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 678D5C433E7 for ; Mon, 12 Oct 2020 15:07:44 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D1B3220665 for ; Mon, 12 Oct 2020 15:07:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="ho5mAtbX" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D1B3220665 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 567AE6B005C; Mon, 12 Oct 2020 11:07:43 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 518406B005D; Mon, 12 Oct 2020 11:07:43 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4074E6B0062; Mon, 12 Oct 2020 11:07:43 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0134.hostedemail.com [216.40.44.134]) by kanga.kvack.org (Postfix) with ESMTP id 110D06B005C for ; Mon, 12 Oct 2020 11:07:43 -0400 (EDT) Received: from smtpin07.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 87FCB8249980 for ; Mon, 12 Oct 2020 15:07:42 +0000 (UTC) X-FDA: 77363602764.07.ocean83_2f0a427271fb Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin07.hostedemail.com (Postfix) with ESMTP id CFAE91803F9A2 for ; Mon, 12 Oct 2020 15:07:41 +0000 (UTC) X-HE-Tag: ocean83_2f0a427271fb X-Filterd-Recvd-Size: 1898 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf19.hostedemail.com (Postfix) with ESMTP for ; Mon, 12 Oct 2020 15:07:40 +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=1602515259; 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=bDvkUn6W/CbGive27aVQ7KFTue7EggU4CcSm4xtTLFQ=; b=ho5mAtbXjxRZyPMPqUQO+TGH47+P7lF3p+cgxwd4wfxnThvAzqJVX56rz9Mgls2X2L1x7s Cux8mQ6tDkT7aqu46sYDYjJoAVfvXJovAEmeCzupYALtPSWD4Z8yFlSRdOAHpyifw+uDxv 7kPDrSu649eP8pP91wspFzJqusKpkBs= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id A0740AC3C; Mon, 12 Oct 2020 15:07:39 +0000 (UTC) Date: Mon, 12 Oct 2020 17:07:38 +0200 From: Michal Hocko To: Jann Horn Cc: mtk.manpages@gmail.com, linux-man@vger.kernel.org, linux-mm@kvack.org, Mark Mossberg Subject: Re: [PATCH] proc.5: Document inaccurate RSS due to SPLIT_RSS_COUNTING Message-ID: <20201012150738.GF29725@dhcp22.suse.cz> References: <20201012114940.1317510-1-jannh@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201012114940.1317510-1-jannh@google.com> 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 Mon 12-10-20 13:49:40, Jann Horn wrote: > Since 34e55232e59f7b19050267a05ff1226e5cd122a5 (introduced back in > v2.6.34), Linux uses per-thread RSS counters to reduce cache contention on > the per-mm counters. With a 4K page size, that means that you can end up > with the counters off by up to 252KiB per thread. Do we actually have any strong case to keep this exception to the accounting? -- Michal Hocko SUSE Labs