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* ksm: fix bad user data when swappingHugh Dickins2010-10-041-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Building under memory pressure, with KSM on 2.6.36-rc5, collapsed with an internal compiler error: typically indicating an error in swapping. Perhaps there's a timing issue which makes it now more likely, perhaps it's just a long time since I tried for so long: this bug goes back to KSM swapping in 2.6.33. Notice how reuse_swap_page() allows an exclusive page to be reused, but only does SetPageDirty if it can delete it from swap cache right then - if it's currently under Writeback, it has to be left in cache and we don't SetPageDirty, but the page can be reused. Fine, the dirty bit will get set in the pte; but notice how zap_pte_range() does not bother to transfer pte_dirty to page_dirty when unmapping a PageAnon. If KSM chooses to share such a page, it will look like a clean copy of swapcache, and not be written out to swap when its memory is needed; then stale data read back from swap when it's needed again. We could fix this in reuse_swap_page() (or even refuse to reuse a page under writeback), but it's more honest to fix my oversight in KSM's write_protect_page(). Several days of testing on three machines confirms that this fixes the issue they showed. Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ksm: fix page_address_in_vma anon_vma oopsHugh Dickins2010-10-041-1/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | 2.6.36-rc1 commit 21d0d443cdc1658a8c1484fdcece4803f0f96d0e "rmap: resurrect page_address_in_vma anon_vma check" was right to resurrect that check; but now that it's comparing anon_vma->roots instead of just anon_vmas, there's a danger of oopsing on a NULL anon_vma. In most cases no NULL anon_vma ever gets here; but it turns out that occasionally KSM, when enabled on a forked or forking process, will itself call page_address_in_vma() on a "half-KSM" page left over from an earlier failed attempt to merge - whose page_anon_vma() is NULL. It's my bug that those should be getting here at all: I thought they were already dealt with, this oops proves me wrong, I'll fix it in the next release - such pages are effectively pinned until their process exits, since rmap cannot find their ptes (though swapoff can). For now just work around it by making page_address_in_vma() safe (and add a comment on why that check is wanted anyway). A similar check in __page_check_anon_rmap() is safe because do_page_add_anon_rmap() already excluded KSM pages. Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Avoid pgoff overflow in remap_file_pagesLarry Woodman2010-09-251-0/+4
| | | | | | | | | | | | Thomas Pollet noticed that the remap_file_pages() system call in fremap.c has a potential overflow in the first part of the if statement below, which could cause it to process bogus input parameters. Specifically the pgoff + size parameters could be wrap thereby preventing the system call from failing when it should. Reported-by: Thomas Pollet <thomas.pollet@gmail.com> Signed-off-by: Larry Woodman <lwoodman@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fremap: get rid of broken 'end' variableLinus Torvalds2010-09-241-2/+1
| | | | | | | | | | | | | | Thomas Pollet points out that the 'end' variable is broken. It was computed based on start/size before they were page-aligned, and as such doesn't actually match any of the other actions we take. The overflow test on end was also redundant, since we had already tested it with the properly aligned version. So just get rid of it entirely. The one remaining use for that broken variable can just use 'start+size' like all the other cases already did. Reported-by: Thomas Pollet <thomas.pollet@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlb, rmap: add BUG_ON(!PageLocked) in hugetlb_add_anon_rmap()Naoya Horiguchi2010-09-231-0/+2
| | | | | | | | | | Confirming page lock is held in hugetlb_add_anon_rmap() may be useful to detect possible future problems. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlb, rmap: fix confusing page locking in hugetlb_cow()Naoya Horiguchi2010-09-231-10/+12
| | | | | | | | | | | | | The "if (!trylock_page)" block in the avoidcopy path of hugetlb_cow() looks confusing and is buggy. Originally this trylock_page() was intended to make sure that old_page is locked even when old_page != pagecache_page, because then only pagecache_page is locked. This patch fixes it by moving page locking into hugetlb_fault(). Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlb, rmap: use hugepage_add_new_anon_rmap() in hugetlb_cow()Naoya Horiguchi2010-09-231-1/+1
| | | | | | | | | | | Obviously, setting anon_vma for COWed hugepage should be done by hugepage_add_new_anon_rmap() to scan vmas faster. This patch fixes it. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: Andrea Arcangeli <aarcange@redhat.com> Reviewed-by: Rik van Riel <riel@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlb, rmap: always use anon_vma root pointerNaoya Horiguchi2010-09-231-6/+7
