Commit Graph

3780 Commits

Author SHA1 Message Date
Linus Torvalds 7b626acb8f Merge branch 'core-iommu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-iommu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (63 commits)
  x86, Calgary IOMMU quirk: Find nearest matching Calgary while walking up the PCI tree
  x86/amd-iommu: Remove amd_iommu_pd_table
  x86/amd-iommu: Move reset_iommu_command_buffer out of locked code
  x86/amd-iommu: Cleanup DTE flushing code
  x86/amd-iommu: Introduce iommu_flush_device() function
  x86/amd-iommu: Cleanup attach/detach_device code
  x86/amd-iommu: Keep devices per domain in a list
  x86/amd-iommu: Add device bind reference counting
  x86/amd-iommu: Use dev->arch->iommu to store iommu related information
  x86/amd-iommu: Remove support for domain sharing
  x86/amd-iommu: Rearrange dma_ops related functions
  x86/amd-iommu: Move some pte allocation functions in the right section
  x86/amd-iommu: Remove iommu parameter from dma_ops_domain_alloc
  x86/amd-iommu: Use get_device_id and check_device where appropriate
  x86/amd-iommu: Move find_protection_domain to helper functions
  x86/amd-iommu: Simplify get_device_resources()
  x86/amd-iommu: Let domain_for_device handle aliases
  x86/amd-iommu: Remove iommu specific handling from dma_ops path
  x86/amd-iommu: Remove iommu parameter from __(un)map_single
  x86/amd-iommu: Make alloc_new_range aware of multiple IOMMUs
  ...
2009-12-05 09:49:07 -08:00
André Goddard Rosa af901ca181 tree-wide: fix assorted typos all over the place
That is "success", "unknown", "through", "performance", "[re|un]mapping"
, "access", "default", "reasonable", "[con]currently", "temperature"
, "channel", "[un]used", "application", "example","hierarchy", "therefore"
, "[over|under]flow", "contiguous", "threshold", "enough" and others.

Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2009-12-04 15:39:55 +01:00
Peng Tao e9de25dda3 mm: fix comments for invalidate_inode_pages2()
invalidate_inode_pages2() returns -EBUSY *NOT* -EIO if any pages could not be
invalidated.

Signed-off-by: Peng Tao <bergwolf@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2009-12-04 15:39:48 +01:00
Wu Fengguang 0d99519efe writeback: remove unused nonblocking and congestion checks
- no one is calling wb_writeback and write_cache_pages with
  wbc.nonblocking=1 any more
- lumpy pageout will want to do nonblocking writeback without the
  congestion wait

So remove the congestion checks as suggested by Chris.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Alex Elder <aelder@sgi.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03 13:54:25 +01:00
OGAWA Hirofumi bf7ec5bb61 flusher: Fix PF_FROZEN race
To touch task->flags directly is racy. thaw_process() still has race
(changing non_current->flags, but this is another issue) though, I think
it's much better off.

So, use thaw_process() instead.

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03 13:49:43 +01:00
James Morris c84d6efd36 Merge branch 'master' into next 2009-12-03 12:03:40 +05:30
Linus Torvalds b54eb1795c Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block
* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  cciss: make device attrs static
  Thaw refrigerated bdi flusher threads before invoking kthread_stop on them
2009-11-30 13:57:03 -08:00
Pekka Enberg ce79ddc8e2 SLAB: Fix lockdep annotations for CPU hotplug
As reported by Paul McKenney:

  I am seeing some lockdep complaints in rcutorture runs that include
  frequent CPU-hotplug operations.  The tests are otherwise successful.
  My first thought was to send a patch that gave each array_cache
  structure's ->lock field its own struct lock_class_key, but you already
  have a init_lock_keys() that seems to be intended to deal with this.

  ------------------------------------------------------------------------

  =============================================
  [ INFO: possible recursive locking detected ]
  2.6.32-rc4-autokern1 #1
  ---------------------------------------------
  syslogd/2908 is trying to acquire lock:
   (&nc->lock){..-...}, at: [<c0000000001407f4>] .kmem_cache_free+0x118/0x2d4

  but task is already holding lock:
   (&nc->lock){..-...}, at: [<c0000000001411bc>] .kfree+0x1f0/0x324

  other info that might help us debug this:
  3 locks held by syslogd/2908:
   #0:  (&u->readlock){+.+.+.}, at: [<c0000000004556f8>] .unix_dgram_recvmsg+0x70/0x338
   #1:  (&nc->lock){..-...}, at: [<c0000000001411bc>] .kfree+0x1f0/0x324
   #2:  (&parent->list_lock){-.-...}, at: [<c000000000140f64>] .__drain_alien_cache+0x50/0xb8

  stack backtrace:
  Call Trace:
  [c0000000e8ccafc0] [c0000000000101e4] .show_stack+0x70/0x184 (unreliable)
  [c0000000e8ccb070] [c0000000000afebc] .validate_chain+0x6ec/0xf58
  [c0000000e8ccb180] [c0000000000b0ff0] .__lock_acquire+0x8c8/0x974
  [c0000000e8ccb280] [c0000000000b2290] .lock_acquire+0x140/0x18c
  [c0000000e8ccb350] [c000000000468df0] ._spin_lock+0x48/0x70
  [c0000000e8ccb3e0] [c0000000001407f4] .kmem_cache_free+0x118/0x2d4
  [c0000000e8ccb4a0] [c000000000140b90] .free_block+0x130/0x1a8
  [c0000000e8ccb540] [c000000000140f94] .__drain_alien_cache+0x80/0xb8
  [c0000000e8ccb5e0] [c0000000001411e0] .kfree+0x214/0x324
  [c0000000e8ccb6a0] [c0000000003ca860] .skb_release_data+0xe8/0x104
  [c0000000e8ccb730] [c0000000003ca2ec] .__kfree_skb+0x20/0xd4
  [c0000000e8ccb7b0] [c0000000003cf2c8] .skb_free_datagram+0x1c/0x5c
  [c0000000e8ccb830] [c00000000045597c] .unix_dgram_recvmsg+0x2f4/0x338
  [c0000000e8ccb920] [c0000000003c0f14] .sock_recvmsg+0xf4/0x13c
  [c0000000e8ccbb30] [c0000000003c28ec] .SyS_recvfrom+0xb4/0x130
  [c0000000e8ccbcb0] [c0000000003bfb78] .sys_recv+0x18/0x2c
  [c0000000e8ccbd20] [c0000000003ed388] .compat_sys_recv+0x14/0x28
  [c0000000e8ccbd90] [c0000000003ee1bc] .compat_sys_socketcall+0x178/0x220
  [c0000000e8ccbe30] [c0000000000085d4] syscall_exit+0x0/0x40

This patch fixes the issue by setting up lockdep annotations during CPU
hotplug.

Reported-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
2009-11-30 19:16:08 +02:00
Pekka Enberg 74e2134ff8 SLUB: Fix __GFP_ZERO unlikely() annotation
The unlikely() annotation in slab_alloc() covers too much of the expression.
It's actually very likely that the object is not NULL so use unlikely() only
for the __GFP_ZERO expression like SLAB does.

The patch reduces kernel text by 29 bytes on x86-64:

   text	   data	    bss	    dec	    hex	filename
  24185	   8560	    176	  32921	   8099	mm/slub.o.orig
  24156	   8560	    176	  32892	   807c	mm/slub.o

Acked-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
2009-11-29 09:01:59 +02:00
Ingo Molnar 4d795fb17a tracing: Fix kmem event exports
Commit 53d0422 ("tracing: Convert some kmem events to DEFINE_EVENT")
moved the kmem tracepoint creation from util.c to page_alloc.c,
but forgot to move the exports.

Move them back.

Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
LKML-Reference: <4B0E286A.2000405@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-26 13:17:43 +01:00
Li Zefan 53d0422c2d tracing: Convert some kmem events to DEFINE_EVENT
Use DECLARE_EVENT_CLASS to remove duplicate code:

   text    data     bss     dec     hex filename
 333987   69800   27228  431015   693a7 mm/built-in.o.old
 330030   69800   27228  427058   68432 mm/built-in.o

8 events are converted:

  kmem_alloc: kmalloc, kmem_cache_alloc
  kmem_alloc_node: kmalloc_node, kmem_cache_alloc_node
  kmem_free: kfree, kmem_cache_free
  mm_page: mm_page_alloc_zone_locked, mm_page_pcpu_drain

No change in functionality.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
LKML-Reference: <4B0E286A.2000405@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-26 09:14:02 +01:00
Vivek Goyal 3b034b0d08 percpu: Fix kdump failure if booted with percpu_alloc=page
o kdump functionality reserves a per cpu area at boot time and exports the
  physical address of that area to user space through sys interface. This
  area stores some dump related information like cpu register states etc
  at the time of crash.

o We were assuming that per cpu area always come from linearly mapped meory
  region and using __pa() to determine physical address.
  With percpu_alloc=page, per cpu area can come from vmalloc region also and
  __pa() breaks.

o This patch implments a new function to convert per cpu address to
  physical address.

Before the patch, crash_notes addresses looked as follows.

cpu0 60fffff49800
cpu1 60fffff60800
cpu2 60fffff77800

These are bogus phsyical addresses.

After the patch, address are following.

cpu0 13eb44000
cpu1 13eb43000
cpu2 13eb42000
cpu3 13eb41000

These look fine. I got 4G of memory and /proc/iomem tell me following.

100000000-13fffffff : System RAM

tj: * added missing asm/io.h include reported by Stephen Rothwell
    * repositioned per_cpu_ptr_phys() in percpu.c and added comment.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
2009-11-25 21:49:22 +09:00
Andi Kleen 6ad696d2cf mm: allow memory hotplug and hibernation in the same kernel
Allow memory hotplug and hibernation in the same kernel

Memory hotplug and hibernation were exclusive in Kconfig.  This is
obviously a problem for distribution kernels who want to support both in
the same image.

After some discussions with Rafael and others the only problem is with
parallel memory hotadd or removal while a hibernation operation is in
process.  It was also working for s390 before.

This patch removes the Kconfig level exclusion, and simply makes the
memory add / remove functions grab the pm_mutex to exclude against
hibernation.

Fixes a regression - old kernels didn't exclude memory hotadd and
hibernation.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-11-17 17:40:33 -08:00
Hidetoshi Seto e13193319d mm/memory_hotplug: fix section mismatch
With CONFIG_MEMORY_HOTPLUG I got following warning:

WARNING: vmlinux.o(.text+0x1276b0): Section mismatch in reference from
the function hotadd_new_pgdat() to the function
.meminit.text:free_area_init_node()
The function hotadd_new_pgdat() references
the function __meminit free_area_init_node().
This is often because hotadd_new_pgdat lacks a __meminit
annotation or the annotation of free_area_init_node is wrong.

Use __ref to fix this.

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-11-17 17:40:33 -08:00
Ingo Molnar 99f4c9de2b Merge commit 'v2.6.32-rc7' into core/iommu
Merge reason: Add fixes we'll depend on.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-17 07:51:07 +01:00
Linus Torvalds e0a2af1e60 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: restructure pcpu_extend_area_map() to fix bugs and improve readability
2009-11-14 12:59:06 -08:00
Tejun Heo 833af8427b percpu: restructure pcpu_extend_area_map() to fix bugs and improve readability
pcpu_extend_area_map() had the following two bugs.

* It should return 1 if pcpu_lock was dropped and reacquired but it
  returned 0.  This could lead to oops if free_percpu() races with
  area map extension.

* pcpu_mem_free() was called under pcpu_lock.  pcpu_mem_free() might
  end up calling vfree() which isn't IRQ safe.  This could lead to
  deadlock through lock order inversion via IRQ.

In addition, Linus pointed out that the temporary lock dropping and
subtle three-way return value of pcpu_extend_area_map() was very ugly
and suggested to split the function into two - pcpu_need_to_extend()
and pcpu_extend_area_map().

This patch restructures pcpu_extend_area_map() as suggested and fixes
the two bugs.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>
2009-11-13 00:55:35 +09:00
KAMEZAWA Hiroyuki e00e431612 memcg: fix wrong pointer initialization at page migration when memcg is disabled.
Lee Schermerhorn reported that he saw bad pointer dereference in
mem_cgroup_end_migration() when he disabled memcg by boot option.

memcg's page migration logic works as

	mem_cgroup_prepare_migration(page, &ptr);
	do page migration
	mem_cgroup_end_migration(page, ptr);

Now, ptr is not initialized in prepare_migration when memcg is disabled
by boot option. This causes panic in end_migration. This patch fixes it.

Reported-by: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-11-12 07:25:56 -08:00
Mel Gorman 9d0ed60fe9 page allocator: Do not allow interrupts to use ALLOC_HARDER
Commit 341ce06f69 ("page allocator:
calculate the alloc_flags for allocation only once") altered watermark
logic slightly by allowing rt_tasks that are handling an interrupt to set
ALLOC_HARDER.  This patch brings the watermark logic more in line with
2.6.30.

This change results in a reduction of the number high-order GFP_ATOMIC
allocation failures reported.  See
http://www.gossamer-threads.com/lists/linux/kernel/1144153

[rientjes@google.com: Spotted the problem]
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-11-12 07:25:56 -08:00
Mel Gorman cc4a685146 page allocator: always wake kswapd when restarting an allocation attempt after direct reclaim failed
If a direct reclaim makes no forward progress, it considers whether it
should go OOM or not.  Whether OOM is triggered or not, it may retry the
allocation afterwards.  In times past, this would always wake kswapd as
well but currently, kswapd is not woken up after direct reclaim fails.
For order-0 allocations, this makes little difference but if there is a
heavy mix of higher-order allocations that direct reclaim is failing for,
it might mean that kswapd is not rewoken for higher orders as much as it
did previously.

This patch wakes up kswapd when an allocation is being retried after a
direct reclaim failure.  It would be expected that kswapd is already
awake, but this has the effect of telling kswapd to reclaim at the higher
order as well.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi>
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>
2009-11-12 07:25:56 -08:00
Romit Dasgupta c62b17a58a Thaw refrigerated bdi flusher threads before invoking kthread_stop on them
Unfreezes the bdi flusher task when the said task needs to exit.

Steps to reproduce this.
1) Mount a file system from MMC/SD card.
2) Unmount the file system. This creates a flusher task.
3) Attempt suspend to RAM. System is unresponsive.

This is because the bdi flusher thread is already in the refrigerator and will
remain so until it is thawed. The MMC driver suspend routine call stack will
ultimately issue a 'kthread_stop' on the bdi flusher thread and will block
until the flusher thread is exited. Since the bdi flusher thread is in the
refrigerator it never cleans up until thawed.

Signed-off-by: Romit Dasgupta <romit@ti.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-11-12 13:08:11 +01:00
Linus Torvalds 961767b75d Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  highmem: Fix debug_kmap_atomic() to also handle KM_IRQ_PTE, KM_NMI, and KM_NMI_PTE
  highmem: Fix race in debug_kmap_atomic() which could cause warn_count to underflow
  rcu: Fix long-grace-period race between forcing and initialization
  uids: Prevent tear down race
2009-11-11 11:30:15 -08:00
FUJITA Tomonori 9f993ac3f7 bootmem: Add free_bootmem_late()
Add a new function for freeing bootmem after the bootmem
allocator has been released and the unreserved pages given to
the page allocator.

This allows us to reserve bootmem and then release it if we
later discover it was not needed.

( This new API will be used by the swiotlb code to recover
  a significant amount of RAM (64MB). )

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: chrisw@sous-sol.org
Cc: dwmw2@infradead.org
Cc: joerg.roedel@amd.com
Cc: muli@il.ibm.com
Cc: hannes@cmpxchg.org
Cc: tj@kernel.org
Cc: akpm@linux-foundation.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <1257849980-22640-7-git-send-email-fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-10 12:31:43 +01:00
Soeren Sandmann d451564669 highmem: Fix debug_kmap_atomic() to also handle KM_IRQ_PTE, KM_NMI, and KM_NMI_PTE
Previously calling debug_kmap_atomic() with these types would
cause spurious warnings.

(triggered by SysProf using perf events)

Signed-off-by: Soeren Sandmann Pedersen <sandmann@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: a.p.zijlstra@chello.nl
Cc: <stable@kernel.org> # .31.x
LKML-Reference: <ye8vdhz8krw.fsf@camel23.daimi.au.dk>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-10 04:15:47 +01:00
Soeren Sandmann 5ebd4c2289 highmem: Fix race in debug_kmap_atomic() which could cause warn_count to underflow
debug_kmap_atomic() tries to prevent ever printing more than 10
warnings, but it does so by testing whether an unsigned integer
is equal to 0. However, if the warning is caused by a nested
IRQ, then this counter may underflow and the stream of warnings
will never end.

Fix that by using a signed integer instead.

Signed-off-by: Soeren Sandmann Pedersen <sandmann@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: a.p.zijlstra@chello.nl
Cc: <stable@kernel.org> # .31.x
LKML-Reference: <ye8zl7b8ktj.fsf@camel23.daimi.au.dk>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-10 04:15:32 +01:00
Hugh Dickins d178f27fc5 ksm: cond_resched in unstable tree
KSM needs a cond_resched() for CONFIG_PREEMPT_NONE, in its unbounded
search of the unstable tree.  The stable tree cases already have one,
and originally there was one down inside get_user_pages();
but I missed it when I converted to follow_page() instead.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: Izik Eidus <ieidus@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-11-09 09:55:44 -08:00
Uwe Kleine-Knig 21ae2956ce tree-wide: fix typos "aquire" -> "acquire", "cumsumed" -> "consumed"
This patch was generated by

	git grep -E -i -l '[Aa]quire' | xargs -r perl -p -i -e 's/([Aa])quire/$1cquire/'

and the cumsumed was found by checking the diff for aquire.

