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authorMichal Hocko <mhocko@suse.com>2016-01-14 15:20:36 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-01-14 16:00:49 -0800
commit5020e285856cb406224e6f977fd893a006077806 (patch)
treef0c0e5b5f18b95cab526c8a7bf96f2f415f9a3c6
parent86760a2c6e827858f8eaf020b12b72b3210faf79 (diff)
mm, oom: give __GFP_NOFAIL allocations access to memory reserves
__GFP_NOFAIL is a big hammer used to ensure that the allocation request can never fail. This is a strong requirement and as such it also deserves a special treatment when the system is OOM. The primary problem here is that the allocation request might have come with some locks held and the oom victim might be blocked on the same locks. This is basically an OOM deadlock situation. This patch tries to reduce the risk of such a deadlocks by giving __GFP_NOFAIL allocations a special treatment and let them dive into memory reserves after oom killer invocation. This should help them to make a progress and release resources they are holding. The OOM victim should compensate for the reserves consumption. Signed-off-by: Michal Hocko <mhocko@suse.com> Suggested-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Johannes Weiner <hannes@cmpxchg.org> 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>
-rw-r--r--mm/page_alloc.c15
1 files changed, 14 insertions, 1 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index d7f5bc895157..ce63d603820f 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2732,8 +2732,21 @@ __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
goto out;
}
/* Exhausted what can be done so it's blamo time */
- if (out_of_memory(&oc) || WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL))
+ if (out_of_memory(&oc) || WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL)) {
*did_some_progress = 1;
+
+ if (gfp_mask & __GFP_NOFAIL) {
+ page = get_page_from_freelist(gfp_mask, order,
+ ALLOC_NO_WATERMARKS|ALLOC_CPUSET, ac);
+ /*
+ * fallback to ignore cpuset restriction if our nodes
+ * are depleted
+ */
+ if (!page)
+ page = get_page_from_freelist(gfp_mask, order,
+ ALLOC_NO_WATERMARKS, ac);
+ }
+ }
out:
mutex_unlock(&oom_lock);
return page;