From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lb0-f199.google.com (mail-lb0-f199.google.com [209.85.217.199]) by kanga.kvack.org (Postfix) with ESMTP id 115096B025E for ; Thu, 16 Jun 2016 03:44:17 -0400 (EDT) Received: by mail-lb0-f199.google.com with SMTP id na2so23488428lbb.1 for ; Thu, 16 Jun 2016 00:44:17 -0700 (PDT) Received: from outbound-smtp05.blacknight.com (outbound-smtp05.blacknight.com. [81.17.249.38]) by mx.google.com with ESMTPS id e13si15369191wme.10.2016.06.16.00.44.15 for (version=TLS1 cipher=AES128-SHA bits=128/128); Thu, 16 Jun 2016 00:44:15 -0700 (PDT) Received: from mail.blacknight.com (pemlinmail04.blacknight.ie [81.17.254.17]) by outbound-smtp05.blacknight.com (Postfix) with ESMTPS id 1CB3398668 for ; Thu, 16 Jun 2016 07:44:15 +0000 (UTC) Date: Thu, 16 Jun 2016 08:44:13 +0100 From: Mel Gorman Subject: Re: [PATCH 05/27] mm, vmscan: Have kswapd only scan based on the highest requested zone Message-ID: <20160616074413.GE1868@techsingularity.net> References: <1465495483-11855-1-git-send-email-mgorman@techsingularity.net> <1465495483-11855-6-git-send-email-mgorman@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Vlastimil Babka Cc: Andrew Morton , Linux-MM , Rik van Riel , Johannes Weiner , LKML On Wed, Jun 15, 2016 at 03:13:13PM +0200, Vlastimil Babka wrote: > On 06/09/2016 08:04 PM, Mel Gorman wrote: > >kswapd checks all eligible zones to see if they need balancing even if it was > >woken for a lower zone. This made sense when we reclaimed on a per-zone basis > >because we wanted to shrink zones fairly so avoid age-inversion problems. > > Now we reclaim a single lru, but still will skip over pages from the higher > zones than reclaim_idx, so this is not much different from per-zone basis > wrt age-inversion? > Yes, but it only applies in the case where the allocation request is zone restricted. Previously, even with fair zone allocation policy, we had problems with a high zone with recently allocated pages being reclaimed simply because the low watermark was reached. Think of bugs in the past where the normal zone was a small percentage of memory. -- 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