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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,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 BAED3C433E1 for ; Thu, 20 Aug 2020 11:15:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9DB212078D for ; Thu, 20 Aug 2020 11:15:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729303AbgHTLOw (ORCPT ); Thu, 20 Aug 2020 07:14:52 -0400 Received: from mx2.suse.de ([195.135.220.15]:46226 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729824AbgHTLOr (ORCPT ); Thu, 20 Aug 2020 07:14:47 -0400 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 B0AB0B80B; Thu, 20 Aug 2020 11:15:12 +0000 (UTC) Date: Thu, 20 Aug 2020 13:14:45 +0200 From: Michal Hocko To: Christian Brauner Cc: Suren Baghdasaryan , mingo@kernel.org, peterz@infradead.org, tglx@linutronix.de, esyr@redhat.com, christian@kellner.me, areber@redhat.com, shakeelb@google.com, cyphar@cyphar.com, oleg@redhat.com, adobriyan@gmail.com, akpm@linux-foundation.org, ebiederm@xmission.com, gladkov.alexey@gmail.com, walken@google.com, daniel.m.jordan@oracle.com, avagin@gmail.com, bernd.edlinger@hotmail.de, john.johansen@canonical.com, laoar.shao@gmail.com, timmurray@google.com, minchan@kernel.org, kernel-team@android.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 1/1] mm, oom_adj: don't loop through tasks in __set_oom_adj when not necessary Message-ID: <20200820111445.GF5033@dhcp22.suse.cz> References: <20200820002053.1424000-1-surenb@google.com> <20200820084654.jdl6jqgxsga7orvf@wittgenstein> <20200820090901.GD5033@dhcp22.suse.cz> <20200820103248.vkzrndewvy5vlncz@wittgenstein> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200820103248.vkzrndewvy5vlncz@wittgenstein> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Thu 20-08-20 12:32:48, Christian Brauner wrote: > On Thu, Aug 20, 2020 at 11:09:01AM +0200, Michal Hocko wrote: > > On Thu 20-08-20 10:46:54, Christian Brauner wrote: [...] > > > > which includes processes with multiple threads (sharing mm and signals). > > > > However for such processes the loop is unnecessary because their signal > > > > structure is shared as well. > > and it seems you want to exclude threads, i.e. only update mm that is > shared not among threads in the same thread-group. > But struct signal and struct sighand_struct are different things, i.e. > they can be shared or not independent of each other. A non-shared > signal_struct where oom_score_adj{_min} live is only implied by > !CLONE_THREAD. So shouldn't this be: > > if (!(clone_flags & CLONE_THREAD)) rather than CLONE_SIGHAND? You are right as I have already replied to Oleg. -- Michal Hocko SUSE Labs