| | | | | | | | | | | | | | | | | This patch applies Andrea's fix given by the following patch into hugepage rmapping code: commit 288468c334e98aacbb7e2fb8bde6bc1adcd55e05 Author: Andrea Arcangeli <aarcange@redhat.com> Date: Mon Aug 9 17:19:09 2010 -0700 This patch uses anon_vma->root and avoids unnecessary overwriting when anon_vma is already set up. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: Andrea Arcangeli <aarcange@redhat.com> Reviewed-by: Rik van Riel <riel@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'for-linus' of ↵Linus Torvalds2010-09-231-1/+1
|\ | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: percpu: fix pcpu_last_unit_cpu
| * percpu: fix pcpu_last_unit_cpuTejun Heo2010-09-211-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | pcpu_first/last_unit_cpu are used to track which cpu has the first and last units assigned. This in turn is used to determine the span of a chunk for man/unmap cache flushes and whether an address belongs to the first chunk or not in per_cpu_ptr_to_phys(). When the number of possible CPUs isn't power of two, a chunk may contain unassigned units towards the end of a chunk. The logic to determine pcpu_last_unit_cpu was incorrect when there was an unused unit at the end of a chunk. It failed to ignore the unused unit and assigned the unused marker NR_CPUS to pcpu_last_unit_cpu. This was discovered through kdump failure which was caused by malfunctioning per_cpu_ptr_to_phys() on a kvm setup with 50 possible CPUs by CAI Qian. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: CAI Qian <caiqian@redhat.com> Cc: stable@kernel.org
* | mmap: call unlink_anon_vmas() in __split_vma() in case of errorAndrea Arcangeli2010-09-221-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If __split_vma fails because of an out of memory condition the anon_vma_chain isn't teardown and freed potentially leading to rmap walks accessing freed vma information plus there's a memleak. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Johannes Weiner <jweiner@redhat.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | oom: filter unkillable tasks from tasklist dumpDavid Rientjes2010-09-221-21/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | /proc/sys/vm/oom_dump_tasks is enabled by default, so it's necessary to limit as much information as possible that it should emit. The tasklist dump should be filtered to only those tasks that are eligible for oom kill. This is already done for memcg ooms, but this patch extends it to both cpuset and mempolicy ooms as well as init. In addition to suppressing irrelevant information, this also reduces confusion since users currently don't know which tasks in the tasklist aren't eligible for kill (such as those attached to cpusets or bound to mempolicies with a disjoint set of mems or nodes, respectively) since that information is not shown. Signed-off-by: David Rientjes <rientjes@google.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | vmscan: check all_unreclaimable in direct reclaim pathMinchan Kim2010-09-221-8/+35
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | M. Vefa Bicakci reported 2.6.35 kernel hang up when hibernation on his 32bit 3GB mem machine. (https://bugzilla.kernel.org/show_bug.cgi?id=16771). Also he bisected the regression to commit bb21c7ce18eff8e6e7877ca1d06c6db719376e3c Author: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Date: Fri Jun 4 14:15:05 2010 -0700 vmscan: fix do_try_to_free_pages() return value when priority==0 reclaim failure At first impression, this seemed very strange because the above commit only chenged function return value and hibernate_preallocate_memory() ignore return value of shrink_all_memory(). But it's related. Now, page allocation from hibernation code may enter infinite loop if the system has highmem. The reasons are that vmscan don't care enough OOM case when oom_killer_disabled. The problem sequence is following as. 1. hibernation 2. oom_disable 3. alloc_pages 4. do_try_to_free_pages if (scanning_global_lru(sc) && !all_unreclaimable) return 1; If kswapd is not freozen, it would set zone->all_unreclaimable to 1 and then shrink_zones maybe return true(ie, all_unreclaimable is true). So at last, alloc_pages could go to _nopage_. If it is, it should have no problem. This patch adds all_unreclaimable check to protect in direct reclaim path, too. It can care of hibernation OOM case and help bailout all_unreclaimable case slightly. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Minchan Kim <minchan.kim@gmail.com> Reported-by: M. Vefa Bicakci <bicave@superonline.com> Reported-by: <caiqian@redhat.com> Reviewed-by: Johannes Weiner <hannes@cmpxchg.org> Tested-by: <caiqian@redhat.com> Acked-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | oom: always return a badness score of non-zero for eligible tasksDavid Rientjes2010-09-221-2/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A task's badness score is roughly a proportion of its rss and swap compared to the system's capacity. The scale ranges from 0 to 1000 with the highest score chosen for kill. Thus, this scale operates on a resolution of 0.1% of RAM + swap. Admin tasks are also given a 3% bonus, so the badness score of an admin task using 3% of memory, for example, would still be 0. It's possible that an exceptionally large number of tasks will combine to exhaust all resources but never have a single task that uses more than 0.1% of RAM and swap (or 3.0% for admin tasks). This patch ensures that the badness score of any eligible task is never 0 so the machine doesn't unnecessarily panic because it cannot find a task to kill. Signed-off-by: David Rientjes <rientjes@google.com> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-blockLinus Torvalds2010-09-221-0/+2
