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 563126B0005 for ; Thu, 14 Jul 2016 06:05:58 -0400 (EDT) Received: by mail-wm0-f71.google.com with SMTP id o80so53137597wme.1 for ; Thu, 14 Jul 2016 03:05:58 -0700 (PDT) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id 15si1019593ljf.24.2016.07.14.03.05.56 for (version=TLS1 cipher=AES128-SHA bits=128/128); Thu, 14 Jul 2016 03:05:56 -0700 (PDT) Subject: Re: [PATCH 22/34] mm, page_alloc: wake kswapd based on the highest eligible zone References: <1467970510-21195-1-git-send-email-mgorman@techsingularity.net> <1467970510-21195-23-git-send-email-mgorman@techsingularity.net> From: Vlastimil Babka Message-ID: <39dcc1fe-d6a6-a9f8-3872-b1d53b491fa3@suse.cz> Date: Thu, 14 Jul 2016 12:05:51 +0200 MIME-Version: 1.0 In-Reply-To: <1467970510-21195-23-git-send-email-mgorman@techsingularity.net> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman , Andrew Morton , Linux-MM Cc: Rik van Riel , Johannes Weiner , Minchan Kim , Joonsoo Kim , LKML On 07/08/2016 11:34 AM, Mel Gorman 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 first 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 Acked-by: Vlastimil Babka > --- > mm/page_alloc.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index bb261885c121..e6ee52f1c15f 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -3415,7 +3415,7 @@ static void wake_all_kswapds(unsigned int order, const struct alloc_context *ac) > for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, > ac->high_zoneidx, ac->nodemask) { > if (last_pgdat != zone->zone_pgdat) > - wakeup_kswapd(zone, order, ac_classzone_idx(ac)); > + wakeup_kswapd(zone, order, ac->high_zoneidx); > last_pgdat = zone->zone_pgdat; > } > } > -- 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