Commit Graph

3808 Commits

Author SHA1 Message Date
Hugh Dickins a7016235a6 mm: fix migratetype bug which slowed swapping
After memory pressure has forced it to dip into the reserves, 2.6.32's
5f8dcc2121 "page-allocator: split per-cpu
list into one-list-per-migrate-type" has been returning MIGRATE_RESERVE
pages to the MIGRATE_MOVABLE free_list: in some sense depleting reserves.

Fix that in the most straightforward way (which, considering the overheads
of alternative approaches, is Mel's preference): the right migratetype is
already in page_private(page), but free_pcppages_bulk() wasn't using it.

How did this bug show up?  As a 20% slowdown in my tmpfs loop kbuild
swapping tests, on PowerMac G5 with SLUB allocator.  Bisecting to that
commit was easy, but explaining the magnitude of the slowdown not easy.

The same effect appears, but much less markedly, with SLAB, and even
less markedly on other machines (the PowerMac divides into fewer zones
than x86, I think that may be a factor).  We guess that lumpy reclaim
of short-lived high-order pages is implicated in some way, and probably
this bug has been tickling a poor decision somewhere in page reclaim.

But instrumentation hasn't told me much, I've run out of time and
imagination to determine exactly what's going on, and shouldn't hold up
the fix any longer: it's valid, and might even fix other misbehaviours.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-01-29 10:28:09 -08:00
Linus Torvalds 0531b2aac5 mm: add new 'read_cache_page_gfp()' helper function
It's a simplified 'read_cache_page()' which takes a page allocation
flag, so that different paths can control how aggressive the memory
allocations are that populate a address space.

In particular, the intel GPU object mapping code wants to be able to do
a certain amount of own internal memory management by automatically
shrinking the address space when memory starts getting tight.  This
allows it to dynamically use different memory allocation policies on a
per-allocation basis, rather than depend on the (static) address space
gfp policy.

The actual new function is a one-liner, but re-organizing the helper
functions to the point where you can do this with a single line of code
is what most of the patch is all about.

Tested-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-01-27 09:20:03 -08:00
Yongseok Koh 88f5004430 vmalloc: remove BUG_ON due to racy counting of VM_LAZY_FREE
In free_unmap_area_noflush(), va->flags is marked as VM_LAZY_FREE first, and
then vmap_lazy_nr is increased atomically.

But, in __purge_vmap_area_lazy(), while traversing of vmap_are_list, nr
is counted by checking VM_LAZY_FREE is set to va->flags.  After counting
the variable nr, kernel reads vmap_lazy_nr atomically and checks a
BUG_ON condition whether nr is greater than vmap_lazy_nr to prevent
vmap_lazy_nr from being negative.

The problem is that, if interrupted right after marking VM_LAZY_FREE,
increment of vmap_lazy_nr can be delayed.  Consequently, BUG_ON
condition can be met because nr is counted more than vmap_lazy_nr.

It is highly probable when vmalloc/vfree are called frequently.  This
scenario have been verified by adding delay between marking VM_LAZY_FREE
and increasing vmap_lazy_nr in free_unmap_area_noflush().

Even the vmap_lazy_nr is for checking high watermark, it never be the
strict watermark.  Although the BUG_ON condition is to prevent
vmap_lazy_nr from being negative, vmap_lazy_nr is signed variable.  So,
it could go down to negative value temporarily.

Consequently, removing the BUG_ON condition is proper.

A possible BUG_ON message is like the below.

   kernel BUG at mm/vmalloc.c:517!
   invalid opcode: 0000 [#1] SMP
   EIP: 0060:[<c04824a4>] EFLAGS: 00010297 CPU: 3
   EIP is at __purge_vmap_area_lazy+0x144/0x150
   EAX: ee8a8818 EBX: c08e77d4 ECX: e7c7ae40 EDX: c08e77ec
   ESI: 000081fe EDI: e7c7ae60 EBP: e7c7ae64 ESP: e7c7ae3c
   DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
   Call Trace:
   [<c0482ad9>] free_unmap_vmap_area_noflush+0x69/0x70
   [<c0482b02>] remove_vm_area+0x22/0x70
   [<c0482c15>] __vunmap+0x45/0xe0
   [<c04831ec>] vmalloc+0x2c/0x30
   Code: 8d 59 e0 eb 04 66 90 89 cb 89 d0 e8 87 fe ff ff 8b 43 20 89 da 8d 48 e0 8d 43 20 3b 04 24 75 e7 fe 05 a8 a5 a3 c0 e9 78 ff ff ff <0f> 0b eb fe 90 8d b4 26 00 00 00 00 56 89 c6 b8 ac a5 a3 c0 31
   EIP: [<c04824a4>] __purge_vmap_area_lazy+0x144/0x150 SS:ESP 0068:e7c7ae3c

[ See also http://marc.info/?l=linux-kernel&m=126335856228090&w=2 ]

Signed-off-by: Yongseok Koh <yongseok.koh@samsung.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-01-21 07:20:06 -08:00
KOSAKI Motohiro 6ccf80eb15 page allocator: update NR_FREE_PAGES only when necessary
commit f2260e6b (page allocator: update NR_FREE_PAGES only as necessary)
made one minor regression.  if __rmqueue() was failed, NR_FREE_PAGES stat
go wrong.  this patch fixes it.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Reported-by: Huang Shijie <shijie8@gmail.com>
Reviewed-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>
2010-01-16 16:53:55 -08:00
David Howells 7e6608724c nommu: fix shared mmap after truncate shrinkage problems
Fix a problem in NOMMU mmap with ramfs whereby a shared mmap can happen
over the end of a truncation.  The problem is that
ramfs_nommu_check_mappings() checks that the reduced file size against the
VMA tree, but not the vm_region tree.

