From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta7.messagelabs.com (mail6.bemta7.messagelabs.com [216.82.255.55]) by kanga.kvack.org (Postfix) with ESMTP id C55796B002D for ; Sun, 9 Oct 2011 04:03:07 -0400 (EDT) Received: by ywe9 with SMTP id 9so6158688ywe.14 for ; Sun, 09 Oct 2011 01:03:05 -0700 (PDT) Date: Sun, 9 Oct 2011 17:02:55 +0900 From: Minchan Kim Subject: Re: [PATCH 1/2] mm: vmscan: Limit direct reclaim for higher order allocations Message-ID: <20111009080255.GC23003@barrios-desktop> References: <1318000643-27996-1-git-send-email-mgorman@suse.de> <1318000643-27996-2-git-send-email-mgorman@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1318000643-27996-2-git-send-email-mgorman@suse.de> Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman Cc: Rik van Riel , Johannes Weiner , akpm@linux-foundation.org, Josh Boyer , aarcange@redhat.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org On Fri, Oct 07, 2011 at 04:17:22PM +0100, Mel Gorman wrote: > From: Rik van Riel > > When suffering from memory fragmentation due to unfreeable pages, > THP page faults will repeatedly try to compact memory. Due to the > unfreeable pages, compaction fails. > > Needless to say, at that point page reclaim also fails to create > free contiguous 2MB areas. However, that doesn't stop the current > code from trying, over and over again, and freeing a minimum of 4MB > (2UL << sc->order pages) at every single invocation. > > This resulted in my 12GB system having 2-3GB free memory, a > corresponding amount of used swap and very sluggish response times. > > This can be avoided by having the direct reclaim code not reclaim from > zones that already have plenty of free memory available for compaction. > > If compaction still fails due to unmovable memory, doing additional > reclaim will only hurt the system, not help. > > Signed-off-by: Rik van Riel > Signed-off-by: Mel Gorman Reviewed-by: Minchan Kim -- Kinds 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org