From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx191.postini.com [74.125.245.191]) by kanga.kvack.org (Postfix) with SMTP id 6FD806B0039 for ; Mon, 8 Apr 2013 15:37:45 -0400 (EDT) Received: from /spool/local by e7.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 8 Apr 2013 15:37:44 -0400 Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by d01dlp01.pok.ibm.com (Postfix) with ESMTP id 8FE9838C8054 for ; Mon, 8 Apr 2013 15:37:39 -0400 (EDT) Received: from d03av03.boulder.ibm.com (d03av03.boulder.ibm.com [9.17.195.169]) by d01relay04.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r38Jbb3f282130 for ; Mon, 8 Apr 2013 15:37:38 -0400 Received: from d03av03.boulder.ibm.com (loopback [127.0.0.1]) by d03av03.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r38JbTC9014350 for ; Mon, 8 Apr 2013 13:37:29 -0600 Message-ID: <51631C70.8010404@linux.vnet.ibm.com> Date: Mon, 08 Apr 2013 12:37:20 -0700 From: Cody P Schafer MIME-Version: 1.0 Subject: Re: [PATCH 0/3] mm: fixup changers of per cpu pageset's ->high and ->batch References: <1365194030-28939-1-git-send-email-cody@linux.vnet.ibm.com> <5160CC94.6040909@gmail.com> In-Reply-To: <5160CC94.6040909@gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Simon Jeons Cc: Andrew Morton , Mel Gorman , Linux MM , LKML On 04/06/2013 06:32 PM, Simon Jeons wrote: > Hi Cody, > On 04/06/2013 04:33 AM, Cody P Schafer wrote: >> In one case while modifying the ->high and ->batch fields of per cpu >> pagesets >> we're unneededly using stop_machine() (patches 1 & 2), and in another >> we don't have any >> syncronization at all (patch 3). > > Do you mean stop_machine() is used for syncronization between each > online cpu? > I mean that it looks like synchronization between cpus is unneeded because of how per cpu pagesets are used, so stop_machine() (which does provide syncro between all cpus) is unnecessarily "strong". -- 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