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 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 5B2CCC4363D for ; Tue, 22 Sep 2020 15:16:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0DB5223A1B for ; Tue, 22 Sep 2020 15:16:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="HpRb403A" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726711AbgIVPQ4 (ORCPT ); Tue, 22 Sep 2020 11:16:56 -0400 Received: from mx2.suse.de ([195.135.220.15]:52078 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726566AbgIVPQ4 (ORCPT ); Tue, 22 Sep 2020 11:16:56 -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=1600787815; 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=rJgGLrQcC32JUla74uN+fGhEo/pFo1Hw1KVkIOSTccw=; b=HpRb403AygbNrLzidxYcwwdgrn0Zjm7gWlIbekXXY1DXA/e0TWZHEa7Tk9jgYju+TjT3GW NI2bUjG4twrmGe1nIwFPhYEPWHooGZwlG4fx+GqPfzx4x+/WEfvwZ3NyQPKdfxRvymPTTv gPn05rxQ9QNhN6aqSgLzYgf4CEKY9jA= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 2A387ACAC; Tue, 22 Sep 2020 15:17:32 +0000 (UTC) Date: Tue, 22 Sep 2020 17:16:54 +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: <20200922151654.GA12990@dhcp22.suse.cz> References: <20200922111202.GY12990@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 06:37:02, Shakeel Butt wrote: [...] > > I would recommend to focus on tracking down the who is blocking the > > further progress. > > I was able to find the CPU next in line for the list_lock from the > dump. I don't think anyone is blocking the progress as such but more > like the spinlock in the irq context is starving the spinlock in the > process context. This is a high traffic machine and there are tens of > thousands of potential network ACKs on the queue. So there is a forward progress but it is too slow to have any reasonable progress in userspace? > I talked about this problem with Johannes at LPC 2019 and I think we > talked about two potential solutions. First was to somehow give memory > reserves to oomd and second was in-kernel PSI based oom-killer. I am > not sure the first one will work in this situation but the second one > might help. Why does your oomd depend on memory allocation? -- Michal Hocko SUSE Labs