From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756040AbcE0QSe (ORCPT ); Fri, 27 May 2016 12:18:34 -0400 Received: from mail-am1on0111.outbound.protection.outlook.com ([157.56.112.111]:33334 "EHLO emea01-am1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752880AbcE0QSc (ORCPT ); Fri, 27 May 2016 12:18:32 -0400 Authentication-Results: kernel.org; dkim=none (message not signed) header.d=none;kernel.org; dmarc=none action=none header.from=virtuozzo.com; Date: Fri, 27 May 2016 19:18:21 +0300 From: Vladimir Davydov To: Michal Hocko CC: , Tetsuo Handa , David Rientjes , Oleg Nesterov , Andrew Morton , LKML Subject: Re: [PATCH 3/6] mm, oom_adj: make sure processes sharing mm have same view of oom_score_adj Message-ID: <20160527161821.GE26059@esperanza> References: <1464266415-15558-1-git-send-email-mhocko@kernel.org> <1464266415-15558-4-git-send-email-mhocko@kernel.org> <20160527111803.GG27686@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; 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X-Microsoft-Exchange-Diagnostics: 1;AM3PR08MB0578;23: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 X-Microsoft-Exchange-Diagnostics: 1;AM3PR08MB0578;5:AO1x1NkcU7XNhoNZUP637O0ylyOOpAxozEV1+P+W4sgN8S+zKIq7sfUBYXa+RFLB9biIz+lkkMeS7fnvA4Dp65KjDtJORYlbC9Kjdj2H3OYRDbFZ5FzgcB6xySJLkeozsPoyM/dXJZTi74xsDWgnVg==;24:6DLSmwnOjatxT7vzInChWMAbgfzFPDwaDN6KwXoOhUyUMwJ1A2BD9sDKv/aU26ER4Si7E+xCWLQsstXGzwuUbkdz2CvZa8Emvd12YAZ5sgE=;7:qg7tUdIfBInE3GrBa3tGE7aeAjrNhFZo+28x8CyGekvGi+33P9sByMSlQs2rktNgrzL66FNuhQQ3D7iQFW2mad2SeYxwWOfoPA9VJ5tZtmkBHdOnmPtlIGkWIfimBvCz8JPKDmSKgtXXtS6nNJQOwnz6+d/TQ5OB8stt8zMeAxgBA9UdDDoHWJQ85UaqO7G1;20:aTKlutzw3zAlAKFtlI7CNAfJ/NF0+ss70458FmcHSIZTdj4W42DpxwTyHuBs78l4FOgFUamORs6Gy8ZmIB25zfyO6LM2JZr72cES+9k5BMS1JYGrFpuxh0x4uovKhFUXrvhcyn8+4GLdYwU5aJSfC1R+IF4jSqUevESLgiTlxCA= SpamDiagnosticOutput: 1:23 SpamDiagnosticMetadata: NSPM X-OriginatorOrg: virtuozzo.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 27 May 2016 16:18:28.4440 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM3PR08MB0578 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 27, 2016 at 01:18:03PM +0200, Michal Hocko wrote: ... > @@ -1087,7 +1105,25 @@ static int __set_oom_adj(struct file *file, int oom_adj, bool legacy) > unlock_task_sighand(task, &flags); > err_put_task: > put_task_struct(task); > + > + if (mm) { > + struct task_struct *p; > + > + rcu_read_lock(); > + for_each_process(p) { > + task_lock(p); > + if (!p->vfork_done && process_shares_mm(p, mm)) { > + p->signal->oom_score_adj = oom_adj; > + if (!legacy && has_capability_noaudit(current, CAP_SYS_RESOURCE)) > + p->signal->oom_score_adj_min = (short)oom_adj; > + } > + task_unlock(p); I.e. you write to /proc/pid1/oom_score_adj and get /proc/pid2/oom_score_adj updated if pid1 and pid2 share mm? IMO that looks unexpected from userspace pov. May be, we'd better add mm->oom_score_adj and set it to the min signal->oom_score_adj over all processes sharing it? This would require iterating over all processes every time oom_score_adj gets updated, but that's a slow path.