Signed-off-by: Uwe Kleine-Knig <u.kleine-koenig@pengutronix.de>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2009-11-09 09:40:57 +01:00
Linus Torvalds 51bb296b09 Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block
* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  cfq-iosched: limit coop preemption
  cfq-iosched: fix bad return value cfq_should_preempt()
  backing-dev: bdi sb prune should be in the unregister path, not destroy
  Fix bio_alloc() and bio_kmalloc() documentation
  bio_put(): add bio_clone() to the list of functions in the comment
2009-11-03 18:16:21 -08:00
Jens Axboe 8c4db3355b backing-dev: bdi sb prune should be in the unregister path, not destroy
Commit 592b09a42f was different from
the tested path, in that it moved the bdi super_block prune from
unregister to destroy context. This doesn't fully fix the sync hang
bug on unexpected device removal, as need to prune the bdi cache
pointer before killing flusher thread.

Tested-by: Artur Skawina <art.08.09@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-11-03 20:18:44 +01:00
Bo Liu 32c5fc10e7 mm: remove incorrect swap_count() from try_to_unuse()
In try_to_unuse(), swcount is a local copy of *swap_map, including the
SWAP_HAS_CACHE bit; but a wrong comparison against swap_count(*swap_map),
which masks off the SWAP_HAS_CACHE bit, succeeded where it should fail.

That had the effect of resetting the mm from which to start searching
for the next swap page, to an irrelevant mm instead of to an mm in which
this swap page had been found: which may increase search time by ~20%.
But we're used to swapoff being slow, so never noticed the slowdown.

Remove that one spurious use of swap_count(): Bo Liu thought it merely
redundant, Hugh rewrote the description since it was measurably wrong.

Signed-off-by: Bo Liu <bo-liu@hotmail.com>
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-11-02 09:44:41 -08:00
David Howells 89a8640279 NOMMU: Don't pass NULL pointers to fput() in do_mmap_pgoff()
Don't pass NULL pointers to fput() in the error handling paths of the NOMMU
do_mmap_pgoff() as it can't handle it.

The following can be used as a test program:

	int main() { static long long a[1024 * 1024 * 20] = { 0 }; return a;}

Without the patch, the code oopses in atomic_long_dec_and_test() as called by
fput() after the kernel complains that it can't allocate that big a chunk of
memory.  With the patch, the kernel just complains about the allocation size
and then the program segfaults during execve() as execve() can't complete the
allocation of all the new ELF program segments.

Reported-by: Robin Getz <rgetz@blackfin.uclinux.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Robin Getz <rgetz@blackfin.uclinux.org>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-31 12:11:37 -07:00
Linus Torvalds 8633322c5f 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:
  sched: move rq_weight data array out of .percpu
  percpu: allow pcpu_alloc() to be called with IRQs off
2009-10-29 09:19:29 -07:00
Linus Torvalds 68e71d1902 Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block
* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  backing-dev: ensure that a removed bdi no longer has super_block referencing it
  block: use after free bug in __blkdev_get
  block: silently error unsupported empty barriers too
2009-10-29 09:17:19 -07:00
Linus Torvalds 0a53f1693c Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
  powerpc/ppc64: Use preempt_schedule_irq instead of preempt_schedule
  powerpc: Minor cleanup to lib/Kconfig.debug
  powerpc: Minor cleanup to sound/ppc/Kconfig
  powerpc: Minor cleanup to init/Kconfig
  powerpc: Limit memory hotplug support to PPC64 Book-3S machines
  powerpc: Limit hugetlbfs support to PPC64 Book-3S machines
  powerpc: Fix compile errors found by new ppc64e_defconfig
  powerpc: Add a Book-3E 64-bit defconfig
  powerpc/booke: Fix xmon single step on PowerPC Book-E
  powerpc: Align vDSO base address
  powerpc: Fix segment mapping in vdso32
  powerpc/iseries: Remove compiler version dependent hack
  powerpc/perf_events: Fix priority of MSR HV vs PR bits
  powerpc/5200: Update defconfigs
  drivers/serial/mpc52xx_uart.c: Use UPIO_MEM rather than SERIAL_IO_MEM
  powerpc/boot/dts: drop obsolete 'fsl5200-clocking'
  of: Remove nested function
  mpc5200: support for the MAN mpc5200 based board mucmc52
  mpc5200: support for the MAN mpc5200 based board uc101
2009-10-29 08:59:06 -07:00
Linus Torvalds 3242f9804b Merge branch 'hwpoison-2.6.32' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6
* 'hwpoison-2.6.32' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6:
  HWPOISON: fix invalid page count in printk output
  HWPOISON: Allow schedule_on_each_cpu() from keventd
  HWPOISON: fix/proc/meminfo alignment
  HWPOISON: fix oops on ksm pages
  HWPOISON: Fix page count leak in hwpoison late kill in do_swap_page
  HWPOISON: return early on non-LRU pages
  HWPOISON: Add brief hwpoison description to Documentation
  HWPOISON: Clean up PR_MCE_KILL interface
2009-10-29 08:20:00 -07:00
Daisuke Nishimura c36987e2ef mm: don't call pte_unmap() against an improper pte
There are some places where we do like:

	pte = pte_map();
	do {
		(do break in some conditions)
	} while (pte++, ...);
	pte_unmap(pte - 1);

But if the loop breaks at the first loop, pte_unmap() unmaps invalid pte.

This patch is a fix for this problem.

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reviewd-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-29 07:39:32 -07:00
Russell King 1a83e175dc mm: fix sparsemem configuration
Currently, sparsemem is only available if EXPERIMENTAL is enabled.
However, it hasn't ever been marked experimental.

It's been about four years since sparsemem was merged, and we have
platforms which depend on it; allow architectures to decide whether
sparsemem should be the default memory model.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-29 07:39:31 -07:00
Johannes Weiner 6a7b95481d vmscan: order evictable rescue in LRU putback
Isolators putting a page back to the LRU do not hold the page lock, and if
the page is mlocked, another thread might munlock it concurrently.

Expecting this, the putback code re-checks the evictability of a page when
it just moved it to the unevictable list in order to correct its decision.

The problem, however, is that ordering is not garuanteed between setting
PG_lru when moving the page to the list and checking PG_mlocked
afterwards:

	#0:				#1

	spin_lock()
					if (TestClearPageMlocked())
					  if (PageLRU())
					    move to evictable list
	SetPageLRU()
	spin_unlock()
	if (!PageMlocked())
	  move to evictable list

The PageMlocked() check may get reordered before SetPageLRU() in #0,
resulting in #0 not moving the still mlocked page, and in #1 failing to
isolate and move the page as well.  The page is now stranded on the
unevictable list.

The race condition is very unlikely.  The consequence currently is one
page falling off the reclaim grid and eventually getting freed with
PG_unevictable set, which triggers a warning in the page allocator.

TestClearPageMlocked() in #1 already provides full memory barrier
semantics.

This patch adds an explicit full barrier to force ordering between
SetPageLRU() and PageMlocked() so that either one of the competitors
rescues the page.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-29 07:39:30 -07:00
KOSAKI Motohiro b05ca7385a do_mbind(): fix memory leak
If migrate_prep is failed, new variable is leaked.  This patch fixes it.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-29 07:39:29 -07:00
KOSAKI Motohiro ab8a3e14e6 mbind(): fix leak of never putback pages
If mbind() receives an invalid address, do_mbind leaks a page.  The
following test program detects this leak.

This patch fixes it.

migrate_efault.c
=======================================
 #include <numaif.h>
 #include <numa.h>
 #include <sys/mman.h>
 #include <stdio.h>
 #include <unistd.h>
 #include <stdlib.h>
 #include <string.h>

static unsigned long pagesize;

static void* make_hole_mapping(void)
{

	void* addr;

	addr = mmap(NULL, pagesize*3, PROT_READ|PROT_WRITE,
		    MAP_ANON|MAP_PRIVATE, 0, 0);
	if (addr == MAP_FAILED)
		return NULL;

	/* make page populate */
	memset(addr, 0, pagesize*3);

	/* make memory hole */
	munmap(addr+pagesize, pagesize);

	return addr;
}

int main(int argc, char** argv)
{
	void* addr;
	int ch;
	int node;
	struct bitmask *nmask = numa_allocate_nodemask();
	int err;
	int node_set = 0;

	while ((ch = getopt(argc, argv, "n:")) != -1){
		switch (ch){
		case 'n':
			node = strtol(optarg, NULL, 0);
			numa_bitmask_setbit(nmask, node);
			node_set = 1;
			break;
		default:
			;
		}
	}
	argc -= optind;
	argv += optind;

	if (!node_set)
		numa_bitmask_setbit(nmask, 0);

	pagesize = getpagesize();

	addr = make_hole_mapping();

	err = mbind(addr, pagesize*3, MPOL_BIND, nmask->maskp, nmask->size, MPOL_MF_MOVE_ALL);
	if (err)
		perror("mbind ");

	return 0;
}
=======================================

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-29 07:39:29 -07:00
Wu Fengguang 41e20983fe vmscan: limit VM_EXEC protection to file pages
It is possible to have !Anon but SwapBacked pages, and some apps could
create huge number of such pages with MAP_SHARED|MAP_ANONYMOUS.  These
pages go into the ANON lru list, and hence shall not be protected: we only
care mapped executable files.  Failing to do so may trigger OOM.

Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-29 07:39:27 -07:00
Andrew Morton b76146ed1a revert "mm: oom analysis: add buffer cache information to show_free_areas()"
Revert

    commit 71de1ccbe1
    Author:     KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
    AuthorDate: Mon Sep 21 17:01:31 2009 -0700
    Commit:     Linus Torvalds <torvalds@linux-foundation.org>
    CommitDate: Tue Sep 22 07:17:27 2009 -0700

        mm: oom analysis: add buffer cache information to show_free_areas()

show_free_areas() is called during page allocation failures, and page
allocation failures can occur in any calling context.

But nr_blockdev_pages() takes VFS locks which should not be taken from
hard IRQ context (at least).  The result is lockdep warnings (and
deadlockability) during page allocation failures.

Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-29 07:39:27 -07:00
KOSAKI Motohiro 58355c7876 congestion_wait(): don't use WRITE
commit 8aa7e847d (Fix congestion_wait() sync/async vs read/write
confusion) replace WRITE with BLK_RW_ASYNC.  Unfortunately, concurrent mm
development made the unchanged place accidentally.

This patch fixes it too.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-29 07:39:25 -07:00
Hugh Dickins 92f7ba70ee hwpoison: fix oops on ksm pages
Memory failure on a KSM page currently oopses on its NULL anon_vma in
page_lock_anon_vma(): that may not be much worse than the consequence of
ignoring it, but it is better to be consistent with how ZERO_PAGE and
hugetlb pages and other awkward cases are treated.  Just skip it.

We could fix it for 2.6.32 at the KSM end, by putting a dummy anon_vma
pointer in there; but that would get harder next time, when KSM will put a
pointer to something else there (and I'm not currently planning to do any
work to open that up to memory_failure).  So I would prefer this simple
PageKsm test, until the other exceptions are handled.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-29 07:39:24 -07:00
Tejun Heo 1871e52c76 percpu: make percpu symbols under kernel/ and mm/ unique
This patch updates percpu related symbols under kernel/ and mm/ such
that percpu symbols are unique and don't clash with local symbols.
This serves two purposes of decreasing the possibility of global
percpu symbol collision and allowing dropping per_cpu__ prefix from
percpu symbols.

* kernel/lockdep.c: s/lock_stats/cpu_lock_stats/

* kernel/sched.c: s/init_rq_rt/init_rt_rq_var/	(any better idea?)
  		  s/sched_group_cpus/sched_groups/

* kernel/softirq.c: s/ksoftirqd/run_ksoftirqd/a

* kernel/softlockup.c: s/(*)_timestamp/softlockup_\1_ts/
  		       s/watchdog_task/softlockup_watchdog/
		       s/timestamp/ts/ for local variables

* kernel/time/timer_stats: s/lookup_lock/tstats_lookup_lock/

* mm/slab.c: s/reap_work/slab_reap_work/
  	     s/reap_node/slab_reap_node/

* mm/vmstat.c: local variable changed to avoid collision with vmstat_work

Partly based on Rusty Russell's "alloc_percpu: rename percpu vars
which cause name clashes" patch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: (slab/vmstat) Christoph Lameter <cl@linux-foundation.org>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>
2009-10-29 22:34:13 +09:00
Tejun Heo 0f5e4816db percpu: remove some sparse warnings
Make the following changes to remove some sparse warnings.

* Make DEFINE_PER_CPU_SECTION() declare __pcpu_unique_* before
  defining it.

* Annotate pcpu_extend_area_map() that it is entered with pcpu_lock
  held, releases it and then reacquires it.

* Make percpu related macros use unique nested variable names.

* While at it, add pcpu prefix to __size_call[_return]() macros as
  to-be-implemented sparse annotations will add percpu specific stuff
  to these macros.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
2009-10-29 22:34:12 +09:00
Tejun Heo 3f04ba8595 vmalloc: fix use of non-existent percpu variable in put_cpu_var()
vmalloc used non-existent percpu variable vmap_cpu_blocks instead of
the intended vmap_block_queue.  This went unnoticed because
put_cpu_var() didn't evaluate the parameter.  Fix it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Nick Piggin <npiggin@suse.de>
2009-10-29 22:34:12 +09:00
Jens Axboe 592b09a42f backing-dev: ensure that a removed bdi no longer has super_block referencing it
When the bdi is being removed, we have to ensure that no super_blocks
currently have that cached in sb->s_bdi. Normally this is ensured by
the sb having a longer life span than the bdi, but if the device is
suddenly yanked, we have to kill this reference. sb->s_bdi is pointed
to freed memory at that point.

This fixes a problem with sync(1) hanging when a USB stick is pulled
without cleanly umounting it first.

Reported-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-29 11:46:12 +01:00
Catalin Marinas 04609ccc40 kmemleak: Reduce the false positives by checking for modified objects
If an object was modified since it was previously suspected as leak, do
not report it. The modification check is done by calculating the
checksum (CRC32) of such object.

Several false positives are caused by objects being removed from linked
lists (e.g. allocation pools) and temporarily breaking the reference
chain since kmemleak runs concurrently with such list mutation
primitives.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2009-10-28 17:07:54 +00:00
Catalin Marinas fefdd336b2 kmemleak: Show the age of an unreferenced object
The jiffies shown for unreferenced objects isn't always meaningful to
people debugging kernel memory leaks. This patch adds the age as well to
the displayed information.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2009-10-28 17:07:54 +00:00
Catalin Marinas 0587da40be kmemleak: Release the object lock before calling put_object()
The put_object() function may free the object if the use_count
dropped to 0. There shouldn't be further accesses to such object unless
it is known that the use_count is non-zero.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2009-10-28 17:07:54 +00:00
Jiri Kosina 403a91b165 percpu: allow pcpu_alloc() to be called with IRQs off
pcpu_alloc() and pcpu_extend_area_map() perform a series of
spin_lock_irq()/spin_unlock_irq() calls, which make them unsafe
with respect to being called from contexts which have IRQs off.

This patch converts the code to perform save/restore of flags instead,
making pcpu_alloc() (or __alloc_percpu() respectively) to be called
from early kernel startup stage, where IRQs are off.

This is needed for proper initialization of per-cpu rq_weight data from
sched_init().

tj: added comment explaining why irqsave/restore is used in alloc path.

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Tejun Heo <tj@kernel.org>
2009-10-29 00:25:59 +09:00
Catalin Marinas c017b4be3e kmemleak: Simplify the kmemleak_scan_area() function prototype
This function was taking non-necessary arguments which can be determined
by kmemleak. The patch also modifies the calling sites.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
2009-10-28 15:11:00 +00:00
Catalin Marinas e7cb55b946 kmemleak: Do not use off-slab management with SLAB_NOLEAKTRACE
With the slab allocator, if off-slab management is enabled for the
kmem_caches used by kmemleak, it leads to recursive calls into
kmemleak_alloc(). Off-slab management can be triggered by other config
options increasing the slab size, e.g. DEBUG_PAGEALLOC.

Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2009-10-28 13:33:08 +00:00
Kumar Gala ed84a07a12 powerpc: Limit memory hotplug support to PPC64 Book-3S machines
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-27 16:42:41 +11:00
Mimi Zohar 6c21a7fb49 LSM: imbed ima calls in the security hooks
Based on discussions on LKML and LSM, where there are consecutive
security_ and ima_ calls in the vfs layer, move the ima_ calls to
the existing security_ hooks.

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2009-10-25 12:22:48 +08:00
Wu Fengguang 7456b0405d HWPOISON: fix invalid page count in printk output
The madvise injector already holds a reference when passing in a page
to the memory-failure code. The code corrects for this additional reference
for its checks, but the final printk output didn't. Fix that.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
2009-10-19 08:15:01 +02:00
Hugh Dickins 01e00f880c HWPOISON: fix oops on ksm pages
Memory failure on a KSM page currently oopses on its NULL anon_vma in
page_lock_anon_vma(): that may not be much worse than the consequence
of ignoring it, but it is better to be consistent with how ZERO_PAGE
and hugetlb pages and other awkward cases are treated.  Just skip it.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
2009-10-19 07:29:20 +02:00
Andi Kleen 4779cb31c0 HWPOISON: Fix page count leak in hwpoison late kill in do_swap_page
When returning due to a poisoned page drop the page count.

It wasn't a fatal problem because noone cares about the page count
on a poisoned page (except when it wraps), but it's cleaner to fix it.

