[patch 08/11 -mmotm] oom: invoke oom killer for __GFP_NOFAIL

From: David Rientjes
Date: Sun May 10 2009 - 18:09:47 EST


The oom killer must be invoked regardless of the order if the allocation
is __GFP_NOFAIL, otherwise it will loop forever when reclaim fails to
free some memory.

Cc: Mel Gorman <mel@xxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Nick Piggin <npiggin@xxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx>
Cc: Dave Hansen <dave@xxxxxxxxxxxxxxxxxx>
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
---
mm/page_alloc.c | 12 +++++++-----
1 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1547,7 +1547,7 @@ __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
goto out;

/* The OOM killer will not help higher order allocs */
- if (order > PAGE_ALLOC_COSTLY_ORDER)
+ if (order > PAGE_ALLOC_COSTLY_ORDER && !(gfp_mask & __GFP_NOFAIL))
goto out;

/* Exhausted what can be done so it's blamo time */
@@ -1765,11 +1765,13 @@ rebalance:
goto got_pg;

/*
- * The OOM killer does not trigger for high-order allocations
- * but if no progress is being made, there are no other
- * options and retrying is unlikely to help
+ * The OOM killer does not trigger for high-order
+ * ~__GFP_NOFAIL allocations so if no progress is being
+ * made, there are no other options and retrying is
+ * unlikely to help.
*/
- if (order > PAGE_ALLOC_COSTLY_ORDER)
+ if (order > PAGE_ALLOC_COSTLY_ORDER &&
+ !(gfp_mask & __GFP_NOFAIL))
goto nopage;

goto restart;
--
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