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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4B182C48BD7 for ; Wed, 15 Nov 2023 14:09:51 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D36676B035F; Wed, 15 Nov 2023 09:09:50 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id CE5486B0361; Wed, 15 Nov 2023 09:09:50 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BAD186B0362; Wed, 15 Nov 2023 09:09:50 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id AABCF6B035F for ; Wed, 15 Nov 2023 09:09:50 -0500 (EST) Received: from smtpin24.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 68E8EC05D0 for ; Wed, 15 Nov 2023 14:09:50 +0000 (UTC) X-FDA: 81460372140.24.AE5D6A7 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by imf23.hostedemail.com (Postfix) with ESMTP id 4788C140021 for ; Wed, 15 Nov 2023 14:09:47 +0000 (UTC) Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=suse.com header.s=susede1 header.b="rjdJ/xwY"; spf=pass (imf23.hostedemail.com: domain of mhocko@suse.com designates 195.135.220.28 as permitted sender) smtp.mailfrom=mhocko@suse.com; dmarc=pass (policy=quarantine) header.from=suse.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1700057388; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=ziC0owFfoL33apf8R/x/Rrhz8VjbOAJrdvgUnGBfRxk=; b=6cSXAK20TlT1ikPEorfaGjfCREjhwrwnmdPe9w8C7eLtCqlU+o0yWACfdR6Xmw1mIRgoKa KQSkw+d6Ml5YthuiBsmH9qqbTuuCrNE9bqQLtzYYDOueko3+3Nq5GYSKnwLwMClSIri6xa qx1fJ0ZfRLGu5mEiOUB4ydkabbt1ejQ= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1700057388; a=rsa-sha256; cv=none; b=jm17Oln1jN8rLuBgXZs6rmXocCSSCuZizHRw0ttjDo6SERb193aNyrvFSqQug/nSmvXazy hNIXVaVfuGQB62yrHe+P4oTnSXZfkMY9qyj3EUelNeEe3lhTAXUXZfbWstPKJsX3TYegQX 03Yv9MSEvK/zX1pxhve/rYZLbemI3kU= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=suse.com header.s=susede1 header.b="rjdJ/xwY"; spf=pass (imf23.hostedemail.com: domain of mhocko@suse.com designates 195.135.220.28 as permitted sender) smtp.mailfrom=mhocko@suse.com; dmarc=pass (policy=quarantine) header.from=suse.com Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 0C395218B2; Wed, 15 Nov 2023 14:09:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1700057386; 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=ziC0owFfoL33apf8R/x/Rrhz8VjbOAJrdvgUnGBfRxk=; b=rjdJ/xwYpj17GNAvoaf1I7+UTjDrp7xW5/P0GpOIXXSJBpZcqsKcbvRushWCo+rQmA9FBP hqxWZG5qLNaeKPC8PGkWC08FzxWtd4EPPaOccGLuowqfRZqRVd1tvwk6XESEpoRTEaOb4T CnfYdxfY5m3Iym86FkSiLgbDB0F60R8= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id D68F313587; Wed, 15 Nov 2023 14:09:45 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id 6t+6LSnRVGXgVAAAMHmgww (envelope-from ); Wed, 15 Nov 2023 14:09:45 +0000 Date: Wed, 15 Nov 2023 15:09:45 +0100 From: Michal Hocko To: Charan Teja Kalla Cc: akpm@linux-foundation.org, mgorman@techsingularity.net, david@redhat.com, vbabka@suse.cz, hannes@cmpxchg.org, quic_pkondeti@quicinc.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH V3 3/3] mm: page_alloc: drain pcp lists before oom kill Message-ID: References: <5c7f25f9-f86b-8e15-8603-e212b9911cac@quicinc.com> <342a8854-eef5-f68a-15e5-275de70e3f01@quicinc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <342a8854-eef5-f68a-15e5-275de70e3f01@quicinc.com> X-Rspamd-Queue-Id: 4788C140021 X-Rspam-User: X-Stat-Signature: iga5gxp7fin5nn1gyx77z3n6q3qa88xd X-Rspamd-Server: rspam03 X-HE-Tag: 1700057387-448426 X-HE-Meta: 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 I5PbqauN WK4LAm/ZN2VEUzdU/LPYT+YH3x2D9/URRpaF+kFBF7g6aDnxmci7fuZFcb2vhEJuL1mRGvPORjNF/wYOhUuDXcQvYJeU1duY6/Wonb8E9mMPt5yF8MxqUxeAa4PuhcQMpvlGYWtPsbZzmndyS4H7iEAxzSvjF/gMQlEej22TEW3QkjR73qhzEPtJILpelw4tMZbgf3TGP/AtkoHXrgSlk3zxOENxwjpATMopT1kb4nuyYyqk= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000008, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue 14-11-23 22:06:45, Charan Teja Kalla wrote: > Thanks Michal!! > > On 11/14/2023 4:18 PM, Michal Hocko wrote: > >> At least in my particular stress test case it just delayed the OOM as i > >> can see that at the time of OOM kill, there are no free pcp pages. My > >> understanding of the OOM is that it should be the last resort and only > >> after doing the enough reclaim retries. CMIW here. > > Yes it is a last resort but it is a heuristic as well. So the real > > questoin is whether this makes any practical difference outside of > > artificial workloads. I do not see anything particularly worrying to > > drain the pcp cache but it should be noted that this won't be 100% > > either as racing freeing of memory will end up on pcp lists first. > > Okay, I don't have any practical scenario where this helped me in > avoiding the OOM. Will comeback If I ever encounter this issue in > practical scenario. > > Also If you have any comments on [PATCH V2 2/3] mm: page_alloc: correct > high atomic reserve calculations will help me. I do not have a strong opinion on that one to be honest. I am not even sure that reserving a full page block (4MB) on small systems as presented is really a good use of memory. -- Michal Hocko SUSE Labs