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 50339C43334 for ; Wed, 15 Jun 2022 16:00:07 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A601A6B0071; Wed, 15 Jun 2022 12:00:06 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A10246B0072; Wed, 15 Jun 2022 12:00:06 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8D6B46B0074; Wed, 15 Jun 2022 12:00:06 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 7E5066B0071 for ; Wed, 15 Jun 2022 12:00:06 -0400 (EDT) Received: from smtpin07.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 4CD5933AC8 for ; Wed, 15 Jun 2022 16:00:06 +0000 (UTC) X-FDA: 79580931612.07.3B48701 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by imf16.hostedemail.com (Postfix) with ESMTP id 50DB9180083 for ; Wed, 15 Jun 2022 16:00:05 +0000 (UTC) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out1.suse.de (Postfix) with ESMTP id B024821AEE; Wed, 15 Jun 2022 16:00:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1655308803; 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=ygjyshnlbg3+pSNVNR1FjCFt/v865tBihLkOKM937/E=; b=mie4c7DI40Uh042n1iLaOmGvSPGdHGfuFfPg5NSbr6YEHCBZpvJc5xMWWe5wsMoeJQHBIJ DvZ4eu+qUis0dtWO1/vup6a6iDlwXBgp4sh8CF2dRMrZk8omjKXagUgfQSgRRkVliKZz8F O9Z/ptPbrKuitAHATw3+GPf98REucWY= Received: from suse.cz (unknown [10.100.201.86]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id CF1062C141; Wed, 15 Jun 2022 16:00:02 +0000 (UTC) Date: Wed, 15 Jun 2022 17:59:59 +0200 From: Michal Hocko To: Tim Chen Cc: linux-mm@kvack.org, akpm@linux-foundation.org, Wei Xu , Huang Ying , Greg Thelen , Yang Shi , Davidlohr Bueso , Brice Goglin , Linux Kernel Mailing List , Hesham Almatary , Dave Hansen , Jonathan Cameron , Alistair Popple , Dan Williams , Feng Tang , Jagdish Gediya , Baolin Wang , David Rientjes , "Aneesh Kumar K . V" , Shakeel Butt Subject: Re: [RFC PATCH 0/3] Cgroup accounting of memory tier usage Message-ID: References: <34f985f63e6dbaa60bb9d1edb6022e83b98304e4.camel@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <34f985f63e6dbaa60bb9d1edb6022e83b98304e4.camel@linux.intel.com> ARC-Authentication-Results: i=1; imf16.hostedemail.com; dkim=pass header.d=suse.com header.s=susede1 header.b=mie4c7DI; dmarc=pass (policy=quarantine) header.from=suse.com; spf=pass (imf16.hostedemail.com: domain of mhocko@suse.com designates 195.135.220.28 as permitted sender) smtp.mailfrom=mhocko@suse.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1655308805; 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=ygjyshnlbg3+pSNVNR1FjCFt/v865tBihLkOKM937/E=; b=ODIr2ZmjrgDfIy+3Fb/A5KISgWfF3gSwO+x6b8OC0kBVKQ7wz+67s/z8xxShB2VOm1dqUL 43LfcINeEd3EAms6r1Y09aobDBIKKJps5qpTDNqnk+sKapD7u8DxmmCdn16n4nysfEZcnY wmCncaQJK14S95a1RR45ckEvoHUOwtg= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1655308805; a=rsa-sha256; cv=none; b=57jQqMXiWjJm/Bbsq8o+wScLoQbsziOIay8gsg6zRq0NC9p/fIS6mSD+eO4dXYhnixlRr5 rRmYYB7Mb4MboTfjY0iYnrijnaBBAVjIKjKk5qYM2SQOqgU+AolG7BJPmMnOlvMtgXfkNS IMdA7hePviY02cV7I8WgRjpiIXuAHJo= X-Stat-Signature: iwehhk3bgtumn6cuwgmo1xn5pdjstrxf X-Rspamd-Queue-Id: 50DB9180083 X-Rspam-User: Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=suse.com header.s=susede1 header.b=mie4c7DI; dmarc=pass (policy=quarantine) header.from=suse.com; spf=pass (imf16.hostedemail.com: domain of mhocko@suse.com designates 195.135.220.28 as permitted sender) smtp.mailfrom=mhocko@suse.com X-Rspamd-Server: rspam10 X-HE-Tag: 1655308805-30488 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 Wed 15-06-22 08:23:56, Tim Chen wrote: > On Wed, 2022-06-15 at 13:11 +0200, Michal Hocko wrote: [...] > > > The patchset works with Aneesh's v6 memory-tiering implementation [1]. > > > It is a preparatory patch set before introducing features to > > > control top tiered memory in cgroups. > > > > > > I'll like to first get feedback to see if > > > (1) Controllng the topmost tiered memory is enough > > > or > > > (2) Multiple tiers at the top levels need to be grouped into "toptier" > > > or > > > (3) There are use cases not covered by (1) and (2). > > > > I would start by asking why do we need a dedicated interface in the > > first place. Why the existing numa_stat is not a proper interface. Right > > now we only report LRU per node stats. Is this insufficient? > > What is userspace expect to do based on the reported data? > > Exporting the toptier information here is convenient for me for debugging > purpose of seeing whether a cgroup's toptier usage is under control. > Otherwise writing a script to parse numastat and the memtier heirachy will > work too. Exporting toptier usage directly is optional and we don't have to do it. Please keep in mind this is an userspace API which has to be maintained for ever. We do not add those just to make debugging more convenient. -- Michal Hocko SUSE Labs