Pointed out by Linus.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
2009-10-19 07:29:20 +02:00
Wu Fengguang e43c3afb36 HWPOISON: return early on non-LRU pages
Right now we have some trouble with non atomic access
to page flags when locking the page. To plug this hole
for now, limit error recovery to LRU pages for now.

This could be better fixed by defining a suitable protocol,
but let's go this simple way for now

This avoids unnecessary races with __set_page_locked() and
__SetPageSlab*() and maybe more non-atomic page flag operations.

This loses isolated pages which are currently in page reclaim, but these
are relatively limited compared to the total memory.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
[AK: new description, bug fixes, cleanups]
2009-10-19 07:28:24 +02:00
David Rientjes 78eb00cc57 slub: allow stats to be cleared
When collecting slub stats for particular workloads, it's necessary to
collect each statistic for all caches before the job is even started
because the counters are usually greater than zero just from boot and
initialization.

This allows a statistic to be cleared on each cpu by writing '0' to its
sysfs file.  This creates a baseline for statistics of interest before
the workload is started.

Setting a statistic to a particular value is not supported, so all values
written to these files other than '0' returns -EINVAL.

Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
2009-10-15 21:34:12 +03:00
Linus Torvalds 80f506918f Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block
* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  cciss: Add cciss_allow_hpsa module parameter
  cciss: Fix multiple calls to pci_release_regions
  blk-settings: fix function parameter kernel-doc notation
  writeback: kill space in debugfs item name
  writeback: account IO throttling wait as iowait
  elv_iosched_store(): fix strstrip() misuse
  cfq-iosched: avoid probable slice overrun when idling
  cfq-iosched: apply bool value where we return 0/1
  cfq-iosched: fix think time allowed for seekers
  cfq-iosched: fix the slice residual sign
  cfq-iosched: abstract out the 'may this cfqq dispatch' logic
  block: use proper BLK_RW_ASYNC in blk_queue_start_tag()
  block: Seperate read and write statistics of in_flight requests v2
  block: get rid of kblock_schedule_delayed_work()
  cfq-iosched: fix possible problem with jiffies wraparound
  cfq-iosched: fix issue with rq-rq merging and fifo list ordering
2009-10-13 10:21:33 -07:00
Linus Torvalds a3bafbbbb5 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 compile warnings
2009-10-13 10:21:12 -07:00
Tejun Heo b7a4c946d0 Merge branch 'for-linus' into for-next 2009-10-12 17:14:18 +09:00
Tejun Heo 1a0c3298d6 percpu: fix compile warnings
Fix the following two compile warnings which show up on i386.

mm/percpu.c:1873: warning: comparison of distinct pointer types lacks a cast
mm/percpu.c:1879: warning: format '%lx' expects type 'long unsigned int', but argument 2 has type 'size_t'

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Randy Dunlap <randy.dunlap@oracle.com>
2009-10-12 17:04:42 +09:00
Alexey Dobriyan d43c36dc6b headers: remove sched.h from interrupt.h
After m68k's task_thread_info() doesn't refer to current,
it's possible to remove sched.h from interrupt.h and not break m68k!
Many thanks to Heiko Carstens for allowing this.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
2009-10-11 11:20:58 -07:00
Catalin Marinas 0d5d1aadc8 kmemleak: Check for NULL pointer returned by create_object()
This patch adds NULL pointer checking in the early_alloc() function.

Reported-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-09 13:28:47 -07:00
Tetsuo Handa c1bcd6b327 kmemleak: Use GFP_ATOMIC for early_alloc().
We can't use GFP_KERNEL inside rcu_read_lock().

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-09 13:28:47 -07:00
Wu Fengguang 961515f613 writeback: kill space in debugfs item name
The space is not script friendly, kill it.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-09 13:01:27 +02:00
Wu Fengguang d25105e891 writeback: account IO throttling wait as iowait
It makes sense to do IOWAIT when someone is blocked
due to IO throttle, as suggested by Kame and Peter.

There is an old comment for not doing IOWAIT on throttle,
however it has been mismatching the code for a long time.

If we stop accounting IOWAIT for 2.6.32, it could be an
undesirable behavior change. So restore the io_schedule.

CC: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-09 12:40:42 +02:00
Linus Torvalds b924f9599d Merge branch 'sparc-perf-events-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'sparc-perf-events-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  mm, perf_event: Make vmalloc_user() align base kernel virtual address to SHMLBA
  perf_event: Provide vmalloc() based mmap() backing
2009-10-08 12:05:50 -07:00
David Miller 2dca6999ee mm, perf_event: Make vmalloc_user() align base kernel virtual address to SHMLBA
When a vmalloc'd area is mmap'd into userspace, some kind of
co-ordination is necessary for this to work on platforms with cpu
D-caches which can have aliases.

Otherwise kernel side writes won't be seen properly in userspace
and vice versa.

If the kernel side mapping and the user side one have the same
alignment, modulo SHMLBA, this can work as long as VM_SHARED is
shared of VMA and for all current users this is true.  VM_SHARED
will force SHMLBA alignment of the user side mmap on platforms with
D-cache aliasing matters.

The bulk of this patch is just making it so that a specific
alignment can be passed down into __get_vm_area_node().  All
existing callers pass in '1' which preserves existing behavior.
vmalloc_user() gives SHMLBA for the alignment.

As a side effect this should get the video media drivers and other
vmalloc_user() users into more working shape on such systems.

Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <200909211922.n8LJMYjw029425@imap1.linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-10-08 17:02:31 +02:00
Jaswinder Singh Rajput 3700c155af mm: includecheck fix: vmalloc.c
fix the following 'make includecheck' warning:

  mm/vmalloc.c: linux/highmem.h is included more than once.

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-08 07:36:38 -07:00
Hugh Dickins c73602ad31 ksm: more on default values
Adjust the max_kernel_pages default to a quarter of totalram_pages,
instead of nr_free_buffer_pages() / 4: the KSM pages themselves come from
highmem, and even on a 16GB PAE machine, 4GB of KSM pages would only be
pinning 32MB of lowmem with their rmap_items, so no need for the more
obscure calculation (nor for its own special init function).

There is no way for the user to switch KSM on if CONFIG_SYSFS is not
enabled, so in that case default run to KSM_RUN_MERGE.

Update KSM Documentation and Kconfig to reflect the new defaults.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-08 07:36:38 -07:00
Linus Torvalds 58e57fbd1c Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block
* 'for-linus' of git://git.kernel.dk/linux-2.6-block: (41 commits)
  Revert "Seperate read and write statistics of in_flight requests"
  cfq-iosched: don't delay async queue if it hasn't dispatched at all
  block: Topology ioctls
  cfq-iosched: use assigned slice sync value, not default
  cfq-iosched: rename 'desktop' sysfs entry to 'low_latency'
  cfq-iosched: implement slower async initiate and queue ramp up
  cfq-iosched: delay async IO dispatch, if sync IO was just done
  cfq-iosched: add a knob for desktop interactiveness
  Add a tracepoint for block request remapping
  block: allow large discard requests
  block: use normal I/O path for discard requests
  swapfile: avoid NULL pointer dereference in swapon when s_bdev is NULL
  fs/bio.c: move EXPORT* macros to line after function
  Add missing blk_trace_remove_sysfs to be in pair with blk_trace_init_sysfs
  cciss: fix build when !PROC_FS
  block: Do not clamp max_hw_sectors for stacking devices
  block: Set max_sectors correctly for stacking devices
  cciss: cciss_host_attr_groups should be const
  cciss: Dynamically allocate the drive_info_struct for each logical drive.
  cciss: Add usage_count attribute to each logical drive in /sys
  ...
2009-10-04 12:39:14 -07:00
Tejun Heo 23fb064bb9 percpu: kill legacy percpu allocator
With ia64 converted, there's no arch left which still uses legacy
percpu allocator.  Kill it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Delightedly-acked-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
2009-10-02 13:29:29 +09:00
KAMEZAWA Hiroyuki ef8745c1e7 memcg: reduce check for softlimit excess
In charge/uncharge/reclaim path, usage_in_excess is calculated repeatedly
and it takes res_counter's spin_lock every time.

This patch removes unnecessary calls for res_count_soft_limit_excess.

Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-01 16:11:13 -07:00
KAMEZAWA Hiroyuki 4e649152cb memcg: some modification to softlimit under hierarchical memory reclaim.
This patch clean up/fixes for memcg's uncharge soft limit path.

Problems:
  Now, res_counter_charge()/uncharge() handles softlimit information at
  charge/uncharge and softlimit-check is done when event counter per memcg
  goes over limit. Now, event counter per memcg is updated only when
  memory usage is over soft limit. Here, considering hierarchical memcg
  management, ancesotors should be taken care of.

  Now, ancerstors(hierarchy) are handled in charge() but not in uncharge().
  This is not good.

  Prolems:
  1. memcg's event counter incremented only when softlimit hits. That's bad.
     It makes event counter hard to be reused for other purpose.

  2. At uncharge, only the lowest level rescounter is handled. This is bug.
     Because ancesotor's event counter is not incremented, children should
     take care of them.

  3. res_counter_uncharge()'s 3rd argument is NULL in most case.
     ops under res_counter->lock should be small. No "if" sentense is better.

Fixes:
  * Removed soft_limit_xx poitner and checks in charge and uncharge.
    Do-check-only-when-necessary scheme works enough well without them.

  * make event-counter of memcg incremented at every charge/uncharge.
    (per-cpu area will be accessed soon anyway)

  * All ancestors are checked at soft-limit-check. This is necessary because
    ancesotor's event counter may never be modified. Then, they should be
    checked at the same time.

Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-01 16:11:13 -07:00
KAMEZAWA Hiroyuki 26251eaf98 memcg: fix refcnt going negative
__mem_cgroup_largest_soft_limit_node() returns a mem_cgroup_per_zone "mz"
with incremnted mz->mem->css's refcnt.  Then, the caller of this function
has to call css_put(mz->mem->css).

But, mz can be !NULL even if "not found" i.e.  without css_get().  By
this, css->refcnt will go down to minus.

This may cause various things...one of results will be
initite-loop in css_tryget()  as this.

INFO: RCU detected CPU 0 stall (t=10000 jiffies)
sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU 0:
<snip>

 <<EOE>>  <IRQ>  [<ffffffff810884bd>] trace_hardirqs_off+0xd/0x10
  [<ffffffff8102a940>] flat_send_IPI_mask+0x90/0xb0
  [<ffffffff8102a9c9>] flat_send_IPI_all+0x69/0x70
  [<ffffffff81027372>] arch_trigger_all_cpu_backtrace+0x62/0xa0
  [<ffffffff810bff8e>] __rcu_pending+0x7e/0x370
  [<ffffffff810c02c7>] rcu_check_callbacks+0x47/0x130
  [<ffffffff81063a26>] update_process_times+0x46/0x70
  [<ffffffff81085930>] tick_sched_timer+0x60/0x160
  [<ffffffff810858d0>] ? tick_sched_timer+0x0/0x160
  [<ffffffff8107a03a>] __run_hrtimer+0xba/0x150
  [<ffffffff8107a325>] hrtimer_interrupt+0xd5/0x1b0
  [<ffffffff81426dfe>] ? trace_hardirqs_off_thunk+0x3a/0x3c
  [<ffffffff8142cacd>] smp_apic_timer_interrupt+0x6d/0x9b
  [<ffffffff8100cb33>] apic_timer_interrupt+0x13/0x20
  <EOI>  [<ffffffff811317b6>] ? mem_cgroup_walk_tree+0x156/0x180
  [<ffffffff811316d3>] ? mem_cgroup_walk_tree+0x73/0x180
  [<ffffffff81131692>] ? mem_cgroup_walk_tree+0x32/0x180
  [<ffffffff81131a00>] ? mem_cgroup_get_local_stat+0x0/0x110
  [<ffffffff81131d5b>] ? mem_control_stat_show+0x14b/0x330
  [<ffffffff810a57fd>] ? cgroup_seqfile_show+0x3d/0x60

Above shows CPU0 caught in css_tryget()'s inifinite loop because
of bad refcnt.

This is a fix to set mz=NULL at the top of retry path.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.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>
2009-10-01 16:11:12 -07:00
Huang Shijie bf89c8c867 mm/rmap.c: fix comment
The page_address_in_vma() is not only used in unuse_vma().

Signed-off-by: Huang Shijie <shijie8@gmail.com>
Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-01 16:11:12 -07:00
Suresh Jayaraman 3bd0f0c763 swapfile: avoid NULL pointer dereference in swapon when s_bdev is NULL
While testing Swap over NFS patchset, I noticed an oops that was triggered
during swapon. Investigating further, the NULL pointer deference is due to the
SSD device check/optimization in the swapon code that assumes s_bdev could never
be NULL.

inode->i_sb->s_bdev could be NULL in a few cases. For e.g. one such case is
loopback NFS mount, there could be others as well. Fix this by ensuring s_bdev
is not NULL before we try to deference s_bdev.

Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-01 21:15:46 +02:00
Tejun Heo f2badb0c95 percpu: make allocation failures more verbose
Warn and dump stack when percpu allocation fails.  percpu allocator is
still young and unchecked NULL percpu pointer usage can result in
random memory corruption when combined with the pointer shifting in
access macros.  Allocation failures should be rare and the warning
message will be disabled after certain times.

Signed-off-by: Tejun Heo <tj@kernel.org>
2009-09-29 09:17:58 +09:00
Tejun Heo 635b75fc18 percpu: make pcpu_setup_first_chunk() failures more verbose
The parameters to pcpu_setup_first_chunk() come from different sources
depending on architecture and can be quite complex.  The function runs
various sanity checks on the parameters and triggers BUG() if
something isn't right.  However, this is very early during the boot
and not reporting exactly what the problem is makes debugging even
harder.

Add PCPU_SETUP_BUG() macro which prints out enough information about
the parameters.  As the macro still puts separate BUG() for each
check, it won't lose any information even on the situations where only
the program counter can be retrieved.

While at it, also bump pcpu_dump_alloc_info() message to KERN_INFO so
that it's visible on the console if boot fails to complete.

Signed-off-by: Tejun Heo <tj@kernel.org>
2009-09-29 09:17:57 +09:00
Tejun Heo 6ea529a203 percpu: make embedding first chunk allocator check vmalloc space size
Embedding first chunk allocator maintains the distances between units
in the vmalloc area and thus needs vmalloc space to be larger than the
maximum distances between units; otherwise, it wouldn't be able to
create any dynamic chunks.  This patch makes the embedding first chunk
allocator check vmalloc space size and if the maximum distance between
units is larger than 75% of it, print warning and, if page mapping
allocator is available, fail initialization so that the system falls
back onto it.

This should work around percpu allocation failure problems on certain
sparc64 configurations where distances between NUMA nodes are larger
than the vmalloc area and makes percpu allocator more robust for
future configurations.

Signed-off-by: Tejun Heo <tj@kernel.org>
2009-09-29 09:17:57 +09:00
Tejun Heo fb59e72e7e percpu: make pcpu_build_alloc_info() clear static buffers
pcpu_build_alloc_info() may be called multiple times when percpu is
falling back to different first chunk allocator.  Make it clear static
buffers so that they don't contain values from previous runs.

Signed-off-by: Tejun Heo <tj@kernel.org>
2009-09-29 09:17:57 +09:00
Tejun Heo ffe0d5a575 percpu: fix unit_map[] verification in pcpu_setup_first_chunk()
pcpu_setup_first_chunk() incorrectly used NR_CPUS as the impossible
unit number while unit number can equal and go over NR_CPUS with
sparse unit map.  This triggers BUG_ON() spuriously on machines which
have non-power-of-two number of cpus.  Use UINT_MAX instead.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-and-tested-by: Tony Vroon <tony@linx.net>
2009-09-29 09:17:56 +09:00
Alexey Dobriyan f0f37e2f77 const: mark struct vm_struct_operations
* mark struct vm_area_struct::vm_ops as const
* mark vm_ops in AGP code

But leave TTM code alone, something is fishy there with global vm_ops
being used.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-27 11:39:25 -07:00
Linus Torvalds d949f36f18 x86: Fix hwpoison code related build failure on 32-bit NUMAQ
This build failure triggers:

 In file included from include/linux/suspend.h:8,
                 from arch/x86/kernel/asm-offsets_32.c:11,
                 from arch/x86/kernel/asm-offsets.c:2:
 include/linux/mm.h:503:2: error: #error SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS

Because due to the hwpoison page flag we ran out of page
flags on 32-bit.

Dont turn on hwpoison on 32-bit NUMA (it's rare in any
case).

Also clean up the Kconfig dependencies in the generic MM
code by introducing ARCH_SUPPORTS_MEMORY_FAILURE.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-27 09:55:11 +02:00
Jens Axboe a72bfd4dea writeback: pass in super_block to bdi_start_writeback()
Sometimes we only want to write pages from a specific super_block,
so allow that to be passed in.

This fixes a problem with commit 56a131dcf7
causing writeback on all super_blocks on a bdi, where we only really
want to sync a specific sb from writeback_inodes_sb().

