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=-5.8 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 7BA5EC47080 for ; Mon, 31 May 2021 11:33:36 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 2CC6F6135C for ; Mon, 31 May 2021 11:33:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2CC6F6135C Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine 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 848E26B006C; Mon, 31 May 2021 07:33:35 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7F9256B006E; Mon, 31 May 2021 07:33:35 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6996B6B0070; Mon, 31 May 2021 07:33:35 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0229.hostedemail.com [216.40.44.229]) by kanga.kvack.org (Postfix) with ESMTP id 32DF66B006C for ; Mon, 31 May 2021 07:33:35 -0400 (EDT) Received: from smtpin07.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id BBE3F181AEF21 for ; Mon, 31 May 2021 11:33:34 +0000 (UTC) X-FDA: 78201315948.07.211DF08 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf07.hostedemail.com (Postfix) with ESMTP id 805E4A000254 for ; Mon, 31 May 2021 11:33:22 +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=1622460813; h=from:from:reply-to: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=r3QrY/uDAlxbmSiPcq2dTQZ/GOIjlE9Ied6yDBeJWZY=; b=KLXKf6jASDzzfqDTufBEdIPJLOcQ00opaF4Ew8+hoFfymQILtLvpjdGFCQBsoMkyQBscIW +oK/mQc04nXjM0KXIYHq7eQlbKziYi2U6sAQ9h2mYlrZqVsS25cAyuqHAaoIvuXH/dyXeL 0jDefYqIikzS8rPXVV8Rni9kuoIevjk= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 06D08B4C1; Mon, 31 May 2021 11:33:33 +0000 (UTC) Date: Mon, 31 May 2021 13:33:32 +0200 From: Michal Hocko To: Aaron Tomlin Cc: linux-mm@kvack.org, akpm@linux-foundation.org, vbabka@suse.cz, willy@infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4] mm/page_alloc: bail out on fatal signal during reclaim/compaction retry attempt Message-ID: References: <20210520142901.3371299-1-atomlin@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210520142901.3371299-1-atomlin@redhat.com> Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=suse.com header.s=susede1 header.b=KLXKf6jA; dmarc=pass (policy=quarantine) header.from=suse.com; spf=pass (imf07.hostedemail.com: domain of mhocko@suse.com designates 195.135.220.15 as permitted sender) smtp.mailfrom=mhocko@suse.com X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 805E4A000254 X-Stat-Signature: 5wa57kqkmshe8ihzd3sxpc4p6nryoeei X-HE-Tag: 1622460802-553512 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 Thu 20-05-21 15:29:01, Aaron Tomlin wrote: > A customer experienced a low-memory situation and decided to issue a > SIGKILL (i.e. a fatal signal). Instead of promptly terminating as one > would expect, the aforementioned task remained unresponsive. > > Further investigation indicated that the task was "stuck" in the > reclaim/compaction retry loop. Now, it does not make sense to retry > compaction when a fatal signal is pending. Is this really true in general? The memory reclaim is retried even when fatal signals are pending. Why should be compaction different? I do agree that retrying way too much is bad but is there any reason why this special case doesn't follow the max retry logic? -- Michal Hocko SUSE Labs