From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 10 Dec 2008 06:09:38 +0100 From: Nick Piggin Subject: Re: [PATCH] vmscan: skip freeing memory from zones with lots free Message-ID: <20081210050938.GF8434@wotan.suse.de> References: <20081129195357.813D.KOSAKI.MOTOHIRO@jp.fujitsu.com> <20081208205842.53F8.KOSAKI.MOTOHIRO@jp.fujitsu.com> <20081208220016.53FB.KOSAKI.MOTOHIRO@jp.fujitsu.com> <493D82A6.9070104@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <493D82A6.9070104@redhat.com> Sender: owner-linux-mm@kvack.org Return-Path: To: Rik van Riel Cc: KOSAKI Motohiro , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Peter Zijlstra , Johannes Weiner , Christoph Lameter List-ID: On Mon, Dec 08, 2008 at 03:25:10PM -0500, Rik van Riel wrote: > KOSAKI Motohiro wrote: > > >+ for (o = order; o < MAX_ORDER; o++) { > >+ if (z->free_area[o].nr_free) > >+ return 1; > > Since page breakup and coalescing always manipulates .nr_free, > I wonder if it would make sense to pack the nr_free variables > in their own cache line(s), so we have fewer cache misses when > going through zone_watermark_ok() ? For order-0 allocations, they should not be touched at all. For higher order allocations in performance critical paths, we should try to fix those to use order-0 ;) -- 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