From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta12.messagelabs.com (mail6.bemta12.messagelabs.com [216.82.250.247]) by kanga.kvack.org (Postfix) with ESMTP id CF4426B0080 for ; Tue, 22 Nov 2011 12:51:02 -0500 (EST) Received: by vcbfk26 with SMTP id fk26so656878vcb.14 for ; Tue, 22 Nov 2011 09:51:00 -0800 (PST) Date: Wed, 23 Nov 2011 02:50:55 +0900 From: Minchan Kim Subject: Re: [PATCH 6/7] mm: page allocator: Limit when direct reclaim is used when compaction is deferred Message-ID: <20111122175055.GE15253@barrios-laptop.redhat.com> References: <1321900608-27687-1-git-send-email-mgorman@suse.de> <1321900608-27687-7-git-send-email-mgorman@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1321900608-27687-7-git-send-email-mgorman@suse.de> Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman Cc: Linux-MM , Andrea Arcangeli , Jan Kara , Andy Isaacson , Johannes Weiner , Rik van Riel , Nai Xia , LKML On Mon, Nov 21, 2011 at 06:36:47PM +0000, Mel Gorman wrote: > If compaction is deferred, we enter direct reclaim to try reclaim the > pages that way. For small high-orders, this has a reasonable chance > of success. However, if the caller as specified __GFP_NO_KSWAPD to > limit the disruption to the system, it makes more sense to fail the > allocation rather than stall the caller in direct reclaim. This patch > will skip direct reclaim if compaction is deferred and the caller > specifies __GFP_NO_KSWAPD. > > Async compaction only considers a subset of pages so it is possible for > compaction to be deferred prematurely and not enter direct reclaim even > in cases where it should. To compensate for this, this patch also defers > compaction only if sync compaction failed. > > Signed-off-by: Mel Gorman Acked-by: Minchan Kim It does make sense to me. -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org