The following sequence of events can cause the problem:

	fd = open("/tmp/x", O_RDWR|O_TRUNC|O_CREAT, 0600);
	ftruncate(fd, 32 * 1024);
	a = mmap(NULL, 32 * 1024, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
	b = mmap(NULL, 16 * 1024, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
	munmap(a, 32 * 1024);
	ftruncate(fd, 16 * 1024);
	c = mmap(NULL, 32 * 1024, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);

Mapping 'a' creates a vm_region covering 32KB of the file.  Mapping 'b'
sees that the vm_region from 'a' is covering the region it wants and so
shares it, pinning it in memory.

Mapping 'a' then goes away and the file is truncated to the end of VMA
'b'.  However, the region allocated by 'a' is still in effect, and has
_not_ been reduced.

Mapping 'c' is then created, and because there's a vm_region covering the
desired region, get_unmapped_area() is _not_ called to repeat the check,
and the mapping is granted, even though the pages from the latter half of
the mapping have been discarded.

However:

	d = mmap(NULL, 16 * 1024, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);

Mapping 'd' should work, and should end up sharing the region allocated by
'a'.

To deal with this, we shrink the vm_region struct during the truncation,
lest do_mmap_pgoff() take it as licence to share the full region
automatically without calling the get_unmapped_area() file op again.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-01-16 12:15:40 -08:00
David Howells efc1a3b169 nommu: don't need get_unmapped_area() for NOMMU
get_unmapped_area() is unnecessary for NOMMU as no-one calls it.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-01-16 12:15:40 -08:00
David Howells 779c10232c nommu: remove a superfluous check of vm_region::vm_usage
In split_vma(), there's no need to check if the VMA being split has a
region that's in use by more than one VMA because:

 (1) The preceding test prohibits splitting of non-anonymous VMAs and regions
     (eg: file or chardev backed VMAs).

 (2) Anonymous regions can't be mapped multiple times because there's no handle
     by which to refer to the already existing region.

 (3) If a VMA has previously been split, then the region backing it has also
     been split into two regions, each of usage 1.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-01-16 12:15:40 -08:00
David Howells 1e2ae599d3 nommu: struct vm_region's vm_usage count need not be atomic
The vm_usage count field in struct vm_region does not need to be atomic as
it's only even modified whilst nommu_region_sem is write locked.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-01-16 12:15:40 -08:00
Daisuke Nishimura fce6647757 memcg: ensure list is empty at rmdir
Current mem_cgroup_force_empty() only ensures mem->res.usage == 0 on
success.  But this doesn't guarantee memcg's LRU is really empty, because
there are some cases in which !PageCgrupUsed pages exist on memcg's LRU.

For example:
- Pages can be uncharged by its owner process while they are on LRU.
- race between mem_cgroup_add_lru_list() and __mem_cgroup_uncharge_common().

So there can be a case in which the usage is zero but some of the LRUs are not empty.

OTOH, mem_cgroup_del_lru_list(), which can be called asynchronously with
rmdir, accesses the mem_cgroup, so this access can cause a problem if it
races with rmdir because the mem_cgroup might have been freed by rmdir.

Actually, I saw a bug which seems to be caused by this race.