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-26 00:10:40 +02:00
Linus Torvalds 6d7f18f6ea Merge branch 'writeback' of git://git.kernel.dk/linux-2.6-block
* 'writeback' of git://git.kernel.dk/linux-2.6-block:
  writeback: writeback_inodes_sb() should use bdi_start_writeback()
  writeback: don't delay inodes redirtied by a fast dirtier
  writeback: make the super_block pinning more efficient
  writeback: don't resort for a single super_block in move_expired_inodes()
  writeback: move inodes from one super_block together
  writeback: get rid to incorrect references to pdflush in comments
  writeback: improve readability of the wb_writeback() continue/break logic
  writeback: cleanup writeback_single_inode()
  writeback: kupdate writeback shall not stop when more io is possible
  writeback: stop background writeback when below background threshold
  writeback: balance_dirty_pages() shall write more than dirtied pages
  fs: Fix busyloop in wb_writeback()
2009-09-25 09:27:30 -07:00
Jens Axboe 5b0830cb90 writeback: get rid to incorrect references to pdflush in comments
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-25 18:08:25 +02:00
Wu Fengguang d3ddec7635 writeback: stop background writeback when below background threshold
Treat bdi_start_writeback(0) as a special request to do background write,
and stop such work when we are below the background dirty threshold.

Also simplify the (nr_pages <= 0) checks. Since we already pass in
nr_pages=LONG_MAX for WB_SYNC_ALL and background writes, we don't
need to worry about it being decreased to zero.

Reported-by: Richard Kennedy <richard@rsk.demon.co.uk>
CC: Jan Kara <jack@suse.cz>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-25 18:08:24 +02:00
Wu Fengguang 3a2e9a5a2a writeback: balance_dirty_pages() shall write more than dirtied pages
Some filesystem may choose to write much more than ratelimit_pages
before calling balance_dirty_pages_ratelimited_nr(). So it is safer to
determine number to write based on real number of dirtied pages.

Otherwise it is possible that
  loop {
    btrfs_file_write():     dirty 1024 pages
    balance_dirty_pages():  write up to 48 pages (= ratelimit_pages * 1.5)
  }
in which the writeback rate cannot keep up with dirty rate, and the
dirty pages go all the way beyond dirty_thresh.

The increased write_chunk may make the dirtier more bumpy.
So filesystems shall be take care not to dirty too much at
a time (eg. > 4MB) without checking the ratelimit.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-25 18:08:24 +02:00
David Howells 06aab5a308 NOMMU: Ignore mmap() address param as it is a hint
Ignore the address parameter given to NOMMU mmap() as it is a hint, rather
than giving an error if it's non-zero.  MAP_FIXED still gets an error.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-24 17:20:29 -07:00
David Howells 645d83c5db NOMMU: Fix MAP_PRIVATE mmap() of objects where the data can be mapped directly
Fix MAP_PRIVATE mmap() of files and devices where the data in the backing store
might be mapped directly.  Use the BDI_CAP_MAP_DIRECT capability flag to govern
whether or not we should be trying to map a file directly.  This can be used to
determine whether or not a region has been filled in at the point where we call
do_mmap_shared() or do_mmap_private().

The BDI_CAP_MAP_DIRECT capability flag is cleared by validate_mmap_request() if
there's any reason we can't use it.  It's also cleared in do_mmap_pgoff() if
f_op->get_unmapped_area() fails.

Without this fix, attempting to run a program from a RomFS image on a
non-mappable MTD partition results in a BUG as the kernel attempts XIP, and
this can be caught in gdb:

Program received signal SIGABRT, Aborted.
0xc005dce8 in add_nommu_region (region=<value optimized out>) at mm/nommu.c:547
(gdb) bt
#0  0xc005dce8 in add_nommu_region (region=<value optimized out>) at mm/nommu.c:547
#1  0xc005f168 in do_mmap_pgoff (file=0xc31a6620, addr=<value optimized out>, len=3808, prot=3, flags=6146, pgoff=0) at mm/nommu.c:1373
#2  0xc00a96b8 in elf_fdpic_map_file (params=0xc33fbbec, file=0xc31a6620, mm=0xc31bef60, what=0xc0213144 "executable") at mm.h:1145
#3  0xc00aa8b4 in load_elf_fdpic_binary (bprm=0xc316cb00, regs=<value optimized out>) at fs/binfmt_elf_fdpic.c:343
#4  0xc006b588 in search_binary_handler (bprm=0x6, regs=0xc33fbce0) at fs/exec.c:1234
#5  0xc006c648 in do_execve (filename=<value optimized out>, argv=0xc3ad14cc, envp=0xc3ad1460, regs=0xc33fbce0) at fs/exec.c:1356
#6  0xc0008cf0 in sys_execve (name=<value optimized out>, argv=0xc3ad14cc, envp=0xc3ad1460) at arch/frv/kernel/process.c:263
#7  0xc00075dc in __syscall_call () at arch/frv/kernel/entry.S:897

Note that this fix does the following commit differently:

	commit a190887b58
	Author: David Howells <dhowells@redhat.com>
	Date:   Sat Sep 5 11:17:07 2009 -0700
	nommu: fix error handling in do_mmap_pgoff()

Reported-by: Graff Yang <graff.yang@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-24 17:18:38 -07:00
Andrew Morton c44972f178 procfs: disable per-task stack usage on NOMMU
It needs walk_page_range().

Reported-by: Michal Simek <monstr@monstr.eu>
Tested-by: Michal Simek <monstr@monstr.eu>
Cc: Stefani Seibold <stefani@seibold.net>
Cc: David Howells <dhowells@redhat.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-24 17:11:24 -07:00
Linus Torvalds 6c5daf012c 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:
  truncate: use new helpers
  truncate: new helpers
  fs: fix overflow in sys_mount() for in-kernel calls
  fs: Make unload_nls() NULL pointer safe
  freeze_bdev: grab active reference to frozen superblocks
  freeze_bdev: kill bd_mount_sem
  exofs: remove BKL from super operations
  fs/romfs: correct error-handling code
  vfs: seq_file: add helpers for data filling
  vfs: remove redundant position check in do_sendfile
  vfs: change sb->s_maxbytes to a loff_t
  vfs: explicitly cast s_maxbytes in fiemap_check_ranges
  libfs: return error code on failed attr set
  seq_file: return a negative error code when seq_path_root() fails.
  vfs: optimize touch_time() too
  vfs: optimization for touch_atime()
  vfs: split generic_forget_inode() so that hugetlbfs does not have to copy it
  fs/inode.c: add dev-id and inode number for debugging in init_special_inode()
  libfs: make simple_read_from_buffer conventional
2009-09-24 08:32:11 -07:00
Linus Torvalds db16826367 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: (21 commits)
  HWPOISON: Enable error_remove_page on btrfs
  HWPOISON: Add simple debugfs interface to inject hwpoison on arbitary PFNs
  HWPOISON: Add madvise() based injector for hardware poisoned pages v4
  HWPOISON: Enable error_remove_page for NFS
  HWPOISON: Enable .remove_error_page for migration aware file systems
  HWPOISON: The high level memory error handler in the VM v7
  HWPOISON: Add PR_MCE_KILL prctl to control early kill behaviour per process
  HWPOISON: shmem: call set_page_dirty() with locked page
  HWPOISON: Define a new error_remove_page address space op for async truncation
  HWPOISON: Add invalidate_inode_page
  HWPOISON: Refactor truncate to allow direct truncating of page v2
  HWPOISON: check and isolate corrupted free pages v2
  HWPOISON: Handle hardware poisoned pages in try_to_unmap
  HWPOISON: Use bitmask/action code for try_to_unmap behaviour
  HWPOISON: x86: Add VM_FAULT_HWPOISON handling to x86 page fault handler v2
  HWPOISON: Add poison check to page fault handling
  HWPOISON: Add basic support for poisoned pages in fault handler v3
  HWPOISON: Add new SIGBUS error codes for hardware poison signals
  HWPOISON: Add support for poison swap entries v2
  HWPOISON: Export some rmap vma locking to outside world
  ...
2009-09-24 07:53:22 -07:00
Alexey Dobriyan 8d65af789f sysctl: remove "struct file *" argument of ->proc_handler
It's unused.

It isn't needed -- read or write flag is already passed and sysctl
shouldn't care about the rest.

It _was_ used in two places at arch/frv for some reason.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-24 07:21:04 -07:00
Daisuke Nishimura 1dd3a27326 memcg: show swap usage in stat file
We now count MEM_CGROUP_STAT_SWAPOUT, so we can show swap usage.  It would
be useful for users to show swap usage in memory.stat file, because they
don't need calculate memsw.usage - res.usage to know swap usage.

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-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>
2009-09-24 07:20:59 -07:00
Balbir Singh 0c3e73e84f memcg: improve resource counter scalability
Reduce the resource counter overhead (mostly spinlock) associated with the
root cgroup.  This is a part of the several patches to reduce mem cgroup
overhead.  I had posted other approaches earlier (including using percpu
counters).  Those patches will be a natural addition and will be added
iteratively on top of these.

The patch stops resource counter accounting for the root cgroup.  The data
for display is derived from the statisitcs we maintain via
mem_cgroup_charge_statistics (which is more scalable).  What happens today
is that, we do double accounting, once using res_counter_charge() and once
using memory_cgroup_charge_statistics().  For the root, since we don't
implement limits any more, we don't need to track every charge via
res_counter_charge() and check for limit being exceeded and reclaim.

The main mem->res usage_in_bytes can be derived by summing the cache and
rss usage data from memory statistics (MEM_CGROUP_STAT_RSS and
MEM_CGROUP_STAT_CACHE).  However, for memsw->res usage_in_bytes, we need
additional data about swapped out memory.  This patch adds a
MEM_CGROUP_STAT_SWAPOUT and uses that along with MEM_CGROUP_STAT_RSS and
MEM_CGROUP_STAT_CACHE to derive the memsw data.  This data is computed
recursively when hierarchy is enabled.

The tests results I see on a 24 way show that

1. The lock contention disappears from /proc/lock_stats
2. The results of the test are comparable to running with
   cgroup_disable=memory.

Here is a sample of my program runs

Without Patch

 Performance counter stats for '/home/balbir/parallel_pagefault':

 7192804.124144  task-clock-msecs         #     23.937 CPUs
         424691  context-switches         #      0.000 M/sec
            267  CPU-migrations           #      0.000 M/sec
       28498113  page-faults              #      0.004 M/sec
  5826093739340  cycles                   #    809.989 M/sec
   408883496292  instructions             #      0.070 IPC
     7057079452  cache-references         #      0.981 M/sec
     3036086243  cache-misses             #      0.422 M/sec

  300.485365680  seconds time elapsed

With cgroup_disable=memory

 Performance counter stats for '/home/balbir/parallel_pagefault':

 7182183.546587  task-clock-msecs         #     23.915 CPUs
         425458  context-switches         #      0.000 M/sec
            203  CPU-migrations           #      0.000 M/sec
       92545093  page-faults              #      0.013 M/sec
  6034363609986  cycles                   #    840.185 M/sec
   437204346785  instructions             #      0.072 IPC
     6636073192  cache-references         #      0.924 M/sec
     2358117732  cache-misses             #      0.328 M/sec

  300.320905827  seconds time elapsed

With this patch applied

 Performance counter stats for '/home/balbir/parallel_pagefault':

 7191619.223977  task-clock-msecs         #     23.955 CPUs
         422579  context-switches         #      0.000 M/sec
             88  CPU-migrations           #      0.000 M/sec
       91946060  page-faults              #      0.013 M/sec
  5957054385619  cycles                   #    828.333 M/sec
  1058117350365  instructions             #      0.178 IPC
     9161776218  cache-references         #      1.274 M/sec
     1920494280  cache-misses             #      0.267 M/sec

  300.218764862  seconds time elapsed

Data from Prarit (kernel compile with make -j64 on a 64
CPU/32G machine)

For a single run

Without patch

real 27m8.988s
user 87m24.916s
sys 382m6.037s

With patch

real    4m18.607s
user    84m58.943s
sys     50m52.682s

With config turned off

real    4m54.972s
user    90m13.456s
sys     50m19.711s

NOTE: The data looks counterintuitive due to the increased performance
with the patch, even over the config being turned off. We probably need
more runs, but so far all testing has shown that the patches definitely
help.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
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>
2009-09-24 07:20:59 -07:00
Balbir Singh 4e41695356 memory controller: soft limit reclaim on contention
Implement reclaim from groups over their soft limit

Permit reclaim from memory cgroups on contention (via the direct reclaim
path).

memory cgroup soft limit reclaim finds the group that exceeds its soft
limit by the largest number of pages and reclaims pages from it and then
reinserts the cgroup into its correct place in the rbtree.

Add additional checks to mem_cgroup_hierarchical_reclaim() to detect long
loops in case all swap is turned off.  The code has been refactored and
the loop check (loop < 2) has been enhanced for soft limits.  For soft
limits, we try to do more targetted reclaim.  Instead of bailing out after
two loops, the routine now reclaims memory proportional to the size by
which the soft limit is exceeded.  The proportion has been empirically
determined.

[akpm@linux-foundation.org: build fix]
[kamezawa.hiroyu@jp.fujitsu.com: fix softlimit css refcnt handling]
[nishimura@mxp.nes.nec.co.jp: refcount of the "victim" should be decremented before exiting the loop]
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-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>
2009-09-24 07:20:59 -07:00
Balbir Singh 75822b4495 memory controller: soft limit refactor reclaim flags
Refactor mem_cgroup_hierarchical_reclaim()

Refactor the arguments passed to mem_cgroup_hierarchical_reclaim() into
flags, so that new parameters don't have to be passed as we make the
reclaim routine more flexible

Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.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>
2009-09-24 07:20:59 -07:00
Balbir Singh f64c3f5494 memory controller: soft limit organize cgroups
Organize cgroups over soft limit in a RB-Tree

Introduce an RB-Tree for storing memory cgroups that are over their soft
limit.  The overall goal is to

1. Add a memory cgroup to the RB-Tree when the soft limit is exceeded.
   We are careful about updates, updates take place only after a particular
   time interval has passed
2. We remove the node from the RB-Tree when the usage goes below the soft
   limit

The next set of patches will exploit the RB-Tree to get the group that is
over its soft limit by the largest amount and reclaim from it, when we
face memory contention.

[hugh.dickins@tiscali.co.uk: CONFIG_CGROUP_MEM_RES_CTLR=y CONFIG_PREEMPT=y fails to boot]
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-24 07:20:59 -07:00
Balbir Singh 296c81d89f memory controller: soft limit interface
Add an interface to allow get/set of soft limits.  Soft limits for memory
plus swap controller (memsw) is currently not supported.  Resource
counters have been enhanced to support soft limits and new type
RES_SOFT_LIMIT has been added.  Unlike hard limits, soft limits can be
directly set and do not need any reclaim or checks before setting them to
a newer value.

Kamezawa-San raised a question as to whether soft limit should belong to
res_counter.  Since all resources understand the basic concepts of hard
and soft limits, it is justified to add soft limits here.  Soft limits are
a generic resource usage feature, even file system quotas support soft
limits.

Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.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>
2009-09-24 07:20:59 -07:00
KAMEZAWA Hiroyuki 261fb61a8b memcg: add comments explaining memory barriers
Add comments for the reason of smp_wmb() in mem_cgroup_commit_charge().

[akpm@linux-foundation.org: coding-style fixes]
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: 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>
2009-09-24 07:20:58 -07:00
Balbir Singh 4b3bde4c98 memcg: remove the overhead associated with the root cgroup
Change the memory cgroup to remove the overhead associated with accounting
all pages in the root cgroup.  As a side-effect, we can no longer set a
memory hard limit in the root cgroup.

A new flag to track whether the page has been accounted or not has been
added as well.  Flags are now set atomically for page_cgroup,
pcg_default_flags is now obsolete and removed.

[akpm@linux-foundation.org: fix a few documentation glitches]
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-24 07:20:58 -07:00
Ben Blum be367d0992 cgroups: let ss->can_attach and ss->attach do whole threadgroups at a time
Alter the ss->can_attach and ss->attach functions to be able to deal with
a whole threadgroup at a time, for use in cgroup_attach_proc.  (This is a
pre-patch to cgroup-procs-writable.patch.)

Currently, new mode of the attach function can only tell the subsystem
about the old cgroup of the threadgroup leader.  No subsystem currently
needs that information for each thread that's being moved, but if one were
to be added (for example, one that counts tasks within a group) this bit
would need to be reworked a bit to tell the subsystem the right
information.

[hidave.darkstar@gmail.com: fix build]
Signed-off-by: Ben Blum <bblum@google.com>
Signed-off-by: Paul Menage <menage@google.com>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Reviewed-by: Matt Helsley <matthltc@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Dave Young <hidave.darkstar@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-24 07:20:58 -07:00
Izik Eidus 2c6854fdad ksm: change default values to better fit into mainline kernel
Now that ksm is in mainline it is better to change the default values to
better fit to most of the users.

This patch change the ksm default values to be:

	ksm_thread_pages_to_scan = 100 (instead of 200)
	ksm_thread_sleep_millisecs = 20 (like before)
	ksm_run = KSM_RUN_STOP (instead of KSM_RUN_MERGE - meaning ksm is
	                        disabled by default)
	ksm_max_kernel_pages = nr_free_buffer_pages / 4 (instead of 2046)

The important aspect of this patch is: it disables ksm by default, and sets
the number of the kernel_pages that can be allocated to be a reasonable
number.

Signed-off-by: Izik Eidus <ieidus@redhat.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-24 07:20:56 -07:00
npiggin@suse.de 25d9e2d152 truncate: new helpers
Introduce new truncate helpers truncate_pagecache and inode_newsize_ok.
vmtruncate is also consolidated from mm/memory.c and mm/nommu.c and
into mm/truncate.c.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-09-24 08:41:47 -04:00
Rusty Russell db79078658 cpumask: use new-style cpumask ops in mm/quicklist.
This slipped past the previous sweeps.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
2009-09-24 09:34:52 +09:30
Hugh Dickins 4266c97a3e nommu: fix two build breakages
My 58fa879e1e "mm: FOLL flags for GUP flags"
broke CONFIG_NOMMU build by forgetting to update nommu.c foll_flags type:

  mm/nommu.c:171: error: conflicting types for `__get_user_pages'
  mm/internal.h:254: error: previous declaration of `__get_user_pages' was here
  make[1]: *** [mm/nommu.o] Error 1

My 03f6462a3a "mm: move highest_memmap_pfn"
broke CONFIG_NOMMU build by forgetting to add a nommu.c highest_memmap_pfn:

  mm/built-in.o: In function `memmap_init_zone':
  (.meminit.text+0x326): undefined reference to `highest_memmap_pfn'
  mm/built-in.o: In function `memmap_init_zone':
  (.meminit.text+0x32d): undefined reference to `highest_memmap_pfn'

Fix both breakages, and give myself 30 lashes (ouch!)

