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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4E062C54EBE for ; Mon, 16 Jan 2023 05:46:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231782AbjAPFqh (ORCPT ); Mon, 16 Jan 2023 00:46:37 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41126 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231724AbjAPFqg (ORCPT ); Mon, 16 Jan 2023 00:46:36 -0500 Received: from mail-wr1-f54.google.com (mail-wr1-f54.google.com [209.85.221.54]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3D1FD868D; Sun, 15 Jan 2023 21:46:35 -0800 (PST) Received: by mail-wr1-f54.google.com with SMTP id t5so21949115wrq.1; Sun, 15 Jan 2023 21:46:35 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=ij+Fr1khqSzHk9heKO9nWr6VaTDuNgkAMouf15x4tOs=; b=WYUyuVwRvVVj6qy7ZQnHhY0CHOKCUu/vXHyDWJADCnGbOAOT+MCvVrcCfcuNjKEDfc DFPaFoSn/t+/XUFovDldH93I0dBMgLtXv7vZW0MLu0YBOcNgoQuOc+K+CNedjoFmrqhL HUY+5hMRfrjnHyuEraY2vjDmKhRS3SunqyjqbzjXtBOHCvnbZIPAxq1PAzpFH5V7B+7D HtIE+7FZxIpB/J42chLaLBqILHawdqtZfl7H/vj/xmRxECzAm67V5CA3GED5CrWrncEf lyyGUr6ZGkSjGzv4M+tDZBO3YPs1dzghW0c+AFmID4C75oTHuW7Rv2oc93fEnAgUMfI3 E5JA== X-Gm-Message-State: AFqh2kp6bNY6+p4/PpSfbUyAuJeFnamKCowLEy7aDDO7KUlxBuoDuZ0n IpQ+iizt5N+H3rWC1UvvQwOYonSTAAo= X-Google-Smtp-Source: AMrXdXtiv0rVXISQvtDiWF1IwLUvKhJ/TdveM3E9DZjGRY4vk+Yd/yR7gZS4PgUl44ZBjq3TQwFu4w== X-Received: by 2002:a05:6000:408c:b0:2bd:fcd8:c778 with SMTP id da12-20020a056000408c00b002bdfcd8c778mr3879153wrb.31.1673847993845; Sun, 15 Jan 2023 21:46:33 -0800 (PST) Received: from ?IPV6:2a0b:e7c0:0:107::aaaa:49? ([2a0b:e7c0:0:107::aaaa:49]) by smtp.gmail.com with ESMTPSA id u14-20020adfdd4e000000b002366e3f1497sm25605422wrm.6.2023.01.15.21.46.32 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 15 Jan 2023 21:46:33 -0800 (PST) Message-ID: Date: Mon, 16 Jan 2023 06:46:32 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.6.1 Subject: Re: + revert-mm-compaction-fix-set-skip-in-fast_find_migrateblock.patch added to mm-hotfixes-unstable branch Content-Language: en-US To: Andrew Morton , mm-commits@vger.kernel.org, zhouchuyi@bytedance.com, stable@vger.kernel.org, regressions@leemhuis.info, pbonzini@redhat.com, mlevitsk@redhat.com, mhocko@kernel.org, mgorman@techsingularity.net, vbabka@suse.cz References: <20230114041117.B372AC43392@smtp.kernel.org> From: Jiri Slaby In-Reply-To: <20230114041117.B372AC43392@smtp.kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org On 14. 01. 23, 5:11, Andrew Morton wrote: > The patch titled > Subject: Revert "mm/compaction: fix set skip in fast_find_migrateblock" > has been added to the -mm mm-hotfixes-unstable branch. Its filename is > revert-mm-compaction-fix-set-skip-in-fast_find_migrateblock.patch > > This patch will shortly appear at > https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/revert-mm-compaction-fix-set-skip-in-fast_find_migrateblock.patch > > This patch will later appear in the mm-hotfixes-unstable branch at > git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm > > Before you just go and hit "reply", please: > a) Consider who else should be cc'ed > b) Prefer to cc a suitable mailing list as well > c) Ideally: find the original patch on the mailing list and do a > reply-to-all to that, adding suitable additional cc's > > *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** > > The -mm tree is included into linux-next via the mm-everything > branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm > and is updated there every 2-3 working days > > ------------------------------------------------------ > From: Vlastimil Babka > Subject: Revert "mm/compaction: fix set skip in fast_find_migrateblock" > Date: Fri, 13 Jan 2023 18:33:45 +0100 > > This reverts commit 7efc3b7261030da79001c00d92bc3392fd6c664c. > > We have got openSUSE reports (Link 1) for 6.1 kernel with khugepaged > stalling CPU for long periods of time. Investigation of tracepoint data > shows that compaction is stuck in repeating fast_find_migrateblock() based > migrate page isolation, and then fails to migrate all isolated pages. > Commit 7efc3b726103 ("mm/compaction: fix set skip in > fast_find_migrateblock") was suspected as it was merged in 6.1 and in > theory can indeed remove a termination condition for > fast_find_migrateblock() under certain conditions, as it removes a place > that always marks a scanned pageblock from being re-scanned. There are > other such places, but those can be skipped under certain conditions, > which seems to match the tracepoint data. > > Testing of revert also appears to have resolved the issue, thus revert the > commit until a more robust solution for the original problem is developed. > It's also likely this will fix qemu stalls with 6.1 kernel reported in > Link 2, but that is not yet confirmed. Preliminary tests suggest this is also fixed: Tested-by: Jiri Slaby > Link: https://bugzilla.suse.com/show_bug.cgi?id=1206848 > Link: https://lore.kernel.org/kvm/b8017e09-f336-3035-8344-c549086c2340@kernel.org/ > Link: https://lkml.kernel.org/r/20230113173345.9692-1-vbabka@suse.cz > Fixes: 7efc3b726103 ("mm/compaction: fix set skip in fast_find_migrateblock") > Cc: Chuyi Zhou > Cc: Jiri Slaby > Cc: Maxim Levitsky > Cc: Mel Gorman > Cc: Michal Hocko > Cc: Paolo Bonzini > Cc: Thorsten Leemhuis > Cc: > Signed-off-by: Andrew Morton > --- > > > --- a/mm/compaction.c~revert-mm-compaction-fix-set-skip-in-fast_find_migrateblock > +++ a/mm/compaction.c > @@ -1839,6 +1839,7 @@ static unsigned long fast_find_migratebl > pfn = cc->zone->zone_start_pfn; > cc->fast_search_fail = 0; > found_block = true; > + set_pageblock_skip(freepage); > break; > } > } > _ > > Patches currently in -mm which might be from vbabka@suse.cz are > > revert-mm-compaction-fix-set-skip-in-fast_find_migrateblock.patch > thanks, -- js suse labs