From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with ESMTP id 97B236B004F for ; Wed, 15 Jul 2009 16:30:26 -0400 (EDT) Date: Wed, 15 Jul 2009 13:30:14 -0700 From: Andrew Morton Subject: Re: [PATCH] page-allocator: Ensure that processes that have been OOM killed exit the page allocator (resend) Message-Id: <20090715133014.a3566bdd.akpm@linux-foundation.org> In-Reply-To: <20090715104944.GC9267@csn.ul.ie> References: <20090715104944.GC9267@csn.ul.ie> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Mel Gorman Cc: rientjes@google.com, npiggin@suse.de, linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: On Wed, 15 Jul 2009 11:49:45 +0100 Mel Gorman 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 > --- > 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. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org