|\ \ | |/ |/| | | | | | | | | | | | | | | * 'for-linus' of git://git.kernel.dk/linux-2.6-block: bdi: Fix warnings in __mark_inode_dirty for /dev/zero and friends char: Mark /dev/zero and /dev/kmem as not capable of writeback bdi: Initialize noop_backing_dev_info properly cfq-iosched: fix a kernel OOPs when usb key is inserted block: fix blk_rq_map_kern bio direction flag cciss: freeing uninitialized data on error path
| * bdi: Initialize noop_backing_dev_info properlyJan Kara2010-09-221-0/+2
| | | | | | | | | | | | | | | | | | Properly initialize this backing dev info so that writeback code does not barf when getting to it e.g. via sb->s_bdi. Cc: stable@kernel.org Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* | mm: further fix swapin race conditionHugh Dickins2010-09-201-3/+5
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 4969c1192d15 ("mm: fix swapin race condition") is now agreed to be incomplete. There's a race, not very much less likely than the original race envisaged, in which it is further necessary to check that the swapcache page's swap has not changed. Here's the reasoning: cast in terms of reuse_swap_page(), but probably could be reformulated to rely on try_to_free_swap() instead, or on swapoff+swapon. A, faults into do_swap_page(): does page1 = lookup_swap_cache(swap1) and comes through the lock_page(page1). B, a racing thread of the same process, faults on the same address: does page1 = lookup_swap_cache(swap1) and now waits in lock_page(page1), but for whatever reason is unlucky not to get the lock any time soon. A carries on through do_swap_page(), a write fault, but cannot reuse the swap page1 (another reference to swap1). Unlocks the page1 (but B doesn't get it yet), does COW in do_wp_page(), page2 now in that pte. C, perhaps the parent of A+B, comes in and write faults the same swap page1 into its mm, reuse_swap_page() succeeds this time, swap1 is freed. kswapd comes in after some time (B still unlucky) and swaps out some pages from A+B and C: it allocates the original swap1 to page2 in A+B, and some other swap2 to the original page1 now in C. But does not immediately free page1 (actually it couldn't: B holds a reference), leaving it in swap cache for now. B at last gets the lock on page1, hooray! Is PageSwapCache(page1)? Yes. Is pte_same(*page_table, orig_pte)? Yes, because page2 has now been given the swap1 which page1 used to have. So B proceeds to insert page1 into A+B's page_table, though its content now belongs to C, quite different from what A wrote there. B ought to have checked that page1's swap was still swap1. Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-blockLinus Torvalds2010-09-101-2/+5
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * 'for-linus' of git://git.kernel.dk/linux-2.6-block: block: Range check cpu in blk_cpu_to_group scatterlist: prevent invalid free when alloc fails writeback: Fix lost wake-up shutting down writeback thread writeback: do not lose wakeup events when forking bdi threads cciss: fix reporting of max queue depth since init block: switch s390 tape_block and mg_disk to elevator_change() block: add function call to switch the IO scheduler from a driver fs/bio-integrity.c: return -ENOMEM on kmalloc failure bio-integrity.c: remove dependency on __GFP_NOFAIL BLOCK: fix bio.bi_rw handling block: put dev->kobj in blk_register_queue fail path cciss: handle allocation failure cfq-iosched: Documentation help for new tunables cfq-iosched: blktrace print per slice sector stats cfq-iosched: Implement tunable group_idle cfq-iosched: Do group share accounting in IOPS when slice_idle=0 cfq-iosched: Do not idle if slice_idle=0 cciss: disable doorbell reset on reset_devices blkio: Fix return code for mkdir calls
