path: root/mm
diff options
authorMel Gorman <>2011-10-24 16:33:42 -0700
committerDan Willemsen <>2011-11-30 21:39:16 -0800
commitf4b5d78d60082b49879fceb6d3a7cb4b75e7c60b (patch)
treed056d5c6b9fa3f332c80193bdace3c2e9d5edec6 /mm
parentcd5997b848fc5081500ff7d7f00795511ad77bc0 (diff)
mm: avoid livelock on !__GFP_FS allocations
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 The gfp conditions are normally invalid, because !__GFP_FS disables most of the reclaim methods that __GFP_WAIT would wait for. However, 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. __alloc_pages_slowpath will loop forever between the rebalance label and should_alloc_retry, unless another thread happens to release enough pages to satisfy the allocation. Add a check to detect when PM has disabled __GFP_FS, and do not retry if reclaim is not making any progress. [taken from patch on lkml by Mel Gorman, commit message by ccross] Change-Id: I864a24e9d9fd98bd0e3d6e9c1e85b6c1b766850e Signed-off-by: Colin Cross <>
Diffstat (limited to 'mm')
1 files changed, 22 insertions, 0 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 41253539b32a..75cd8d74a1a5 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -127,6 +127,20 @@ void pm_restrict_gfp_mask(void)
saved_gfp_mask = gfp_allowed_mask;
gfp_allowed_mask &= ~GFP_IOFS;
+static bool pm_suspending(void)
+ if ((gfp_allowed_mask & GFP_IOFS) == GFP_IOFS)
+ return false;
+ return true;
+static bool pm_suspending(void)
+ return false;
#endif /* CONFIG_PM_SLEEP */
@@ -2208,6 +2222,14 @@ rebalance:
goto restart;
+ /*
+ * Suspend converts GFP_KERNEL to __GFP_WAIT which can
+ * prevent reclaim making forward progress without
+ * invoking OOM. Bail if we are suspending
+ */
+ if (pm_suspending())
+ goto nopage;
/* Check if we should retry the allocation */