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| author | David Rientjes <rientjes@google.com> | 2007-05-06 23:50:00 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-05-07 21:12:55 +0200 |
| commit | 2b45ab3398a0ba119b1f672c7c56fd5a431b7f0a (patch) | |
| tree | 302238b786d2137111244702345acf6d4a17d4b7 /mm | |
| parent | mm: fix handling of panic_on_oom when cpusets are in use (diff) | |
| download | linux-2b45ab3398a0ba119b1f672c7c56fd5a431b7f0a.tar.xz linux-2b45ab3398a0ba119b1f672c7c56fd5a431b7f0a.zip | |
oom: fix constraint deadlock
Fixes a deadlock in the OOM killer for allocations that are not
__GFP_HARDWALL.
Before the OOM killer checks for the allocation constraint, it takes
callback_mutex.
constrained_alloc() iterates through each zone in the allocation zonelist
and calls cpuset_zone_allowed_softwall() to determine whether an allocation
for gfp_mask is possible. If a zone's node is not in the OOM-triggering
task's mems_allowed, it is not exiting, and we did not fail on a
__GFP_HARDWALL allocation, cpuset_zone_allowed_softwall() attempts to take
callback_mutex to check the nearest exclusive ancestor of current's cpuset.
This results in deadlock.
We now take callback_mutex after iterating through the zonelist since we
don't need it yet.
Cc: Andi Kleen <ak@suse.de>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Christoph Lameter <clameter@engr.sgi.com>
Cc: Martin J. Bligh <mbligh@mbligh.org>
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/oom_kill.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 038d2234f139..a7001410ab15 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -399,6 +399,7 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order) struct task_struct *p; unsigned long points = 0; unsigned long freed = 0; + int constraint; blocking_notifier_call_chain(&oom_notify_list, 0, &freed); if (freed > 0) @@ -416,14 +417,15 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order) if (sysctl_panic_on_oom == 2) panic("out of memory. Compulsory panic_on_oom is selected.\n"); - cpuset_lock(); - read_lock(&tasklist_lock); - /* * Check if there were limitations on the allocation (only relevant for * NUMA) that may require different handling. */ - switch (constrained_alloc(zonelist, gfp_mask)) { + constraint = constrained_alloc(zonelist, gfp_mask); + cpuset_lock(); + read_lock(&tasklist_lock); + + switch (constraint) { case CONSTRAINT_MEMORY_POLICY: oom_kill_process(current, points, "No available memory (MPOL_BIND)"); |