

Note that this patch defines the refcount of HWPoisoned hugepage
dequeued from freelist is 1, deviated from present 0, thereby we
can avoid race between unpoison and memory failure on free hugepage.
This is reasonable because unlikely to free buddy pages, free hugepage
is governed by hugetlbfs even after error handling finishes.
And it also makes unpoison code added in the later patch cleaner.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
2010-10-08 09:32:45 +02:00
Naoya Horiguchi a9869b837c hugetlb: move refcounting in hugepage allocation inside hugetlb_lock
Currently alloc_huge_page() raises page refcount outside hugetlb_lock.
but it causes race when dequeue_hwpoison_huge_page() runs concurrently
with alloc_huge_page().
To avoid it, this patch moves set_page_refcounted() in hugetlb_lock.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
2010-10-08 09:32:45 +02:00
Naoya Horiguchi 6de2b1aab9 HWPOISON, hugetlb: add free check to dequeue_hwpoison_huge_page()
This check is necessary to avoid race between dequeue and allocation,
which can cause a free hugepage to be dequeued twice and get kernel unstable.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
2010-10-08 09:32:45 +02:00
Naoya Horiguchi 290408d4a2 hugetlb: hugepage migration core
This patch extends page migration code to support hugepage migration.
One of the potential users of this feature is soft offlining which
is triggered by memory corrected errors (added by the next patch.)

Todo:
- there are other users of page migration such as memory policy,
  memory hotplug and memocy compaction.
  They are not ready for hugepage support for now.

ChangeLog since v4:
- define migrate_huge_pages()
- remove changes on isolation/putback_lru_page()

ChangeLog since v2:
- refactor isolate/putback_lru_page() to handle hugepage
- add comment about race on unmap_and_move_huge_page()

ChangeLog since v1:
- divide migration code path for hugepage
- define routine checking migration swap entry for hugetlb
- replace "goto" with "if/else" in remove_migration_pte()

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
2010-10-08 09:32:45 +02:00
Naoya Horiguchi 0ebabb416f hugetlb: redefine hugepage copy functions
This patch modifies hugepage copy functions to have only destination
and source hugepages as arguments for later use.
The old ones are renamed from copy_{gigantic,huge}_page() to
copy_user_{gigantic,huge}_page().
This naming convention is consistent with that between copy_highpage()
and copy_user_highpage().

ChangeLog since v4:
- add blank line between local declaration and code
- remove unnecessary might_sleep()

ChangeLog since v2:
- change copy_huge_page() from macro to inline dummy function
  to avoid compile warning when !CONFIG_HUGETLB_PAGE.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
2010-10-08 09:32:44 +02:00
Naoya Horiguchi bf50bab2b3 hugetlb: add allocate function for hugepage migration
We can't use existing hugepage allocation functions to allocate hugepage
for page migration, because page migration can happen asynchronously with
the running processes and page migration users should call the allocation
function with physical addresses (not virtual addresses) as arguments.

ChangeLog since v3:
- unify alloc_buddy_huge_page() and alloc_buddy_huge_page_node()

ChangeLog since v2:
- remove unnecessary get/put_mems_allowed() (thanks to David Rientjes)

ChangeLog since v1:
- add comment on top of alloc_huge_page_no_vma()

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
2010-10-08 09:32:44 +02:00
Naoya Horiguchi 998b4382c1 hugetlb: fix metadata corruption in hugetlb_fault()
Since the PageHWPoison() check is for avoiding hwpoisoned page remained
in pagecache mapping to the process, it should be done in "found in pagecache"
branch, not in the common path.
Otherwise, metadata corruption occurs if memory failure happens between
alloc_huge_page() and lock_page() because page fault fails with metadata
changes remained (such as refcount, mapcount, etc.)

This patch moves the check to "found in pagecache" branch and fix the problem.

ChangeLog since v2:
- remove retry check in "new allocation" path.
- make description more detailed
- change patch name from "HWPOISON, hugetlb: move PG_HWPoison bit check"

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Wu Fengguang <fengguang.wu@intel.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
2010-10-08 09:32:44 +02:00
Ingo Molnar 153db80f8c Merge commit 'v2.6.36-rc7' into core/memblock
Merge reason: Update from -rc3 to -rc7.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-10-08 09:15:00 +02:00
Linus Torvalds 6b0cd00bc3 Merge branch 'hwpoison-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6
* 'hwpoison-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6:
  HWPOISON: Stop shrinking at right page count
  HWPOISON: Report correct address granuality for AO huge page errors
  HWPOISON: Copy si_addr_lsb to user
  page-types.c: fix name of unpoison interface
2010-10-07 13:59:32 -07:00
Kirill A. Shutemov ad4ca5f4b7 memcg: fix thresholds with use_hierarchy == 1
We need to check parent's thresholds if parent has use_hierarchy == 1 to
be sure that parent's threshold events will be triggered even if parent
itself is not active (no MEM_CGROUP_EVENTS).

Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-07 13:31:21 -07:00
Robin Holt f241e6607b mm: alloc_large_system_hash() printk overflow on 16TB boot
During boot of a 16TB system, the following is printed:
Dentry cache hash table entries: -2147483648 (order: 22, 17179869184 bytes)

Signed-off-by: Robin Holt <holt@sgi.com>
Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-07 13:31:21 -07:00
Andi Kleen 47f43e7efa HWPOISON: Stop shrinking at right page count
When we call the slab shrinker to free a page we need to stop at
page count one because the caller always holds a single reference, not zero.

This avoids useless looping over slab shrinkers and freeing too much
memory.

Reviewed-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
2010-10-07 09:47:10 +02:00
Andi Kleen 0d9ee6a2d4 HWPOISON: Report correct address granuality for AO huge page errors
The SIGBUS user space signalling is supposed to report the
address granuality of a corruption. Pass this information correctly
for huge pages by querying the hpage order.

Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
2010-10-07 09:45:44 +02:00
Pekka Enberg 92a5bbc11f SLUB: Fix memory hotplug with !NUMA
This patch fixes the following build breakage when memory hotplug is enabled on
UMA configurations:

  /home/test/linux-2.6/mm/slub.c: In function 'kmem_cache_init':
  /home/test/linux-2.6/mm/slub.c:3031:2: error: 'slab_memory_callback'
  undeclared (first use in this function)
  /home/test/linux-2.6/mm/slub.c:3031:2: note: each undeclared
  identifier is reported only once for each function it appears in
  make[2]: *** [mm/slub.o] Error 1
  make[1]: *** [mm] Error 2
  make: *** [sub-make] Error 2

Reported-by: Zimny Lech <napohybelskurwysynom2010@gmail.com>
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2010-10-06 21:16:42 +03:00
Christoph Lameter a5a84755c5 slub: Move functions to reduce #ifdefs
There is a lot of #ifdef/#endifs that can be avoided if functions would be in different
places. Move them around and reduce #ifdef.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2010-10-06 16:54:37 +03:00
Christoph Lameter ab4d5ed5ee slub: Enable sysfs support for !CONFIG_SLUB_DEBUG
Currently disabling CONFIG_SLUB_DEBUG also disabled SYSFS support meaning
that the slabs cannot be tuned without DEBUG.

Make SYSFS support independent of CONFIG_SLUB_DEBUG

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2010-10-06 16:54:36 +03:00
Pekka Enberg 15b7c51420 SLUB: Optimize slab_free() debug check
This patch optimizes slab_free() debug check to use "c->node != NUMA_NO_NODE"
instead of "c->node >= 0" because the former generates smaller code on x86-64:

  Before:

    4736:       48 39 70 08             cmp    %rsi,0x8(%rax)
    473a:       75 26                   jne    4762 <kfree+0xa2>
    473c:       44 8b 48 10             mov    0x10(%rax),%r9d
    4740:       45 85 c9                test   %r9d,%r9d
    4743:       78 1d                   js     4762 <kfree+0xa2>

  After:

    4736:       48 39 70 08             cmp    %rsi,0x8(%rax)
    473a:       75 23                   jne    475f <kfree+0x9f>
    473c:       83 78 10 ff             cmpl   $0xffffffffffffffff,0x10(%rax)
    4740:       74 1d                   je     475f <kfree+0x9f>

This patch also cleans up __slab_alloc() to use NUMA_NO_NODE instead of "-1"
for enabling debugging for a per-CPU cache.

Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2010-10-06 16:52:26 +03:00
Yinghai Lu f1af98c762 memblock: Fix wraparound in find_region()
When trying to find huge range for crashkernel, get

[    0.000000] ------------[ cut here ]------------
[    0.000000] WARNING: at arch/x86/mm/memblock.c:248 memblock_x86_reserve_range+0x40/0x7a()
[    0.000000] Hardware name: Sun Fire x4800
[    0.000000] memblock_x86_reserve_range: wrong range [0xffffffff37000000, 0x137000000)
[    0.000000] Modules linked in:
[    0.000000] Pid: 0, comm: swapper Not tainted 2.6.36-rc5-tip-yh-01876-g1cac214-dirty #59
[    0.000000] Call Trace:
[    0.000000]  [<ffffffff82816f7e>] ? memblock_x86_reserve_range+0x40/0x7a
[    0.000000]  [<ffffffff81078c2d>] warn_slowpath_common+0x85/0x9e
[    0.000000]  [<ffffffff81078d38>] warn_slowpath_fmt+0x6e/0x70
[    0.000000]  [<ffffffff8281e77c>] ? memblock_find_region+0x40/0x78
[    0.000000]  [<ffffffff8281eb1f>] ? memblock_find_base+0x9a/0xb9
[    0.000000]  [<ffffffff82816f7e>] memblock_x86_reserve_range+0x40/0x7a
[    0.000000]  [<ffffffff8280452c>] setup_arch+0x99d/0xb2a
[    0.000000]  [<ffffffff810a3e02>] ? trace_hardirqs_off+0xd/0xf
[    0.000000]  [<ffffffff81cec7d8>] ? _raw_spin_unlock_irqrestore+0x3d/0x4c
[    0.000000]  [<ffffffff827ffcec>] start_kernel+0xde/0x3f1
[    0.000000]  [<ffffffff827ff2d4>] x86_64_start_reservations+0xa0/0xa4
[    0.000000]  [<ffffffff827ff3de>] x86_64_start_kernel+0x106/0x10d
[    0.000000] ---[ end trace a7919e7f17c0a725 ]---
[    0.000000] Reserving 8192MB of memory at 17592186041200MB for crashkernel (System RAM: 526336MB)

This is caused by a wraparound in the test due to size > end;
explicitly check for this condition and fail.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <4CAA4DD3.1080401@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2010-10-05 21:45:35 -07:00
Hugh Dickins 4e31635c36 ksm: fix bad user data when swapping
Building under memory pressure, with KSM on 2.6.36-rc5, collapsed with
an internal compiler error: typically indicating an error in swapping.

Perhaps there's a timing issue which makes it now more likely, perhaps
it's just a long time since I tried for so long: this bug goes back to
KSM swapping in 2.6.33.

Notice how reuse_swap_page() allows an exclusive page to be reused, but
only does SetPageDirty if it can delete it from swap cache right then -
if it's currently under Writeback, it has to be left in cache and we
don't SetPageDirty, but the page can be reused.  Fine, the dirty bit
will get set in the pte; but notice how zap_pte_range() does not bother
to transfer pte_dirty to page_dirty when unmapping a PageAnon.

If KSM chooses to share such a page, it will look like a clean copy of
swapcache, and not be written out to swap when its memory is needed;
then stale data read back from swap when it's needed again.

We could fix this in reuse_swap_page() (or even refuse to reuse a
page under writeback), but it's more honest to fix my oversight in
KSM's write_protect_page().  Several days of testing on three machines
confirms that this fixes the issue they showed.

Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-04 11:09:53 -07:00
Hugh Dickins 4829b906cc ksm: fix page_address_in_vma anon_vma oops
2.6.36-rc1 commit 21d0d443cd "rmap:
resurrect page_address_in_vma anon_vma check" was right to resurrect
that check; but now that it's comparing anon_vma->roots instead of
just anon_vmas, there's a danger of oopsing on a NULL anon_vma.

In most cases no NULL anon_vma ever gets here; but it turns out that
occasionally KSM, when enabled on a forked or forking process, will
itself call page_address_in_vma() on a "half-KSM" page left over from
an earlier failed attempt to merge - whose page_anon_vma() is NULL.

It's my bug that those should be getting here at all: I thought they
were already dealt with, this oops proves me wrong, I'll fix it in
the next release - such pages are effectively pinned until their
process exits, since rmap cannot find their ptes (though swapoff can).

For now just work around it by making page_address_in_vma() safe (and
add a comment on why that check is wanted anyway).  A similar check
in __page_check_anon_rmap() is safe because do_page_add_anon_rmap()
already excluded KSM pages.

Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-04 11:09:53 -07:00
Namhyung Kim 5d1f57e4d3 slub: Move NUMA-related functions under CONFIG_NUMA
Make kmalloc_cache_alloc_node_notrace(), kmalloc_large_node()
and __kmalloc_node_track_caller() to be compiled only when
CONFIG_NUMA is selected.

Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2010-10-02 10:47:53 +03:00
Namhyung Kim 3478973ded slub: Add lock release annotation
The unfreeze_slab() releases page's PG_locked bit but was missing
proper annotation. The deactivate_slab() needs to be marked also
since it calls unfreeze_slab() without grabbing the lock.

Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2010-10-02 10:47:53 +03:00
Namhyung Kim a5dd5c117c slub: Fix signedness warnings
The bit-ops routines require its arg to be a pointer to unsigned long.
This leads sparse to complain about different signedness as follows:

 mm/slub.c:2425:49: warning: incorrect type in argument 2 (different signedness)
 mm/slub.c:2425:49:    expected unsigned long volatile *addr
 mm/slub.c:2425:49:    got long *map

Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2010-10-02 10:47:52 +03:00
Christoph Lameter 62e346a830 slub: extract common code to remove objects from partial list without locking
There are a couple of places where repeat the same statements when removing
a page from the partial list. Consolidate that into __remove_partial().

Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2010-10-02 10:44:10 +03:00
Christoph Lameter f7cb193362 SLUB: Pass active and inactive redzone flags instead of boolean to debug functions
Pass the actual values used for inactive and active redzoning to the
functions that check the objects. Avoids a lot of the ? : things to
lookup the values in the functions.

Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2010-10-02 10:44:10 +03:00
Christoph Lameter 7340cc8414 slub: reduce differences between SMP and NUMA
Reduce the #ifdefs and simplify bootstrap by making SMP and NUMA as much alike
as possible. This means that there will be an additional indirection to get to
the kmem_cache_node field under SMP.

Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2010-10-02 10:44:10 +03:00
Pekka Enberg ed59ecbf89 Revert "Slub: UP bandaid"
This reverts commit 5249d039500f05a5ab379286b1d23ab9b04d3f2c. It's not needed
after commit bbddff0545 ("percpu: use percpu
allocator on UP too").
2010-10-02 10:28:55 +03:00
Tejun Heo ed6c1115c8 percpu: clear memory allocated with the km allocator
Percpu allocator should clear memory before returning it but the km
allocator forgot to do it.  Fix it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
2010-10-02 10:28:42 +03:00
Tejun Heo 9b8327bb24 percpu: use percpu allocator on UP too
On UP, percpu allocations were redirected to kmalloc.  This has the
following problems.

* For certain amount of allocations (determined by
  PERCPU_DYNAMIC_EARLY_SLOTS and PERCPU_DYNAMIC_EARLY_SIZE), percpu
  allocator can be used before the usual kernel memory allocator is
  brought online.  On SMP, this is used to initialize the kernel
  memory allocator.

* percpu allocator honors alignment upto PAGE_SIZE but kmalloc()
  doesn't.  For example, workqueue makes use of larger alignments for
  cpu_workqueues.

Currently, users of percpu allocators need to handle UP differently,
which is somewhat fragile and ugly.  Other than small amount of
memory, there isn't much to lose by enabling percpu allocator on UP.
It can simply use kernel memory based chunk allocation which was added
for SMP archs w/o MMUs.

This patch removes mm/percpu_up.c, builds mm/percpu.c on UP too and
makes UP build use percpu-km.  As percpu addresses and kernel
addresses are always identity mapped and static percpu variables don't
need any special treatment, nothing is arch dependent and mm/percpu.c
implements generic setup_per_cpu_areas() for UP.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
2010-10-02 10:26:05 +03:00
Tejun Heo 0bc1406241 vmalloc: pcpu_get/free_vm_areas() aren't needed on UP
These functions are used only by percpu memory allocator on SMP.
Don't build them on UP.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Nick Piggin <npiggin@kernel.dk>
2010-10-02 10:25:25 +03:00
Pekka Enberg 84c1cf6246 SLUB: Fix merged slab cache names
As explained by Linus "I'm Proud to be an American" Torvalds:

  Looking at the merging code, I actually think it's totally
  buggy. If you have something like this:

   - load module A: create slab cache A

   - load module B: create slab cache B that can merge with A

   - unload module A

   - "cat /proc/slabinfo": BOOM. Oops.

  exactly because the name is not handled correctly, and you'll have
  module B holding open a slab cache that has a name pointer that points
  to module A that no longer exists.

This patch fixes the problem by using kstrdup() to allocate dynamic memory for
->name of "struct kmem_cache" as suggested by Christoph Lameter.

Acked-by: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

Conflicts:

	mm/slub.c
2010-10-02 10:24:29 +03:00
Christoph Lameter db210e70e5 Slub: UP bandaid
Since the percpu allocator does not provide early allocation in UP mode (only
in SMP configurations) use __get_free_page() to improvise a compound page
allocation that can be later freed via kfree().

Compound pages will be released when the cpu caches are resized.

Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2010-10-02 10:24:29 +03:00
David Rientjes a016471a16 slub: fix SLUB_RESILIENCY_TEST for dynamic kmalloc caches
Now that the kmalloc_caches array is dynamically allocated at boot,
SLUB_RESILIENCY_TEST needs to be fixed to pass the correct type.

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2010-10-02 10:24:29 +03:00
Christoph Lameter 8de66a0c02 slub: Fix up missing kmalloc_cache -> kmem_cache_node case for memoryhotplug
Memory hotplug allocates and frees per node structures. Use the correct name.

Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2010-10-02 10:24:28 +03:00
Christoph Lameter 7d550c56a2 slub: Add dummy functions for the !SLUB_DEBUG case
On Wed, 25 Aug 2010, Randy Dunlap wrote:
> mm/slub.c:1732: error: implicit declaration of function 'slab_pre_alloc_hook'
> mm/slub.c:1751: error: implicit declaration of function 'slab_post_alloc_hook'
> mm/slub.c:1881: error: implicit declaration of function 'slab_free_hook'
> mm/slub.c:1886: error: implicit declaration of function 'slab_free_hook_irq'

Empty functions are missing if the runtime debuggability option is compiled
out.