	[1530745.949906] BUG: unable to handle kernel NULL pointer dereference at 0000000000000230
	[1530745.950651] IP: [<ffffffff810fbc11>] mem_cgroup_del_lru_list+0x30/0x80
	[1530745.950651] PGD 3863de067 PUD 3862c7067 PMD 0
	[1530745.950651] Oops: 0002 [#1] SMP
	[1530745.950651] last sysfs file: /sys/devices/system/cpu/cpu7/cache/index1/shared_cpu_map
	[1530745.950651] CPU 3
	[1530745.950651] Modules linked in: configs ipt_REJECT xt_tcpudp iptable_filter ip_tables x_tables bridge stp nfsd nfs_acl auth_rpcgss exportfs autofs4 hidp rfcomm l2cap crc16 bluetooth lockd sunrpc ib_iser rdma_cm ib_cm iw_cm ib_sa ib_mad ib_core ib_addr iscsi_tcp bnx2i cnic uio ipv6 cxgb3i cxgb3 mdio libiscsi_tcp libiscsi scsi_transport_iscsi dm_mirror dm_multipath scsi_dh video output sbs sbshc battery ac lp kvm_intel kvm sg ide_cd_mod cdrom serio_raw tpm_tis tpm tpm_bios acpi_memhotplug button parport_pc parport rtc_cmos rtc_core rtc_lib e1000 i2c_i801 i2c_core pcspkr dm_region_hash dm_log dm_mod ata_piix libata shpchp megaraid_mbox sd_mod scsi_mod megaraid_mm ext3 jbd uhci_hcd ohci_hcd ehci_hcd [last unloaded: freq_table]
	[1530745.950651] Pid: 19653, comm: shmem_test_02 Tainted: G   M       2.6.32-mm1-00701-g2b04386 #3 Express5800/140Rd-4 [N8100-1065]
	[1530745.950651] RIP: 0010:[<ffffffff810fbc11>]  [<ffffffff810fbc11>] mem_cgroup_del_lru_list+0x30/0x80
	[1530745.950651] RSP: 0018:ffff8803863ddcb8  EFLAGS: 00010002
	[1530745.950651] RAX: 00000000000001e0 RBX: ffff8803abc02238 RCX: 00000000000001e0
	[1530745.950651] RDX: 0000000000000000 RSI: ffff88038611a000 RDI: ffff8803abc02238
	[1530745.950651] RBP: ffff8803863ddcc8 R08: 0000000000000002 R09: ffff8803a04c8643
	[1530745.950651] R10: 0000000000000000 R11: ffffffff810c7333 R12: 0000000000000000
	[1530745.950651] R13: ffff880000017f00 R14: 0000000000000092 R15: ffff8800179d0310
	[1530745.950651] FS:  0000000000000000(0000) GS:ffff880017800000(0000) knlGS:0000000000000000
	[1530745.950651] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
	[1530745.950651] CR2: 0000000000000230 CR3: 0000000379d87000 CR4: 00000000000006e0
	[1530745.950651] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
	[1530745.950651] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
	[1530745.950651] Process shmem_test_02 (pid: 19653, threadinfo ffff8803863dc000, task ffff88038612a8a0)
	[1530745.950651] Stack:
	[1530745.950651]  ffffea00040c2fe8 0000000000000000 ffff8803863ddd98 ffffffff810c739a
	[1530745.950651] <0> 00000000863ddd18 000000000000000c 0000000000000000 0000000000000000
	[1530745.950651] <0> 0000000000000002 0000000000000000 ffff8803863ddd68 0000000000000046
	[1530745.950651] Call Trace:
	[1530745.950651]  [<ffffffff810c739a>] release_pages+0x142/0x1e7
	[1530745.950651]  [<ffffffff810c778f>] ? pagevec_move_tail+0x6e/0x112
	[1530745.950651]  [<ffffffff810c781e>] pagevec_move_tail+0xfd/0x112
	[1530745.950651]  [<ffffffff810c78a9>] lru_add_drain+0x76/0x94
	[1530745.950651]  [<ffffffff810dba0c>] exit_mmap+0x6e/0x145
	[1530745.950651]  [<ffffffff8103f52d>] mmput+0x5e/0xcf
	[1530745.950651]  [<ffffffff81043ea8>] exit_mm+0x11c/0x129
	[1530745.950651]  [<ffffffff8108fb29>] ? audit_free+0x196/0x1c9
	[1530745.950651]  [<ffffffff81045353>] do_exit+0x1f5/0x6b7
	[1530745.950651]  [<ffffffff8106133f>] ? up_read+0x2b/0x2f
	[1530745.950651]  [<ffffffff8137d187>] ? lockdep_sys_exit_thunk+0x35/0x67
	[1530745.950651]  [<ffffffff81045898>] do_group_exit+0x83/0xb0
	[1530745.950651]  [<ffffffff810458dc>] sys_exit_group+0x17/0x1b
	[1530745.950651]  [<ffffffff81002c1b>] system_call_fastpath+0x16/0x1b
	[1530745.950651] Code: 54 53 0f 1f 44 00 00 83 3d cc 29 7c 00 00 41 89 f4 75 63 eb 4e 48 83 7b 08 00 75 04 0f 0b eb fe 48 89 df e8 18 f3 ff ff 44 89 e2 <48> ff 4c d0 50 48 8b 05 2b 2d 7c 00 48 39 43 08 74 39 48 8b 4b
	[1530745.950651] RIP  [<ffffffff810fbc11>] mem_cgroup_del_lru_list+0x30/0x80
	[1530745.950651]  RSP <ffff8803863ddcb8>
	[1530745.950651] CR2: 0000000000000230
	[1530745.950651] ---[ end trace c3419c1bb8acc34f ]---
	[1530745.950651] Fixing recursive fault but reboot is needed!

The problem here is pages on LRU may contain pointer to stale memcg.  To
make res->usage to be 0, all pages on memcg must be uncharged or moved to
another(parent) memcg.  Moved page_cgroup have already removed from
original LRU, but uncharged page_cgroup contains pointer to memcg withou
PCG_USED bit.  (This asynchronous LRU work is for improving performance.)
If PCG_USED bit is not set, page_cgroup will never be added to memcg's
LRU.  So, about pages not on LRU, they never access stale pointer.  Then,
what we have to take care of is page_cgroup _on_ LRU list.  This patch
fixes this problem by making mem_cgroup_force_empty() visit all LRUs
before exiting its loop and guarantee there are no pages on its LRU.

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-01-16 12:15:39 -08:00
KOSAKI Motohiro de3fab3934 vmscan: kswapd: don't retry balance_pgdat() if all zones are unreclaimable
Commit f50de2d3 (vmscan: have kswapd sleep for a short interval and double
check it should be asleep) can cause kswapd to enter an infinite loop if
running on a single-CPU system.  If all zones are unreclaimble,
sleeping_prematurely return 1 and kswapd will call balance_pgdat() again.
but it's totally meaningless, balance_pgdat() doesn't anything against
unreclaimable zone!

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Reported-by: Will Newton <will.newton@gmail.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Tested-by: Will Newton <will.newton@gmail.com>
Reviewed-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>
2010-01-16 12:15:39 -08:00
Kazuhisa Ichikawa d2dbe08ddc mm/page_alloc: fix the range check for backward merging
The current check for 'backward merging' within add_active_range() does
not seem correct.  start_pfn must be compared against
early_node_map[i].start_pfn (and NOT against .end_pfn) to find out whether
the new region is backward-mergeable with the existing range.

Signed-off-by: Kazuhisa Ichikawa <ki@epsilou.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-01-16 12:15:38 -08:00
OGAWA Hirofumi cedabed49b vfs: Fix vmtruncate() regression
If __block_prepare_write() was failed in block_write_begin(), the
allocated blocks can be outside of ->i_size.

But new truncate_pagecache() in vmtuncate() does nothing if new < old.
It means the above usage is not working anymore.

So, this patch fixes it by removing "new < old" check. It would need
more cleanup/change. But, now -rc and truncate working is in progress,
so, this tried to fix it minimum change.