Reported-by: Michal Simek <michal.simek@petalogix.com>
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-23 09:22:10 -07:00
KAMEZAWA Hiroyuki 81ac3ad906 kcore: register module area in generic way
Some archs define MODULED_VADDR/MODULES_END which is not in VMALLOC area.
This is handled only in x86-64.  This patch make it more generic.  And we
can use vread/vwrite to access the area.  Fix it.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Jiri Slaby <jirislaby@gmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-23 07:39:42 -07:00
KAMEZAWA Hiroyuki 908eedc616 walk system ram range
Originally, walk_memory_resource() was introduced to traverse all memory
of "System RAM" for detecting memory hotplug/unplug range.  For doing so,
flags of IORESOUCE_MEM|IORESOURCE_BUSY was used and this was enough for
memory hotplug.

But for using other purpose, /proc/kcore, this may includes some firmware
area marked as IORESOURCE_BUSY | IORESOUCE_MEM.  This patch makes the
check strict to find out busy "System RAM".

Note: PPC64 keeps their own walk_memory_resouce(), which walk through
ppc64's lmb informaton.  Because old kclist_add() is called per lmb, this
patch makes no difference in behavior, finally.

And this patch removes CONFIG_MEMORY_HOTPLUG check from this function.
Because pfn_valid() just show "there is memmap or not* and cannot be used
for "there is physical memory or not", this function is useful in generic
to scan physical memory range.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Américo Wang <xiyou.wangcong@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-23 07:39:41 -07:00
Stefani Seibold d899bf7b55 procfs: provide stack information for threads
A patch to give a better overview of the userland application stack usage,
especially for embedded linux.

Currently you are only able to dump the main process/thread stack usage
which is showed in /proc/pid/status by the "VmStk" Value.  But you get no
information about the consumed stack memory of the the threads.

There is an enhancement in the /proc/<pid>/{task/*,}/*maps and which marks
the vm mapping where the thread stack pointer reside with "[thread stack
xxxxxxxx]".  xxxxxxxx is the maximum size of stack.  This is a value
information, because libpthread doesn't set the start of the stack to the
top of the mapped area, depending of the pthread usage.

A sample output of /proc/<pid>/task/<tid>/maps looks like:

08048000-08049000 r-xp 00000000 03:00 8312       /opt/z
08049000-0804a000 rw-p 00001000 03:00 8312       /opt/z
0804a000-0806b000 rw-p 00000000 00:00 0          [heap]
a7d12000-a7d13000 ---p 00000000 00:00 0
a7d13000-a7f13000 rw-p 00000000 00:00 0          [thread stack: 001ff4b4]
a7f13000-a7f14000 ---p 00000000 00:00 0
a7f14000-a7f36000 rw-p 00000000 00:00 0
a7f36000-a8069000 r-xp 00000000 03:00 4222       /lib/libc.so.6
a8069000-a806b000 r--p 00133000 03:00 4222       /lib/libc.so.6
a806b000-a806c000 rw-p 00135000 03:00 4222       /lib/libc.so.6
a806c000-a806f000 rw-p 00000000 00:00 0
a806f000-a8083000 r-xp 00000000 03:00 14462      /lib/libpthread.so.0
a8083000-a8084000 r--p 00013000 03:00 14462      /lib/libpthread.so.0
a8084000-a8085000 rw-p 00014000 03:00 14462      /lib/libpthread.so.0
a8085000-a8088000 rw-p 00000000 00:00 0
a8088000-a80a4000 r-xp 00000000 03:00 8317       /lib/ld-linux.so.2
a80a4000-a80a5000 r--p 0001b000 03:00 8317       /lib/ld-linux.so.2
a80a5000-a80a6000 rw-p 0001c000 03:00 8317       /lib/ld-linux.so.2
afaf5000-afb0a000 rw-p 00000000 00:00 0          [stack]
ffffe000-fffff000 r-xp 00000000 00:00 0          [vdso]

Also there is a new entry "stack usage" in /proc/<pid>/{task/*,}/status
which will you give the current stack usage in kb.

A sample output of /proc/self/status looks like:

Name:	cat
State:	R (running)
Tgid:	507
Pid:	507
.
.
.
CapBnd:	fffffffffffffeff
voluntary_ctxt_switches:	0
nonvoluntary_ctxt_switches:	0
Stack usage:	12 kB

I also fixed stack base address in /proc/<pid>/{task/*,}/stat to the base
address of the associated thread stack and not the one of the main
process.  This makes more sense.

[akpm@linux-foundation.org: fs/proc/array.c now needs walk_page_range()]
Signed-off-by: Stefani Seibold <stefani@seibold.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-23 07:39:41 -07:00
Linus Torvalds 342ff1a1b5 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (34 commits)
  trivial: fix typo in aic7xxx comment
  trivial: fix comment typo in drivers/ata/pata_hpt37x.c
  trivial: typo in kernel-parameters.txt
  trivial: fix typo in tracing documentation
  trivial: add __init/__exit macros in drivers/gpio/bt8xxgpio.c
  trivial: add __init macro/ fix of __exit macro location in ipmi_poweroff.c
  trivial: remove unnecessary semicolons
  trivial: Fix duplicated word "options" in comment
  trivial: kbuild: remove extraneous blank line after declaration of usage()
  trivial: improve help text for mm debug config options
  trivial: doc: hpfall: accept disk device to unload as argument
  trivial: doc: hpfall: reduce risk that hpfall can do harm
  trivial: SubmittingPatches: Fix reference to renumbered step
  trivial: fix typos "man[ae]g?ment" -> "management"
  trivial: media/video/cx88: add __init/__exit macros to cx88 drivers
  trivial: fix typo in CONFIG_DEBUG_FS in gcov doc
  trivial: fix missing printk space in amd_k7_smp_check
  trivial: fix typo s/ketymap/keymap/ in comment
  trivial: fix typo "to to" in multiple files
  trivial: fix typos in comments s/DGBU/DBGU/
  ...
2009-09-22 07:51:45 -07:00
Bernd Schmidt eb8cdec4a9 nommu: add support for Memory Protection Units (MPU)
Some architectures (like the Blackfin arch) implement some of the
"simpler" features that one would expect out of a MMU such as memory
protection.

In our case, we actually get read/write/exec protection down to the page
boundary so processes can't stomp on each other let alone the kernel.

There is a performance decrease (which depends greatly on the workload)
however as the hardware/software interaction was not optimized at design
time.

Signed-off-by: Bernd Schmidt <bernds_cb1@t-online.de>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Acked-by: David Howells <dhowells@redhat.com>
Acked-by: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:43 -07:00
Michael S. Tsirkin f68e148050 mm: reduce atomic use on use_mm fast path
When the mm being switched to matches the active mm, we don't need to
increment and then drop the mm count.  In a simple benchmark this happens
in about 50% of time.  Making that conditional reduces contention on that
cacheline on SMP systems.

Acked-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:42 -07:00
Michael S. Tsirkin 3d2d827f5c mm: move use_mm/unuse_mm from aio.c to mm/
Anyone who wants to do copy to/from user from a kernel thread, needs
use_mm (like what fs/aio has).  Move that into mm/, to make reusing and
exporting easier down the line, and make aio use it.  Next intended user,
besides aio, will be vhost-net.

Acked-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:42 -07:00
Pekka Enberg 425fbf047c shmem: initialize struct shmem_sb_info to zero
Fixes the following kmemcheck false positive (the compiler is using
a 32-bit mov to load the 16-bit sbinfo->mode in shmem_fill_super):

[    0.337000] Total of 1 processors activated (3088.38 BogoMIPS).
[    0.352000] CPU0 attaching NULL sched-domain.
[    0.360000] WARNING: kmemcheck: Caught 32-bit read from uninitialized
memory (9f8020fc)
[    0.361000]
a44240820000000041f6998100000000000000000000000000000000ff030000
[    0.368000]  i i i i i i i i i i i i i i i i u u u u i i i i i i i i i i u
u
[    0.375000]                                                          ^
[    0.376000]
[    0.377000] Pid: 9, comm: khelper Not tainted (2.6.31-tip #206) P4DC6
[    0.378000] EIP: 0060:[<810a3a95>] EFLAGS: 00010246 CPU: 0
[    0.379000] EIP is at shmem_fill_super+0xb5/0x120
[    0.380000] EAX: 00000000 EBX: 9f845400 ECX: 824042a4 EDX: 8199f641
[    0.381000] ESI: 9f8020c0 EDI: 9f845400 EBP: 9f81af68 ESP: 81cd6eec
[    0.382000]  DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
[    0.383000] CR0: 8005003b CR2: 9f806200 CR3: 01ccd000 CR4: 000006d0
[    0.384000] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
[    0.385000] DR6: ffff4ff0 DR7: 00000400
[    0.386000]  [<810c25fc>] get_sb_nodev+0x3c/0x80
[    0.388000]  [<810a3514>] shmem_get_sb+0x14/0x20
[    0.390000]  [<810c207f>] vfs_kern_mount+0x4f/0x120
[    0.392000]  [<81b2849e>] init_tmpfs+0x7e/0xb0
[    0.394000]  [<81b11597>] do_basic_setup+0x17/0x30
[    0.396000]  [<81b11907>] kernel_init+0x57/0xa0
[    0.398000]  [<810039b7>] kernel_thread_helper+0x7/0x10
[    0.400000]  [<ffffffff>] 0xffffffff
[    0.402000] khelper used greatest stack depth: 2820 bytes left
[    0.407000] calling  init_mmap_min_addr+0x0/0x10 @ 1
[    0.408000] initcall init_mmap_min_addr+0x0/0x10 returned 0 after 0 usecs

Reported-by: Ingo Molnar <mingo@elte.hu>
Analysed-by: Vegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:42 -07:00
Eric B Munson 4e52780d41 hugetlb: add MAP_HUGETLB for mmaping pseudo-anonymous huge page regions
Add a flag for mmap that will be used to request a huge page region that
will look like anonymous memory to userspace.  This is accomplished by
using a file on the internal vfsmount.  MAP_HUGETLB is a modifier of
MAP_ANONYMOUS and so must be specified with it.  The region will behave
the same as a MAP_ANONYMOUS region using small pages.

[akpm@linux-foundation.org: fix arch definitions of MAP_HUGETLB]
Signed-off-by: Eric B Munson <ebmunson@us.ibm.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Adam Litke <agl@us.ibm.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:42 -07:00
Huang Shijie f8dbf0a7a4 mmap: save some cycles for the shared anonymous mapping
shmem_zero_setup() does not change vm_start, pgoff or vm_flags, only some
drivers change them (such as /driver/video/bfin-t350mcqb-fb.c).

Move these codes to a more proper place to save cycles for shared
anonymous mapping.

Signed-off-by: Huang Shijie <shijie8@gmail.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:41 -07:00
Lee Schermerhorn 252c5f94d9 mmap: avoid unnecessary anon_vma lock acquisition in vma_adjust()
We noticed very erratic behavior [throughput] with the AIM7 shared
workload running on recent distro [SLES11] and mainline kernels on an
8-socket, 32-core, 256GB x86_64 platform.  On the SLES11 kernel
[2.6.27.19+] with Barcelona processors, as we increased the load [10s of
thousands of tasks], the throughput would vary between two "plateaus"--one
at ~65K jobs per minute and one at ~130K jpm.  The simple patch below
causes the results to smooth out at the ~130k plateau.

But wait, there's more:

We do not see this behavior on smaller platforms--e.g., 4 socket/8 core.
This could be the result of the larger number of cpus on the larger
platform--a scalability issue--or it could be the result of the larger
number of interconnect "hops" between some nodes in this platform and how
the tasks for a given load end up distributed over the nodes' cpus and
memories--a stochastic NUMA effect.

The variability in the results are less pronounced [on the same platform]
with Shanghai processors and with mainline kernels.  With 31-rc6 on
Shanghai processors and 288 file systems on 288 fibre attached storage
volumes, the curves [jpm vs load] are both quite flat with the patched
kernel consistently producing ~3.9% better throughput [~80K jpm vs ~77K
jpm] than the unpatched kernel.

Profiling indicated that the "slow" runs were incurring high[er]
contention on an anon_vma lock in vma_adjust(), apparently called from the
sbrk() system call.

The patch:

A comment in mm/mmap.c:vma_adjust() suggests that we don't really need the
anon_vma lock when we're only adjusting the end of a vma, as is the case
for brk().  The comment questions whether it's worth while to optimize for
this case.  Apparently, on the newer, larger x86_64 platforms, with
interesting NUMA topologies, it is worth while--especially considering
that the patch [if correct!] is quite simple.

We can detect this condition--no overlap with next vma--by noting a NULL
"importer".  The anon_vma pointer will also be NULL in this case, so
simply avoid loading vma->anon_vma to avoid the lock.

However, we DO need to take the anon_vma lock when we're inserting a vma
['insert' non-NULL] even when we have no overlap [NULL "importer"], so we
need to check for 'insert', as well.  And Hugh points out that we should
also take it when adjusting vm_start (so that rmap.c can rely upon
vma_address() while it holds the anon_vma lock).

akpm: Zhang Yanmin reprts a 150% throughput improvement with aim7, so it
might be -stable material even though thiss isn't a regression: "this
issue is not clear on dual socket Nehalem machine (2*4*2 cpu), but is
severe on large machine (4*8*2 cpu)"

[hugh.dickins@tiscali.co.uk: test vma start too]
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Eric Whitney <eric.whitney@hp.com>
Tested-by: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:41 -07:00
Hugh Dickins 3f96b79ad9 tmpfs: depend on shmem
CONFIG_SHMEM off gives you (ramfs masquerading as) tmpfs, even when
CONFIG_TMPFS is off: that's a little anomalous, and I'd intended to make
more sense of it by removing CONFIG_TMPFS altogether, always enabling its
code when CONFIG_SHMEM; but so many defconfigs have CONFIG_SHMEM on
CONFIG_TMPFS off that we'd better leave that as is.

But there is no point in asking for CONFIG_TMPFS if CONFIG_SHMEM is off:
make TMPFS depend on SHMEM, which also prevents TMPFS_POSIX_ACL
shmem_acl.o being pointlessly built into the kernel when SHMEM is off.

And a selfish change, to prevent the world from being rebuilt when I
switch between CONFIG_SHMEM on and off: the only CONFIG_SHMEM in the
header files is mm.h shmem_lock() - give that a shmem.c stub instead.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:41 -07:00
Huang Shijie cdf7b3418a mmap: remove unnecessary code
If (flags & MAP_LOCKED) is true, it means vm_flags has already contained
the bit VM_LOCKED which is set by calc_vm_flag_bits().

So there is no need to reset it again, just remove it.

Signed-off-by: Huang Shijie <shijie8@gmail.com>
Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:41 -07:00
Hugh Dickins 03f6462a3a mm: move highest_memmap_pfn
Move highest_memmap_pfn __read_mostly from page_alloc.c next to zero_pfn
__read_mostly in memory.c: to help them share a cacheline, since they're
very often tested together in vm_normal_page().

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Rik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Mel Gorman <mel@csn.ul.ie>
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>
2009-09-22 07:17:41 -07:00
Hugh Dickins 62eede62da mm: ZERO_PAGE without PTE_SPECIAL
Reinstate anonymous use of ZERO_PAGE to all architectures, not just to
those which __HAVE_ARCH_PTE_SPECIAL: as suggested by Nick Piggin.

Contrary to how I'd imagined it, there's nothing ugly about this, just a
zero_pfn test built into one or another block of vm_normal_page().

But the MIPS ZERO_PAGE-of-many-colours case demands is_zero_pfn() and
my_zero_pfn() inlines.  Reinstate its mremap move_pte() shuffling of
ZERO_PAGEs we did from 2.6.17 to 2.6.19?  Not unless someone shouts for
that: it would have to take vm_flags to weed out some cases.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Rik van Riel <riel@redhat.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:41 -07:00
Hugh Dickins 3ae77f43b1 mm: hugetlbfs_pagecache_present
Rename hugetlbfs_backed() to hugetlbfs_pagecache_present()
and add more comments, as suggested by Mel Gorman.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Rik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Mel Gorman <mel@csn.ul.ie>
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>
2009-09-22 07:17:41 -07:00
Hugh Dickins 6e919717c8 mm: m(un)lock avoid ZERO_PAGE
I'm still reluctant to clutter __get_user_pages() with another flag, just
to avoid touching ZERO_PAGE count in mlock(); though we can add that later
if it shows up as an issue in practice.

But when mlocking, we can test page->mapping slightly earlier, to avoid
the potentially bouncy rescheduling of lock_page on ZERO_PAGE - mlock
didn't lock_page in olden ZERO_PAGE days, so we might have regressed.

