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=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 6B5BEC4363D for ; Tue, 22 Sep 2020 17:01:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2302123A75 for ; Tue, 22 Sep 2020 17:01:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="VxXRGDcw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726643AbgIVRBI (ORCPT ); Tue, 22 Sep 2020 13:01:08 -0400 Received: from mx2.suse.de ([195.135.220.15]:44518 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726566AbgIVRBH (ORCPT ); Tue, 22 Sep 2020 13:01:07 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1600794066; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=uoRTNE0li2f5w49NlqYezoCQ6/u5c+NnH/4Xsxw2QEg=; b=VxXRGDcwBaxWDlnWl8EMkQZcVSoulvuH49g/1H+HNKBZSsYLV0zzQGYzFbX/84Hv6eYTnO kmstxEdnmN7X5K0MJdrKyqtb7/WviBsn5HZ8lqgSY1EZt4DNe4lEPUKEekk6C1tqLtDcUi LNmia1RBx6qxn7ceJU+FL80ZvAa38zc= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 9CB1FAD0B; Tue, 22 Sep 2020 17:01:43 +0000 (UTC) Date: Tue, 22 Sep 2020 19:01:06 +0200 From: Michal Hocko To: Shakeel Butt Cc: Johannes Weiner , Linux MM , Andrew Morton , Roman Gushchin , LKML , Greg Thelen Subject: Re: Machine lockups on extreme memory pressure Message-ID: <20200922170106.GE12990@dhcp22.suse.cz> References: <20200922111202.GY12990@dhcp22.suse.cz> <20200922151654.GA12990@dhcp22.suse.cz> <20200922163401.GC12990@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 22-09-20 09:51:30, Shakeel Butt wrote: > On Tue, Sep 22, 2020 at 9:34 AM Michal Hocko wrote: > > > > On Tue 22-09-20 09:29:48, Shakeel Butt wrote: [...] > > > Anyways, what do you think of the in-kernel PSI based > > > oom-kill trigger. I think Johannes had a prototype as well. > > > > We have talked about something like that in the past and established > > that auto tuning for oom killer based on PSI is almost impossible to get > > right for all potential workloads and that so this belongs to userspace. > > The kernel's oom killer is there as a last resort when system gets close > > to meltdown. > > The system is already in meltdown state from the users perspective. I > still think allowing the users to optionally set the oom-kill trigger > based on PSI makes sense. Something like 'if all processes on the > system are stuck for 60 sec, trigger oom-killer'. We already do have watchdogs for that no? If you cannot really schedule anything then soft lockup detector should fire. In a meltdown state like that the reboot is likely the best way forward anyway. -- Michal Hocko SUSE Labs