Acked-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-01-13 16:09:33 -08:00
Andrea Arcangeli 74dbdd239b mm: hugetlb: fix clear_huge_page()
sz is in bytes, MAX_ORDER_NR_PAGES is in pages.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: David Gibson <dwg@au1.ibm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: David Rientjes <rientjes@google.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-01-11 09:34:06 -08:00
Andrew Morton 129182e562 percpu: avoid calling __pcpu_ptr_to_addr(NULL)
__pcpu_ptr_to_addr() can be overridden by the architecture and might not
behave well if passed a NULL pointer.  So avoid calling it until we have
verified that its arg is not NULL.

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Kamalesh Babulal <kamalesh@linux.vnet.ibm.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>
2010-01-11 09:34:04 -08:00
Jason Wessel 6144a85a0e maccess,probe_kernel: Allow arch specific override probe_kernel_(read|write)
Some archs such as blackfin, would like to have an arch specific
probe_kernel_read() and probe_kernel_write() implementation which can
fall back to the generic implementation if no special operations are
needed.

CC: Thomas Gleixner <tglx@linutronix.de>
CC: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-01-07 11:58:36 -06:00
Jie Zhang 7959722b95 NOMMU: Use copy_*_user_page() in access_process_vm()
The MMU code uses the copy_*_user_page() variants in access_process_vm()
rather than copy_*_user() as the former includes an icache flush.  This
is important when doing things like setting software breakpoints with
gdb.  So switch the NOMMU code over to do the same.

This patch makes the reasonable assumption that copy_from_user_page()
won't fail - which is probably fine, as we've checked the VMA from which
we're copying is usable, and the copy is not allowed to cross VMAs.  The
one case where it might go wrong is if the VMA is a device rather than
RAM, and that device returns an error which - in which case rubbish will
be returned rather than EIO.

Signed-off-by: Jie Zhang <jie.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: David McCullough <david_mccullough@mcafee.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Acked-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-01-06 18:16:02 -08:00
Mike Frysinger cfe79c00a2 NOMMU: Avoiding duplicate icache flushes of shared maps
When working with FDPIC, there are many shared mappings of read-only
code regions between applications (the C library, applet packages like
busybox, etc.), but the current do_mmap_pgoff() function will issue an
icache flush whenever a VMA is added to an MM instead of only doing it
when the map is initially created.

The flush can instead be done when a region is first mmapped PROT_EXEC.
Note that we may not rely on the first mapping of a region being
executable - it's possible for it to be PROT_READ only, so we have to
remember whether we've flushed the region or not, and then flush the
entire region when a bit of it is made executable.

However, this also affects the brk area.  That will no longer be
executable.  We can mprotect() it to PROT_EXEC on MPU-mode kernels, but
for NOMMU mode kernels, when it increases the brk allocation, making
sys_brk() flush the extra from the icache should suffice.  The brk area
probably isn't used by NOMMU programs since the brk area can only use up
the leavings from the stack allocation, where the stack allocation is
larger than requested.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-01-06 18:16:02 -08:00
Linus Torvalds f8e9766dd1 Merge branch 'slab/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6
* 'slab/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6:
  SLAB: Fix lockdep annotation breakage
2009-12-30 13:14:25 -08:00
Hugh Dickins 66f0dc481e mm: move sys_mmap_pgoff from util.c
Move sys_mmap_pgoff() from mm/util.c to mm/mmap.c and mm/nommu.c,
where we'd expect to find such code: especially now that it contains
the MAP_HUGETLB handling.  Revert mm/util.c to how it was in 2.6.32.

This patch just ignores MAP_HUGETLB in the nommu case, as in 2.6.32,
whereas 2.6.33-rc2 reported -ENOSYS.  Perhaps validate_mmap_request()
should reject it with -EINVAL?  Add that later if necessary.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-30 12:23:27 -08:00
Pekka Enberg 00afa75806 SLAB: Fix lockdep annotation breakage
Commit ce79ddc8e2 ("SLAB: Fix lockdep annotations
for CPU hotplug") broke init_node_lock_keys() off-slab logic which causes
lockdep false positives.

Fix that up by reverting the logic back to original while keeping CPU hotplug
fixes intact.

Reported-and-tested-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reported-and-tested-by: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
2009-12-28 20:57:27 +02:00
Linus Torvalds 0b5e2588d8 Merge branch 'sysctl' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-misc-2.6
* 'sysctl' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-misc-2.6:
  SYSCTL: Add a mutex to the page_alloc zone order sysctl
  SYSCTL: Print binary sysctl warnings (nearly) only once
2009-12-24 13:01:29 -08:00
Linus Torvalds 6067d7e4f0 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:
  HWPOISON: Add PROC_FS dependency to hwpoison injector v2
2009-12-24 13:01:13 -08:00
Andi Kleen 443c6f145d SYSCTL: Add a mutex to the page_alloc zone order sysctl
The zone list code clearly cannot tolerate concurrent writers (I couldn't
find any locks for that), so simply add a global mutex. No need for RCU
in this case.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
2009-12-23 21:01:16 +01:00
Linus Torvalds dd508ae2db 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: (36 commits)
  powerpc/gc/wii: Remove get_irq_desc()
  powerpc/gc/wii: hlwd-pic: convert irq_desc.lock to raw_spinlock
  powerpc/gamecube/wii: Fix off-by-one error in ugecon/usbgecko_udbg
  powerpc/mpic: Fix problem that affinity is not updated
  powerpc/mm: Fix stupid bug in subpge protection handling
  powerpc/iseries: use DECLARE_COMPLETION_ONSTACK for non-constant completion
  powerpc: Fix MSI support on U4 bridge PCIe slot
  powerpc: Handle VSX alignment faults correctly in little-endian mode
  powerpc/mm: Fix typo of cpumask_clear_cpu()
  powerpc/mm: Fix hash_utils_64.c compile errors with DEBUG enabled.
  powerpc: Convert BUG() to use unreachable()
  powerpc/pseries: Make declarations of cpu_hotplug_driver_lock() ANSI compatible.
  powerpc/pseries: Don't panic when H_PROD fails during cpu-online.
  powerpc/mm: Fix a WARN_ON() with CONFIG_DEBUG_PAGEALLOC and CONFIG_DEBUG_VM
  powerpc/defconfigs: Set HZ=100 on pseries and ppc64 defconfigs
  powerpc/defconfigs: Disable token ring in powerpc defconfigs
  powerpc/defconfigs: Reduce 64bit vmlinux by making acenic and cramfs modules
  powerpc/pseries: Select XICS and PCI_MSI PSERIES
  powerpc/85xx: Wrong variable returned on error
  powerpc/iseries: Convert to proc_fops
  ...
2009-12-22 14:18:13 -08:00
Andi Kleen 27df5068e2 HWPOISON: Add PROC_FS dependency to hwpoison injector v2
The injector filter requires stable_page_flags() which is supplied
by procfs. So make it dependent on that.