And when munlocking, it turns out that FOLL_DUMP coincidentally does
what's needed to avoid all updates to ZERO_PAGE, so use that here also.
Plus add comment suggested by KAMEZAWA Hiroyuki.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Rik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@suse.de>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan.kim@gmail.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>
2009-09-22 07:17:40 -07:00
Hugh Dickins 58fa879e1e mm: FOLL flags for GUP flags
__get_user_pages() has been taking its own GUP flags, then processing
them into FOLL flags for follow_page().  Though oddly named, the FOLL
flags are more widely used, so pass them to __get_user_pages() now.
Sorry, VM flags, VM_FAULT flags and FAULT_FLAGs are still distinct.

(The patch to __get_user_pages() looks peculiar, with both gup_flags
and foll_flags: the gup_flags remain constant; but as before there's
an exceptional case, out of scope of the patch, in which foll_flags
per page have FOLL_WRITE masked off.)

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Rik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Mel Gorman <mel@csn.ul.ie>
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>
2009-09-22 07:17:40 -07:00
Hugh Dickins a13ea5b759 mm: reinstate ZERO_PAGE
KAMEZAWA Hiroyuki has observed customers of earlier kernels taking
advantage of the ZERO_PAGE: which we stopped do_anonymous_page() from
using in 2.6.24.  And there were a couple of regression reports on LKML.

Following suggestions from Linus, reinstate do_anonymous_page() use of
the ZERO_PAGE; but this time avoid dirtying its struct page cacheline
with (map)count updates - let vm_normal_page() regard it as abnormal.

Use it only on arches which __HAVE_ARCH_PTE_SPECIAL (x86, s390, sh32,
most powerpc): that's not essential, but minimizes additional branches
(keeping them in the unlikely pte_special case); and incidentally
excludes mips (some models of which needed eight colours of ZERO_PAGE
to avoid costly exceptions).

Don't be fanatical about avoiding ZERO_PAGE updates: get_user_pages()
callers won't want to make exceptions for it, so increment its count
there.  Changes to mlock and migration? happily seems not needed.

In most places it's quicker to check pfn than struct page address:
prepare a __read_mostly zero_pfn for that.  Does get_dump_page()
still need its ZERO_PAGE check? probably not, but keep it anyway.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Mel Gorman <mel@csn.ul.ie>
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>
2009-09-22 07:17:40 -07:00
Hugh Dickins 1ac0cb5d0e mm: fix anonymous dirtying
do_anonymous_page() has been wrong to dirty the pte regardless.
If it's not going to mark the pte writable, then it won't help
to mark it dirty here, and clogs up memory with pages which will
need swap instead of being thrown away.  Especially wrong if no
overcommit is chosen, and this vma is not yet VM_ACCOUNTed -
we could exceed the limit and OOM despite no overcommit.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: <stable@kernel.org>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Mel Gorman <mel@csn.ul.ie>
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>
2009-09-22 07:17:40 -07:00
Hugh Dickins 2a15efc953 mm: follow_hugetlb_page flags
follow_hugetlb_page() shouldn't be guessing about the coredump case
either: pass the foll_flags down to it, instead of just the write bit.

Remove that obscure huge_zeropage_ok() test.  The decision is easy,
though unlike the non-huge case - here vm_ops->fault is always set.
But we know that a fault would serve up zeroes, unless there's
already a hugetlbfs pagecache page to back the range.

(Alternatively, since hugetlb pages aren't swapped out under pressure,
you could save more dump space by arguing that a page not yet faulted
into this process cannot be relevant to the dump; but that would be
more surprising.)

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Mel Gorman <mel@csn.ul.ie>
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>
2009-09-22 07:17:40 -07:00
Hugh Dickins 8e4b9a6071 mm: FOLL_DUMP replace FOLL_ANON
The "FOLL_ANON optimization" and its use_zero_page() test have caused
confusion and bugs: why does it test VM_SHARED? for the very good but
unsatisfying reason that VMware crashed without.  As we look to maybe
reinstating anonymous use of the ZERO_PAGE, we need to sort this out.

Easily done: it's silly for __get_user_pages() and follow_page() to
be guessing whether it's safe to assume that they're being used for
a coredump (which can take a shortcut snapshot where other uses must
handle a fault) - just tell them with GUP_FLAGS_DUMP and FOLL_DUMP.

get_dump_page() doesn't even want a ZERO_PAGE: an error suits fine.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:40 -07:00
Hugh Dickins f3e8fccd06 mm: add get_dump_page
In preparation for the next patch, add a simple get_dump_page(addr)
interface for the CONFIG_ELF_CORE dumpers to use, instead of calling
get_user_pages() directly.  They're not interested in errors: they
just want to use holes as much as possible, to save space and make
sure that the data is aligned where the headers said it would be.

Oh, and don't use that horrid DUMP_SEEK(off) macro!

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Mel Gorman <mel@csn.ul.ie>
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>
2009-09-22 07:17:40 -07:00
Hugh Dickins 1c3aff1cee mm: remove unused GUP flags
GUP_FLAGS_IGNORE_VMA_PERMISSIONS and GUP_FLAGS_IGNORE_SIGKILL were
flags added solely to prevent __get_user_pages() from doing some of
what it usually does, in the munlock case: we can now remove them.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Mel Gorman <mel@csn.ul.ie>
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>
2009-09-22 07:17:40 -07:00
Hugh Dickins 408e82b78b mm: munlock use follow_page
Hiroaki Wakabayashi points out that when mlock() has been interrupted
by SIGKILL, the subsequent munlock() takes unnecessarily long because
its use of __get_user_pages() insists on faulting in all the pages
which mlock() never reached.

It's worse than slowness if mlock() is terminated by Out Of Memory kill:
the munlock_vma_pages_all() in exit_mmap() insists on faulting in all the
pages which mlock() could not find memory for; so innocent bystanders are
killed too, and perhaps the system hangs.

__get_user_pages() does a lot that's silly for munlock(): so remove the
munlock option from __mlock_vma_pages_range(), and use a simple loop of
follow_page()s in munlock_vma_pages_range() instead; ignoring absent
pages, and not marking present pages as accessed or dirty.

(Change munlock() to only go so far as mlock() reached?  That does not
work out, given the convention that mlock() claims complete success even
when it has to give up early - in part so that an underlying file can be
extended later, and those pages locked which earlier would give SIGBUS.)

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: <stable@kernel.org>
Acked-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Hiroaki Wakabayashi <primulaelatior@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:40 -07:00
Mel Gorman a6f9edd65b page-allocator: maintain rolling count of pages to free from the PCP
When round-robin freeing pages from the PCP lists, empty lists may be
encountered.  In the event one of the lists has more pages than another,
there may be numerous checks for list_empty() which is undesirable.  This
patch maintains a count of pages to free which is incremented when empty
lists are encountered.  The intention is that more pages will then be
freed from fuller lists than the empty ones reducing the number of empty
list checks in the free path.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Christoph Lameter <cl@linux-foundation.org>
Reviewed-by: Minchan Kim <minchan.kim@gmail.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>
2009-09-22 07:17:39 -07:00
Mel Gorman 5f8dcc2121 page-allocator: split per-cpu list into one-list-per-migrate-type
The following two patches remove searching in the page allocator fast-path
by maintaining multiple free-lists in the per-cpu structure.  At the time
the search was introduced, increasing the per-cpu structures would waste a
lot of memory as per-cpu structures were statically allocated at
compile-time.  This is no longer the case.

The patches are as follows. They are based on mmotm-2009-08-27.

Patch 1 adds multiple lists to struct per_cpu_pages, one per
	migratetype that can be stored on the PCP lists.

Patch 2 notes that the pcpu drain path check empty lists multiple times. The
	patch reduces the number of checks by maintaining a count of free
	lists encountered. Lists containing pages will then free multiple
	pages in batch

The patches were tested with kernbench, netperf udp/tcp, hackbench and
sysbench.  The netperf tests were not bound to any CPU in particular and
were run such that the results should be 99% confidence that the reported
results are within 1% of the estimated mean.  sysbench was run with a
postgres background and read-only tests.  Similar to netperf, it was run
multiple times so that it's 99% confidence results are within 1%.  The
patches were tested on x86, x86-64 and ppc64 as

x86:	Intel Pentium D 3GHz with 8G RAM (no-brand machine)
	kernbench	- No significant difference, variance well within noise
	netperf-udp	- 1.34% to 2.28% gain
	netperf-tcp	- 0.45% to 1.22% gain
	hackbench	- Small variances, very close to noise
	sysbench	- Very small gains

x86-64:	AMD Phenom 9950 1.3GHz with 8G RAM (no-brand machine)
	kernbench	- No significant difference, variance well within noise
	netperf-udp	- 1.83% to 10.42% gains
	netperf-tcp	- No conclusive until buffer >= PAGE_SIZE
				4096	+15.83%
				8192	+ 0.34% (not significant)
				16384	+ 1%
	hackbench	- Small gains, very close to noise
	sysbench	- 0.79% to 1.6% gain

ppc64:	PPC970MP 2.5GHz with 10GB RAM (it's a terrasoft powerstation)
	kernbench	- No significant difference, variance well within noise
	netperf-udp	- 2-3% gain for almost all buffer sizes tested
	netperf-tcp	- losses on small buffers, gains on larger buffers
			  possibly indicates some bad caching effect.
	hackbench	- No significant difference
	sysbench	- 2-4% gain

This patch:

Currently the per-cpu page allocator searches the PCP list for pages of
the correct migrate-type to reduce the possibility of pages being
inappropriate placed from a fragmentation perspective.  This search is
potentially expensive in a fast-path and undesirable.  Splitting the
per-cpu list into multiple lists increases the size of a per-cpu structure
and this was potentially a major problem at the time the search was
introduced.  These problem has been mitigated as now only the necessary
number of structures is allocated for the running system.

This patch replaces a list search in the per-cpu allocator with one list
per migrate type.  The potential snag with this approach is when bulk
freeing pages.  We round-robin free pages based on migrate type which has
little bearing on the cache hotness of the page and potentially checks
empty lists repeatedly in the event the majority of PCP pages are of one
type.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Nick Piggin <npiggin@suse.de>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Minchan Kim <minchan.kim@gmail.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>
2009-09-22 07:17:39 -07:00
KOSAKI Motohiro 8c5cd6f3a1 oom: oom_kill doesn't kill vfork parent (or child)
Current oom_kill doesn't only kill the victim process, but also kill all
thas shread the same mm.  it mean vfork parent will be killed.

This is definitely incorrect.  another process have another oom_adj.  we
shouldn't ignore their oom_adj (it might have OOM_DISABLE).

following caller hit the minefield.

===============================
        switch (constraint) {
        case CONSTRAINT_MEMORY_POLICY:
                oom_kill_process(current, gfp_mask, order, 0, NULL,
                                "No available memory (MPOL_BIND)");
                break;

Note: force_sig(SIGKILL) send SIGKILL to all thread in the process.
We don't need to care multi thread in here.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:39 -07:00
KOSAKI Motohiro 495789a51a oom: make oom_score to per-process value
oom-killer kills a process, not task.  Then oom_score should be calculated
as per-process too.  it makes consistency more and makes speed up
select_bad_process().

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:39 -07:00
KOSAKI Motohiro 28b83c5193 oom: move oom_adj value from task_struct to signal_struct
Currently, OOM logic callflow is here.

    __out_of_memory()
        select_bad_process()            for each task
            badness()                   calculate badness of one task
                oom_kill_process()      search child
                    oom_kill_task()     kill target task and mm shared tasks with it

example, process-A have two thread, thread-A and thread-B and it have very
fat memory and each thread have following oom_adj and oom_score.

     thread-A: oom_adj = OOM_DISABLE, oom_score = 0
     thread-B: oom_adj = 0,           oom_score = very-high

Then, select_bad_process() select thread-B, but oom_kill_task() refuse
kill the task because thread-A have OOM_DISABLE.  Thus __out_of_memory()
call select_bad_process() again.  but select_bad_process() select the same
task.  It mean kernel fall in livelock.

The fact is, select_bad_process() must select killable task.  otherwise
OOM logic go into livelock.

And root cause is, oom_adj shouldn't be per-thread value.  it should be
per-process value because OOM-killer kill a process, not thread.  Thus
This patch moves oomkilladj (now more appropriately named oom_adj) from
struct task_struct to struct signal_struct.  it naturally prevent
select_bad_process() choose wrong task.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:39 -07:00
Vincent Li f168e1b639 mm/vmscan: remove page_queue_congested() comment
Commit 084f71ae5c(kill page_queue_congested()) removed
page_queue_congested().  Remove the page_queue_congested() comment in
vmscan pageout() too.

Signed-off-by: Vincent Li <macli@brc.ubc.ca>
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>
2009-09-22 07:17:39 -07:00
Wu Fengguang f862963174 mm: do batched scans for mem_cgroup
For mem_cgroup, shrink_zone() may call shrink_list() with nr_to_scan=1, in
which case shrink_list() _still_ calls isolate_pages() with the much
larger SWAP_CLUSTER_MAX.  It effectively scales up the inactive list scan
rate by up to 32 times.

For example, with 16k inactive pages and DEF_PRIORITY=12, (16k >> 12)=4.
So when shrink_zone() expects to scan 4 pages in the active/inactive list,
the active list will be scanned 4 pages, while the inactive list will be
(over) scanned SWAP_CLUSTER_MAX=32 pages in effect.  And that could break
the balance between the two lists.

It can further impact the scan of anon active list, due to the anon
active/inactive ratio rebalance logic in balance_pgdat()/shrink_zone():

inactive anon list over scanned => inactive_anon_is_low() == TRUE
                                => shrink_active_list()
                                => active anon list over scanned

So the end result may be

- anon inactive  => over scanned
- anon active    => over scanned (maybe not as much)
- file inactive  => over scanned
- file active    => under scanned (relatively)

The accesses to nr_saved_scan are not lock protected and so not 100%
accurate, however we can tolerate small errors and the resulted small
imbalanced scan rates between zones.

Cc: Rik van Riel <riel@redhat.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:39 -07:00
Vincent Li 0b21767637 mm/vmscan: rename zone_nr_pages() to zone_nr_lru_pages()
The name `zone_nr_pages' can be mis-read as zone's (total) number pages,
but it actually returns zone's LRU list number pages.

Signed-off-by: Vincent Li <macli@brc.ubc.ca>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.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>
2009-09-22 07:17:38 -07:00
Jan Beulich 2c85f51d22 mm: also use alloc_large_system_hash() for the PID hash table
This is being done by allowing boot time allocations to specify that they
may want a sub-page sized amount of memory.

Overall this seems more consistent with the other hash table allocations,
and allows making two supposedly mm-only variables really mm-only
(nr_{kernel,all}_pages).

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "Eric W. Biederman" <ebiederm@xmission.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>
2009-09-22 07:17:38 -07:00
Jan Beulich 4481374ce8 mm: replace various uses of num_physpages by totalram_pages
Sizing of memory allocations shouldn't depend on the number of physical
pages found in a system, as that generally includes (perhaps a huge amount
of) non-RAM pages.  The amount of what actually is usable as storage
should instead be used as a basis here.

Some of the calculations (i.e.  those not intending to use high memory)
should likely even use (totalram_pages - totalhigh_pages).

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Dave Airlie <airlied@linux.ie>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Patrick McHardy <kaber@trash.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:38 -07:00
Jan Beulich 4738e1b9cf memory hotplug: fix updating of num_physpages for hot plugged memory
Sizing of memory allocations shouldn't depend on the number of physical
pages found in a system, as that generally includes (perhaps a huge amount
of) non-RAM pages.  The amount of what actually is usable as storage
should instead be used as a basis here.

In line with that, the memory hotplug code should update num_physpages in
a way that it retains its original (post-boot) meaning; in particular,
decreasing the value should at best be done with great care - this patch
doesn't try to ever decrease this value at all as it doesn't really seem
meaningful to do so.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Dave Hansen <haveblue@us.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>
2009-09-22 07:17:38 -07:00
Mel Gorman 78986a678f page-allocator: limit the number of MIGRATE_RESERVE pageblocks per zone
After anti-fragmentation was merged, a bug was reported whereby devices
that depended on high-order atomic allocations were failing.  The solution
was to preserve a property in the buddy allocator which tended to keep the
minimum number of free pages in the zone at the lower physical addresses
and contiguous.  To preserve this property, MIGRATE_RESERVE was introduced
and a number of pageblocks at the start of a zone would be marked
"reserve", the number of which depended on min_free_kbytes.

Anti-fragmentation works by avoiding the mixing of page migratetypes
within the same pageblock.  One way of helping this is to increase
min_free_kbytes because it becomes less like that it will be necessary to
place pages of of MIGRATE_RESERVE is unbounded, the free memory is kept
there in large contiguous blocks instead of helping anti-fragmentation as
much as it should.  With the page-allocator tracepoint patches applied, it
was found during anti-fragmentation tests that the number of
fragmentation-related events were far higher than expected even with
min_free_kbytes at higher values.

This patch limits the number of MIGRATE_RESERVE blocks that exist per zone
to two.  For example, with a sufficient min_free_kbytes, 4MB of memory
will be kept aside on an x86-64 and remain more or less free and
contiguous for the systems uptime.  This should be sufficient for devices
depending on high-order atomic allocations while helping fragmentation
control when min_free_kbytes is tuned appropriately.  As side-effect of
this patch is that the reserve variable is converted to int as unsigned
long was the wrong type to use when ensuring that only the required number
of reserve blocks are created.

With the patches applied, fragmentation-related events as measured by the
page allocator tracepoints were significantly reduced when running some
fragmentation stress-tests on systems with min_free_kbytes tuned to a
value appropriate for hugepage allocations at runtime.  On x86, the events
recorded were reduced by 99.8%, on x86-64 by 99.72% and on ppc64 by
99.83%.

