linux/mm
Michal Hocko 49550b6055 oom: add helpers for setting and clearing TIF_MEMDIE
This patchset addresses a race which was described in the changelog for
5695be142e ("OOM, PM: OOM killed task shouldn't escape PM suspend"):

: PM freezer relies on having all tasks frozen by the time devices are
: getting frozen so that no task will touch them while they are getting
: frozen.  But OOM killer is allowed to kill an already frozen task in order
: to handle OOM situtation.  In order to protect from late wake ups OOM
: killer is disabled after all tasks are frozen.  This, however, still keeps
: a window open when a killed task didn't manage to die by the time
: freeze_processes finishes.

The original patch hasn't closed the race window completely because that
would require a more complex solution as it can be seen by this patchset.

The primary motivation was to close the race condition between OOM killer
and PM freezer _completely_.  As Tejun pointed out, even though the race
condition is unlikely the harder it would be to debug weird bugs deep in
the PM freezer when the debugging options are reduced considerably.  I can
only speculate what might happen when a task is still runnable
unexpectedly.

On a plus side and as a side effect the oom enable/disable has a better
(full barrier) semantic without polluting hot paths.

I have tested the series in KVM with 100M RAM:
- many small tasks (20M anon mmap) which are triggering OOM continually
- s2ram which resumes automatically is triggered in a loop
	echo processors > /sys/power/pm_test
	while true
	do
		echo mem > /sys/power/state
		sleep 1s
	done
- simple module which allocates and frees 20M in 8K chunks. If it sees
  freezing(current) then it tries another round of allocation before calling
  try_to_freeze
- debugging messages of PM stages and OOM killer enable/disable/fail added
  and unmark_oom_victim is delayed by 1s after it clears TIF_MEMDIE and before
  it wakes up waiters.
- rebased on top of the current mmotm which means some necessary updates
  in mm/oom_kill.c. mark_tsk_oom_victim is now called under task_lock but
  I think this should be OK because __thaw_task shouldn't interfere with any
  locking down wake_up_process. Oleg?

As expected there are no OOM killed tasks after oom is disabled and
allocations requested by the kernel thread are failing after all the tasks
are frozen and OOM disabled.  I wasn't able to catch a race where
oom_killer_disable would really have to wait but I kinda expected the race
is really unlikely.

[  242.609330] Killed process 2992 (mem_eater) total-vm:24412kB, anon-rss:2164kB, file-rss:4kB
[  243.628071] Unmarking 2992 OOM victim. oom_victims: 1
[  243.636072] (elapsed 2.837 seconds) done.
[  243.641985] Trying to disable OOM killer
[  243.643032] Waiting for concurent OOM victims
[  243.644342] OOM killer disabled
[  243.645447] Freezing remaining freezable tasks ... (elapsed 0.005 seconds) done.
[  243.652983] Suspending console(s) (use no_console_suspend to debug)
[  243.903299] kmem_eater: page allocation failure: order:1, mode:0x204010
[...]
[  243.992600] PM: suspend of devices complete after 336.667 msecs
[  243.993264] PM: late suspend of devices complete after 0.660 msecs
[  243.994713] PM: noirq suspend of devices complete after 1.446 msecs
[  243.994717] ACPI: Preparing to enter system sleep state S3
[  243.994795] PM: Saving platform NVS memory
[  243.994796] Disabling non-boot CPUs ...

The first 2 patches are simple cleanups for OOM.  They should go in
regardless the rest IMO.

Patches 3 and 4 are trivial printk -> pr_info conversion and they should
go in ditto.

The main patch is the last one and I would appreciate acks from Tejun and
Rafael.  I think the OOM part should be OK (except for __thaw_task vs.
task_lock where a look from Oleg would appreciated) but I am not so sure I
haven't screwed anything in the freezer code.  I have found several
surprises there.

This patch (of 5):

This patch is just a preparatory and it doesn't introduce any functional
change.

Note:
I am utterly unhappy about lowmemory killer abusing TIF_MEMDIE just to
wait for the oom victim and to prevent from new killing. This is
just a side effect of the flag. The primary meaning is to give the oom
victim access to the memory reserves and that shouldn't be necessary
here.

