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 860F2C4727C for ; Tue, 22 Sep 2020 15:16:58 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 087CD239D2 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" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 087CD239D2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 92F32900068; Tue, 22 Sep 2020 11:16:57 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8E0F190000F; Tue, 22 Sep 2020 11:16:57 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7F5CA900068; Tue, 22 Sep 2020 11:16:57 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0005.hostedemail.com [216.40.44.5]) by kanga.kvack.org (Postfix) with ESMTP id 653C590000F for ; Tue, 22 Sep 2020 11:16:57 -0400 (EDT) Received: from smtpin05.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 262008249980 for ; Tue, 22 Sep 2020 15:16:57 +0000 (UTC) X-FDA: 77291050074.05.actor97_070de0a2714e Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin05.hostedemail.com (Postfix) with ESMTP id 0064818021475 for ; Tue, 22 Sep 2020 15:16:56 +0000 (UTC) X-HE-Tag: actor97_070de0a2714e X-Filterd-Recvd-Size: 2698 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf30.hostedemail.com (Postfix) with ESMTP for ; Tue, 22 Sep 2020 15:16:56 +0000 (UTC) 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: X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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