Signed-off-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>
2009-09-22 07:17:38 -07:00
Johannes Weiner ceddc3a52d mm: document is_page_cache_freeable()
Enlighten the reader of this code about what reference count makes a page
cache page freeable.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux-foundation.org>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
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>
2009-09-22 07:17:38 -07:00
Johannes Weiner edcf4748cd mm: return boolean from page_has_private()
Make page_has_private() return a true boolean value and remove the double
negations from the two callsites using it for arithmetic.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux-foundation.org>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
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>
2009-09-22 07:17:38 -07:00
Johannes Weiner 6c0b13519d mm: return boolean from page_is_file_cache()
page_is_file_cache() has been used for both boolean checks and LRU
arithmetic, which was always a bit weird.

Now that page_lru_base_type() exists for LRU arithmetic, make
page_is_file_cache() a real predicate function and adjust the
boolean-using callsites to drop those pesky double negations.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
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>
2009-09-22 07:17:37 -07:00
Johannes Weiner 401a8e1c16 mm: introduce page_lru_base_type()
Instead of abusing page_is_file_cache() for LRU list index arithmetic, add
another helper with a more appropriate name and convert the non-boolean
users of page_is_file_cache() accordingly.

This new helper gives the LRU base type a page is supposed to live on,
inactive anon or inactive file.

[hugh.dickins@tiscali.co.uk: convert del_page_from_lru() also]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Minchan Kim <minchan.kim@gmail.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>
2009-09-22 07:17:35 -07:00
Johannes Weiner b7c46d151c mm: drop unneeded double negations
Remove double negations where the operand is already boolean.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mel@csn.ul.ie>
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>
2009-09-22 07:17:35 -07:00
Sage Weil bba7881954 mm: remove broken 'kzalloc' mempool
The kzalloc mempool zeros items when they are initially allocated, but
does not rezero used items that are returned to the pool.  Consequently
mempool_alloc()s may return non-zeroed memory.

Since there are/were only two in-tree users for
mempool_create_kzalloc_pool(), and 'fixing' this in a way that will
re-zero used (but not new) items before first use is non-trivial, just
remove it.

Signed-off-by: Sage Weil <sage@newdream.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:35 -07:00
Jaswinder Singh Rajput 72ff13b703 mm: includecheck fix for mm/nommu.c
Fix the following 'make includecheck' warning:

  mm/nommu.c: internal.h is included more than once.

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Acked-by: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:35 -07:00
Jaswinder Singh Rajput cff397e6b3 mm: includecheck fix for mm/shmem.c
Fix the following 'make includecheck' warning:

  mm/shmem.c: linux/vfs.h is included more than once.

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:35 -07:00
Daisuke Nishimura 2ca4532a49 mm: add_to_swap_cache() does not return -EEXIST
After commit 355cfa73 ("mm: modify swap_map and add SWAP_HAS_CACHE flag"),
only the context which have set SWAP_HAS_CACHE flag by swapcache_prepare()
or get_swap_page() would call add_to_swap_cache().  So add_to_swap_cache()
doesn't return -EEXIST any more.

Even though it doesn't return -EEXIST, it's not good behavior conceptually
to call swapcache_prepare() in the -EEXIST case, because it means clearing
SWAP_HAS_CACHE flag while the entry is on swap cache.

This patch removes redundant codes and comments from callers of it, and
adds VM_BUG_ON() in error path of add_to_swap_cache() and some comments.

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:35 -07:00
Daisuke Nishimura 31a5639623 mm: add_to_swap_cache() must not sleep
After commit 355cfa73 ("mm: modify swap_map and add SWAP_HAS_CACHE flag"),
read_swap_cache_async() will busy-wait while a entry doesn't exist in swap
cache but it has SWAP_HAS_CACHE flag.

Such entries can exist on add/delete path of swap cache.  On add path,
add_to_swap_cache() is called soon after SWAP_HAS_CACHE flag is set, and
on delete path, swapcache_free() will be called (SWAP_HAS_CACHE flag is
cleared) soon after __delete_from_swap_cache() is called.  So, the
busy-wait works well in most cases.

But this mechanism can cause soft lockup if add_to_swap_cache() sleeps and
read_swap_cache_async() tries to swap-in the same entry on the same cpu.

This patch calls radix_tree_preload() before swapcache_prepare() and
divides add_to_swap_cache() into two part: radix_tree_preload() part and
radix_tree_insert() part(define it as __add_to_swap_cache()).

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:35 -07:00
Mel Gorman 0d3d062a6e tracing, page-allocator: add trace event for page traffic related to the buddy lists
The page allocation trace event reports that a page was successfully
allocated but it does not specify where it came from.  When analysing
performance, it can be important to distinguish between pages coming from
the per-cpu allocator and pages coming from the buddy lists as the latter
requires the zone lock to the taken and more data structures to be
examined.

This patch adds a trace event for __rmqueue reporting when a page is being
allocated from the buddy lists.  It distinguishes between being called to
refill the per-cpu lists or whether it is a high-order allocation.
Similarly, this patch adds an event to catch when the PCP lists are being
drained a little and pages are going back to the buddy lists.

This is trickier to draw conclusions from but high activity on those
events could explain why there were a large number of cache misses on a
page-allocator-intensive workload.  The coalescing and splitting of
buddies involves a lot of writing of page metadata and cache line bounces
not to mention the acquisition of an interrupt-safe lock necessary to
enter this path.

[akpm@linux-foundation.org: fix build]
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Li Ming Chun <macli@brc.ubc.ca>
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>
2009-09-22 07:17:34 -07:00
Mel Gorman e0fff1bd12 tracing, page-allocator: add trace events for anti-fragmentation falling back to other migratetypes
Fragmentation avoidance depends on being able to use free pages from lists
of the appropriate migrate type.  In the event this is not possible,
__rmqueue_fallback() selects a different list and in some circumstances
change the migratetype of the pageblock.  Simplistically, the more times
this event occurs, the more likely that fragmentation will be a problem
later for hugepage allocation at least but there are other considerations
such as the order of page being split to satisfy the allocation.

This patch adds a trace event for __rmqueue_fallback() that reports what
page is being used for the fallback, the orders of relevant pages, the
desired migratetype and the migratetype of the lists being used, whether
the pageblock changed type and whether this event is important with
respect to fragmentation avoidance or not.  This information can be used
to help analyse fragmentation avoidance and help decide whether
min_free_kbytes should be increased or not.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Li Ming Chun <macli@brc.ubc.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:34 -07:00
Mel Gorman 4b4f278c03 tracing, page-allocator: add trace events for page allocation and page freeing
This patch adds trace events for the allocation and freeing of pages,
including the freeing of pagevecs.  Using the events, it will be known
what struct page and pfns are being allocated and freed and what the call
site was in many cases.

The page alloc tracepoints be used as an indicator as to whether the
workload was heavily dependant on the page allocator or not.  You can make
a guess based on vmstat but you can't get a per-process breakdown.
Depending on the call path, the call_site for page allocation may be
__get_free_pages() instead of a useful callsite.  Instead of passing down
a return address similar to slab debugging, the user should enable the
stacktrace and seg-addr options to get a proper stack trace.

The pagevec free tracepoint has a different usecase.  It can be used to
get a idea of how many pages are being dumped off the LRU and whether it
is kswapd doing the work or a process doing direct reclaim.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Li Ming Chun <macli@brc.ubc.ca>
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>
2009-09-22 07:17:34 -07:00
Mel Gorman 38a398572f page-allocator: remove dead function free_cold_page()
The function free_cold_page() has no callers so delete it.

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>
2009-09-22 07:17:34 -07:00
KAMEZAWA Hiroyuki d0107eb073 kcore: fix vread/vwrite to be aware of holes
vread/vwrite access vmalloc area without checking there is a page or not.
In most case, this works well.

In old ages, the caller of get_vm_ara() is only IOREMAP and there is no
memory hole within vm_struct's [addr...addr + size - PAGE_SIZE] (
-PAGE_SIZE is for a guard page.)

After per-cpu-alloc patch, it uses get_vm_area() for reserve continuous
virtual address but remap _later_.  There tend to be a hole in valid
vmalloc area in vm_struct lists.  Then, skip the hole (not mapped page) is
necessary.  This patch updates vread/vwrite() for avoiding memory hole.

Routines which access vmalloc area without knowing for which addr is used
are
  - /proc/kcore
  - /dev/kmem

kcore checks IOREMAP, /dev/kmem doesn't.  After this patch, IOREMAP is
checked and /dev/kmem will avoid to read/write it.  Fixes to /proc/kcore
will be in the next patch in series.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Mike Smith <scgtrp@gmail.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>
2009-09-22 07:17:34 -07:00
KAMEZAWA Hiroyuki dd32c27998 vmalloc: unmap vmalloc area after hiding it
vmap area should be purged after vm_struct is removed from the list
because vread/vwrite etc...believes the range is valid while it's on
vm_struct list.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Mike Smith <scgtrp@gmail.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>
2009-09-22 07:17:33 -07:00
Mel Gorman 2f66a68f3f page-allocator: change migratetype for all pageblocks within a high-order page during __rmqueue_fallback
When there are no pages of a target migratetype free, the page allocator
selects a high-order block of another migratetype to allocate from.  When
the order of the page taken is greater than pageblock_order, all
pageblocks within that high-order page should change migratetype so that
pages are later freed to the correct free-lists.

The current behaviour is that pageblocks change migratetype if the order
being split matches the pageblock_order.  When pageblock_order <
MAX_ORDER-1, ownership is not changing correct and pages are being later
freed to the incorrect list and this impacts fragmentation avoidance.

This patch changes all pageblocks within the high-order page being split
to the correct migratetype.  Without the patch, allocation success rates
for hugepages under stress were about 59% of physical memory on x86-64.
With the patch applied, this goes up to 65%.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Cc: Andy Whitcroft <apw@shadowen.org>
Cc: 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>
2009-09-22 07:17:33 -07:00
Benjamin Herrenschmidt fe1ff49d0d mm: kmem_cache_create(): make it easier to catch NULL cache names
Right now, if you inadvertently pass NULL to kmem_cache_create() at boot
time, it crashes much later after boot somewhere deep inside sysfs which
makes it very non obvious to figure out what's going on.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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>
2009-09-22 07:17:33 -07:00
Hugh Dickins 7103ad323b ksm: mremap use err from ksm_madvise
mremap move's use of ksm_madvise() was assuming -ENOMEM on failure,
because ksm_madvise used to say -EAGAIN for that; but ksm_madvise now says
-ENOMEM (letting madvise convert that to -EAGAIN), and can also say
-ERESTARTSYS when signalled: so pass the error from ksm_madvise.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:33 -07:00
Hugh Dickins 35451beecb ksm: unmerge is an origin of OOMs
Just as the swapoff system call allocates many pages of RAM to various
processes, perhaps triggering OOM, so "echo 2 >/sys/kernel/mm/ksm/run"
(unmerge) is liable to allocate many pages of RAM to various processes,
perhaps triggering OOM; and each is normally run from a modest admin
process (swapoff or shell), easily repeated until it succeeds.

So treat unmerge_and_remove_all_rmap_items() in the same way that we treat
try_to_unuse(): generalize PF_SWAPOFF to PF_OOM_ORIGIN, and bracket both
with that, to ask the OOM killer to kill them first, to prevent them from
spawning more and more OOM kills.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:33 -07:00
Hugh Dickins a913e182ab ksm: clean up obsolete references
A few cleanups, given the munlock fix: the comment on ksm_test_exit() no
longer applies, and it can be made private to ksm.c; there's no more
reference to mmu_gather or tlb.h, and mmap.c doesn't need ksm.h.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:33 -07:00
Hugh Dickins 8314c4f24a ksm: remove VM_MERGEABLE_FLAGS
KSM originally stood for Kernel Shared Memory: but the kernel has long
supported shared memory, and VM_SHARED and VM_MAYSHARE vmas, and KSM is
something else.  So we switched to saying "merge" instead of "share".

But Chris Wright points out that this is confusing where mmap.c merges
adjacent vmas: most especially in the name VM_MERGEABLE_FLAGS, used by
is_mergeable_vma() to let vmas be merged despite flags being different.

Call it VMA_MERGE_DESPITE_FLAGS?  Perhaps, but at present it consists
only of VM_CAN_NONLINEAR: so for now it's clearer on all sides to use
that directly, with a comment on it in is_mergeable_vma().

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:33 -07:00
Hugh Dickins 7701c9c0f5 ksm: add some documentation
Add Documentation/vm/ksm.txt: how to use the Kernel Samepage Merging feature

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:33 -07:00
Hugh Dickins 2ffd8679c8 ksm: sysfs and defaults
At present KSM is just a waste of space if you don't have CONFIG_SYSFS=y
to provide the /sys/kernel/mm/ksm files to tune and activate it.

Make KSM depend on SYSFS?  Could do, but it might be better to provide
some defaults so that KSM works out-of-the-box, ready for testers to
madvise MADV_MERGEABLE, even without SYSFS.

Though anyone serious is likely to want to retune the numbers to their
taste once they have experience; and whether these settings ever reach
2.6.32 can be discussed along the way.

Save 1kB from tiny kernels by #ifdef'ing the SYSFS side of it.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:32 -07:00
Andrea Arcangeli 1c2fb7a4c2 ksm: fix deadlock with munlock in exit_mmap
Rawhide users have reported hang at startup when cryptsetup is run: the
same problem can be simply reproduced by running a program int main() {
mlockall(MCL_CURRENT | MCL_FUTURE); return 0; }

The problem is that exit_mmap() applies munlock_vma_pages_all() to
clean up VM_LOCKED areas, and its current implementation (stupidly)
tries to fault in absent pages, for example where PROT_NONE prevented
them being faulted in when mlocking.  Whereas the "ksm: fix oom
deadlock" patch, knowing there's a race by which KSM might try to fault
in pages after exit_mmap() had finally zapped the range, backs out of
such faults doing nothing when its ksm_test_exit() notices mm_users 0.

So revert that part of "ksm: fix oom deadlock" which moved the
ksm_exit() call from before exit_mmap() to the middle of exit_mmap();
and remove those ksm_test_exit() checks from the page fault paths, so
allowing the munlocking to proceed without interference.

ksm_exit, if there are rmap_items still chained on this mm slot, takes
mmap_sem write side: so preventing KSM from working on an mm while
exit_mmap runs.  And KSM will bail out as soon as it notices that
mm_users is already zero, thanks to its internal ksm_test_exit checks.
So that when a task is killed by OOM killer or the user, KSM will not
indefinitely prevent it from running exit_mmap to release its memory.

This does break a part of what "ksm: fix oom deadlock" was trying to
achieve.  When unmerging KSM (echo 2 >/sys/kernel/mm/ksm), and even
when ksmd itself has to cancel a KSM page, it is possible that the
first OOM-kill victim would be the KSM process being faulted: then its
memory won't be freed until a second victim has been selected (freeing
memory for the unmerging fault to complete).

But the OOM killer is already liable to kill a second victim once the
intended victim's p->mm goes to NULL: so there's not much point in
rejecting this KSM patch before fixing that OOM behaviour.  It is very
much more important to allow KSM users to boot up, than to haggle over
an unlikely and poorly supported OOM case.

We also intend to fix munlocking to not fault pages: at which point
this patch _could_ be reverted; though that would be controversial, so
we hope to find a better solution.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Justin M. Forbes <jforbes@redhat.com>
Acked-for-now-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Izik Eidus <ieidus@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:32 -07:00
Hugh Dickins 9ba6929480 ksm: fix oom deadlock
There's a now-obvious deadlock in KSM's out-of-memory handling:
imagine ksmd or KSM_RUN_UNMERGE handling, holding ksm_thread_mutex,
trying to allocate a page to break KSM in an mm which becomes the
OOM victim (quite likely in the unmerge case): it's killed and goes
to exit, and hangs there waiting to acquire ksm_thread_mutex.

Clearly we must not require ksm_thread_mutex in __ksm_exit, simple
though that made everything else: perhaps use mmap_sem somehow?
And part of the answer lies in the comments on unmerge_ksm_pages:
__ksm_exit should also leave all the rmap_item removal to ksmd.

But there's a fundamental problem, that KSM relies upon mmap_sem to
guarantee the consistency of the mm it's dealing with, yet exit_mmap
tears down an mm without taking mmap_sem.  And bumping mm_users won't
help at all, that just ensures that the pages the OOM killer assumes
are on their way to being freed will not be freed.

The best answer seems to be, to move the ksm_exit callout from just
before exit_mmap, to the middle of exit_mmap: after the mm's pages
have been freed (if the mmu_gather is flushed), but before its page
tables and vma structures have been freed; and down_write,up_write
mmap_sem there to serialize with KSM's own reliance on mmap_sem.

But KSM then needs to be careful, whenever it downs mmap_sem, to
check that the mm is not already exiting: there's a danger of using
find_vma on a layout that's being torn apart, or writing into page
tables which have been freed for reuse; and even do_anonymous_page
and __do_fault need to check they're not being called by break_ksm
to reinstate a pte after zap_pte_range has zapped that page table.

Though it might be clearer to add an exiting flag, set while holding
mmap_sem in __ksm_exit, that wouldn't cover the issue of reinstating
a zapped pte.  All we need is to check whether mm_users is 0 - but
must remember that ksmd may detect that before __ksm_exit is reached.
So, ksm_test_exit(mm) added to comment such checks on mm->mm_users.

__ksm_exit now has to leave clearing up the rmap_items to ksmd,
that needs ksm_thread_mutex; but shift the exiting mm just after the
ksm_scan cursor so that it will soon be dealt with.  __ksm_enter raise
mm_count to hold the mm_struct, ksmd's exit processing (exactly like
its processing when it finds all VM_MERGEABLEs unmapped) mmdrop it,
similar procedure for KSM_RUN_UNMERGE (which has stopped ksmd).

