From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f71.google.com (mail-wm0-f71.google.com [74.125.82.71]) by kanga.kvack.org (Postfix) with ESMTP id C13ED6B0253 for ; Tue, 5 Jul 2016 06:49:31 -0400 (EDT) Received: by mail-wm0-f71.google.com with SMTP id c82so85202682wme.2 for ; Tue, 05 Jul 2016 03:49:31 -0700 (PDT) Received: from outbound-smtp07.blacknight.com (outbound-smtp07.blacknight.com. [46.22.139.12]) by mx.google.com with ESMTPS id pg5si3444894wjb.179.2016.07.05.03.49.30 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 05 Jul 2016 03:49:30 -0700 (PDT) Received: from mail.blacknight.com (pemlinmail04.blacknight.ie [81.17.254.17]) by outbound-smtp07.blacknight.com (Postfix) with ESMTPS id 45EFE1C1EF4 for ; Tue, 5 Jul 2016 11:49:30 +0100 (IST) Date: Tue, 5 Jul 2016 11:49:28 +0100 From: Mel Gorman Subject: Re: [PATCH 21/31] mm, page_alloc: Wake kswapd based on the highest eligible zone Message-ID: <20160705104928.GJ11498@techsingularity.net> References: <00e101d1d689$b9a1d730$2ce58590$@alibaba-inc.com> <00e201d1d68a$84b72100$8e256300$@alibaba-inc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <00e201d1d68a$84b72100$8e256300$@alibaba-inc.com> Sender: owner-linux-mm@kvack.org List-ID: To: Hillf Danton Cc: linux-kernel , linux-mm@kvack.org, Andrew Morton On Tue, Jul 05, 2016 at 02:57:38PM +0800, Hillf Danton wrote: > > > > The ac_classzone_idx is used as the basis for waking kswapd and that is based > > on the preferred zoneref. If the preferred zoneref's highest zone is lower > > than what is available on other nodes, it's possible that kswapd is woken > > on a zone with only higher, but still eligible, zones. As classzone_idx > > is strictly adhered to now, it causes a problem because eligible pages > > are skipped. > > > > For example, node 0 has only DMA32 and node 1 has only NORMAL. An allocating > > context running on node 0 may wake kswapd on node 1 telling it to skip > > all NORMAL pages. > > > > Signed-off-by: Mel Gorman > > --- > Acked-by: Hillf Danton > Thanks. I also noticed when applying the ack that "zoneref's highest zone" should have been "zoneref's first zone" so fixed that too. -- 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