Provide the fall back functions to empty hooks if SLUB_DEBUG is not set.

Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2010-10-02 10:24:28 +03:00
David Rientjes 8df275af8d slob: fix gfp flags for order-0 page allocations
kmalloc_node() may allocate higher order slob pages, but the __GFP_COMP
bit is only passed to the page allocator and not represented in the
tracepoint event.  The bit should be passed to trace_kmalloc_node() as
well.

Acked-by: Matt Mackall <mpm@selenic.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2010-10-02 10:24:28 +03:00
Christoph Lameter c1d508365e slub: Move gfpflag masking out of the hotpath
Move the gfpflags masking into the hooks for checkers and into the slowpaths.
gfpflag masking requires access to a global variable and thus adds an
additional cacheline reference to the hotpaths.

If no hooks are active then the gfpflag masking will result in
code that the compiler can toss out.

Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2010-10-02 10:24:27 +03:00
Christoph Lameter c016b0bdee slub: Extract hooks for memory checkers from hotpaths
Extract the code that memory checkers and other verification tools use from
the hotpaths. Makes it easier to add new ones and reduces the disturbances
of the hotpaths.

Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2010-10-02 10:24:27 +03:00
Christoph Lameter 51df114281 slub: Dynamically size kmalloc cache allocations
kmalloc caches are statically defined and may take up a lot of space just
because the sizes of the node array has to be dimensioned for the largest
node count supported.

This patch makes the size of the kmem_cache structure dynamic throughout by
creating a kmem_cache slab cache for the kmem_cache objects. The bootstrap
occurs by allocating the initial one or two kmem_cache objects from the
page allocator.

C2->C3
	- Fix various issues indicated by David
	- Make create kmalloc_cache return a kmem_cache * pointer.

Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2010-10-02 10:24:27 +03:00
Christoph Lameter 6c182dc0de slub: Remove static kmem_cache_cpu array for boot
The percpu allocator can now handle allocations during early boot.
So drop the static kmem_cache_cpu array.

Cc: Tejun Heo <tj@kernel.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2010-10-02 10:24:26 +03:00
Christoph Lameter 55136592fe slub: Remove dynamic dma slab allocation
Remove the dynamic dma slab allocation since this causes too many issues with
nested locks etc etc. The change avoids passing gfpflags into many functions.

V3->V4:
- Create dma caches in kmem_cache_init() instead of kmem_cache_init_late().

Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2010-10-02 10:24:26 +03:00
Christoph Lameter 1537066c69 slub: Force no inlining of debug functions
Compiler folds the debgging functions into the critical paths.
Avoid that by adding noinline to the functions that check for
problems.

Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2010-10-02 10:24:26 +03:00
Larry Woodman 5ec1055aa5 Avoid pgoff overflow in remap_file_pages
Thomas Pollet noticed that the remap_file_pages() system call in
fremap.c has a potential overflow in the first part of the if statement
below, which could cause it to process bogus input parameters.
Specifically the pgoff + size parameters could be wrap thereby
preventing the system call from failing when it should.

Reported-by: Thomas Pollet <thomas.pollet@gmail.com>
Signed-off-by: Larry Woodman <lwoodman@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-25 09:34:58 -07:00
Linus Torvalds e92b05dec8 fremap: get rid of broken 'end' variable
Thomas Pollet points out that the 'end' variable is broken.  It was
computed based on start/size before they were page-aligned, and as such
doesn't actually match any of the other actions we take.  The overflow
test on end was also redundant, since we had already tested it with the
properly aligned version.

So just get rid of it entirely.  The one remaining use for that broken
variable can just use 'start+size' like all the other cases already did.

Reported-by: Thomas Pollet <thomas.pollet@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-24 14:13:57 -07:00
Naoya Horiguchi a850ea3037 hugetlb, rmap: add BUG_ON(!PageLocked) in hugetlb_add_anon_rmap()
Confirming page lock is held in hugetlb_add_anon_rmap() may be useful
to detect possible future problems.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-23 17:29:19 -07:00
Naoya Horiguchi 56c9cfb13c hugetlb, rmap: fix confusing page locking in hugetlb_cow()
The "if (!trylock_page)" block in the avoidcopy path of hugetlb_cow()
looks confusing and is buggy.  Originally this trylock_page() was
intended to make sure that old_page is locked even when old_page !=
pagecache_page, because then only pagecache_page is locked.

This patch fixes it by moving page locking into hugetlb_fault().

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-23 17:29:18 -07:00
Naoya Horiguchi cd67f0d2a9 hugetlb, rmap: use hugepage_add_new_anon_rmap() in hugetlb_cow()
Obviously, setting anon_vma for COWed hugepage should be done
by hugepage_add_new_anon_rmap() to scan vmas faster.
This patch fixes it.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-23 17:29:18 -07:00
Naoya Horiguchi 433abed6c6 hugetlb, rmap: always use anon_vma root pointer
This patch applies Andrea's fix given by the following patch into hugepage
rmapping code:

  commit 288468c334
  Author: Andrea Arcangeli <aarcange@redhat.com>
  Date:   Mon Aug 9 17:19:09 2010 -0700

This patch uses anon_vma->root and avoids unnecessary overwriting when
anon_vma is already set up.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-23 17:29:18 -07:00
Linus Torvalds 57aebd7739 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
  percpu: fix pcpu_last_unit_cpu
2010-09-23 08:06:55 -07:00
Andrea Arcangeli 2aeadc30de mmap: call unlink_anon_vmas() in __split_vma() in case of error
If __split_vma fails because of an out of memory condition the
anon_vma_chain isn't teardown and freed potentially leading to rmap walks
accessing freed vma information plus there's a memleak.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Johannes Weiner <jweiner@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-22 17:22:40 -07:00
David Rientjes e85bfd3aa7 oom: filter unkillable tasks from tasklist dump
/proc/sys/vm/oom_dump_tasks is enabled by default, so it's necessary to
limit as much information as possible that it should emit.

The tasklist dump should be filtered to only those tasks that are eligible
for oom kill.  This is already done for memcg ooms, but this patch extends
it to both cpuset and mempolicy ooms as well as init.

In addition to suppressing irrelevant information, this also reduces
confusion since users currently don't know which tasks in the tasklist
aren't eligible for kill (such as those attached to cpusets or bound to
mempolicies with a disjoint set of mems or nodes, respectively) since that
information is not shown.

Signed-off-by: David Rientjes <rientjes@google.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-22 17:22:39 -07:00
Minchan Kim d1908362ae vmscan: check all_unreclaimable in direct reclaim path
M.  Vefa Bicakci reported 2.6.35 kernel hang up when hibernation on his
32bit 3GB mem machine.
(https://bugzilla.kernel.org/show_bug.cgi?id=16771). Also he bisected
the regression to

  commit bb21c7ce18
  Author: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
  Date:   Fri Jun 4 14:15:05 2010 -0700

     vmscan: fix do_try_to_free_pages() return value when priority==0 reclaim failure

At first impression, this seemed very strange because the above commit
only chenged function return value and hibernate_preallocate_memory()
ignore return value of shrink_all_memory().  But it's related.

Now, page allocation from hibernation code may enter infinite loop if the
system has highmem.  The reasons are that vmscan don't care enough OOM
case when oom_killer_disabled.

The problem sequence is following as.

1. hibernation
2. oom_disable
3. alloc_pages
4. do_try_to_free_pages
       if (scanning_global_lru(sc) && !all_unreclaimable)
               return 1;

If kswapd is not freozen, it would set zone->all_unreclaimable to 1 and
then shrink_zones maybe return true(ie, all_unreclaimable is true).  So at
last, alloc_pages could go to _nopage_.  If it is, it should have no
problem.

This patch adds all_unreclaimable check to protect in direct reclaim path,
too.  It can care of hibernation OOM case and help bailout
all_unreclaimable case slightly.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Reported-by: M. Vefa Bicakci <bicave@superonline.com>
Reported-by: <caiqian@redhat.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Tested-by: <caiqian@redhat.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-22 17:22:39 -07:00
David Rientjes f19e8aa11a oom: always return a badness score of non-zero for eligible tasks
A task's badness score is roughly a proportion of its rss and swap
compared to the system's capacity.  The scale ranges from 0 to 1000 with
the highest score chosen for kill.  Thus, this scale operates on a
resolution of 0.1% of RAM + swap.  Admin tasks are also given a 3% bonus,
so the badness score of an admin task using 3% of memory, for example,
would still be 0.

It's possible that an exceptionally large number of tasks will combine to
exhaust all resources but never have a single task that uses more than
0.1% of RAM and swap (or 3.0% for admin tasks).

This patch ensures that the badness score of any eligible task is never 0
so the machine doesn't unnecessarily panic because it cannot find a task
to kill.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-22 17:22:38 -07:00
Linus Torvalds b68e9d4581 Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block
* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  bdi: Fix warnings in __mark_inode_dirty for /dev/zero and friends
  char: Mark /dev/zero and /dev/kmem as not capable of writeback
  bdi: Initialize noop_backing_dev_info properly
  cfq-iosched: fix a kernel OOPs when usb key is inserted
  block: fix blk_rq_map_kern bio direction flag
  cciss: freeing uninitialized data on error path
2010-09-22 09:12:37 -07:00
Jan Kara 976e48f8a5 bdi: Initialize noop_backing_dev_info properly
Properly initialize this backing dev info so that writeback code does not
barf when getting to it e.g. via sb->s_bdi.