| * writeback: do not lose wakeup events when forking bdi threadsArtem Bityutskiy2010-08-271-2/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes the following issue: INFO: task mount.nfs4:1120 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. mount.nfs4 D 00000000fffc6a21 0 1120 1119 0x00000000 ffff880235643948 0000000000000046 ffffffff00000000 ffffffff00000000 ffff880235643fd8 ffff880235314760 00000000001d44c0 ffff880235643fd8 00000000001d44c0 00000000001d44c0 00000000001d44c0 00000000001d44c0 Call Trace: [<ffffffff813bc747>] schedule_timeout+0x34/0xf1 [<ffffffff813bc530>] ? wait_for_common+0x3f/0x130 [<ffffffff8106b50b>] ? trace_hardirqs_on+0xd/0xf [<ffffffff813bc5c3>] wait_for_common+0xd2/0x130 [<ffffffff8104159c>] ? default_wake_function+0x0/0xf [<ffffffff813beaa0>] ? _raw_spin_unlock+0x26/0x2a [<ffffffff813bc6bb>] wait_for_completion+0x18/0x1a [<ffffffff81101a03>] sync_inodes_sb+0xca/0x1bc [<ffffffff811056a6>] __sync_filesystem+0x47/0x7e [<ffffffff81105798>] sync_filesystem+0x47/0x4b [<ffffffff810e7ffd>] generic_shutdown_super+0x22/0xd2 [<ffffffff810e80f8>] kill_anon_super+0x11/0x4f [<ffffffffa00d06d7>] nfs4_kill_super+0x3f/0x72 [nfs] [<ffffffff810e7b68>] deactivate_locked_super+0x21/0x41 [<ffffffff810e7fd6>] deactivate_super+0x40/0x45 [<ffffffff810fc66c>] mntput_no_expire+0xb8/0xed [<ffffffff810fc73b>] release_mounts+0x9a/0xb0 [<ffffffff810fc7bb>] put_mnt_ns+0x6a/0x7b [<ffffffffa00d0fb2>] nfs_follow_remote_path+0x19a/0x296 [nfs] [<ffffffffa00d11ca>] nfs4_try_mount+0x75/0xaf [nfs] [<ffffffffa00d1790>] nfs4_get_sb+0x276/0x2ff [nfs] [<ffffffff810e7dba>] vfs_kern_mount+0xb8/0x196 [<ffffffff810e7ef6>] do_kern_mount+0x48/0xe8 [<ffffffff810fdf68>] do_mount+0x771/0x7e8 [<ffffffff810fe062>] sys_mount+0x83/0xbd [<ffffffff810089c2>] system_call_fastpath+0x16/0x1b The reason of this hang was a race condition: when the flusher thread is forking a bdi thread, we use 'kthread_run()', so we run it _before_ we make it visible in 'bdi->wb.task'. The bdi thread runs, does all works, and goes sleep. 'bdi->wb.task' is still NULL. And this is a dangerous time window. If at this time someone queues a work for this bdi, he does not see the bdi thread and wakes up the forker thread instead! But the forker has already forked this bdi thread, but just did not make it visible yet! The result is that we lose the wake up event for this bdi thread and the NFS4 code waits forever. To fix the problem, we should use 'ktrhead_create()' for creating bdi threads, then make them visible in 'bdi->wb.task', and only after this wake them up. This is exactly what this patch does. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* | mm: page allocator: drain per-cpu lists after direct reclaim allocation failsMel Gorman2010-09-091-4/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When under significant memory pressure, a process enters direct reclaim and immediately afterwards tries to allocate a page. If it fails and no further progress is made, it's possible the system will go OOM. However, on systems with large amounts of memory, it's possible that a significant number of pages are on per-cpu lists and inaccessible to the calling process. This leads to a process entering direct reclaim more often than it should increasing the pressure on the system and compounding the problem. This patch notes that if direct reclaim is making progress but allocations are still failing that the system is already under heavy pressure. In this case, it drains the per-cpu lists and tries the allocation a second time before continuing. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: Christoph Lameter <cl@linux.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: page allocator: calculate a better estimate of NR_FREE_PAGES when memory ↵Christoph Lameter2010-09-093-3/+37
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | is low and kswapd is awake Ordinarily watermark checks are based on the vmstat NR_FREE_PAGES as it is cheaper than scanning a number of lists. To avoid synchronization overhead, counter deltas are maintained on a per-cpu basis and drained both periodically and when the delta is above a threshold. On large CPU systems, the difference between the estimated and real value of NR_FREE_PAGES can be very high. If NR_FREE_PAGES is much higher than number of real free page in buddy, the VM can allocate pages below min watermark, at worst reducing the real number of pages to zero. Even if the OOM killer kills some victim for freeing memory, it may not free memory if the exit path requires a new page resulting in livelock. This patch introduces a zone_page_state_snapshot() function (courtesy of Christoph) that takes a slightly more accurate view of an arbitrary vmstat counter. It is used to read NR_FREE_PAGES while kswapd is awake to avoid the watermark being accidentally broken. The estimate is not perfect and may result in cache line bounces but is expected to be lighter than the IPI calls necessary to continually drain the per-cpu counters while kswapd is awake. Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: page allocator: update free page counters after pages are placed on the ↵Mel Gorman2010-09-091-4/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | free list When allocating a page, the system uses NR_FREE_PAGES counters to determine if watermarks would remain intact after the allocation was made. This check is made without interrupts disabled or the zone lock held and so is race-prone by nature. Unfortunately, when pages are being freed in batch, the counters are updated before the pages are added on the list. During this window, the counters are misleading as the pages do not exist yet. When under significant pressure on systems with large numbers of CPUs, it's possible for processes to make progress even though they should have been stalled. This is particularly problematic if a number of the processes are using GFP_ATOMIC as the min watermark can be accidentally breached and in extreme cases, the system can livelock. This patch updates the counters after the pages have been added to the list. This makes the allocator more cautious with respect to preserving the watermarks and mitigates livelock possibilities. [akpm@linux-foundation.org: avoid modifying incoming args] Signed-off-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: Rik van Riel <riel@redhat.