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 SMTP id F2D496B0083 for ; Mon, 18 Jul 2011 10:56:35 -0400 (EDT) Date: Mon, 18 Jul 2011 09:56:31 -0500 (CDT) From: Christoph Lameter Subject: Re: [PATCH 1/2] mm: page allocator: Initialise ZLC for first zone eligible for zone_reclaim In-Reply-To: <1310742540-22780-2-git-send-email-mgorman@suse.de> Message-ID: References: <1310742540-22780-1-git-send-email-mgorman@suse.de> <1310742540-22780-2-git-send-email-mgorman@suse.de> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman Cc: Andrew Morton , Minchan Kim , KOSAKI Motohiro , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Fri, 15 Jul 2011, Mel Gorman wrote: > Currently the zonelist cache is setup only after the first zone has > been considered and zone_reclaim() has been called. The objective was > to avoid a costly setup but zone_reclaim is itself quite expensive. If > it is failing regularly such as the first eligible zone having mostly > mapped pages, the cost in scanning and allocation stalls is far higher > than the ZLC initialisation step. Would it not be easier to set zlc_active and allowednodes based on the zone having an active ZLC at the start of get_pages()? Buffered_rmqueue is handling the situation of a zone with an ZLC in a weird way right now since it ignores the (potentially existing) ZLC for the first pass. zlc_setup() does a lot of things. So that is because there is a performance benefit? -- 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