Cc: stable@kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-09-22 09:48:47 +02:00
Tejun Heo 46b30ea9bc percpu: fix pcpu_last_unit_cpu
pcpu_first/last_unit_cpu are used to track which cpu has the first and
last units assigned.  This in turn is used to determine the span of a
chunk for man/unmap cache flushes and whether an address belongs to
the first chunk or not in per_cpu_ptr_to_phys().

When the number of possible CPUs isn't power of two, a chunk may
contain unassigned units towards the end of a chunk.  The logic to
determine pcpu_last_unit_cpu was incorrect when there was an unused
unit at the end of a chunk.  It failed to ignore the unused unit and
assigned the unused marker NR_CPUS to pcpu_last_unit_cpu.

This was discovered through kdump failure which was caused by
malfunctioning per_cpu_ptr_to_phys() on a kvm setup with 50 possible
CPUs by CAI Qian.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: CAI Qian <caiqian@redhat.com>
Cc: stable@kernel.org
2010-09-21 08:12:25 +02:00
Hugh Dickins 31c4a3d3a0 mm: further fix swapin race condition
Commit 4969c1192d ("mm: fix swapin race condition") is now agreed to
be incomplete.  There's a race, not very much less likely than the
original race envisaged, in which it is further necessary to check that
the swapcache page's swap has not changed.

Here's the reasoning: cast in terms of reuse_swap_page(), but probably
could be reformulated to rely on try_to_free_swap() instead, or on
swapoff+swapon.

A, faults into do_swap_page(): does page1 = lookup_swap_cache(swap1) and
comes through the lock_page(page1).

B, a racing thread of the same process, faults on the same address: does
page1 = lookup_swap_cache(swap1) and now waits in lock_page(page1), but
for whatever reason is unlucky not to get the lock any time soon.

A carries on through do_swap_page(), a write fault, but cannot reuse the
swap page1 (another reference to swap1).  Unlocks the page1 (but B
doesn't get it yet), does COW in do_wp_page(), page2 now in that pte.

C, perhaps the parent of A+B, comes in and write faults the same swap
page1 into its mm, reuse_swap_page() succeeds this time, swap1 is freed.

kswapd comes in after some time (B still unlucky) and swaps out some
pages from A+B and C: it allocates the original swap1 to page2 in A+B,
and some other swap2 to the original page1 now in C.  But does not
immediately free page1 (actually it couldn't: B holds a reference),
leaving it in swap cache for now.

B at last gets the lock on page1, hooray! Is PageSwapCache(page1)? Yes.
Is pte_same(*page_table, orig_pte)? Yes, because page2 has now been
given the swap1 which page1 used to have.  So B proceeds to insert page1
into A+B's page_table, though its content now belongs to C, quite
different from what A wrote there.

B ought to have checked that page1's swap was still swap1.

Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-20 10:44:37 -07:00
Cliff Wickman 3ee48b6af4 mm, x86: Saving vmcore with non-lazy freeing of vmas
During the reading of /proc/vmcore the kernel is doing
ioremap()/iounmap() repeatedly. And the buildup of un-flushed
vm_area_struct's is causing a great deal of overhead. (rb_next()
is chewing up most of that time).

This solution is to provide function set_iounmap_nonlazy(). It
causes a subsequent call to iounmap() to immediately purge the
vma area (with try_purge_vmap_area_lazy()).

With this patch we have seen the time for writing a 250MB
compressed dump drop from 71 seconds to 44 seconds.

Signed-off-by: Cliff Wickman <cpw@sgi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: kexec@lists.infradead.org
Cc: <stable@kernel.org>
LKML-Reference: <E1OwHZ4-0005WK-Tw@eag09.americas.sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-09-17 09:11:56 +02:00
Christoph Hellwig dd3932eddf block: remove BLKDEV_IFL_WAIT
All the blkdev_issue_* helpers can only sanely be used for synchronous
caller.  To issue cache flushes or barriers asynchronously the caller needs
to set up a bio by itself with a completion callback to move the asynchronous
state machine ahead.  So drop the BLKDEV_IFL_WAIT flag that is always
specified when calling blkdev_issue_* and also remove the now unused flags
argument to blkdev_issue_flush and blkdev_issue_zeroout.  For
blkdev_issue_discard we need to keep it for the secure discard flag, which
gains a more descriptive name and loses the bitops vs flag confusion.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-09-16 20:52:58 +02:00
Yinghai Lu 3661ca66a4 memblock: Fix section mismatch warnings
Stephen found a bunch of section mismatch warnings with the
new memblock changes.

Use __init_memblock to replace __init in memblock.c and remove
__init in memblock.h. We should not use __init in header files.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Tested-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Yinghai Lu <Yinghai@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
LKML-Reference: <4C912709.2090201@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-09-15 22:17:13 +02:00
Linus Torvalds ff3cb3fec3 Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block
* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  block: Range check cpu in blk_cpu_to_group
  scatterlist: prevent invalid free when alloc fails
  writeback: Fix lost wake-up shutting down writeback thread
  writeback: do not lose wakeup events when forking bdi threads
  cciss: fix reporting of max queue depth since init
  block: switch s390 tape_block and mg_disk to elevator_change()
  block: add function call to switch the IO scheduler from a driver
  fs/bio-integrity.c: return -ENOMEM on kmalloc failure
  bio-integrity.c: remove dependency on __GFP_NOFAIL
  BLOCK: fix bio.bi_rw handling
  block: put dev->kobj in blk_register_queue fail path
  cciss: handle allocation failure
  cfq-iosched: Documentation help for new tunables
  cfq-iosched: blktrace print per slice sector stats
  cfq-iosched: Implement tunable group_idle
  cfq-iosched: Do group share accounting in IOPS when slice_idle=0
  cfq-iosched: Do not idle if slice_idle=0
  cciss: disable doorbell reset on reset_devices
  blkio: Fix return code for mkdir calls
2010-09-10 07:26:27 -07:00
Christoph Hellwig 349f429eec swap: do not send discards as barriers
The swap code already uses synchronous discards, no need to add I/O barriers.

tj: superflous newlines removed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Hugh Dickins <hughd@google.com>
Tested-by: Nigel Cunningham <nigel@tuxonice.net>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-09-10 12:35:39 +02:00
Tejun Heo 9329ba9704 percpu: update comments to reflect that percpu allocations are always zero-filled
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Stephane Eranian <eranian@google.com>
2010-09-10 11:01:56 +02:00
Tejun Heo fc1481a956 percpu: clear memory allocated with the km allocator
Percpu allocator should clear memory before returning it but the km
allocator forgot to do it.  Fix it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
2010-09-10 10:56:24 +02:00
Mel Gorman 9ee493ce0a mm: page allocator: drain per-cpu lists after direct reclaim allocation fails
When under significant memory pressure, a process enters direct reclaim
and immediately afterwards tries to allocate a page.  If it fails and no
further progress is made, it's possible the system will go OOM.  However,
on systems with large amounts of memory, it's possible that a significant
number of pages are on per-cpu lists and inaccessible to the calling
process.  This leads to a process entering direct reclaim more often than
it should increasing the pressure on the system and compounding the
problem.

This patch notes that if direct reclaim is making progress but allocations
are still failing that the system is already under heavy pressure.  In
this case, it drains the per-cpu lists and tries the allocation a second
time before continuing.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-09 18:57:25 -07:00
Christoph Lameter aa45484031 mm: page allocator: calculate a better estimate of NR_FREE_PAGES when memory is low and kswapd is awake
Ordinarily watermark checks are based on the vmstat NR_FREE_PAGES as it is
cheaper than scanning a number of lists.  To avoid synchronization
overhead, counter deltas are maintained on a per-cpu basis and drained
both periodically and when the delta is above a threshold.  On large CPU
systems, the difference between the estimated and real value of
NR_FREE_PAGES can be very high.  If NR_FREE_PAGES is much higher than
number of real free page in buddy, the VM can allocate pages below min
watermark, at worst reducing the real number of pages to zero.  Even if
the OOM killer kills some victim for freeing memory, it may not free
memory if the exit path requires a new page resulting in livelock.

This patch introduces a zone_page_state_snapshot() function (courtesy of
Christoph) that takes a slightly more accurate view of an arbitrary vmstat
counter.  It is used to read NR_FREE_PAGES while kswapd is awake to avoid
the watermark being accidentally broken.  The estimate is not perfect and
may result in cache line bounces but is expected to be lighter than the
IPI calls necessary to continually drain the per-cpu counters while kswapd
is awake.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-09 18:57:25 -07:00
Mel Gorman 72853e2991 mm: page allocator: update free page counters after pages are placed on the free list
When allocating a page, the system uses NR_FREE_PAGES counters to
determine if watermarks would remain intact after the allocation was made.
This check is made without interrupts disabled or the zone lock held and
so is race-prone by nature.  Unfortunately, when pages are being freed in
batch, the counters are updated before the pages are added on the list.
During this window, the counters are misleading as the pages do not exist
yet.  When under significant pressure on systems with large numbers of
CPUs, it's possible for processes to make progress even though they should
have been stalled.  This is particularly problematic if a number of the
processes are using GFP_ATOMIC as the min watermark can be accidentally
breached and in extreme cases, the system can livelock.

This patch updates the counters after the pages have been added to the
list.  This makes the allocator more cautious with respect to preserving
the watermarks and mitigates livelock possibilities.