But also give __ksm_exit a fast path: when there's no complication
(no rmap_items attached to mm and it's not at the ksm_scan cursor),
it can safely do all the exiting work itself.  This is not just an
optimization: when ksmd is not running, the raised mm_count would
otherwise leak mm_structs.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:32 -07:00
Hugh Dickins cd551f9751 ksm: distribute remove_mm_from_lists
Do some housekeeping in ksm.c, to help make the next patch easier
to understand: remove the function remove_mm_from_lists, distributing
its code to its callsites scan_get_next_rmap_item and __ksm_exit.

That turns out to be a win in scan_get_next_rmap_item: move its
remove_trailing_rmap_items and cursor advancement up, and it becomes
simpler than before.  __ksm_exit becomes messier, but will change
again; and moving its remove_trailing_rmap_items up lets us strengthen
the unstable tree item's age condition in remove_rmap_item_from_tree.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:32 -07:00
Hugh Dickins d952b79136 ksm: fix endless loop on oom
break_ksm has been looping endlessly ignoring VM_FAULT_OOM: that should
only be a problem for ksmd when a memory control group imposes limits
(normally the OOM killer will kill others with an mm until it succeeds);
but in general (especially for MADV_UNMERGEABLE and KSM_RUN_UNMERGE) we
do need to route the error (or kill) back to the caller (or sighandling).

Test signal_pending in unmerge_ksm_pages, which could be a lengthy
procedure if it has to spill into swap: returning -ERESTARTSYS so that
trivial signals will restart but fatals will terminate (is that right?
we do different things in different places in mm, none exactly this).

unmerge_and_remove_all_rmap_items was forgetting to lock when going
down the mm_list: fix that.  Whether it's successful or not, reset
ksm_scan cursor to head; but only if it's successful, reset seqnr
(shown in full_scans) - page counts will have gone down to zero.

This patch leaves a significant OOM deadlock, but it's a good step
on the way, and that deadlock is fixed in a subsequent patch.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:32 -07:00
Hugh Dickins 81464e3060 ksm: five little cleanups
1. We don't use __break_cow entry point now: merge it into break_cow.
2. remove_all_slot_rmap_items is just a special case of
   remove_trailing_rmap_items: use the latter instead.
3. Extend comment on unmerge_ksm_pages and rmap_items.
4. try_to_merge_two_pages should use try_to_merge_with_ksm_page
   instead of duplicating its code; and so swap them around.
5. Comment on cmp_and_merge_page described last year's: update it.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:32 -07:00
Hugh Dickins 6e15838425 ksm: keep quiet while list empty
ksm_scan_thread already sleeps in wait_event_interruptible until setting
ksm_run activates it; but if there's nothing on its list to look at, i.e.
nobody has yet said madvise MADV_MERGEABLE, it's a shame to be clocking
up system time and full_scans: ksmd_should_run added to check that too.

And move the mutex_lock out around it: the new counts showed that when
ksm_run is stopped, a little work often got done afterwards, because it
had been read before taking the mutex.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:32 -07:00
Hugh Dickins 26465d3ea5 ksm: break cow once unshared
We kept agreeing not to bother about the unswappable shared KSM pages
which later become unshared by others: observation suggests they're not
a significant proportion.  But they are disadvantageous, and it is easier
to break COW to replace them by swappable pages, than offer statistics
to show that they don't matter; then we can stop worrying about them.

Doing this in ksm_do_scan, they don't go through cmp_and_merge_page on
this pass: give them a good chance of getting into the unstable tree
on the next pass, or back into the stable, by computing checksum now.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:32 -07:00
Hugh Dickins 473b0ce4d1 ksm: pages_unshared and pages_volatile
The pages_shared and pages_sharing counts give a good picture of how
successful KSM is at sharing; but no clue to how much wasted work it's
doing to get there.  Add pages_unshared (count of unique pages waiting
in the unstable tree, hoping to find a mate) and pages_volatile.

pages_volatile is harder to define.  It includes those pages changing
too fast to get into the unstable tree, but also whatever other edge
conditions prevent a page getting into the trees: a high value may
deserve investigation.  Don't try to calculate it from the various
conditions: it's the total of rmap_items less those accounted for.

Also show full_scans: the number of completed scans of everything
registered in the mm list.

The locking for all these counts is simply ksm_thread_mutex.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: Izik Eidus <ieidus@redhat.com>
Acked-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:32 -07:00
Hugh Dickins e178dfde39 ksm: move pages_sharing updates
The pages_shared count is incremented and decremented when adding a node
to and removing a node from the stable tree: easy to understand.  But the
pages_sharing count was hard to follow, being adjusted in various places:
increment and decrement it when adding to and removing from the stable tree.

And the pages_sharing variable used to include the pages_shared, then those
were subtracted when shown in the pages_sharing sysfs file: now keep it as
an exclusive count of leaves hanging off the stable tree nodes, throughout.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: Izik Eidus <ieidus@redhat.com>
Acked-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:32 -07:00
Hugh Dickins b402826033 ksm: rename kernel_pages_allocated
We're not implementing swapping of KSM pages in its first release;
but when that follows, "kernel_pages_allocated" will be a very poor
name for the sysfs file showing number of nodes in the stable tree:
rename that to "pages_shared" throughout.

But we already have a "pages_shared", counting those page slots
sharing the shared pages: first rename that to... "pages_sharing".

What will become of "max_kernel_pages" when the pages shared can
be swapped?  I guess it will just be removed, so keep that name.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: Izik Eidus <ieidus@redhat.com>
Acked-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:32 -07:00
Izik Eidus 339aa62469 ksm: change ksm nice level to be 5
ksm should try not to disturb other tasks as much as possible.

Signed-off-by: Izik Eidus <ieidus@redhat.com>
Cc: Chris Wright <chrisw@redhat.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Avi Kivity <avi@redhat.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>
2009-09-22 07:17:31 -07:00
Izik Eidus 36b2528dc1 ksm: change copyright message
Adding Hugh Dickins into the authors list.

Signed-off-by: Izik Eidus <ieidus@redhat.com>
Cc: Chris Wright <chrisw@redhat.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Avi Kivity <avi@redhat.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>
2009-09-22 07:17:31 -07:00
Hugh Dickins 1ff8299573 ksm: prevent mremap move poisoning
KSM's scan allows for user pages to be COWed or unmapped at any time,
without requiring any notification.  But its stable tree does assume that
when it finds a KSM page where it placed a KSM page, then it is the same
KSM page that it placed there.

mremap move could break that assumption: if an area containing a KSM page
was unmapped, then an area containing a different KSM page was moved with
mremap into the place of the original, before KSM's scan came around to
notice.  That could then poison a node of the stable tree, so that memcmps
would "lie" and upset the ordering of the tree.

Probably noone will ever need mremap move on a VM_MERGEABLE area; except
that prohibiting it would make trouble for schemes in which we try making
everything VM_MERGEABLE e.g.  for testing: an mremap which normally works
would then fail mysteriously.

There's no need to go to any trouble, such as re-sorting KSM's list of
rmap_items to match the new layout: simply unmerge the area to COW all its
KSM pages before moving, but leave VM_MERGEABLE on so that they're
remerged later.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Chris Wright <chrisw@redhat.com>
Signed-off-by: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Avi Kivity <avi@redhat.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>
2009-09-22 07:17:31 -07:00
Izik Eidus 31dbd01f31 ksm: Kernel SamePage Merging
Ksm is code that allows merging of identical pages between one or more
applications, in a way invisible to the applications that use it.  Pages
that are merged are marked as read-only, then COWed when any application
tries to change them.

Whereas fork() allows sharing anonymous pages between parent and child,
ksm can share anonymous pages between unrelated processes.

Ksm works by walking over the memory pages of the applications it scans,
in order to find identical pages.  It uses two sorted data structures,
called the stable and unstable trees, to locate identical pages in an
effective way.

When ksm finds two identical pages, it marks them as readonly and merges
them into a single page.  After the pages have been marked as readonly and
merged into one, Linux treats them as normal copy-on-write pages, copying
to a fresh anonymous page if write access is required later.

Ksm scans and merges anonymous pages only in those memory areas that have
been registered with it by madvise(addr, length, MADV_MERGEABLE).

The ksm scanner is controlled by sysfs files in /sys/kernel/mm/ksm/:

max_kernel_pages - the maximum number of unswappable kernel pages
                   which may be allocated by ksm (0 for unlimited).

kernel_pages_allocated - how many ksm pages are currently allocated,
                         sharing identical content between different
                         processes (pages unswappable in this release).

pages_shared - how many pages have been saved by sharing with ksm pages
               (kernel_pages_allocated being excluded from this count).

pages_to_scan - how many pages ksm should scan before sleeping.

sleep_millisecs - how many milliseconds ksm should sleep between scans.

run - write 0 to disable ksm, read 0 while ksm is disabled (default),
      write 1 to run ksm, read 1 while ksm is running,
      write 2 to disable ksm and unmerge all its pages.

Includes contributions by Andrea Arcangeli Chris Wright and Hugh Dickins.

[hugh.dickins@tiscali.co.uk: fix rare page leak]
Signed-off-by: Izik Eidus <ieidus@redhat.com>
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Chris Wright <chrisw@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Avi Kivity <avi@redhat.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>
2009-09-22 07:17:31 -07:00
Hugh Dickins 9a84089514 ksm: identify PageKsm pages
KSM will need to identify its kernel merged pages unambiguously, and
/proc/kpageflags will probably like to do so too.

Since KSM will only be substituting anonymous pages, statistics are best
preserved by making a PageKsm page a special PageAnon page: one with no
anon_vma.

But KSM then needs its own page_add_ksm_rmap() - keep it in ksm.h near
PageKsm; and do_wp_page() must COW them, unlike singly mapped PageAnons.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Chris Wright <chrisw@redhat.com>
Signed-off-by: Izik Eidus <ieidus@redhat.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Avi Kivity <avi@redhat.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>
2009-09-22 07:17:31 -07:00
Hugh Dickins 21333b2b66 ksm: no debug in page_dup_rmap()
page_dup_rmap(), used on each mapped page when forking, was originally
just an inline atomic_inc of mapcount.  2.6.22 added CONFIG_DEBUG_VM
out-of-line checks to it, which would need to be ever-so-slightly
complicated to allow for the PageKsm() we're about to define.

But I think these checks never caught anything.  And if it's coding errors
we're worried about, such checks should be in page_remove_rmap() too, not
just when forking; whereas if it's pagetable corruption we're worried
about, then they shouldn't be limited to CONFIG_DEBUG_VM.

Oh, just revert page_dup_rmap() to an inline atomic_inc of mapcount.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Chris Wright <chrisw@redhat.com>
Signed-off-by: Izik Eidus <ieidus@redhat.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Avi Kivity <avi@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:31 -07:00
Hugh Dickins f8af4da3b4 ksm: the mm interface to ksm
This patch presents the mm interface to a dummy version of ksm.c, for
better scrutiny of that interface: the real ksm.c follows later.

When CONFIG_KSM is not set, madvise(2) reject MADV_MERGEABLE and
MADV_UNMERGEABLE with EINVAL, since that seems more helpful than
pretending that they can be serviced.  But when CONFIG_KSM=y, accept them
even if KSM is not currently running, and even on areas which KSM will not
touch (e.g.  hugetlb or shared file or special driver mappings).

Like other madvices, report ENOMEM despite success if any area in the
range is unmapped, and use EAGAIN to report out of memory.

Define vma flag VM_MERGEABLE to identify an area on which KSM may try
merging pages: leave it to ksm_madvise() to decide whether to set it.
Define mm flag MMF_VM_MERGEABLE to identify an mm which might contain
VM_MERGEABLE areas, to minimize callouts when forking or exiting.

Based upon earlier patches by Chris Wright and Izik Eidus.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Chris Wright <chrisw@redhat.com>
Signed-off-by: Izik Eidus <ieidus@redhat.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Avi Kivity <avi@redhat.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>
2009-09-22 07:17:31 -07:00
Hugh Dickins 3866ea90d3 ksm: first tidy up madvise_vma()
madvise.c has several levels of switch statements, what to do in which?
Move MADV_DOFORK code down from madvise_vma() to madvise_behavior(), so
madvise_vma() can be a simple router, to madvise_behavior() by default.

vma->vm_flags is an unsigned long so use the same type for new_flags.  Add
missing comment lines to describe MADV_DONTFORK and MADV_DOFORK.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Chris Wright <chrisw@redhat.com>
Signed-off-by: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Avi Kivity <avi@redhat.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>
2009-09-22 07:17:31 -07:00
Izik Eidus 828502d300 ksm: add mmu_notifier set_pte_at_notify()
KSM is a linux driver that allows dynamicly sharing identical memory pages
between one or more processes.

Unlike tradtional page sharing that is made at the allocation of the
memory, ksm do it dynamicly after the memory was created.  Memory is
periodically scanned; identical pages are identified and merged.

The sharing is made in a transparent way to the processes that use it.

Ksm is highly important for hypervisors (kvm), where in production
enviorments there might be many copys of the same data data among the host
memory.  This kind of data can be: similar kernels, librarys, cache, and
so on.

Even that ksm was wrote for kvm, any userspace application that want to
use it to share its data can try it.

Ksm may be useful for any application that might have similar (page
aligment) data strctures among the memory, ksm will find this data merge
it to one copy, and even if it will be changed and thereforew copy on
writed, ksm will merge it again as soon as it will be identical again.

Another reason to consider using ksm is the fact that it might simplify
alot the userspace code of application that want to use shared private
data, instead that the application will mange shared area, ksm will do
this for the application, and even write to this data will be allowed
without any synchinization acts from the application.

Ksm was designed to be a loadable module that doesn't change the VM code
of linux.

This patch:

The set_pte_at_notify() macro allows setting a pte in the shadow page
table directly, instead of flushing the shadow page table entry and then
getting vmexit to set it.  It uses a new change_pte() callback to do so.

set_pte_at_notify() is an optimization for kvm, and other users of
mmu_notifiers, for COW pages.  It is useful for kvm when ksm is used,
because it allows kvm not to have to receive vmexit and only then map the
ksm page into the shadow page table, but instead map it directly at the
same time as Linux maps the page into the host page table.

Users of mmu_notifiers who don't implement new mmu_notifier_change_pte()
callback will just receive the mmu_notifier_invalidate_page() callback.

Signed-off-by: Izik Eidus <ieidus@redhat.com>
Signed-off-by: Chris Wright <chrisw@redhat.com>
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Avi Kivity <avi@redhat.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>
2009-09-22 07:17:31 -07:00
Johannes Weiner 451ea25da7 mm: perform non-atomic test-clear of PG_mlocked on free
By the time PG_mlocked is cleared in the page freeing path, nobody else is
looking at our page->flags anymore.

It is thus safe to make the test-and-clear non-atomic and thereby removing
an unnecessary and expensive operation from a hotpath.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Mel Gorman <mel@csn.ul.ie>
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>
2009-09-22 07:17:30 -07:00
Figo.zhang bf88c8c83e vmalloc.c: fix double error checking
There is no need for double error checking.

Signed-off-by: Figo.zhang <figo1802@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:30 -07:00
Akinobu Mita 945a11136e mm: add gfp mask checking for __get_free_pages()
__get_free_pages() with __GFP_HIGHMEM is not safe because the return
address cannot represent a highmem page.  get_zeroed_page() already has
such a debug checking.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:30 -07:00
KOSAKI Motohiro a26f5320c4 vmscan: kill unnecessary prefetch
The pages in the list passed move_active_pages_to_lru() are already
touched by shrink_active_list().  IOW the prefetch in
move_active_pages_to_lru() don't populate any cache.  it's pointless.

This patch remove it.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: 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>
2009-09-22 07:17:30 -07:00
KOSAKI Motohiro 74a1c48fb4 vmscan: kill unnecessary page flag test
The page_lru() already evaluate PageActive() and PageSwapBacked().  We
don't need to re-evaluate it.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: 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>
2009-09-22 07:17:30 -07:00
KOSAKI Motohiro 5205e56eea vmscan: move ClearPageActive from move_active_pages() to shrink_active_list()
The move_active_pages_to_lru() function is called under irq disabled and
ClearPageActive() doesn't need irq disabling.

Then, this patch move it into shrink_active_list().

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: 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>
2009-09-22 07:17:30 -07:00
Minchan Kim de2e7567c7 vmscan: don't attempt to reclaim anon page in lumpy reclaim when no swap space is available
The VM already avoids attempting to reclaim anon pages in various places,
But it doesn't avoid it for lumpy reclaim.

It shuffles lru list unnecessary so that it is pointless.

[akpm@linux-foundation.org: cleanup]
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Rik van Riel <riel@redhat.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>
2009-09-22 07:17:30 -07:00
Wu Fengguang adea02a1be mm: count only reclaimable lru pages
global_lru_pages() / zone_lru_pages() can be used in two ways:
- to estimate max reclaimable pages in determine_dirtyable_memory()
- to calculate the slab scan ratio

When swap is full or not present, the anon lru lists are not reclaimable
and also won't be scanned.  So the anon pages shall not be counted in both
usage scenarios.  Also rename to _reclaimable_pages: now they are counting
the possibly reclaimable lru pages.

It can greatly (and correctly) increase the slab scan rate under high
memory pressure (when most file pages have been reclaimed and swap is
full/absent), thus reduce false OOM kills.

Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: David Howells <dhowells@redhat.com>
Cc: "Li, Ming Chun" <macli@brc.ubc.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:30 -07:00