From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with SMTP id 5E9F06B01F0 for ; Mon, 16 Aug 2010 22:57:32 -0400 (EDT) Received: by vws16 with SMTP id 16so4808812vws.14 for ; Mon, 16 Aug 2010 19:57:31 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <1281951733-29466-4-git-send-email-mel@csn.ul.ie> References: <1281951733-29466-1-git-send-email-mel@csn.ul.ie> <1281951733-29466-4-git-send-email-mel@csn.ul.ie> Date: Tue, 17 Aug 2010 11:57:31 +0900 Message-ID: Subject: Re: [PATCH 3/3] mm: page allocator: Drain per-cpu lists after direct reclaim allocation fails From: Minchan Kim Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org To: Mel Gorman Cc: linux-mm@kvack.org, Rik van Riel , Nick Piggin , Johannes Weiner , KAMEZAWA Hiroyuki , KOSAKI Motohiro List-ID: On Mon, Aug 16, 2010 at 6:42 PM, Mel Gorman wrote: > When under significant memory pressure, a process enters direct reclaim > and immediately afterwards tries to allocate a page. If it fails and no > further progress is made, it's possible the system will go OOM. However, > on systems with large amounts of memory, it's possible that a significant > number of pages are on per-cpu lists and inaccessible to the calling > process. This leads to a process entering direct reclaim more often than > it should increasing the pressure on the system and compounding the problem. > > This patch notes that if direct reclaim is making progress but > allocations are still failing that the system is already under heavy > pressure. In this case, it drains the per-cpu lists and tries the > allocation a second time before continuing. > > Signed-off-by: Mel Gorman Reviewed-by: Minchan Kim IPI overhead would be good rather than going OOM or nopage. In addition, here isn't a hot path and frequent case. -- Kind regards, Minchan Kim -- 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