[akpm@linux-foundation.org: avoid modifying incoming args]
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-09 18:57:25 -07:00
KAMEZAWA Hiroyuki 5ee28a4476 vmstat: update zone stat threshold when onlining a cpu
refresh_zone_stat_thresholds() calculates parameter based on the number of
online cpus.  It's called at cpu offlining but needs to be called at
onlining, too.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-09 18:57:25 -07:00
Hugh Dickins 3399446632 swap: discard while swapping only if SWAP_FLAG_DISCARD
Tests with recent firmware on Intel X25-M 80GB and OCZ Vertex 60GB SSDs
show a shift since I last tested in December: in part because of firmware
updates, in part because of the necessary move from barriers to awaiting
completion at the block layer.  While discard at swapon still shows as
slightly beneficial on both, discarding 1MB swap cluster when allocating
is now disadvanteous: adds 25% overhead on Intel, adds 230% on OCZ (YMMV).

Surrender: discard as presently implemented is more hindrance than help
for swap; but might prove useful on other devices, or with improvements.
So continue to do the discard at swapon, but make discard while swapping
conditional on a SWAP_FLAG_DISCARD to sys_swapon() (which has been using
only the lower 16 bits of int flags).

We can add a --discard or -d to swapon(8), and a "discard" to swap in
/etc/fstab: matching the mount option for btrfs, ext4, fat, gfs2, nilfs2.

Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Nigel Cunningham <nigel@tuxonice.net>
Cc: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <jaxboe@fusionio.com>
Cc: James Bottomley <James.Bottomley@hansenpartnership.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-09 18:57:25 -07:00
Christoph Hellwig 8f2ae0faa3 swap: do not send discards as barriers
The swap code already uses synchronous discards, no need to add I/O
barriers.

This fixes the worst of the terrible slowdown in swap allocation for
hibernation, reported on 2.6.35 by Nigel Cunningham; but does not entirely
eliminate that regression.

[tj@kernel.org: superflous newlines removed]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Nigel Cunningham <nigel@tuxonice.net>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Jens Axboe <jaxboe@fusionio.com>
Cc: James Bottomley <James.Bottomley@hansenpartnership.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-09 18:57:25 -07:00
Hugh Dickins b73d7fcecd swap: prevent reuse during hibernation
Move the hibernation check from scan_swap_map() into try_to_free_swap():
to catch not only the common case when hibernation's allocation itself
triggers swap reuse, but also the less likely case when concurrent page
reclaim (shrink_page_list) might happen to try_to_free_swap from a page.

Hibernation already clears __GFP_IO from the gfp_allowed_mask, to stop
reclaim from going to swap: check that to prevent swap reuse too.

Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Ondrej Zary <linux@rainbow-software.org>
Cc: Andrea Gelmini <andrea.gelmini@gmail.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Nigel Cunningham <nigel@tuxonice.net>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-09 18:57:25 -07:00
Hugh Dickins 910321ea81 swap: revert special hibernation allocation
Please revert 2.6.36-rc commit d2997b1042
"hibernation: freeze swap at hibernation".  It complicated matters by
adding a second swap allocation path, just for hibernation; without in any
way fixing the issue that it was intended to address - page reclaim after
fixing the hibernation image might free swap from a page already imaged as
swapcache, letting its swap be reallocated to store a different page of
the image: resulting in data corruption if the imaged page were freed as
clean then swapped back in.  Pages freed to si->swap_map were still in
danger of being reallocated by the alternative allocation path.

I guess it inadvertently fixed slow SSD swap allocation for hibernation,
as reported by Nigel Cunningham: by missing out the discards that occur on
the usual swap allocation path; but that was unintentional, and needs a
separate fix.

Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Ondrej Zary <linux@rainbow-software.org>
Cc: Andrea Gelmini <andrea.gelmini@gmail.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Nigel Cunningham <nigel@tuxonice.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-09 18:57:25 -07:00
Gary King ac8456d6f9 bounce: call flush_dcache_page() after bounce_copy_vec()
I have been seeing problems on Tegra 2 (ARMv7 SMP) systems with HIGHMEM
enabled on 2.6.35 (plus some patches targetted at 2.6.36 to perform cache
maintenance lazily), and the root cause appears to be that the mm bouncing
code is calling flush_dcache_page before it copies the bounce buffer into
the bio.

The bounced page needs to be flushed after data is copied into it, to
ensure that architecture implementations can synchronize instruction and
data caches if necessary.

Signed-off-by: Gary King <gking@nvidia.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Acked-by: Jens Axboe <axboe@kernel.dk>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-09 18:57:25 -07:00
KAMEZAWA Hiroyuki 0dcc48c15f memory hotplug: fix next block calculation in is_removable
next_active_pageblock() is for finding next _used_ freeblock.  It skips
several blocks when it finds there are a chunk of free pages lager than
pageblock.  But it has 2 bugs.

  1. We have no lock. page_order(page) - pageblock_order can be minus.
  2. pageblocks_stride += is wrong. it should skip page_order(p) of pages.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-09 18:57:24 -07:00
Minchan Kim bc69304574 mm: compaction: handle active and inactive fairly in too_many_isolated
Iram reported that compaction's too_many_isolated() loops forever.
(http://www.spinics.net/lists/linux-mm/msg08123.html)

The meminfo when the situation happened was inactive anon is zero.  That's
because the system has no memory pressure until then.  While all anon
pages were in the active lru, compaction could select active lru as well
as inactive lru.  That's a different thing from vmscan's isolated.  So we
has been two too_many_isolated.

While compaction can isolate pages in both active and inactive, current
implementation of too_many_isolated only considers inactive.  It made
Iram's problem.

This patch handles active and inactive fairly.  That's because we can't
expect where from and how many compaction would isolated pages.

This patch changes (nr_isolated > nr_inactive) with
nr_isolated > (nr_active + nr_inactive) / 2.

Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Reported-by: Iram Shahzad <iram.shahzad@jp.fujitsu.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-09 18:57:24 -07:00
Andrea Arcangeli 152e0659fc mm: avoid warning when COMPACTION is selected
COMPACTION enables MIGRATION, but MIGRATION spawns a warning if numa or
memhotplug aren't selected.  However MIGRATION doesn't depend on them.  I
guess it's just trying to be strict doing a double check on who's enabling
it, but it doesn't know that compaction also enables MIGRATION.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-09 18:57:24 -07:00
Andrea Arcangeli 4969c1192d mm: fix swapin race condition
The pte_same check is reliable only if the swap entry remains pinned (by
the page lock on swapcache).  We've also to ensure the swapcache isn't
removed before we take the lock as try_to_free_swap won't care about the
page pin.

One of the possible impacts of this patch is that a KSM-shared page can
point to the anon_vma of another process, which could exit before the page
is freed.

This can leave a page with a pointer to a recycled anon_vma object, or
worse, a pointer to something that is no longer an anon_vma.

[riel@redhat.com: changelog help]
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-09 18:57:24 -07:00
Stefan Bader 39aa3cb3e8 mm: Move vma_stack_continue into mm.h
So it can be used by all that need to check for that.

Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-09 09:05:06 -07:00
Tejun Heo 3c9a024fde percpu: fix build breakage on s390 and cleanup build configuration tests
Commit bbddff05 (percpu: use percpu allocator on UP too) incorrectly
excluded pcpu_build_alloc_info() on SMP configurations which use
generic setup_per_cpu_area() like s390.  The config ifdefs are
becoming confusing.  Fix and clean it up by,

* Move pcpu_build_alloc_info() right on top of its two users -
  pcpu_{embed|page}_first_chunk() which are already in CONFIG_SMP
  block.

* Define BUILD_{EMBED|PAGE}_FIRST_CHUNK which indicate whether each
  first chunk function needs to be included and use them to control
  inclusion of the three functions to reduce confusion.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Sachin Sant <sachinp@in.ibm.com>
2010-09-09 18:00:15 +02:00
Tejun Heo bbddff0545 percpu: use percpu allocator on UP too
On UP, percpu allocations were redirected to kmalloc.  This has the
following problems.

* For certain amount of allocations (determined by
  PERCPU_DYNAMIC_EARLY_SLOTS and PERCPU_DYNAMIC_EARLY_SIZE), percpu
  allocator can be used before the usual kernel memory allocator is
  brought online.  On SMP, this is used to initialize the kernel
  memory allocator.

* percpu allocator honors alignment upto PAGE_SIZE but kmalloc()
  doesn't.  For example, workqueue makes use of larger alignments for
  cpu_workqueues.

Currently, users of percpu allocators need to handle UP differently,
which is somewhat fragile and ugly.  Other than small amount of
memory, there isn't much to lose by enabling percpu allocator on UP.
It can simply use kernel memory based chunk allocation which was added
for SMP archs w/o MMUs.

