Messages in this thread | | | Date | Thu, 16 Jul 2009 12:05:57 +0100 | From | Mel Gorman <> | Subject | Re: [PATCH] page-allocator: Ensure that processes that have been OOM killed exit the page allocator (resend) |
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On Wed, Jul 15, 2009 at 01:30:14PM -0700, Andrew Morton wrote: > On Wed, 15 Jul 2009 11:49:45 +0100 > Mel Gorman <mel@csn.ul.ie> wrote: > > > Processes that have been OOM killed set the thread flag TIF_MEMDIE. A process > > such as this is expected to exit the page allocator but potentially, it > > loops forever. This patch checks TIF_MEMDIE when deciding whether to loop > > again in the page allocator. If set, and __GFP_NOFAIL is not specified > > then the loop will exit on the assumption it's no longer important for the > > process to make forward progress. Note that a process that has just been > > OOM-killed will still loop at least one more time retrying the allocation > > before the thread flag is checked. > > > > Signed-off-by: Mel Gorman <mel@csn.ul.ie> > > --- > > mm/page_alloc.c | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > > index f8902e7..5c98d02 100644 > > --- a/mm/page_alloc.c > > +++ b/mm/page_alloc.c > > @@ -1547,6 +1547,14 @@ should_alloc_retry(gfp_t gfp_mask, unsigned int order, > > if (gfp_mask & __GFP_NORETRY) > > return 0; > > > > + /* Do not loop if OOM-killed unless __GFP_NOFAIL is specified */ > > + if (test_thread_flag(TIF_MEMDIE)) { > > + if (gfp_mask & __GFP_NOFAIL) > > + WARN(1, "Potential infinite loop with __GFP_NOFAIL"); > > + else > > + return 0; > > + } > > + > > /* > > * In this implementation, order <= PAGE_ALLOC_COSTLY_ORDER > > * means __GFP_NOFAIL, but that may not be true in other > > This fixes a post-2.6.30 regression, yes? > > I dug out the commit ID a while back but lost it. Ho hum. >
You made a note at the time "Offending commit 341ce06 handled the PF_MEMALLOC case but forgot about the TIF_MEMDIE case."
-- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab
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