From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f70.google.com (mail-pl0-f70.google.com [209.85.160.70]) by kanga.kvack.org (Postfix) with ESMTP id 9974E6B000D for ; Thu, 5 Apr 2018 04:05:52 -0400 (EDT) Received: by mail-pl0-f70.google.com with SMTP id t1-v6so18085733plb.5 for ; Thu, 05 Apr 2018 01:05:52 -0700 (PDT) Received: from lgeamrelo12.lge.com (lgeamrelo12.lge.com. [156.147.23.52]) by mx.google.com with ESMTP id r30si5146171pgu.587.2018.04.05.01.05.51 for ; Thu, 05 Apr 2018 01:05:51 -0700 (PDT) Date: Thu, 5 Apr 2018 17:05:39 +0900 From: Joonsoo Kim Subject: Re: [PATCH] mm/thp: don't count ZONE_MOVABLE as the target for freepage reserving Message-ID: <20180405080539.GA631@js1304-desktop> References: <1522913236-15776-1-git-send-email-iamjoonsoo.kim@lge.com> <20180405075753.GZ6312@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180405075753.GZ6312@dhcp22.suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Andrew Morton , "Kirill A . Shutemov" , Mel Gorman , Vlastimil Babka , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Thu, Apr 05, 2018 at 09:57:53AM +0200, Michal Hocko wrote: > On Thu 05-04-18 16:27:16, Joonsoo Kim wrote: > > From: Joonsoo Kim > > > > ZONE_MOVABLE only has movable pages so we don't need to keep enough > > freepages to avoid or deal with fragmentation. So, don't count it. > > > > This changes min_free_kbytes and thus min_watermark greatly > > if ZONE_MOVABLE is used. It will make the user uses more memory. > > OK, but why does it matter. Has anybody seen this as an issue? There was a regression report for CMA patchset and I think that it is related to this problem. CMA patchset makes the system uses one more zone (ZONE_MOVABLE) and then increase min_free_kbytes. It reduces usable memory and it could cause regression. http://lkml.kernel.org/r/20180102063528.GG30397@yexl-desktop Thanks.