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authorDavid Rientjes <rientjes@google.com>2014-01-21 15:51:12 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-01-21 16:19:49 -0800
commitaed0a0e32de387da831284fda25021de32477195 (patch)
tree503af52f3d2d7ae2d3cdccb648fcd7977658f9ea /mm/page_alloc.c
parent55b7c4c99f6a448f72179297fe6432544f220063 (diff)
downloadop-kernel-dev-aed0a0e32de387da831284fda25021de32477195.zip
op-kernel-dev-aed0a0e32de387da831284fda25021de32477195.tar.gz
mm, page_alloc: warn for non-blockable __GFP_NOFAIL allocation failure
__GFP_NOFAIL may return NULL when coupled with GFP_NOWAIT or GFP_ATOMIC. Luckily, nothing currently does such craziness. So instead of causing such allocations to loop (potentially forever), we maintain the current behavior and also warn about the new users of the deprecated flag. Suggested-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David Rientjes <rientjes@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page_alloc.c')
-rw-r--r--mm/page_alloc.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 84da0e3..533e214 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2525,8 +2525,15 @@ rebalance:
}
/* Atomic allocations - we can't balance anything */
- if (!wait)
+ if (!wait) {
+ /*
+ * All existing users of the deprecated __GFP_NOFAIL are
+ * blockable, so warn of any new users that actually allow this
+ * type of allocation to fail.
+ */
+ WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL);
goto nopage;
+ }
/* Avoid recursion of direct reclaim */
if (current->flags & PF_MEMALLOC)
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