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authorAndrew Morton <akpm@linux-foundation.org>2009-06-16 15:32:37 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-06-16 19:47:40 -0700
commitdab48dab37d2770824420d1e01730a107fade1aa (patch)
tree81e949d2521d4d8d979808feaa9c2a570337a98c /mm
parent720b17e759a50635c429ccaa2ec3d01edb4f92d6 (diff)
downloadlinux-dab48dab37d2770824420d1e01730a107fade1aa.tar.gz
page-allocator: warn if __GFP_NOFAIL is used for a large allocation
__GFP_NOFAIL is a bad fiction. Allocations _can_ fail, and callers should detect and suitably handle this (and not by lamely moving the infinite loop up to the caller level either). Attempting to use __GFP_NOFAIL for a higher-order allocation is even worse, so add a once-off runtime check for this to slap people around for even thinking about trying it. Cc: David Rientjes <rientjes@google.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> 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/page_alloc.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 076463cb21b..61290ea721c 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1128,6 +1128,19 @@ again:
list_del(&page->lru);
pcp->count--;
} else {
+ if (unlikely(gfp_flags & __GFP_NOFAIL)) {
+ /*
+ * __GFP_NOFAIL is not to be used in new code.
+ *
+ * All __GFP_NOFAIL callers should be fixed so that they
+ * properly detect and handle allocation failures.
+ *
+ * We most definitely don't want callers attempting to
+ * allocate greater than single-page units with
+ * __GFP_NOFAIL.
+ */
+ WARN_ON_ONCE(order > 0);
+ }
spin_lock_irqsave(&zone->lock, flags);
page = __rmqueue(zone, order, migratetype);
__mod_zone_page_state(zone, NR_FREE_PAGES, -(1 << order));