From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f49.google.com (mail-pa0-f49.google.com [209.85.220.49]) by kanga.kvack.org (Postfix) with ESMTP id B21E26B0035 for ; Thu, 7 Aug 2014 04:23:56 -0400 (EDT) Received: by mail-pa0-f49.google.com with SMTP id hz1so4937350pad.22 for ; Thu, 07 Aug 2014 01:23:56 -0700 (PDT) Received: from lgeamrelo01.lge.com (lgeamrelo01.lge.com. [156.147.1.125]) by mx.google.com with ESMTP id p6si1458433pdn.18.2014.08.07.01.23.54 for ; Thu, 07 Aug 2014 01:23:55 -0700 (PDT) Date: Thu, 7 Aug 2014 17:23:53 +0900 From: Joonsoo Kim Subject: Re: [PATCH v2 3/8] mm/page_alloc: fix pcp high, batch management Message-ID: <20140807082353.GC2427@js1304-P5Q-DELUXE> References: <1407309517-3270-1-git-send-email-iamjoonsoo.kim@lge.com> <1407309517-3270-7-git-send-email-iamjoonsoo.kim@lge.com> <53E2E042.3070803@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <53E2E042.3070803@cn.fujitsu.com> Sender: owner-linux-mm@kvack.org List-ID: To: Zhang Yanfei Cc: Andrew Morton , "Kirill A. Shutemov" , Rik van Riel , Mel Gorman , Johannes Weiner , Minchan Kim , Yasuaki Ishimatsu , "Srivatsa S. Bhat" , Tang Chen , Naoya Horiguchi , Bartlomiej Zolnierkiewicz , Wen Congyang , Marek Szyprowski , Michal Nazarewicz , Laura Abbott , Heesub Shin , "Aneesh Kumar K.V" , Ritesh Harjani , t.stanislaws@samsung.com, Gioh Kim , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Thu, Aug 07, 2014 at 10:11:14AM +0800, Zhang Yanfei wrote: > Hi Joonsoo, > > On 08/06/2014 03:18 PM, Joonsoo Kim wrote: > > per cpu pages structure, aka pcp, has high and batch values to control > > how many pages we perform caching. This values could be updated > > asynchronously and updater should ensure that this doesn't make any > > problem. For this purpose, pageset_update() is implemented and do some > > memory synchronization. But, it turns out to be wrong when I implemented > > new feature using this. There is no corresponding smp_rmb() in read-side > > Out of curiosity, what new feature are you implementing? I mean just zone_pcp_disable() and zone_pcp_enable(). :) > IIRC, pageset_update() is used to update high and batch which can be changed > during: > > system boot > sysfs > memory hot-plug > > So it seems to me that the latter two would have the problems you described here. Yes, I think so. But I'm not sure, because I didn't look at it in detail. :) Thanks. -- 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