Also add ifdefs around the filter code in memory-failure.c so that
when the filter is disabled due to missing dependencies the whole
code still builds.

Reported-by: Ingo Molnar
Signed-off-by: Andi Kleen <ak@linux.intel.com>
2009-12-21 19:56:42 +01:00
Linus Torvalds 3981e15286 Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, irq: Allow 0xff for /proc/irq/[n]/smp_affinity on an 8-cpu system
  Makefile: Unexport LC_ALL instead of clearing it
  x86: Fix objdump version check in arch/x86/tools/chkobjdump.awk
  x86: Reenable TSC sync check at boot, even with NONSTOP_TSC
  x86: Don't use POSIX character classes in gen-insn-attr-x86.awk
  Makefile: set LC_CTYPE, LC_COLLATE, LC_NUMERIC to C
  x86: Increase MAX_EARLY_RES; insufficient on 32-bit NUMA
  x86: Fix checking of SRAT when node 0 ram is not from 0
  x86, cpuid: Add "volatile" to asm in native_cpuid()
  x86, msr: msrs_alloc/free for CONFIG_SMP=n
  x86, amd: Get multi-node CPU info from NodeId MSR instead of PCI config space
  x86: Add IA32_TSC_AUX MSR and use it
  x86, msr/cpuid: Register enough minors for the MSR and CPUID drivers
  initramfs: add missing decompressor error check
  bzip2: Add missing checks for malloc returning NULL
  bzip2/lzma/gzip: pre-boot malloc doesn't return NULL on failure
2009-12-19 09:48:14 -08:00
Robert Jennings 925cc71e51 mm: Add notifier in pageblock isolation for balloon drivers
Memory balloon drivers can allocate a large amount of memory which is not
movable but could be freed to accomodate memory hotplug remove.

Prior to calling the memory hotplug notifier chain the memory in the
pageblock is isolated.  Currently, if the migrate type is not
MIGRATE_MOVABLE the isolation will not proceed, causing the memory removal
for that page range to fail.

Rather than failing pageblock isolation if the migrateteype is not
MIGRATE_MOVABLE, this patch checks if all of the pages in the pageblock,
and not on the LRU, are owned by a registered balloon driver (or other
entity) using a notifier chain.  If all of the non-movable pages are owned
by a balloon, they can be freed later through the memory notifier chain
and the range can still be isolated in set_migratetype_isolate().

Signed-off-by: Robert Jennings <rcj@linux.vnet.ibm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Brian King <brking@linux.vnet.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Gerald Schaefer <geralds@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-12-18 14:53:36 +11:00
Linus Torvalds 55db493b65 Merge branch 'cpumask-cleanups' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus
* 'cpumask-cleanups' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
  cpumask: rename tsk_cpumask to tsk_cpus_allowed
  cpumask: don't recommend set_cpus_allowed hack in Documentation/cpu-hotplug.txt
  cpumask: avoid dereferencing struct cpumask
  cpumask: convert drivers/idle/i7300_idle.c to cpumask_var_t
  cpumask: use modern cpumask style in drivers/scsi/fcoe/fcoe.c
  cpumask: avoid deprecated function in mm/slab.c
  cpumask: use cpu_online in kernel/perf_event.c
2009-12-17 17:00:20 -08:00
Linus Torvalds efc8e7f4c8 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6:
  Keys: KEYCTL_SESSION_TO_PARENT needs TIF_NOTIFY_RESUME architecture support
  NOMMU: Optimise away the {dac_,}mmap_min_addr tests
  security/min_addr.c: make init_mmap_min_addr() static
  keys: PTR_ERR return of wrong pointer in keyctl_get_security()
2009-12-17 16:58:26 -08:00
Linus Torvalds dcc7cd0112 Merge branch 'kmemleak' of git://linux-arm.org/linux-2.6
* 'kmemleak' of git://linux-arm.org/linux-2.6:
  kmemleak: fix kconfig for crc32 build error
  kmemleak: Reduce the false positives by checking for modified objects
  kmemleak: Show the age of an unreferenced object
  kmemleak: Release the object lock before calling put_object()
  kmemleak: Scan the _ftrace_events section in modules
  kmemleak: Simplify the kmemleak_scan_area() function prototype
  kmemleak: Do not use off-slab management with SLAB_NOLEAKTRACE
2009-12-17 16:00:19 -08:00
Hisashi Hifumi 65a80b4c61 readahead: add blk_run_backing_dev
I added blk_run_backing_dev on page_cache_async_readahead so readahead I/O
is unpluged to improve throughput on especially RAID environment.

