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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AEF87C43334 for ; Wed, 15 Jun 2022 11:11:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241264AbiFOLLp (ORCPT ); Wed, 15 Jun 2022 07:11:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37340 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235185AbiFOLLm (ORCPT ); Wed, 15 Jun 2022 07:11:42 -0400 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 60B7541627 for ; Wed, 15 Jun 2022 04:11:41 -0700 (PDT) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id 1B4F21F38D; Wed, 15 Jun 2022 11:11:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1655291500; 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=2rItd1ojkTsOwmaVczGGbIEFSm9A7rqtW6hIDanRzN4=; b=Coxyj/JBf7TTWY4B+qracSbRGznAkf6jOmVjaP+KpeSYgTI6s6ELGfQ/VB3v8AiGQdfWHv ks1V+v1QKORYwiiukKRiGiVVo/9VOqjHxpf1xmGva00W9hi73lhWyqxIWiwN9nW/sBfZuQ UfXwQ8R92LSa3pa8XeAY29Aacud9TK4= 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 245E52C141; Wed, 15 Jun 2022 11:11:37 +0000 (UTC) Date: Wed, 15 Jun 2022 13:11:34 +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: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 14-06-22 15:25:32, Tim Chen wrote: > For controlling usage of a top tiered memory by a cgroup, accounting > of top tier memory usage is needed. This patch set implements the > following: > > Patch 1 introduces interface and simple implementation to retrieve > cgroup tiered memory usage > Patch 2 introduces more efficient accounting with top tier memory page counter > Patch 3 provides a sysfs interface to repot the the top tiered memory > usage. I guess you meant cgroupfs here, right? > 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? -- Michal Hocko SUSE Labs