From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 30068C5517A for ; Fri, 30 Oct 2020 09:43:15 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 918762072C for ; Fri, 30 Oct 2020 09:43:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="Qk8xKAH6" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 918762072C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id C6B916B0062; Fri, 30 Oct 2020 05:43:13 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id BF45B6B006C; Fri, 30 Oct 2020 05:43:13 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B32836B006E; Fri, 30 Oct 2020 05:43:13 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0198.hostedemail.com [216.40.44.198]) by kanga.kvack.org (Postfix) with ESMTP id 855396B0062 for ; Fri, 30 Oct 2020 05:43:13 -0400 (EDT) Received: from smtpin16.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 254A7B9E1 for ; Fri, 30 Oct 2020 09:43:13 +0000 (UTC) X-FDA: 77428103466.16.fight02_0216ead27295 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin16.hostedemail.com (Postfix) with ESMTP id F345C100E7FA5 for ; Fri, 30 Oct 2020 09:43:12 +0000 (UTC) X-HE-Tag: fight02_0216ead27295 X-Filterd-Recvd-Size: 3083 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf21.hostedemail.com (Postfix) with ESMTP for ; Fri, 30 Oct 2020 09:43:12 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1604050991; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=gW6rXL0xOJtuSZA4czIEKpIyYPqMh5pKjDm6Kj1ppXA=; b=Qk8xKAH6MT53xLObk/CIJp7ZTYxN3ioKcYbgVqYnVuXXBbfLb08DBybQKXLVHr4SH8OC2D sEenGfV+rHgM3Y8Hl4OQT2+CR8I+EBkRK6QHxidqn3fo+AH0axwrwZP/I6JKMZNTmrEJSc ahgM/spuXLIvfuk4Ddesotk9kRxl5pg= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 1FCD6AD49; Fri, 30 Oct 2020 09:43:11 +0000 (UTC) Date: Fri, 30 Oct 2020 10:43:08 +0100 From: Michal Hocko To: Zi Yan Cc: Andrew Morton , linux-mm@kvack.org, Rik van Riel , linux-kernel@vger.kernel.org, Vlastimil Babka Subject: Re: [PATCH] mm/compaction: count pages and stop correctly during page isolation. Message-ID: <20201030094308.GG1478@dhcp22.suse.cz> References: <20201029200435.3386066-1-zi.yan@sent.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201029200435.3386066-1-zi.yan@sent.com> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: [Cc Vlastimil] On Thu 29-10-20 16:04:35, Zi Yan wrote: > From: Zi Yan > > In isolate_migratepages_block, when cc->alloc_contig is true, we are > able to isolate compound pages, nr_migratepages and nr_isolated did not > count compound pages correctly, causing us to isolate more pages than we > thought. Use thp_nr_pages to count pages. Otherwise, we might be trapped > in too_many_isolated while loop, since the actual isolated pages can go > up to COMPACT_CLUSTER_MAX*512=16384, where COMPACT_CLUSTER_MAX is 32, > since we stop isolation after cc->nr_migratepages reaches to > COMPACT_CLUSTER_MAX. > > In addition, after we fix the issue above, cc->nr_migratepages could > never be equal to COMPACT_CLUSTER_MAX if compound pages are isolated, > thus page isolation could not stop as we intended. Change the isolation > stop condition to >=. > > Signed-off-by: Zi Yan > --- > mm/compaction.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/mm/compaction.c b/mm/compaction.c > index ee1f8439369e..0683a4999581 100644 > --- a/mm/compaction.c > +++ b/mm/compaction.c > @@ -1012,8 +1012,8 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, > > isolate_success: > list_add(&page->lru, &cc->migratepages); > - cc->nr_migratepages++; > - nr_isolated++; > + cc->nr_migratepages += thp_nr_pages(page); > + nr_isolated += thp_nr_pages(page); Does thp_nr_pages work for __PageMovable pages? -- Michal Hocko SUSE Labs