The normal case is, if page N become uptodate at time T(N), then T(N) <=
T(N+1) holds.  With RAID (and NFS to some degree), there is no strict
ordering, the data arrival time depends on runtime status of individual
disks, which breaks that formula.  So in do_generic_file_read(), just
after submitting the async readahead IO request, the current page may well
be uptodate, so the page won't be locked, and the block device won't be
implicitly unplugged:

               if (PageReadahead(page))
                        page_cache_async_readahead()
                if (!PageUptodate(page))
                                goto page_not_up_to_date;
                //...
page_not_up_to_date:
                lock_page_killable(page);

Therefore explicit unplugging can help.

Following is the test result with dd.

#dd if=testdir/testfile of=/dev/null bs=16384

-2.6.30-rc6
1048576+0 records in
1048576+0 records out
17179869184 bytes (17 GB) copied, 224.182 seconds, 76.6 MB/s

-2.6.30-rc6-patched
1048576+0 records in
1048576+0 records out
17179869184 bytes (17 GB) copied, 206.465 seconds, 83.2 MB/s

(7Disks RAID-0 Array)

-2.6.30-rc6
1054976+0 records in
1054976+0 records out
17284726784 bytes (17 GB) copied, 212.233 seconds, 81.4 MB/s

-2.6.30-rc6-patched
1054976+0 records out
17284726784 bytes (17 GB) copied, 198.878 seconds, 86.9 MB/s

(7Disks RAID-5 Array)

The patch was found to improve performance with the SCST scsi target
driver.  See
http://sourceforge.net/mailarchive/forum.php?thread_name=a0272b440906030714g67eabc5k8f847fb1e538cc62%40mail.gmail.com&forum_name=scst-devel

[akpm@linux-foundation.org: unbust comment layout]
[akpm@linux-foundation.org: "fix" CONFIG_BLOCK=n]
Signed-off-by: Hisashi Hifumi <hifumi.hisashi@oss.ntt.co.jp>
Acked-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Tested-by: Ronald <intercommit@gmail.com>
Cc: Bart Van Assche <bart.vanassche@gmail.com>
Cc: Vladislav Bolkhovitin <vst@vlnb.net>
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>
2009-12-17 15:45:32 -08:00
Rusty Russell 58463c1fe2 cpumask: avoid deprecated function in mm/slab.c
These days we use cpumask_empty() which takes a pointer.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
2009-12-17 11:43:13 +10:30
Al Viro 718deb6b61 Fix breakage in shmem.c
Replacing
	error = 0;
	if (error)
		op
with nothing is not quite an equivalent transformation ;-)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-12-16 19:48:48 -05:00
Yinghai Lu 3299625036 x86: Fix checking of SRAT when node 0 ram is not from 0
Found one system that boot from socket1 instead of socket0, SRAT get rejected...

[    0.000000] SRAT: Node 1 PXM 0 0-a0000
[    0.000000] SRAT: Node 1 PXM 0 100000-80000000
[    0.000000] SRAT: Node 1 PXM 0 100000000-2080000000
[    0.000000] SRAT: Node 0 PXM 1 2080000000-4080000000
[    0.000000] SRAT: Node 2 PXM 2 4080000000-6080000000
[    0.000000] SRAT: Node 3 PXM 3 6080000000-8080000000
[    0.000000] SRAT: Node 4 PXM 4 8080000000-a080000000
[    0.000000] SRAT: Node 5 PXM 5 a080000000-c080000000
[    0.000000] SRAT: Node 6 PXM 6 c080000000-e080000000
[    0.000000] SRAT: Node 7 PXM 7 e080000000-10080000000
...
[    0.000000] NUMA: Allocated memnodemap from 500000 - 701040
[    0.000000] NUMA: Using 20 for the hash shift.
[    0.000000] Adding active range (0, 0x2080000, 0x4080000) 0 entries of 3200 used
[    0.000000] Adding active range (1, 0x0, 0x96) 1 entries of 3200 used
[    0.000000] Adding active range (1, 0x100, 0x7f750) 2 entries of 3200 used
[    0.000000] Adding active range (1, 0x100000, 0x2080000) 3 entries of 3200 used
[    0.000000] Adding active range (2, 0x4080000, 0x6080000) 4 entries of 3200 used
[    0.000000] Adding active range (3, 0x6080000, 0x8080000) 5 entries of 3200 used
[    0.000000] Adding active range (4, 0x8080000, 0xa080000) 6 entries of 3200 used
[    0.000000] Adding active range (5, 0xa080000, 0xc080000) 7 entries of 3200 used
[    0.000000] Adding active range (6, 0xc080000, 0xe080000) 8 entries of 3200 used
[    0.000000] Adding active range (7, 0xe080000, 0x10080000) 9 entries of 3200 used
[    0.000000] SRAT: PXMs only cover 917504MB of your 1048566MB e820 RAM. Not used.
[    0.000000] SRAT: SRAT not used.

the early_node_map is not sorted because node0 with non zero start come first.

so try to sort it right away after all regions are registered.

also fixs refression by 8716273c (x86: Export srat physical topology)

-v2: make it more solid to handle cross node case like node0 [0,4g), [8,12g) and node1 [4g, 8g), [12g, 16g)
-v3: update comments.

