From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f200.google.com (mail-qk0-f200.google.com [209.85.220.200]) by kanga.kvack.org (Postfix) with ESMTP id 7C9416B0006 for ; Tue, 24 Jul 2018 18:38:41 -0400 (EDT) Received: by mail-qk0-f200.google.com with SMTP id a70-v6so4816919qkb.16 for ; Tue, 24 Jul 2018 15:38:41 -0700 (PDT) Received: from mail-sor-f41.google.com (mail-sor-f41.google.com. [209.85.220.41]) by mx.google.com with SMTPS id m63-v6sor6131176qkd.12.2018.07.24.15.38.40 for (Google Transport Security); Tue, 24 Jul 2018 15:38:40 -0700 (PDT) Subject: Re: freepage accounting bug with CMA/migrate isolation References: <86bea4f7-229a-7cbb-1e8a-7e6d96f0f087@oracle.com> From: Laura Abbott Message-ID: <92636e32-c71b-0092-02bf-a802065075ef@redhat.com> Date: Tue, 24 Jul 2018 15:38:37 -0700 MIME-Version: 1.0 In-Reply-To: <86bea4f7-229a-7cbb-1e8a-7e6d96f0f087@oracle.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Mike Kravetz , "linux-mm@kvack.org" Cc: Vlastimil Babka , 'Joonsoo Kim' On 07/23/2018 09:24 PM, Mike Kravetz wrote: > With v4.17, I can see an issue like those addressed in commits 3c605096d315 > ("mm/page_alloc: restrict max order of merging on isolated pageblock") > and d9dddbf55667 ("mm/page_alloc: prevent merging between isolated and > other pageblocks"). After running a CMA stress test for a while, I see: > MemTotal: 8168384 kB > MemFree: 8457232 kB > MemAvailable: 9204844 kB > If I let the test run, MemFree and MemAvailable will continue to grow. > > I am certain the issue is with pageblocks of migratetype ISOLATED. If > I disable all special 'is_migrate_isolate' checks in freepage accounting, > the issue goes away. Further, I am pretty sure the issue has to do with > pageblock merging and or page orders spanning pageblocks. If I make > pageblock_order equal MAX_ORDER-1, the issue also goes away. > > Just looking for suggesting in where/how to debug. I've been hacking on > this without much success. > -- > Mike Kravetz > If you revert d883c6cf3b39 ("Revert "mm/cma: manage the memory of the CMA area by using the ZONE_MOVABLE"") do you still see the issue? I thought there was another isolation edge case which was fixed by that series. Thanks, Laura