From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lb0-f176.google.com (mail-lb0-f176.google.com [209.85.217.176]) by kanga.kvack.org (Postfix) with ESMTP id D37206B0055 for ; Fri, 29 Aug 2014 04:12:17 -0400 (EDT) Received: by mail-lb0-f176.google.com with SMTP id s7so2155202lbd.21 for ; Fri, 29 Aug 2014 01:12:16 -0700 (PDT) Received: from mx2.suse.de (cantor2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id r6si8639161lar.128.2014.08.29.01.12.15 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 29 Aug 2014 01:12:15 -0700 (PDT) Date: Fri, 29 Aug 2014 09:12:11 +0100 From: Mel Gorman Subject: Re: [PATCH] mm: page_alloc: avoid wakeup kswapd on the unintended node Message-ID: <20140829081211.GF12424@suse.de> References: <000001cfc357$74db64a0$5e922de0$%yang@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <000001cfc357$74db64a0$5e922de0$%yang@samsung.com> Sender: owner-linux-mm@kvack.org List-ID: To: Weijie Yang Cc: 'Andrew Morton' , 'Rik van Riel' , 'Johannes Weiner' , rientjes@google.com, 'Weijie Yang' , 'linux-kernel' , 'Linux-MM' On Fri, Aug 29, 2014 at 03:03:19PM +0800, Weijie Yang wrote: > When enter page_alloc slowpath, we wakeup kswapd on every pgdat > according to the zonelist and high_zoneidx. However, this doesn't > take nodemask into account, and could prematurely wakeup kswapd on > some unintended nodes. > > This patch uses for_each_zone_zonelist_nodemask() instead of > for_each_zone_zonelist() in wake_all_kswapds() to avoid the above situation. > > Signed-off-by: Weijie Yang Just out of curiousity, did you measure a problem due to this or is the patch due to code inspection? It was known that we examined useless nodes but assumed to not be a problem because the watermark check should prevent spurious wakeups. However, we do a cpuset check and this patch is consistent with that so regardless of why you wrote the patch Acked-by: Mel Gorman -- Mel Gorman SUSE Labs -- 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