Reported-and-tested-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <4B2579D2.3010201@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-12-16 16:43:37 -08:00
David Howells 6e14154676 NOMMU: Optimise away the {dac_,}mmap_min_addr tests
In NOMMU mode clamp dac_mmap_min_addr to zero to cause the tests on it to be
skipped by the compiler.  We do this as the minimum mmap address doesn't make
any sense in NOMMU mode.

mmap_min_addr and round_hint_to_min() can be discarded entirely in NOMMU mode.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
2009-12-17 09:25:19 +11:00
Linus Torvalds d4220f987c 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: (34 commits)
  HWPOISON: Remove stray phrase in a comment
  HWPOISON: Try to allocate migration page on the same node
  HWPOISON: Don't do early filtering if filter is disabled
  HWPOISON: Add a madvise() injector for soft page offlining
  HWPOISON: Add soft page offline support
  HWPOISON: Undefine short-hand macros after use to avoid namespace conflict
  HWPOISON: Use new shake_page in memory_failure
  HWPOISON: Use correct name for MADV_HWPOISON in documentation
  HWPOISON: mention HWPoison in Kconfig entry
  HWPOISON: Use get_user_page_fast in hwpoison madvise
  HWPOISON: add an interface to switch off/on all the page filters
  HWPOISON: add memory cgroup filter
  memcg: add accessor to mem_cgroup.css
  memcg: rename and export try_get_mem_cgroup_from_page()
  HWPOISON: add page flags filter
  mm: export stable page flags
  HWPOISON: limit hwpoison injector to known page types
  HWPOISON: add fs/device filters
  HWPOISON: return 0 to indicate success reliably
  HWPOISON: make semantics of IGNORED/DELAYED clear
  ...
2009-12-16 12:36:49 -08:00
Linus Torvalds bac5e54c29 Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (38 commits)
  direct I/O fallback sync simplification
  ocfs: stop using do_sync_mapping_range
  cleanup blockdev_direct_IO locking
  make generic_acl slightly more generic
  sanitize xattr handler prototypes
  libfs: move EXPORT_SYMBOL for d_alloc_name
  vfs: force reval of target when following LAST_BIND symlinks (try #7)
  ima: limit imbalance msg
  Untangling ima mess, part 3: kill dead code in ima
  Untangling ima mess, part 2: deal with counters
  Untangling ima mess, part 1: alloc_file()
  O_TRUNC open shouldn't fail after file truncation
  ima: call ima_inode_free ima_inode_free
  IMA: clean up the IMA counts updating code
  ima: only insert at inode creation time
  ima: valid return code from ima_inode_alloc
  fs: move get_empty_filp() deffinition to internal.h
  Sanitize exec_permission_lite()
  Kill cached_lookup() and real_lookup()
  Kill path_lookup_open()
  ...

Trivial conflicts in fs/direct-io.c
2009-12-16 12:04:02 -08:00
Christoph Hellwig c05c4edd87 direct I/O fallback sync simplification
In the case of direct I/O falling back to buffered I/O we sync data
twice currently: once at the end of generic_file_buffered_write using
filemap_write_and_wait_range and once a little later in
__generic_file_aio_write using do_sync_mapping_range with all flags set.

The wait before write of the do_sync_mapping_range call does not make
any sense, so just keep the filemap_write_and_wait_range call and move
it to the right spot.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-12-16 12:16:50 -05:00
Christoph Hellwig 1c7c474c31 make generic_acl slightly more generic
Now that we cache the ACL pointers in the generic inode all the generic_acl
cruft can go away and generic_acl.c can directly implement xattr handlers
dealing with the full Posix ACL semantics for in-memory filesystems.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-12-16 12:16:49 -05:00
Christoph Hellwig 431547b3c4 sanitize xattr handler prototypes
Add a flags argument to struct xattr_handler and pass it to all xattr
handler methods.  This allows using the same methods for multiple
handlers, e.g. for the ACL methods which perform exactly the same action
for the access and default ACLs, just using a different underlying
attribute.  With a little more groundwork it'll also allow sharing the
methods for the regular user/trusted/secure handlers in extN, ocfs2 and
jffs2 like it's already done for xfs in this patch.

Also change the inode argument to the handlers to a dentry to allow
using the handlers mechnism for filesystems that require it later,
e.g. cifs.

[with GFS2 bits updated by Steven Whitehouse <swhiteho@redhat.com>]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: James Morris <jmorris@namei.org>
Acked-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-12-16 12:16:49 -05:00
Al Viro 0552f879d4 Untangling ima mess, part 1: alloc_file()
There are 2 groups of alloc_file() callers:
	* ones that are followed by ima_counts_get
	* ones giving non-regular files
So let's pull that ima_counts_get() into alloc_file();
it's a no-op in case of non-regular files.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-12-16 12:16:47 -05:00
Al Viro 2c48b9c455 switch alloc_file() to passing struct path
... and have the caller grab both mnt and dentry; kill
leak in infiniband, while we are at it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-12-16 12:16:42 -05:00
Al Viro 4b42af81f0 switch shmem_file_setup() to alloc_file()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-12-16 12:16:40 -05:00
Bob Liu aa20d489ce memcg: code clean, remove unused variable in mem_cgroup_resize_limit()
Variable `progress' isn't used in mem_cgroup_resize_limit() any more.
Remove it.

[akpm@linux-foundation.org: cleanup]
Signed-off-by: Bob Liu <lliubbo@gmail.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
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>
2009-12-16 07:20:08 -08:00
Daisuke Nishimura 9ab322caa3 memcg: remove memcg_tasklist
memcg_tasklist was introduced at commit 7f4d454d(memcg: avoid deadlock
caused by race between oom and cpuset_attach) instead of cgroup_mutex to
fix a deadlock problem.  The cgroup_mutex, which was removed by the
commit, in mem_cgroup_out_of_memory() was originally introduced at commit
c7ba5c9e (Memory controller: OOM handling).