This patch removes mm/percpu_up.c, builds mm/percpu.c on UP too and
makes UP build use percpu-km.  As percpu addresses and kernel
addresses are always identity mapped and static percpu variables don't
need any special treatment, nothing is arch dependent and mm/percpu.c
implements generic setup_per_cpu_areas() for UP.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
2010-09-08 11:11:23 +02:00
Tejun Heo 4f8b02b4e5 vmalloc: pcpu_get/free_vm_areas() aren't needed on UP
These functions are used only by percpu memory allocator on SMP.
Don't build them on UP.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Nick Piggin <npiggin@kernel.dk>
Reviewed-by: Chrsitoph Lameter <cl@linux.com>
2010-09-08 11:10:47 +02:00
Linus Torvalds ce7db282a3 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
  percpu: fix a mismatch between code and comment
  percpu: fix a memory leak in pcpu_extend_area_map()
  percpu: add __percpu notations to UP allocator
  percpu: handle __percpu notations in UP accessors
2010-09-07 14:08:37 -07:00
Ingo Molnar daab7fc734 Merge commit 'v2.6.36-rc3' into x86/memblock
Conflicts:
	arch/x86/kernel/trampoline.c
	mm/memblock.c

Merge reason: Resolve the conflicts, update to latest upstream.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-08-31 09:45:46 +02:00
Linus Torvalds 997396a73a Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
  ceph: fix get_ticket_handler() error handling
  ceph: don't BUG on ENOMEM during mds reconnect
  ceph: ceph_mdsc_build_path() returns an ERR_PTR
  ceph: Fix warnings
  ceph: ceph_get_inode() returns an ERR_PTR
  ceph: initialize fields on new dentry_infos
  ceph: maintain i_head_snapc when any caps are dirty, not just for data
  ceph: fix osd request lru adjustment when sending request
  ceph: don't improperly set dir complete when holding EXCL cap
  mm: exporting account_page_dirty
  ceph: direct requests in snapped namespace based on nonsnap parent
  ceph: queue cap snap writeback for realm children on snap update
  ceph: include dirty xattrs state in snapped caps
  ceph: fix xattr cap writeback
  ceph: fix multiple mds session shutdown
2010-08-28 14:07:20 -07:00
Hugh Dickins f18194275c mm: fix hang on anon_vma->root->lock
After several hours, kbuild tests hang with anon_vma_prepare() spinning on
a newly allocated anon_vma's lock - on a box with CONFIG_TREE_PREEMPT_RCU=y
(which makes this very much more likely, but it could happen without).

The ever-subtle page_lock_anon_vma() now needs a further twist: since
anon_vma_prepare() and anon_vma_fork() are liable to change the ->root
of a reused anon_vma structure at any moment, page_lock_anon_vma()
needs to check page_mapped() again before succeeding, otherwise
page_unlock_anon_vma() might address a different root->lock.

Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-28 13:54:12 -07:00
Yinghai Lu a9ce6bc151 x86, memblock: Replace e820_/_early string with memblock_
1.include linux/memblock.h directly. so later could reduce e820.h reference.
2 this patch is done by sed scripts mainly

-v2: use MEMBLOCK_ERROR instead of -1ULL or -1UL

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2010-08-27 11:13:47 -07:00
Yinghai Lu 72d7c3b33c x86: Use memblock to replace early_res
1. replace find_e820_area with memblock_find_in_range
2. replace reserve_early with memblock_x86_reserve_range
3. replace free_early with memblock_x86_free_range.
4. NO_BOOTMEM will switch to use memblock too.
5. use _e820, _early wrap in the patch, in following patch, will
   replace them all
6. because memblock_x86_free_range support partial free, we can remove some special care
7. Need to make sure that memblock_find_in_range() is called after memblock_x86_fill()
   so adjust some calling later in setup.c::setup_arch()
   -- corruption_check and mptable_update

-v2: Move reserve_brk() early
    Before fill_memblock_area, to avoid overlap between brk and memblock_find_in_range()
    that could happen We have more then 128 RAM entry in E820 tables, and
    memblock_x86_fill() could use memblock_find_in_range() to find a new place for
    memblock.memory.region array.
    and We don't need to use extend_brk() after fill_memblock_area()
    So move reserve_brk() early before fill_memblock_area().
-v3: Move find_smp_config early
    To make sure memblock_find_in_range not find wrong place, if BIOS doesn't put mptable
    in right place.
-v4: Treat RESERVED_KERN as RAM in memblock.memory. and they are already in
    memblock.reserved already..
    use __NOT_KEEP_MEMBLOCK to make sure memblock related code could be freed later.
-v5: Generic version __memblock_find_in_range() is going from high to low, and for 32bit
    active_region for 32bit does include high pages
    need to replace the limit with memblock.default_alloc_limit, aka get_max_mapped()
-v6: Use current_limit instead
-v7: check with MEMBLOCK_ERROR instead of -1ULL or -1L
-v8: Set memblock_can_resize early to handle EFI with more RAM entries
-v9: update after kmemleak changes in mainline

Suggested-by: David S. Miller <davem@davemloft.net>
Suggested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2010-08-27 11:12:29 -07:00
Yinghai Lu edbe7d23b4 memblock: Add find_memory_core_early()
According to node range in early_node_map[] with __memblock_find_in_range
to find free range.

Will be used by memblock_x86_find_in_range_node()

memblock_x86_find_in_range_node will be used to find right buffer for NODE_DATA

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2010-08-27 11:10:54 -07:00
Yinghai Lu f88eff74aa bootmem, x86: Add weak version of reserve_bootmem_generic
It will be used memblock_x86_to_bootmem converting

It is an wrapper for reserve_bootmem, and x86 64bit is using special one.

Also clean up that version for x86_64. We don't need to take care of numa
path for that, bootmem can handle it how

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2010-08-27 11:08:13 -07:00
Yinghai Lu 7950c407c0 memblock: Add memblock_free/reserve_reserved_regions()
So we can avoid export memblock_reserved_init_regions()
Suggested by Ben.

-v2: use __init_memblock attribute

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2010-08-27 11:07:56 -07:00
Namhyung Kim 54157c4447 percpu: fix a mismatch between code and comment
When pcpu_build_alloc_info() searches best_upa value, it ignores current value
if the number of waste units exceeds 1/3 of the number of total cpus. But the
comment on the code says that it will ignore if wastage is over 25%.
Modify the comment.

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2010-08-27 11:36:19 +02:00
Huang Shijie a002d14842 percpu: fix a memory leak in pcpu_extend_area_map()
The original code did not free the old map.  This patch fixes it.

tj: use @old as memcpy source instead of @chunk->map, and indentation
    and description update

Signed-off-by: Huang Shijie <shijie8@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@kernel.org
2010-08-27 11:36:08 +02:00
Artem Bityutskiy 6628bc74f1 writeback: do not lose wakeup events when forking bdi threads
This patch fixes the following issue:

INFO: task mount.nfs4:1120 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
mount.nfs4    D 00000000fffc6a21     0  1120   1119 0x00000000
 ffff880235643948 0000000000000046 ffffffff00000000 ffffffff00000000
 ffff880235643fd8 ffff880235314760 00000000001d44c0 ffff880235643fd8
 00000000001d44c0 00000000001d44c0 00000000001d44c0 00000000001d44c0
Call Trace:
 [<ffffffff813bc747>] schedule_timeout+0x34/0xf1
 [<ffffffff813bc530>] ? wait_for_common+0x3f/0x130
 [<ffffffff8106b50b>] ? trace_hardirqs_on+0xd/0xf
 [<ffffffff813bc5c3>] wait_for_common+0xd2/0x130
 [<ffffffff8104159c>] ? default_wake_function+0x0/0xf
 [<ffffffff813beaa0>] ? _raw_spin_unlock+0x26/0x2a
 [<ffffffff813bc6bb>] wait_for_completion+0x18/0x1a
 [<ffffffff81101a03>] sync_inodes_sb+0xca/0x1bc
 [<ffffffff811056a6>] __sync_filesystem+0x47/0x7e
 [<ffffffff81105798>] sync_filesystem+0x47/0x4b
 [<ffffffff810e7ffd>] generic_shutdown_super+0x22/0xd2
 [<ffffffff810e80f8>] kill_anon_super+0x11/0x4f
 [<ffffffffa00d06d7>] nfs4_kill_super+0x3f/0x72 [nfs]
 [<ffffffff810e7b68>] deactivate_locked_super+0x21/0x41
 [<ffffffff810e7fd6>] deactivate_super+0x40/0x45
 [<ffffffff810fc66c>] mntput_no_expire+0xb8/0xed
 [<ffffffff810fc73b>] release_mounts+0x9a/0xb0
 [<ffffffff810fc7bb>] put_mnt_ns+0x6a/0x7b
 [<ffffffffa00d0fb2>] nfs_follow_remote_path+0x19a/0x296 [nfs]
 [<ffffffffa00d11ca>] nfs4_try_mount+0x75/0xaf [nfs]
 [<ffffffffa00d1790>] nfs4_get_sb+0x276/0x2ff [nfs]
 [<ffffffff810e7dba>] vfs_kern_mount+0xb8/0x196
 [<ffffffff810e7ef6>] do_kern_mount+0x48/0xe8
 [<ffffffff810fdf68>] do_mount+0x771/0x7e8
 [<ffffffff810fe062>] sys_mount+0x83/0xbd
 [<ffffffff810089c2>] system_call_fastpath+0x16/0x1b

The reason of this hang was a race condition: when the flusher thread is
forking a bdi thread, we use 'kthread_run()', so we run it _before_ we make it
visible in 'bdi->wb.task'. The bdi thread runs, does all works, and goes sleep.
'bdi->wb.task' is still NULL. And this is a dangerous time window.

If at this time someone queues a work for this bdi, he does not see the bdi
thread and wakes up the forker thread instead! But the forker has already
forked this bdi thread, but just did not make it visible yet!

The result is that we lose the wake up event for this bdi thread and the NFS4
code waits forever.

