From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id 2B12C6B0092 for ; Mon, 24 Jan 2011 12:10:25 -0500 (EST) Message-ID: <4D3DB234.4050703@redhat.com> Date: Mon, 24 Jan 2011 12:09:08 -0500 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [patch] mm: clear pages_scanned only if draining a pcp adds pages to the buddy allocator References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: David Rientjes Cc: Andrew Morton , Mel Gorman , Johannes Weiner , Minchan Kim , Wu Fengguang , KAMEZAWA Hiroyuki , KOSAKI Motohiro , Jens Axboe , linux-mm@kvack.org List-ID: On 01/23/2011 05:58 PM, David Rientjes wrote: > 0e093d99763e (writeback: do not sleep on the congestion queue if there > are no congested BDIs or if significant congestion is not being > encountered in the current zone) uncovered a livelock in the page > allocator that resulted in tasks infinitely looping trying to find memory > and kswapd running at 100% cpu. > > The issue occurs because drain_all_pages() is called immediately > following direct reclaim when no memory is freed and try_to_free_pages() > returns non-zero because all zones in the zonelist do not have their > all_unreclaimable flag set. Reviewed-by: Rik van Riel -- 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/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org