Messages in this thread Patch in this message | | | From | Colin Cross <> | Subject | [PATCH] mm: avoid livelock on !__GFP_FS allocations | Date | Mon, 24 Oct 2011 23:39:49 -0700 |
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Under the following conditions, __alloc_pages_slowpath can loop forever: gfp_mask & __GFP_WAIT is true gfp_mask & __GFP_FS is false reclaim and compaction make no progress order <= PAGE_ALLOC_COSTLY_ORDER
These conditions happen very often during suspend and resume, when pm_restrict_gfp_mask() effectively converts all GFP_KERNEL allocations into __GFP_WAIT.
The oom killer is not run because gfp_mask & __GFP_FS is false, but should_alloc_retry will always return true when order is less than PAGE_ALLOC_COSTLY_ORDER.
Fix __alloc_pages_slowpath to skip retrying when oom killer is not allowed by the GFP flags, the same way it would skip if the oom killer was allowed but disabled.
Signed-off-by: Colin Cross <ccross@android.com> ---
An alternative patch would add a did_some_progress argument to __alloc_pages_may_oom, and remove the checks in __alloc_pages_slowpath that require knowledge of when __alloc_pages_may_oom chooses to run out_of_memory. If did_some_progress was still zero, it would goto nopage whether or not __alloc_pages_may_oom was actually called.
mm/page_alloc.c | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index fef8dc3..dcd99b3 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2193,6 +2193,10 @@ rebalance: } goto restart; + } else { + /* If we aren't going to try the OOM killer, give up */ + if (!(gfp_mask & __GFP_NOFAIL)) + goto nopage; } } -- 1.7.4.1
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