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 CC27D6B0089 for ; Fri, 10 Sep 2010 02:18:36 -0400 (EDT) Date: Fri, 10 Sep 2010 16:17:46 +1000 From: Dave Chinner Subject: Re: [PATCH 3/3] mm: page allocator: Drain per-cpu lists after direct reclaim allocation fails Message-ID: <20100910061746.GE705@dastard> References: <20100905015400.GA10714@localhost> <20100905021555.GG705@dastard> <20100905060539.GA17450@localhost> <20100905131447.GJ705@dastard> <20100905134554.GA7083@localhost> <20100906040243.GA7362@dastard> <20100906084015.GJ8384@csn.ul.ie> <20100906215023.GC7362@dastard> <20100908084923.GW705@dastard> <20100909123910.GP29263@csn.ul.ie> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100909123910.GP29263@csn.ul.ie> Sender: owner-linux-mm@kvack.org To: Wu Fengguang , Andrew Morton , Linux Kernel List , "linux-mm@kvack.org" , Rik van Riel , Johannes Weiner , Minchan Kim , Christoph Lameter , KAMEZAWA Hiroyuki , KOSAKI Motohiro , David Rientjes List-ID: On Thu, Sep 09, 2010 at 01:39:10PM +0100, wrote: > It has been pointed out that the fix potentially increases the number of > IPIs sent. On larger machines, I worry that these delays could be severe > and we'll see other problems down the line. Hence, I'd like to reduce > the number of calls to drain_all_pages() without eliminating them > entirely. I'm currently in the process of testing the following patch > but can you try it as well please? > > In particular, I am curious to see if the performance of fs_mark > improves any and if the interrupt counts drop as a result of the patch. The interrupt counts have definitely dropped - this is after creating 200M inodes and then removing them all: CAL: 11154 10596 11804 15366 10048 12916 13049 9864 That's in the same ballpark as a single 50M inode create run without the patch. Performance seems a bit lower, though (2-3% maybe less), and CPU usage seems a bit higher (stays much closer to 800% than 700-750% without the patch). Those are subjective observations from watching graphs and counters, so take them with a grain of salt. Cheers, Dave. -- Dave Chinner david@fromorbit.com -- 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