To fix the problem, we should use 'ktrhead_create()' for creating bdi threads,
then make them visible in 'bdi->wb.task', and only after this wake them up.
This is exactly what this patch does.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-08-27 09:16:18 +02:00
Linus Torvalds 871eae4891 Merge branch '2.6.36-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/xfsdev
* '2.6.36-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/xfsdev:
  xfs: do not discard page cache data on EAGAIN
  xfs: don't do memory allocation under the CIL context lock
  xfs: Reduce log force overhead for delayed logging
  xfs: dummy transactions should not dirty VFS state
  xfs: ensure f_ffree returned by statfs() is non-negative
  xfs: handle negative wbc->nr_to_write during sync writeback
  writeback: write_cache_pages doesn't terminate at nr_to_write <= 0
  xfs: fix untrusted inode number lookup
  xfs: ensure we mark all inodes in a freed cluster XFS_ISTALE
  xfs: unlock items before allowing the CIL to commit
2010-08-25 08:39:07 -07:00
Luck, Tony 8ca3eb0809 guard page for stacks that grow upwards
pa-risc and ia64 have stacks that grow upwards. Check that
they do not run into other mappings. By making VM_GROWSUP
0x0 on architectures that do not ever use it, we can avoid
some unpleasant #ifdefs in check_stack_guard_page().

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-24 12:13:20 -07:00
Dave Chinner 546a192422 writeback: write_cache_pages doesn't terminate at nr_to_write <= 0
I noticed XFS writeback in 2.6.36-rc1 was much slower than it should have
been. Enabling writeback tracing showed:

    flush-253:16-8516  [007] 1342952.351608: wbc_writepage: bdi 253:16: towrt=1024 skip=0 mode=0 kupd=0 bgrd=1 reclm=0 cyclic=1 more=0 older=0x0 start=0x0 end=0x0
    flush-253:16-8516  [007] 1342952.351654: wbc_writepage: bdi 253:16: towrt=1023 skip=0 mode=0 kupd=0 bgrd=1 reclm=0 cyclic=1 more=0 older=0x0 start=0x0 end=0x0
    flush-253:16-8516  [000] 1342952.369520: wbc_writepage: bdi 253:16: towrt=0 skip=0 mode=0 kupd=0 bgrd=1 reclm=0 cyclic=1 more=0 older=0x0 start=0x0 end=0x0
    flush-253:16-8516  [000] 1342952.369542: wbc_writepage: bdi 253:16: towrt=-1 skip=0 mode=0 kupd=0 bgrd=1 reclm=0 cyclic=1 more=0 older=0x0 start=0x0 end=0x0
    flush-253:16-8516  [000] 1342952.369549: wbc_writepage: bdi 253:16: towrt=-2 skip=0 mode=0 kupd=0 bgrd=1 reclm=0 cyclic=1 more=0 older=0x0 start=0x0 end=0x0

Writeback is not terminating in background writeback if ->writepage is
returning with wbc->nr_to_write == 0, resulting in sub-optimal single page
writeback on XFS.

Fix the write_cache_pages loop to terminate correctly when this situation
occurs and so prevent this sub-optimal background writeback pattern. This
improves sustained sequential buffered write performance from around
250MB/s to 750MB/s for a 100GB file on an XFS filesystem on my 8p test VM.

Cc:<stable@kernel.org>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Wu Fengguang <fengguang.wu@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-08-24 11:44:34 +10:00
Shaohua Li 61c77326d1 x86, mm: Avoid unnecessary TLB flush
In x86, access and dirty bits are set automatically by CPU when CPU accesses
memory. When we go into the code path of below flush_tlb_fix_spurious_fault(),
we already set dirty bit for pte and don't need flush tlb. This might mean
tlb entry in some CPUs hasn't dirty bit set, but this doesn't matter. When
the CPUs do page write, they will automatically check the bit and no software
involved.

On the other hand, flush tlb in below position is harmful. Test creates CPU
number of threads, each thread writes to a same but random address in same vma
range and we measure the total time. Under a 4 socket system, original time is
1.96s, while with the patch, the time is 0.8s. Under a 2 socket system, there is
20% time cut too. perf shows a lot of time are taking to send ipi/handle ipi for
tlb flush.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
LKML-Reference: <20100816011655.GA362@sli10-desk.sh.intel.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Andrea Archangeli <aarcange@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2010-08-23 10:04:57 -07:00
Michael Rubin 679ceace84 mm: exporting account_page_dirty
This allows code outside of the mm core to safely manipulate page state
and not worry about the other accounting. Not using these routines means
that some code will lose track of the accounting and we get bugs. This
has happened once already.

Signed-off-by: Michael Rubin <mrubin@google.com>
Signed-off-by: Sage Weil <sage@newdream.net>
2010-08-22 15:16:51 -07:00
Linus Torvalds bc584c5107 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6:
  slab: fix object alignment
  slub: add missing __percpu markup in mm/slub_def.h
2010-08-22 10:08:52 -07:00
Linus Torvalds 0e8e50e20c mm: make stack guard page logic use vm_prev pointer
Like the mlock() change previously, this makes the stack guard check
code use vma->vm_prev to see what the mapping below the current stack
is, rather than have to look it up with find_vma().

Also, accept an abutting stack segment, since that happens naturally if
you split the stack with mlock or mprotect.

Tested-by: Ian Campbell <ijc@hellion.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-21 08:50:00 -07:00
Linus Torvalds 7798330ac8 mm: make the mlock() stack guard page checks stricter
If we've split the stack vma, only the lowest one has the guard page.
Now that we have a doubly linked list of vma's, checking this is trivial.

Tested-by: Ian Campbell <ijc@hellion.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-21 08:49:50 -07:00
Linus Torvalds 297c5eee37 mm: make the vma list be doubly linked
It's a really simple list, and several of the users want to go backwards
in it to find the previous vma.  So rather than have to look up the
previous entry with 'find_vma_prev()' or something similar, just make it
doubly linked instead.

Tested-by: Ian Campbell <ijc@hellion.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-21 08:49:21 -07:00
KOSAKI Motohiro 8d6c83f0ba oom: __task_cred() need rcu_read_lock()
dump_tasks() needs to hold the RCU read lock around its access of the
target task's UID.  To this end it should use task_uid() as it only needs
that one thing from the creds.

The fact that dump_tasks() holds tasklist_lock is insufficient to prevent the
target process replacing its credentials on another CPU.

Then, this patch change to call rcu_read_lock() explicitly.

	===================================================
	[ INFO: suspicious rcu_dereference_check() usage. ]
	---------------------------------------------------
	mm/oom_kill.c:410 invoked rcu_dereference_check() without protection!

	other info that might help us debug this:

	rcu_scheduler_active = 1, debug_locks = 1
	4 locks held by kworker/1:2/651:
	 #0:  (events){+.+.+.}, at: [<ffffffff8106aae7>]
	process_one_work+0x137/0x4a0
	 #1:  (moom_work){+.+...}, at: [<ffffffff8106aae7>]
	process_one_work+0x137/0x4a0
	 #2:  (tasklist_lock){.+.+..}, at: [<ffffffff810fafd4>]
	out_of_memory+0x164/0x3f0
	 #3:  (&(&p->alloc_lock)->rlock){+.+...}, at: [<ffffffff810fa48e>]
	find_lock_task_mm+0x2e/0x70

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-20 09:34:55 -07:00
KOSAKI Motohiro b52723c560 oom: fix tasklist_lock leak
Commit 0aad4b3124 ("oom: fold __out_of_memory into out_of_memory")
introduced a tasklist_lock leak.  Then it caused following obvious
danger warnings and panic.

    ================================================
    [ BUG: lock held when returning to user space! ]
    ------------------------------------------------
    rsyslogd/1422 is leaving the kernel with locks still held!
    1 lock held by rsyslogd/1422:
     #0:  (tasklist_lock){.+.+.+}, at: [<ffffffff810faf64>] out_of_memory+0x164/0x3f0
    BUG: scheduling while atomic: rsyslogd/1422/0x00000002
    INFO: lockdep is turned off.

This patch fixes it.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-20 09:34:55 -07:00
KOSAKI Motohiro be71cf2202 oom: fix NULL pointer dereference
Commit b940fd7035 ("oom: remove unnecessary code and cleanup") added an
unnecessary NULL pointer dereference.  remove it.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-20 09:34:55 -07:00
Jan Kara d5ed3a4af7 lib/radix-tree.c: fix overflow in radix_tree_range_tag_if_tagged()
When radix_tree_maxindex() is ~0UL, it can happen that scanning overflows
index and tree traversal code goes astray reading memory until it hits
unreadable memory.  Check for overflow and exit in that case.

Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-20 09:34:55 -07:00
Nikanth Karthikesan 415b54e37a Fix typo s/contenious/continuous in comment
Fix typo s/contenious/continuous in comment.

Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2010-08-18 10:22:24 +02:00
Hugh Dickins 602586a83b shmem: put_super must percpu_counter_destroy
list_add() corruption messages reported from shmem_fill_super()'s recently
introduced percpu_counter_init(): shmem_put_super() needs to remember to
percpu_counter_destroy().  And also check error from percpu_counter_init().

Reported-bisected-and-tested-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-17 18:33:11 -07:00
Linus Torvalds d7824370e2 mm: fix up some user-visible effects of the stack guard page
This commit makes the stack guard page somewhat less visible to user
space. It does this by:

 - not showing the guard page in /proc/<pid>/maps

   It looks like lvm-tools will actually read /proc/self/maps to figure
   out where all its mappings are, and effectively do a specialized
   "mlockall()" in user space.  By not showing the guard page as part of
   the mapping (by just adding PAGE_SIZE to the start for grows-up
   pages), lvm-tools ends up not being aware of it.

 - by also teaching the _real_ mlock() functionality not to try to lock
   the guard page.