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Christoph Lameter <cl@linux.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | vmstat: update zone stat threshold when onlining a cpuKAMEZAWA Hiroyuki2010-09-091-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | refresh_zone_stat_thresholds() calculates parameter based on the number of online cpus. It's called at cpu offlining but needs to be called at onlining, too. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Christoph Lameter <cl@linux-foundation.org> Acked-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | swap: discard while swapping only if SWAP_FLAG_DISCARDHugh Dickins2010-09-091-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Tests with recent firmware on Intel X25-M 80GB and OCZ Vertex 60GB SSDs show a shift since I last tested in December: in part because of firmware updates, in part because of the necessary move from barriers to awaiting completion at the block layer. While discard at swapon still shows as slightly beneficial on both, discarding 1MB swap cluster when allocating is now disadvanteous: adds 25% overhead on Intel, adds 230% on OCZ (YMMV). Surrender: discard as presently implemented is more hindrance than help for swap; but might prove useful on other devices, or with improvements. So continue to do the discard at swapon, but make discard while swapping conditional on a SWAP_FLAG_DISCARD to sys_swapon() (which has been using only the lower 16 bits of int flags). We can add a --discard or -d to swapon(8), and a "discard" to swap in /etc/fstab: matching the mount option for btrfs, ext4, fat, gfs2, nilfs2. Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Nigel Cunningham <nigel@tuxonice.net> Cc: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <jaxboe@fusionio.com> Cc: James Bottomley <James.Bottomley@hansenpartnership.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | swap: do not send discards as barriersChristoph Hellwig2010-09-091-6/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The swap code already uses synchronous discards, no need to add I/O barriers. This fixes the worst of the terrible slowdown in swap allocation for hibernation, reported on 2.6.35 by Nigel Cunningham; but does not entirely eliminate that regression. [tj@kernel.org: superflous newlines removed] Signed-off-by: Christoph Hellwig <hch@lst.de> Tested-by: Nigel Cunningham <nigel@tuxonice.net> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Jens Axboe <jaxboe@fusionio.com> Cc: James Bottomley <James.Bottomley@hansenpartnership.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | swap: prevent reuse during hibernationHugh Dickins2010-09-091-4/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move the hibernation check from scan_swap_map() into try_to_free_swap(): to catch not only the common case when hibernation's allocation itself triggers swap reuse, but also the less likely case when concurrent page reclaim (shrink_page_list) might happen to try_to_free_swap from a page. Hibernation already clears __GFP_IO from the gfp_allowed_mask, to stop reclaim from going to swap: check that to prevent swap reuse too. Signed-off-by: Hugh Dickins <hughd@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Ondrej Zary <linux@rainbow-software.org> Cc: Andrea Gelmini <andrea.gelmini@gmail.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Nigel Cunningham <nigel@tuxonice.net> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | swap: revert special hibernation allocationHugh Dickins2010-09-091-72/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Please revert 2.6.36-rc commit d2997b1042ec150616c1963b5e5e919ffd0b0ebf "hibernation: freeze swap at hibernation". It complicated matters by adding a second swap allocation path, just for hibernation; without in any way fixing the issue that it was intended to address - page reclaim after fixing the hibernation image might free swap from a page already imaged as swapcache, letting its swap be reallocated to store a different page of the image: resulting in data corruption if the imaged page were freed as clean then swapped back in. Pages freed to si->swap_map were still in danger of being reallocated by the alternative allocation path. I guess it inadvertently fixed slow SSD swap allocation for hibernation, as reported by Nigel Cunningham: by missing out the discards that occur on the usual swap allocation path; but that was unintentional, and needs a separate fix. Signed-off-by: Hugh Dickins <hughd@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Ondrej Zary <linux@rainbow-software.org> Cc: Andrea Gelmini <andrea.gelmini@gmail.