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=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 C72B7C433DB for ; Thu, 18 Mar 2021 11:04:06 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 511AD64F04 for ; Thu, 18 Mar 2021 11:04:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 511AD64F04 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id CC3C36B0070; Thu, 18 Mar 2021 07:04:05 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C73406B0071; Thu, 18 Mar 2021 07:04:05 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B13C16B0072; Thu, 18 Mar 2021 07:04:05 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0197.hostedemail.com [216.40.44.197]) by kanga.kvack.org (Postfix) with ESMTP id 915346B0070 for ; Thu, 18 Mar 2021 07:04:05 -0400 (EDT) Received: from smtpin36.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 4A39C1802EC11 for ; Thu, 18 Mar 2021 11:04:05 +0000 (UTC) X-FDA: 77932710450.36.70F6BBD Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf19.hostedemail.com (Postfix) with ESMTP id 2556290009EA for ; Thu, 18 Mar 2021 11:04:04 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id DBB43AC1E; Thu, 18 Mar 2021 11:04:02 +0000 (UTC) Date: Thu, 18 Mar 2021 12:04:00 +0100 From: Oscar Salvador To: Michal Hocko Cc: Andrew Morton , Vlastimil Babka , David Hildenbrand , Muchun Song , Mike Kravetz , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 1/5] mm,page_alloc: Bail out earlier on -ENOMEM in alloc_contig_migrate_range Message-ID: References: <20210317111251.17808-1-osalvador@suse.de> <20210317111251.17808-2-osalvador@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Stat-Signature: xf7ws4x9rrbuskxan3o85fx846abmsmb X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 2556290009EA Received-SPF: none (suse.de>: No applicable sender policy available) receiver=imf19; identity=mailfrom; envelope-from=""; helo=mx2.suse.de; client-ip=195.135.220.15 X-HE-DKIM-Result: none/none X-HE-Tag: 1616065444-146501 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: On Wed, Mar 17, 2021 at 03:05:40PM +0100, Michal Hocko wrote: > That being said, bailing out early makes sense to me. But now that > you've made me look into the migrate_pages excellent error state reporting > I suspect we have a bug here. Note the > "Returns the number of pages that were not migrated, or an error code." > > but I do not see putback_movable_pages for ret > 0 so it seems we might > leak some pages. I fell for the same thing when looking at that code. It took a while until I realized what was really going on. > > Signed-off-by: Oscar Salvador > > Acked-by: Vlastimil Babka > > Reviewed-by: David Hildenbrand > > The patch itself looks reasonable but make sure to mention this is mere > cosmetic change unless there is a real problem fixed by this. > Acked-by: Michal Hocko What about appending the following in the changelog: "Note that this is not fixing a real issue, just a cosmetic change. Although we can save some cycles by backing off ealier." -- Oscar Salvador SUSE L3