From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx123.postini.com [74.125.245.123]) by kanga.kvack.org (Postfix) with SMTP id BAF996B004D for ; Fri, 2 Nov 2012 02:22:17 -0400 (EDT) Message-ID: <509367F5.9060801@cn.fujitsu.com> Date: Fri, 02 Nov 2012 14:28:05 +0800 From: Wen Congyang MIME-Version: 1.0 Subject: Re: [PART6 Patch] mempolicy: fix is_valid_nodemask() References: <1351675458-11859-1-git-send-email-wency@cn.fujitsu.com> <1351675458-11859-2-git-send-email-wency@cn.fujitsu.com> In-Reply-To: Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: David Rientjes Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-doc@vger.kernel.org, Rob Landley , Andrew Morton , Yasuaki Ishimatsu , Lai Jiangshan , Jiang Liu , KOSAKI Motohiro , Minchan Kim , Mel Gorman , Yinghai Lu , "rusty@rustcorp.com.au" At 11/01/2012 02:21 AM, David Rientjes Wrote: > On Wed, 31 Oct 2012, Wen Congyang wrote: > >> From: Lai Jiangshan >> >> is_valid_nodemask() is introduced by 19770b32. but it does not match >> its comments, because it does not check the zone which > policy_zone. >> >> Also in b377fd, this commits told us, if highest zone is ZONE_MOVABLE, >> we should also apply memory policies to it. so ZONE_MOVABLE should be valid zone >> for policies. is_valid_nodemask() need to be changed to match it. >> >> Fix: check all zones, even its zoneid > policy_zone. >> Use nodes_intersects() instead open code to check it. >> > > This changes the semantics of MPOL_BIND to be considerably different than > what it is today: slab allocations are no longer bound by such a policy > which isn't consistent with what userspace expects or is specified by > set_mempolicy() and there's no way, with your patch, to actually specify > that we don't care about ZONE_MOVABLE and that the slab allocations > _should_ actually be allocated on movable-only zones. You have to respect > cases where people aren't interested in node hotplug and not cause a > regression. > Should we allow the user to bind a task to a node which has only ZONE_MOVABLE memory? Thanks Wen Congyang -- 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