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Cc: Tejun Heo <tj@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-11 17:06:03 -08:00
..
backing-dev.c Merge branch 'for-3.18/core' of git://git.kernel.dk/linux-block 2014-10-18 11:53:51 -07:00
balloon_compaction.c mm/balloon_compaction: fix deflation when compaction is disabled 2014-10-29 16:33:15 -07:00
bootmem.c mem-hotplug: reset node managed pages when hot-adding a new pgdat 2014-11-13 16:17:06 -08:00
cleancache.c mm: fix cleancache debugfs directory path 2015-01-20 14:08:31 +01:00
cma.c mm: cma: split cma-reserved in dmesg log 2014-12-18 19:08:10 -08:00
compaction.c mm: reduce try_to_compact_pages parameters 2015-02-11 17:06:02 -08:00
debug-pagealloc.c mm/debug-pagealloc: make debug-pagealloc boottime configurable 2014-12-13 12:42:48 -08:00
debug.c mm: remove rest usage of VM_NONLINEAR and pte_file() 2015-02-10 14:30:31 -08:00
dmapool.c mm/dmapool.c: fixed a brace coding style issue 2014-10-09 22:26:00 -04:00
early_ioremap.c mm: create generic early_ioremap() support 2014-04-07 16:36:15 -07:00
fadvise.c mm: fadvise: document the fadvise(FADV_DONTNEED) behaviour for partial pages 2014-12-13 12:42:49 -08:00
failslab.c
filemap_xip.c mm: drop vm_ops->remap_pages and generic_file_remap_pages() stub 2015-02-10 14:30:30 -08:00
filemap.c mm: drop vm_ops->remap_pages and generic_file_remap_pages() stub 2015-02-10 14:30:30 -08:00
frontswap.c mm/frontswap.c: fix the condition in BUG_ON 2014-12-10 17:41:08 -08:00
gup.c mm/hugetlb: take page table lock in follow_huge_pmd() 2015-02-11 17:06:01 -08:00
highmem.c mm/highmem: make kmap cache coloring aware 2014-08-06 18:01:22 -07:00
huge_memory.c mm:add KPF_ZERO_PAGE flag for /proc/kpageflags 2015-02-11 17:06:00 -08:00
hugetlb_cgroup.c mm: page_counter: pull "-1" handling out of page_counter_memparse() 2015-02-11 17:06:02 -08:00
hugetlb.c mm/hugetlb: add migration entry check in __unmap_hugepage_range 2015-02-11 17:06:01 -08:00
hwpoison-inject.c mm/hwpoison-inject.c: remove unnecessary null test before debugfs_remove_recursive 2014-08-06 18:01:19 -07:00
init-mm.c
internal.h mm: reduce try_to_compact_pages parameters 2015-02-11 17:06:02 -08:00
interval_tree.c mm: replace vma->sharead.linear with vma->shared 2015-02-10 14:30:31 -08:00
iov_iter.c copy_from_iter_nocache() 2014-12-08 20:25:23 -05:00
Kconfig rcu: Make SRCU optional by using CONFIG_SRCU 2015-01-06 11:04:29 -08:00
Kconfig.debug mm/debug_pagealloc: remove obsolete Kconfig options 2015-01-08 15:10:52 -08:00
kmemcheck.c mm/slab_common: move kmem_cache definition to internal header 2014-10-09 22:25:50 -04:00
kmemleak-test.c mm/kmemleak-test.c: use pr_fmt for logging 2014-06-06 16:08:18 -07:00
kmemleak.c mm: introduce kmemleak_update_trace() 2014-06-06 16:08:17 -07:00
ksm.c mm: remove rest usage of VM_NONLINEAR and pte_file() 2015-02-10 14:30:31 -08:00
list_lru.c mm: keep page cache radix tree nodes in check 2014-04-03 16:21:01 -07:00
maccess.c
madvise.c mm: remove rest usage of VM_NONLINEAR and pte_file() 2015-02-10 14:30:31 -08:00
Makefile mm: replace remap_file_pages() syscall with emulation 2015-02-10 14:30:30 -08:00
memblock.c mm/memblock.c: refactor functions to set/clear MEMBLOCK_HOTPLUG 2014-12-13 12:42:46 -08:00
memcontrol.c oom: add helpers for setting and clearing TIF_MEMDIE 2015-02-11 17:06:03 -08:00
memory_hotplug.c mm, memory_hotplug/failure: drain single zone pcplists 2014-12-10 17:41:05 -08:00
memory-failure.c mm: vmscan: invoke slab shrinkers from shrink_zone() 2014-12-13 12:42:48 -08:00
memory.c Merge branch 'akpm' (patches from Andrew) 2015-02-10 16:45:56 -08:00
mempolicy.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-12-19 18:19:19 -08:00
mempool.c mm/mempool.c: update the kmemleak stack trace for mempool allocations 2014-06-06 16:08:17 -07:00
migrate.c mm/hugetlb: take page table lock in follow_huge_pmd() 2015-02-11 17:06:01 -08:00
mincore.c mm: remove rest usage of VM_NONLINEAR and pte_file() 2015-02-10 14:30:31 -08:00
mlock.c Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-10-13 15:44:12 +02:00
mm_init.c
mmap.c rmap: drop support of non-linear mappings 2015-02-10 14:30:31 -08:00
