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=-4.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 B12B4C433E2 for ; Tue, 21 Jul 2020 12:17:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 877DC22CF6 for ; Tue, 21 Jul 2020 12:17:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595333878; bh=Spt2Exb8HT7Dykg3qDYB/7gUc4yxbpePjA2NDk2Rt9A=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=DzfMcR8KRGcJDTXzJzfXM8wOkCzx996IDgcN171nKk/4eWV4XiOLL4SWm9/1LcBgG 9SLDdly2WK3nwsDlyuDav4oAXwqqYdNoocZzCAgotYKzW09HEY2wm9kZm4alaC4VMX +x9yqJGqZFGEPeEaDo9ALNayWLzEkExBTaRfJduc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729927AbgGUMR5 (ORCPT ); Tue, 21 Jul 2020 08:17:57 -0400 Received: from mail-wr1-f66.google.com ([209.85.221.66]:33587 "EHLO mail-wr1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726715AbgGUMR4 (ORCPT ); Tue, 21 Jul 2020 08:17:56 -0400 Received: by mail-wr1-f66.google.com with SMTP id f18so21033023wrs.0 for ; Tue, 21 Jul 2020 05:17:55 -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=dJvVQh1+L1IfifarBH4M4EwzY4CvwCn4HIgD+1uPERQ=; b=mgN7wA1dBxVrnfCi1HLaMnN+bZMq1MLSXA+lq0VBoctQpivPT7uhIuCByGUCuVsbsk ZuSTb2bU/ryVrNbtdLQAk0O+CFY5U4BzTWypx067Oup53MR3VuXwwYaUfwJ3udz3S7t2 4i4rZg+Pk7DQ62UmPvRH1pQTUGtUbmuR8JXwhFfsBRhUWJ6LANtYYveDxA5JdRQKvTdL cU8NeO+GHWusQPqt/Bd+a7WfSh7meUenrqfQI3UiXuJERMhCYeACMrRpf11HeaiAf7Jj QjtMcpJLI6BYiGluxvZmCe1zjmA3WmddlwsEhUoGS0Rtfr6abpoz6kpdLNTmz4DrtvHK mftA== X-Gm-Message-State: AOAM533n93ekl1qysNyRNIZGzQVc2N3FI+UF65CDUU/xWMrR+wGgEH40 N7BaQjx2CC/FoRi0z3ZWj68= X-Google-Smtp-Source: ABdhPJwDGRt8F636vOy7k2pds/V9jjrF0/7h59KQuRE0uck5kZSb5Vaw2he31fwyAFBLJb7El9Qg7A== X-Received: by 2002:a5d:5651:: with SMTP id j17mr25144930wrw.145.1595333874568; Tue, 21 Jul 2020 05:17:54 -0700 (PDT) Received: from localhost (ip-37-188-169-187.eurotel.cz. [37.188.169.187]) by smtp.gmail.com with ESMTPSA id c17sm23700986wrc.42.2020.07.21.05.17.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 21 Jul 2020 05:17:53 -0700 (PDT) Date: Tue, 21 Jul 2020 14:17:52 +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: <20200721121752.GK4061@dhcp22.suse.cz> References: <20200721112529.GJ4061@dhcp22.suse.cz> <664A07B6-DBCD-4520-84F1-241A4E7A339F@lca.pw> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <664A07B6-DBCD-4520-84F1-241A4E7A339F@lca.pw> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 21-07-20 07:44:07, Qian Cai wrote: > > > > On Jul 21, 2020, at 7:25 AM, Michal Hocko wrote: > > > > Are these really important? I believe I can dig that out from the bug > > report but I didn't really consider that important enough. > > Please dig them out. We have also been running those things on > “large” powerpc as well and never saw such soft-lockups. Those > details may give us some clues about the actual problem. I strongly suspect this is not really relevant but just FYI this is 16Node, 11.9TB with 1536CPUs system. > Once we > understand the problem better, we may judge if this “hack” is > really worth it. I do not have access to the machine so I can only judge from the boot log I have in hands. And from that it is pretty clear that $ grep BUG tmp/attachment.txt | wc -l 896 $ grep BUG tmp/attachment.txt | grep "\[systemd" | wc -l 860 $ grep do_fault+0x448 tmp/attachment.txt | wc -l 860 that the boot struggles, lockups happen from udev workers and most of them are stuck at the very same place which is unlock_page. The rest is a part of the changelog. -- Michal Hocko SUSE Labs