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Nigel Cunningham <nigel@tuxonice.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | bounce: call flush_dcache_page() after bounce_copy_vec()Gary King2010-09-091-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I have been seeing problems on Tegra 2 (ARMv7 SMP) systems with HIGHMEM enabled on 2.6.35 (plus some patches targetted at 2.6.36 to perform cache maintenance lazily), and the root cause appears to be that the mm bouncing code is calling flush_dcache_page before it copies the bounce buffer into the bio. The bounced page needs to be flushed after data is copied into it, to ensure that architecture implementations can synchronize instruction and data caches if necessary. Signed-off-by: Gary King <gking@nvidia.com> Cc: Tejun Heo <tj@kernel.org> Cc: Russell King <rmk@arm.linux.org.uk> Acked-by: Jens Axboe <axboe@kernel.dk> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | memory hotplug: fix next block calculation in is_removableKAMEZAWA Hiroyuki2010-09-091-8/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | next_active_pageblock() is for finding next _used_ freeblock. It skips several blocks when it finds there are a chunk of free pages lager than pageblock. But it has 2 bugs. 1. We have no lock. page_order(page) - pageblock_order can be minus. 2. pageblocks_stride += is wrong. it should skip page_order(p) of pages. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: compaction: handle active and inactive fairly in too_many_isolatedMinchan Kim2010-09-091-3/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Iram reported that compaction's too_many_isolated() loops forever. (http://www.spinics.net/lists/linux-mm/msg08123.html) The meminfo when the situation happened was inactive anon is zero. That's because the system has no memory pressure until then. While all anon pages were in the active lru, compaction could select active lru as well as inactive lru. That's a different thing from vmscan's isolated. So we has been two too_many_isolated. While compaction can isolate pages in both active and inactive, current implementation of too_many_isolated only considers inactive. It made Iram's problem. This patch handles active and inactive fairly. That's because we can't expect where from and how many compaction would isolated pages. This patch changes (nr_isolated > nr_inactive) with nr_isolated > (nr_active + nr_inactive) / 2. Signed-off-by: Minchan Kim <minchan.kim@gmail.com> Reported-by: Iram Shahzad <iram.shahzad@jp.fujitsu.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Wu Fengguang <fengguang.wu@intel.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: avoid warning when COMPACTION is selectedAndrea Arcangeli2010-09-091-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | COMPACTION enables MIGRATION, but MIGRATION spawns a warning if numa or memhotplug aren't selected. However MIGRATION doesn't depend on them. I guess it's just trying to be strict doing a double check on who's enabling it, but it doesn't know that compaction also enables MIGRATION. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: fix swapin race conditionAndrea Arcangeli2010-09-092-8/+34
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The pte_same check is reliable only if the swap entry remains pinned (by the page lock on swapcache). We've also to ensure the swapcache isn't removed before we take the lock as try_to_free_swap won't care about the page pin. One of the possible impacts of this patch is that a KSM-shared page can point to the anon_vma of another process, which could exit before the page is freed. This can leave a page with a pointer to a recycled anon_vma object, or worse, a pointer to something that is no longer an anon_vma. [riel@redhat.com: changelog help] Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Hugh Dickins <hughd@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: Move vma_stack_continue into mm.hStefan Bader2010-09-091-6/+0
| | | | | | | | | | | | | | So it can be used by all that need to check for that. Signed-off-by: Stefan Bader <stefan.bader@canonical.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Merge branch 'for-linus' of ↵Linus Torvalds2010-09-072-4/+6
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: percpu: fix a mismatch between code and comment percpu: fix a memory leak in pcpu_extend_area_map() percpu: add __percpu notations to UP allocator percpu: handle __percpu notations in UP accessors
| * | percpu: fix a mismatch between code and commentNamhyung Kim2010-08-271-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When pcpu_build_alloc_info() searches best_upa value, it ignores current value if the number of waste units exceeds 1/3 of the number of total cpus. But the comment on the code says that it will ignore if wastage is over 25%. Modify the comment. Signed-off-by: Namhyung Kim <namhyung@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
