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=-4.0 required=3.0 tests=BAYES_00,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 ACA21C433E2 for ; Tue, 21 Jul 2020 11:25:36 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 791CC2064C for ; Tue, 21 Jul 2020 11:25:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 791CC2064C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id D249C6B0005; Tue, 21 Jul 2020 07:25:35 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id CAD816B0006; Tue, 21 Jul 2020 07:25:35 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B9D616B0007; Tue, 21 Jul 2020 07:25:35 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0150.hostedemail.com [216.40.44.150]) by kanga.kvack.org (Postfix) with ESMTP id A02616B0005 for ; Tue, 21 Jul 2020 07:25:35 -0400 (EDT) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 37F3B180938E6 for ; Tue, 21 Jul 2020 11:25:35 +0000 (UTC) X-FDA: 77061852630.29.badge91_220addb26f2d Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin29.hostedemail.com (Postfix) with ESMTP id 1CD811802FA37 for ; Tue, 21 Jul 2020 11:25:33 +0000 (UTC) X-HE-Tag: badge91_220addb26f2d X-Filterd-Recvd-Size: 3507 Received: from mail-wr1-f68.google.com (mail-wr1-f68.google.com [209.85.221.68]) by imf06.hostedemail.com (Postfix) with ESMTP for ; Tue, 21 Jul 2020 11:25:32 +0000 (UTC) Received: by mail-wr1-f68.google.com with SMTP id f18so20880172wrs.0 for ; Tue, 21 Jul 2020 04:25:32 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=eDTdOZ1dDPKD1UqSkexaZR5dMf1fmObppvOA9WWtcgo=; b=NJcZtExuw7jlUrE7i6XyhISH0PZ7bTedRsWOJ/76oO1M0H3CF9NF+lhdBNdY2UGfb2 4EeB0iTidQuZlGXJ6KI2ysPxdS3zvgsWPM+2/fzJVJKxsOx7qtmGwaaJlmf4NBb2Vltz Tl5B63F0ZS0NtQSv3wbvDOT3Nv6rv1QqamgMX/TPEmtgjiZ6+Ck5sHvTubQeRmw1C8Tn 0uCxo9lLtnFj0xlmQ6+mQ+8EFbV1xPfEPbDrMsNyMgSSqjjPavDo7WL+vlrkUK6JTA+0 /9iZAcxcB7pV1/vvcOKiLOLYK82LR4JHCWnyC5T8cn4Hp2yP2V+Rk5JqZUWMMmOaa6OO HdPg== X-Gm-Message-State: AOAM533WeNqmid+DowwU5wmaui7EvhKg4/a2x+cjBBtr5wySJ5ge+GBK KRSi0G2ADdYrMvMygbfPT94= X-Google-Smtp-Source: ABdhPJzZKaTi9QRRHmX+Uo51vDunXQdue9WmRqUSRKPrkIu061TGYiIPW/mozoV1jdvTv2eoWOEt+Q== X-Received: by 2002:a5d:4b0c:: with SMTP id v12mr17163309wrq.199.1595330731618; Tue, 21 Jul 2020 04:25:31 -0700 (PDT) Received: from localhost (ip-37-188-169-187.eurotel.cz. [37.188.169.187]) by smtp.gmail.com with ESMTPSA id o21sm3068116wmh.18.2020.07.21.04.25.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 21 Jul 2020 04:25:30 -0700 (PDT) Date: Tue, 21 Jul 2020 13:25:29 +0200 From: Michal Hocko To: Qian Cai Cc: linux-mm@kvack.org, LKML , Andrew Morton , Linus Torvalds , Tim Chen Subject: Re: [RFC PATCH] mm: silence soft lockups from unlock_page Message-ID: <20200721112529.GJ4061@dhcp22.suse.cz> References: <20200721063258.17140-1-mhocko@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: 1CD811802FA37 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000108, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue 21-07-20 07:10:14, Qian Cai wrote: >=20 >=20 > > On Jul 21, 2020, at 2:33 AM, Michal Hocko wrote: > >=20 > > on a large ppc machine. The very likely cause is a suboptimal > > configuration when systed-udev spawns way too many workders to bring = the > > system up. >=20 > This is strange. The problem description is missing quite a few > important details. For example, what systems exactly are those? How > many CPUs, memory and NUMA nodes were you talking about? Are these really important? I believe I can dig that out from the bug report but I didn't really consider that important enough. > Which kernel version was it reported? It is a SLES 4.12 based kernel with the said commit backported. The page lock internals are thus in line with the upstream kernel. > How many workers from systemd-udev was =E2=80=9Cmisconfigured=E2=80=9D? I do not know that information. I believe that it used whatever systemd comes with as a default. And that can be a lot. Do you have any actual feedback to the patch? --=20 Michal Hocko SUSE Labs