   That would just expand the mapping down to create a new guard page,
   so there really is no point in trying to lock it in place.

It would perhaps be nice to show the guard page specially in
/proc/<pid>/maps (or at least mark grow-down segments some way), but
let's not open ourselves up to more breakage by user space from programs
that depends on the exact deails of the 'maps' file.

Special thanks to Henrique de Moraes Holschuh for diving into lvm-tools
source code to see what was going on with the whole new warning.

Reported-and-tested-by: François Valenduc <francois.valenduc@tvcablenet.be
Reported-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-15 11:35:52 -07:00
Randy Dunlap 03ab450f03 mm/page-writeback: fix non-kernel-doc function comments
Remove leading /** from non-kernel-doc function comments to prevent
kernel-doc warnings.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-14 16:20:59 -07:00
Linus Torvalds 11ac552477 mm: fix page table unmap for stack guard page properly
We do in fact need to unmap the page table _before_ doing the whole
stack guard page logic, because if it is needed (mainly 32-bit x86 with
PAE and CONFIG_HIGHPTE, but other architectures may use it too) then it
will do a kmap_atomic/kunmap_atomic.

And those kmaps will create an atomic region that we cannot do
allocations in.  However, the whole stack expand code will need to do
anon_vma_prepare() and vma_lock_anon_vma() and they cannot do that in an
atomic region.

Now, a better model might actually be to do the anon_vma_prepare() when
_creating_ a VM_GROWSDOWN segment, and not have to worry about any of
this at page fault time.  But in the meantime, this is the
straightforward fix for the issue.

See https://bugzilla.kernel.org/show_bug.cgi?id=16588 for details.

Reported-by: Wylda <wylda@volny.cz>
Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Reported-by: Mike Pagano <mpagano@gentoo.org>
Reported-by: François Valenduc <francois.valenduc@tvcablenet.be>
Tested-by: Ed Tomlinson <edt@aei.ca>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Greg KH <gregkh@suse.de>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-14 11:44:56 -07:00
David Howells fe622e76fd NOMMU: Remove an extraneous no_printk()
Remove an extraneous no_printk() in mm/nommu.c that got missed when the
function got generalised from several things that used it in commit
12fdff3fc2 ("Add a dummy printk function for the maintenance of unused
printks").

Without this, the following error is observed:

  mm/nommu.c:41: error: conflicting types for 'no_printk'
  include/linux/kernel.h:314: error: previous definition of 'no_printk' was here

Reported-by: Michal Simek <monstr@monstr.eu>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-13 16:55:25 -07:00
Linus Torvalds 5528f9132c mm: fix missing page table unmap for stack guard page failure case
.. which didn't show up in my tests because it's a no-op on x86-64 and
most other architectures.  But we enter the function with the last-level
page table mapped, and should unmap it at exit.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-13 09:24:04 -07:00
Linus Torvalds 320b2b8de1 mm: keep a guard page below a grow-down stack segment
This is a rather minimally invasive patch to solve the problem of the
user stack growing into a memory mapped area below it.  Whenever we fill
the first page of the stack segment, expand the segment down by one
page.

Now, admittedly some odd application might _want_ the stack to grow down
into the preceding memory mapping, and so we may at some point need to
make this a process tunable (some people might also want to have more
than a single page of guarding), but let's try the minimal approach
first.

Tested with trivial application that maps a single page just below the
stack, and then starts recursing.  Without this, we will get a SIGSEGV
_after_ the stack has smashed the mapping.  With this patch, we'll get a
nice SIGBUS just as the stack touches the page just above the mapping.

Requested-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-12 17:54:33 -07:00
Linus Torvalds 1021a64534 Merge branch 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6
* 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6:
  hugetlb: add missing unlock in avoidcopy path in hugetlb_cow()
  hwpoison: rename CONFIG
  HWPOISON, hugetlb: support hwpoison injection for hugepage
  HWPOISON, hugetlb: detect hwpoison in hugetlb code
  HWPOISON, hugetlb: isolate corrupted hugepage
  HWPOISON, hugetlb: maintain mce_bad_pages in handling hugepage error
  HWPOISON, hugetlb: set/clear PG_hwpoison bits on hugepage
  HWPOISON, hugetlb: enable error handling path for hugepage
  hugetlb, rmap: add reverse mapping for hugepage
  hugetlb: move definition of is_vm_hugetlb_page() to hugepage_inline.h

Fix up trivial conflicts in mm/memory-failure.c
2010-08-12 10:15:10 -07:00
Linus Torvalds 26f0cf9181 Merge branch 'stable/xen-swiotlb-0.8.6' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen
* 'stable/xen-swiotlb-0.8.6' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  x86: Detect whether we should use Xen SWIOTLB.
  pci-swiotlb-xen: Add glue code to setup dma_ops utilizing xen_swiotlb_* functions.
  swiotlb-xen: SWIOTLB library for Xen PV guest with PCI passthrough.
  xen/mmu: inhibit vmap aliases rather than trying to clear them out
  vmap: add flag to allow lazy unmap to be disabled at runtime
  xen: Add xen_create_contiguous_region
  xen: Rename the balloon lock
  xen: Allow unprivileged Xen domains to create iomap pages
  xen: use _PAGE_IOMAP in ioremap to do machine mappings

Fix up trivial conflicts (adding both xen swiotlb and xen pci platform
driver setup close to each other) in drivers/xen/{Kconfig,Makefile} and
include/xen/xen-ops.h
2010-08-12 09:09:41 -07:00
Wu Fengguang 1babe18385 writeback: add comment to the dirty limit functions
Document global_dirty_limits() and bdi_dirty_limit().

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-12 08:43:30 -07:00
Wu Fengguang 16c4042f08 writeback: avoid unnecessary calculation of bdi dirty thresholds
Split get_dirty_limits() into global_dirty_limits()+bdi_dirty_limit(), so
that the latter can be avoided when under global dirty background
threshold (which is the normal state for most systems).

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-12 08:43:29 -07:00
Wu Fengguang e50e37201a writeback: balance_dirty_pages(): reduce calls to global_page_state
Reducing the number of times balance_dirty_pages calls global_page_state
reduces the cache references and so improves write performance on a
variety of workloads.

'perf stats' of simple fio write tests shows the reduction in cache
access.  Where the test is fio 'write,mmap,600Mb,pre_read' on AMD AthlonX2
with 3Gb memory (dirty_threshold approx 600 Mb) running each test 10
times, dropping the fasted & slowest values then taking the average &
standard deviation

		average (s.d.) in millions (10^6)
2.6.31-rc8	648.6 (14.6)
+patch		620.1 (16.5)

Achieving this reduction is by dropping clip_bdi_dirty_limit as it rereads
the counters to apply the dirty_threshold and moving this check up into
balance_dirty_pages where it has already read the counters.

Also by rearrange the for loop to only contain one copy of the limit tests
allows the pdflush test after the loop to use the local copies of the
counters rather than rereading them.

In the common case with no throttling it now calls global_page_state 5
fewer times and bdi_stat 2 fewer.

Fengguang:

This patch slightly changes behavior by replacing clip_bdi_dirty_limit()
with the explicit check (nr_reclaimable + nr_writeback >= dirty_thresh) to
avoid exceeding the dirty limit.  Since the bdi dirty limit is mostly
accurate we don't need to do routinely clip.  A simple dirty limit check
would be enough.

The check is necessary because, in principle we should throttle everything
calling balance_dirty_pages() when we're over the total limit, as said by
Peter.

We now set and clear dirty_exceeded not only based on bdi dirty limits,
but also on the global dirty limit.  The global limit check is added in
place of clip_bdi_dirty_limit() for safety and not intended as a behavior
change.  The bdi limits should be tight enough to keep all dirty pages
under the global limit at most time; occasional small exceeding should be
OK though.  The change makes the logic more obvious: the global limit is
the ultimate goal and shall be always imposed.

We may now start background writeback work based on outdated conditions.
That's safe because the bdi flush thread will (and have to) double check
the states.  It reduces overall overheads because the test based on old
states still have good chance to be right.

[akpm@linux-foundation.org] fix uninitialized dirty_exceeded
Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Jan Kara <jack@suse.cz>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-12 08:43:29 -07:00
Randy Dunlap 3c111a071d mm: fix fatal kernel-doc error
Fix a fatal kernel-doc error due to a #define coming between a function's
kernel-doc notation and the function signature.  (kernel-doc cannot handle
this)

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-12 08:43:29 -07:00
KOSAKI Motohiro 13d7e3a2db memcg: convert to use zone_to_nid() from bare zone->zone_pgdat->node_id
We have zone_to_nid().  this patch convert all existing users of
zone->zone_pgdat->node_id.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Nishimura Daisuke <d-nishimura@mtf.biglobe.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11 08:59:19 -07:00
KOSAKI Motohiro 00918b6ab8 memcg: remove nid and zid argument from mem_cgroup_soft_limit_reclaim()
mem_cgroup_soft_limit_reclaim() has zone, nid and zid argument.  but nid
and zid can be calculated from zone.  So remove it.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Nishimura Daisuke <d-nishimura@mtf.biglobe.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11 08:59:19 -07:00
KOSAKI Motohiro 14fec79680 memcg: mem_cgroup_shrink_node_zone() doesn't need sc.nodemask
Currently mem_cgroup_shrink_node_zone() call shrink_zone() directly.  thus
it doesn't need to initialize sc.nodemask because shrink_zone() doesn't
use it at all.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Nishimura Daisuke <d-nishimura@mtf.biglobe.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11 08:59:19 -07:00