IIUC, the intention of this cgroup_mutex was to prevent task move during
select_bad_process() so that situations like below can be avoided.

  Assume cgroup "foo" has exceeded its limit and is about to trigger oom.
  1. Process A, which has been in cgroup "baa" and uses large memory, is just
     moved to cgroup "foo". Process A can be the candidates for being killed.
  2. Process B, which has been in cgroup "foo" and uses large memory, is just
     moved from cgroup "foo". Process B can be excluded from the candidates for
     being killed.

But these race window exists anyway even if we hold a lock, because
__mem_cgroup_try_charge() decides wether it should trigger oom or not
outside of the lock.  So the original cgroup_mutex in
mem_cgroup_out_of_memory and thus current memcg_tasklist has no use.  And
IMHO, those races are not so critical for users.

This patch removes it and make codes simpler.

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:07 -08:00
Daisuke Nishimura d31f56dbf8 memcg: avoid oom-killing innocent task in case of use_hierarchy
task_in_mem_cgroup(), which is called by select_bad_process() to check
whether a task can be a candidate for being oom-killed from memcg's limit,
checks "curr->use_hierarchy"("curr" is the mem_cgroup the task belongs
to).

But this check return true(it's false positive) when:

	<some path>/aa		use_hierarchy == 0	<- hitting limit
	  <some path>/aa/00	use_hierarchy == 1	<- the task belongs to

This leads to killing an innocent task in aa/00.  This patch is a fix for
this bug.  And this patch also fixes the arg for
mem_cgroup_print_oom_info().  We should print information of mem_cgroup
which the task being killed, not current, belongs to.

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:07 -08:00
Daisuke Nishimura 57f9fd7d25 memcg: cleanup mem_cgroup_move_parent()
mem_cgroup_move_parent() calls try_charge first and cancel_charge on
failure.  IMHO, charge/uncharge(especially charge) is high cost operation,
so we should avoid it as far as possible.

This patch tries to delay try_charge in mem_cgroup_move_parent() by
re-ordering checks it does.

And this patch renames mem_cgroup_move_account() to
__mem_cgroup_move_account(), changes the return value of
__mem_cgroup_move_account() from int to void, and adds a new
wrapper(mem_cgroup_move_account()), which checks whether a @pc is valid
for moving account and calls __mem_cgroup_move_account().

This patch removes the last caller of trylock_page_cgroup(), so removes
its definition too.

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: 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>
2009-12-16 07:20:07 -08:00
Daisuke Nishimura a3032a2c15 memcg: add mem_cgroup_cancel_charge()
There are some places calling both res_counter_uncharge() and css_put() to
cancel the charge and the refcnt we have got by mem_cgroup_tyr_charge().

This patch introduces mem_cgroup_cancel_charge() and call it in those
places.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
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>
2009-12-16 07:20:07 -08:00
KAMEZAWA Hiroyuki d8046582d5 memcg: make memcg's file mapped consistent with global VM
In global VM, FILE_MAPPED is used but memcg uses MAPPED_FILE.  This makes
grep difficult.  Replace memcg's MAPPED_FILE with FILE_MAPPED

And in global VM, mapped shared memory is accounted into FILE_MAPPED.
But memcg doesn't. fix it.
Note:
  page_is_file_cache() just checks SwapBacked or not.
  So, we need to check PageAnon.

Cc: Balbir Singh <balbir@in.ibm.com>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
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>
2009-12-16 07:20:07 -08:00
KAMEZAWA Hiroyuki cdec2e4265 memcg: coalesce charging via percpu storage
This is a patch for coalescing access to res_counter at charging by percpu
caching.  At charge, memcg charges 64pages and remember it in percpu
cache.  Because it's cache, drain/flush if necessary.

This version uses public percpu area.
 2 benefits for using public percpu area.
 1. Sum of stocked charge in the system is limited to # of cpus
    not to the number of memcg. This shows better synchonization.
 2. drain code for flush/cpuhotplug is very easy (and quick)

The most important point of this patch is that we never touch res_counter
in fast path. The res_counter is system-wide shared counter which is modified
very frequently. We shouldn't touch it as far as we can for avoiding
false sharing.

On x86-64 8cpu server, I tested overheads of memcg at page fault by
running a program which does map/fault/unmap in a loop. Running
a task per a cpu by taskset and see sum of the number of page faults
in 60secs.

[without memcg config]
  40156968  page-faults              #      0.085 M/sec   ( +-   0.046% )
  27.67 cache-miss/faults

[root cgroup]
  36659599  page-faults              #      0.077 M/sec   ( +-   0.247% )
  31.58 cache miss/faults

[in a child cgroup]
  18444157  page-faults              #      0.039 M/sec   ( +-   0.133% )
  69.96 cache miss/faults

[ + coalescing uncharge patch]
  27133719  page-faults              #      0.057 M/sec   ( +-   0.155% )
  47.16 cache miss/faults

[ + coalescing uncharge patch + this patch ]
  34224709  page-faults              #      0.072 M/sec   ( +-   0.173% )
  34.69 cache miss/faults

Changelog (since Oct/2):
  - updated comments
  - replaced get_cpu_var() with __get_cpu_var() if possible.
  - removed mutex for system-wide drain. adds a counter instead of it.
  - removed CONFIG_HOTPLUG_CPU

Changelog (old):
  - rebased onto the latest mmotm
  - moved charge size check before __GFP_WAIT check for avoiding unnecesary
  - added asynchronous flush routine.
  - fixed bugs pointed out by Nishimura-san.

[akpm@linux-foundation.org: tweak comments]
[nishimura@mxp.nes.nec.co.jp: don't do INIT_WORK() repeatedly against the same work_struct]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.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>
2009-12-16 07:20:07 -08:00