| * | percpu: fix a memory leak in pcpu_extend_area_map()Huang Shijie2010-08-271-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The original code did not free the old map. This patch fixes it. tj: use @old as memcpy source instead of @chunk->map, and indentation and description update Signed-off-by: Huang Shijie <shijie8@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: stable@kernel.org
| * | percpu: add __percpu notations to UP allocatorNamhyung Kim2010-08-071-2/+2
| | | | | | | | | | | | | | | | | | | | | Add __percpu notations to UP percpu allocator. Signed-off-by: Namhyung Kim <namhyung@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* | | Merge branch 'for-linus' of ↵Linus Torvalds2010-08-281-0/+1
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client: ceph: fix get_ticket_handler() error handling ceph: don't BUG on ENOMEM during mds reconnect ceph: ceph_mdsc_build_path() returns an ERR_PTR ceph: Fix warnings ceph: ceph_get_inode() returns an ERR_PTR ceph: initialize fields on new dentry_infos ceph: maintain i_head_snapc when any caps are dirty, not just for data ceph: fix osd request lru adjustment when sending request ceph: don't improperly set dir complete when holding EXCL cap mm: exporting account_page_dirty ceph: direct requests in snapped namespace based on nonsnap parent ceph: queue cap snap writeback for realm children on snap update ceph: include dirty xattrs state in snapped caps ceph: fix xattr cap writeback ceph: fix multiple mds session shutdown
| * | | mm: exporting account_page_dirtyMichael Rubin2010-08-221-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This allows code outside of the mm core to safely manipulate page state and not worry about the other accounting. Not using these routines means that some code will lose track of the accounting and we get bugs. This has happened once already. Signed-off-by: Michael Rubin <mrubin@google.com> Signed-off-by: Sage Weil <sage@newdream.net>
* | | | mm: fix hang on anon_vma->root->lockHugh Dickins2010-08-281-3/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After several hours, kbuild tests hang with anon_vma_prepare() spinning on a newly allocated anon_vma's lock - on a box with CONFIG_TREE_PREEMPT_RCU=y (which makes this very much more likely, but it could happen without). The ever-subtle page_lock_anon_vma() now needs a further twist: since anon_vma_prepare() and anon_vma_fork() are liable to change the ->root of a reused anon_vma structure at any moment, page_lock_anon_vma() needs to check page_mapped() again before succeeding, otherwise page_unlock_anon_vma() might address a different root->lock. Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Christoph Lameter <cl@linux.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | | Merge branch '2.6.36-fixes' of ↵Linus Torvalds2010-08-251-16/+10
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/dgc/xfsdev * '2.6.36-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/xfsdev: xfs: do not discard page cache data on EAGAIN xfs: don't do memory allocation under the CIL context lock xfs: Reduce log force overhead for delayed logging xfs: dummy transactions should not dirty VFS state xfs: ensure f_ffree returned by statfs() is non-negative xfs: handle negative wbc->nr_to_write during sync writeback writeback: write_cache_pages doesn't terminate at nr_to_write <= 0 xfs: fix untrusted inode number lookup xfs: ensure we mark all inodes in a freed cluster XFS_ISTALE xfs: unlock items before allowing the CIL to commit
| * | | | writeback: write_cache_pages doesn't terminate at nr_to_write <= 0Dave Chinner2010-08-241-16/+10
| | |_|/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I noticed XFS writeback in 2.6.36-rc1 was much slower than it should have been. Enabling writeback tracing showed: flush-253:16-8516 [007] 1342952.351608: wbc_writepage: bdi 253:16: towrt=1024 skip=0 mode=0 kupd=0 bgrd=1 reclm=0 cyclic=1 more=0 older=0x0 start=0x0 end=0x0 flush-253:16-8516 [007] 1342952.351654: wbc_writepage: bdi 253:16: towrt=1023 skip=0 mode=0 kupd=0 bgrd=1 reclm=0 cyclic=1 more=0 older=0x0 start=0x0 end=0x0 flush-253:16-8516 [000] 1342952.369520: wbc_writepage: bdi 253:16: towrt=0 skip=0 mode=0 kupd=0 bgrd=1 reclm=0 cyclic=1 more=0 older=0x0 start=0x0 end=0x0 flush-253:16-8516 [000] 1342952.369542: wbc_writepage: bdi 253:16: towrt=-1 skip=0 mode=0 kupd=0 bgrd=1 reclm=0 cyclic=1 more=0 older=0x0 start=0x0 end=0x0 flush-253:16-8516 [000] 1342952.369549: wbc_writepage: bdi 253:16: towrt=-2 skip=0 mode=0 kupd=0 bgrd=1 reclm=0 cyclic=1 more=0 older=0x0 start=0x0 end=0x0 Writeback is not terminating in background writeback if ->writepage is returning with wbc->nr_to_write == 0, resulting in sub-optimal single page writeback on XFS. Fix the write_cache_pages loop to terminate correctly when this situation occurs and so prevent this sub-optimal background writeback pattern. This improves sustained sequential buffered write performance from around 250MB/s to 750MB/s for a 100GB file on an XFS filesystem on my 8p test VM. Cc:<stable@kernel.org> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Wu Fengguang <fengguang.wu@intel.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