mmu_context.c
mmu_notifier.c mmu_notifier: add the callback for mmu_notifier_invalidate_range() 2014-11-13 13:46:09 +11:00
mmzone.c mm: microoptimize zonelist operations 2015-02-11 17:06:02 -08:00
mprotect.c mm: remove rest usage of VM_NONLINEAR and pte_file() 2015-02-10 14:30:31 -08:00
mremap.c mm: remove rest usage of VM_NONLINEAR and pte_file() 2015-02-10 14:30:31 -08:00
msync.c mm: remove rest usage of VM_NONLINEAR and pte_file() 2015-02-10 14:30:31 -08:00
nobootmem.c mem-hotplug: reset node managed pages when hot-adding a new pgdat 2014-11-13 16:17:06 -08:00
nommu.c mm: replace remap_file_pages() syscall with emulation 2015-02-10 14:30:30 -08:00
oom_kill.c oom: add helpers for setting and clearing TIF_MEMDIE 2015-02-11 17:06:03 -08:00
page_alloc.c mm: use correct format specifiers when printing address ranges 2015-02-11 17:06:02 -08:00
page_counter.c mm: page_counter: pull "-1" handling out of page_counter_memparse() 2015-02-11 17:06:02 -08:00
page_ext.c mm/page_owner: keep track of page owners 2014-12-13 12:42:48 -08:00
page_io.c fix __swap_writepage() compile failure on old gcc versions 2014-06-14 19:30:48 -05:00
page_isolation.c mm, page_isolation: drain single zone pcplists 2014-12-10 17:41:05 -08:00
page_owner.c mm/page_owner: correct owner information for early allocated pages 2014-12-13 12:42:48 -08:00
page-writeback.c mm: memcontrol: track move_lock state internally 2015-02-11 17:06:00 -08:00
pagewalk.c mm: pagewalk: call pte_hole() for VM_PFNMAP during walk_page_range 2015-02-05 13:35:29 -08:00
percpu-km.c percpu: implmeent pcpu_nr_empty_pop_pages and chunk->nr_populated 2014-09-02 14:46:05 -04:00
percpu-vm.c percpu: move region iterations out of pcpu_[de]populate_chunk() 2014-09-02 14:46:02 -04:00
percpu.c percpu: off by one in BUG_ON() 2014-10-29 10:34:34 -04:00
pgtable-generic.c mm: actually clear pmd_numa before invalidating 2014-08-29 16:28:15 -07:00
process_vm_access.c start adding the tag to iov_iter 2014-05-06 17:32:49 -04:00
quicklist.c
readahead.c mm/readahead.c: remove unused file_ra_state from count_history_pages 2014-08-06 18:01:15 -07:00
rmap.c mm: memcontrol: track move_lock state internally 2015-02-11 17:06:00 -08:00
shmem.c swap: remove unused mem_cgroup_uncharge_swapcache declaration 2015-02-11 17:06:00 -08:00
slab_common.c memcg: zap memcg_slab_caches and memcg_slab_mutex 2015-02-10 14:30:34 -08:00
slab.c slab: fix cpuset check in fallback_alloc 2014-12-13 12:42:53 -08:00
slab.h memcg: zap __memcg_{charge,uncharge}_slab 2015-02-10 14:30:34 -08:00
slob.c mm/sl[ao]b: always track caller in kmalloc_(node_)track_caller() 2014-10-09 22:25:50 -04:00
slub.c mm/slub.c: fix typo in comment 2015-02-10 14:30:30 -08:00
sparse-vmemmap.c
sparse.c mm: use macros from compiler.h instead of __attribute__((...)) 2014-04-07 16:35:54 -07:00
swap_cgroup.c mm: page_cgroup: rename file to mm/swap_cgroup.c 2014-12-10 17:41:09 -08:00
swap_state.c mm: page_cgroup: rename file to mm/swap_cgroup.c 2014-12-10 17:41:09 -08:00
swap.c rmap: drop support of non-linear mappings 2015-02-10 14:30:31 -08:00
swapfile.c mm: page_cgroup: rename file to mm/swap_cgroup.c 2014-12-10 17:41:09 -08:00
truncate.c mm: Fix comment before truncate_setsize() 2014-11-07 08:29:25 +11:00
util.c proc/maps: make vm_is_stack() logic namespace-friendly 2014-10-09 22:25:50 -04:00
vmacache.c mm,vmacache: count number of system-wide flushes 2014-12-13 12:42:48 -08:00
vmalloc.c mm/vmalloc.c: fix memory ordering bug 2014-12-13 12:42:49 -08:00
vmpressure.c mm/vmpressure.c: fix race in vmpressure_work_fn() 2014-12-02 17:32:07 -08:00
vmscan.c mm: memcontrol: default hierarchy interface for memory 2015-02-11 17:06:02 -08:00
vmstat.c mm/vmstat.c: fix/cleanup ifdefs 2015-02-10 14:30:30 -08:00
workingset.c mm: keep page cache radix tree nodes in check 2014-04-03 16:21:01 -07:00
zbud.c mm/zbud: init user ops only when it is needed 2014-12-13 12:42:51 -08:00
zpool.c mm/zpool: use prefixed module loading 2014-08-29 16:28:16 -07:00
zsmalloc.c mm/zsmalloc: adjust order of functions 2014-12-18 19:08:11 -08:00
zswap.c mm/zswap: delete unnecessary check before calling free_percpu() 2014-12-13 12:42:50 -08:00