From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-101.freemail.mail.aliyun.com (out30-101.freemail.mail.aliyun.com [115.124.30.101]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DC79C127E18; Sat, 24 May 2025 01:29:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.101 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748050171; cv=none; b=uABHLdsBb7FGXPz7ShbArShCGzFHXX/7DUPtGjZBMnyHzex6/pZGIeQgQwxAOAcb0Ypgq6So7rlHOLbS82Q+s+Q26uWquI87CeyOhkcYnCltZtebtV9ZXNnD27W46n5Mt4Zf8r4DJ93YrAjS32BOGx06eDXJq2/1pJ38+r/LO5M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748050171; c=relaxed/simple; bh=Ee7PbT9GaRaRs+NY1P3k7sBexoErNT6M4ozPGrZAUzY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Ounp9Zsq/Ffal7ojGte578HfI4YEJiVNAyjt+m7Gkix/PJhuFzfy63bBzCapPGsTMQCpWTC1cLBXNHMmgtKMRudKdcCnef/hQuWHyMoFwogs7X6ZHvRC3DHyj6CAGDs1ZShSma4t5k2X2YikDkL0er2KWxES2cdrOp9/c6nGijU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=GducTPmj; arc=none smtp.client-ip=115.124.30.101 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="GducTPmj" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1748050160; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=N29YGrSzA3zqIkby0ImioiElpY0ZMtKGfk9pdQlO27M=; b=GducTPmjx9rEIPAjz9aAn5WJhyslApKA3b+HsCD2WM5vfLgjE+LOAHT7cj4bQsqY7HIa6kkBL7MZvsTlr7IRFztHEmKLDoi4xY7ZbPBoTkO/GrlC9A0bMtZBCmMGeZzL0MaxkAtC71z+04A5qxsq0/H+sWgH3sxJt2pCPCuYvZw= Received: from 30.171.233.170(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0WbcLI26_1748050156 cluster:ay36) by smtp.aliyun-inc.com; Sat, 24 May 2025 09:29:18 +0800 Message-ID: <99e39ac1-d766-4d6e-a69a-525c49662ac0@linux.alibaba.com> Date: Sat, 24 May 2025 09:29:16 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH] mm: fix the inaccurate memory statistics issue for users To: SeongJae Park Cc: akpm@linux-foundation.org, david@redhat.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, shakeel.butt@linux.dev References: <20250523172305.57843-1-sj@kernel.org> From: Baolin Wang In-Reply-To: <20250523172305.57843-1-sj@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2025/5/24 01:23, SeongJae Park wrote: > On Fri, 23 May 2025 10:20:29 -0700 SeongJae Park wrote: > >> On Fri, 23 May 2025 11:16:13 +0800 Baolin Wang wrote: >> >>> On some large machines with a high number of CPUs running a 64K kernel, >> >> What does 64K kernel means? Sorry for not being clear. I mean a 64K pagesize kernel on Arm servers. >>> we found that the 'RES' field is always 0 displayed by the top command >>> for some processes, which will cause a lot of confusion for users. >>> >>> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND >>> 875525 root 20 0 12480 0 0 R 0.3 0.0 0:00.08 top >>> 1 root 20 0 172800 0 0 S 0.0 0.0 0:04.52 systemd >>> >>> The main reason is that the batch size of the percpu counter is quite large >>> on these machines, caching a significant percpu value, since converting mm's >>> rss stats into percpu_counter by commit f1a7941243c1 ("mm: convert mm's rss >>> stats into percpu_counter"). > > Forgot asking this, sorry. Should we add Fixes: tag and Cc stable@? Yes, will add the Fixes tag in next version. Thanks for reviewing.