* / | | guard page for stacks that grow upwardsLuck, Tony2010-08-242-7/+11
|/ / / | | | | | | | | | | | | | | | | | | | | | | | | | | | pa-risc and ia64 have stacks that grow upwards. Check that they do not run into other mappings. By making VM_GROWSUP 0x0 on architectures that do not ever use it, we can avoid some unpleasant #ifdefs in check_stack_guard_page(). Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | Merge branch 'for-linus' of ↵Linus Torvalds2010-08-221-2/+2
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6 * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6: slab: fix object alignment slub: add missing __percpu markup in mm/slub_def.h
| * | | slab: fix object alignmentCarsten Otte2010-08-091-2/+2
| | |/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes alignment of slab objects in case CONFIG_DEBUG_PAGEALLOC is active. Before this spot in kmem_cache_create, we have this situation: - align contains the required alignment of the object - cachep->obj_offset is 0 or equals align in case of CONFIG_DEBUG_SLAB - size equals the size of the object, or object plus trailing redzone in case of CONFIG_DEBUG_SLAB This spot tries to fill one page per object if the object is in certain size limits, however setting obj_offset to PAGE_SIZE - size does break the object alignment since size may not be aligned with the required alignment. This patch simply adds an ALIGN(size, align) to the equation and fixes the object size detection accordingly. This code in drivers/s390/cio/qdio_setup_init has lead to incorrectly aligned slab objects (sizeof(struct qdio_q) equals 1792): qdio_q_cache = kmem_cache_create("qdio_q", sizeof(struct qdio_q), 256, 0, NULL); Acked-by: Christoph Lameter <cl@linux.com> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
* | | mm: make stack guard page logic use vm_prev pointerLinus Torvalds2010-08-211-4/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Like the mlock() change previously, this makes the stack guard check code use vma->vm_prev to see what the mapping below the current stack is, rather than have to look it up with find_vma(). Also, accept an abutting stack segment, since that happens naturally if you split the stack with mlock or mprotect. Tested-by: Ian Campbell <ijc@hellion.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | mm: make the mlock() stack guard page checks stricterLinus Torvalds2010-08-211-5/+16
| | | | | | | | | | | | | | | | | | | | | | | | If we've split the stack vma, only the lowest one has the guard page. Now that we have a doubly linked list of vma's, checking this is trivial. Tested-by: Ian Campbell <ijc@hellion.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | mm: make the vma list be doubly linkedLinus Torvalds2010-08-212-6/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It's a really simple list, and several of the users want to go backwards in it to find the previous vma. So rather than have to look up the previous entry with 'find_vma_prev()' or something similar, just make it doubly linked instead. Tested-by: Ian Campbell <ijc@hellion.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | oom: __task_cred() need rcu_read_lock()KOSAKI Motohiro2010-08-201-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | dump_tasks() needs to hold the RCU read lock around its access of the target task's UID. To this end it should use task_uid() as it only needs that one thing from the creds. The fact that dump_tasks() holds tasklist_lock is insufficient to prevent the target process replacing its credentials on another CPU. Then, this patch change to call rcu_read_lock() explicitly. =================================================== [ INFO: suspicious rcu_dereference_check() usage. ] --------------------------------------------------- mm/oom_kill.c:410 invoked rcu_dereference_check() without protection! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 1 4 locks held by kworker/1:2/651: #0: (events){+.+.+.}, at: [<ffffffff8106aae7>] process_one_work+0x137/0x4a0 #1: (moom_work){+.+...}, at: [<ffffffff8106aae7>] process_one_work+0x137/0x4a0 #2: (tasklist_lock){.+.+..}, at: [<ffffffff810fafd4>] out_of_memory+0x164/0x3f0 #3: (&(&p->alloc_lock)->rlock){+.+...}, at: [<ffffffff810fa48e>] find_lock_task_mm+0x2e/0x70 Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | oom: fix tasklist_lock leakKOSAKI Motohiro2010-08-201-3/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 0aad4b3124 ("oom: fold __out_of_memory into out_of_memory") introduced a tasklist_lock leak. Then it caused following obvious danger warnings and panic. ================================================ [ BUG: lock held when returning to user space! ] ------------------------------------------------ rsyslogd/1422 is leaving the kernel with locks still held! 1 lock held by rsyslogd/1422: #0: (tasklist_lock){.+.+.+}, at: [<ffffffff810faf64>] out_of_memory+0x164/0x3f0 BUG: scheduling while atomic: rsyslogd/1422/0x00000002 INFO: lockdep is turned off. This patch fixes it. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>