From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751180AbdAaQB5 (ORCPT ); Tue, 31 Jan 2017 11:01:57 -0500 Received: from mx2.suse.de ([195.135.220.15]:43204 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751039AbdAaQBx (ORCPT ); Tue, 31 Jan 2017 11:01:53 -0500 Date: Tue, 31 Jan 2017 16:00:29 +0000 From: Mel Gorman To: Anshuman Khandual Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, mhocko@suse.com, vbabka@suse.cz, minchan@kernel.org, aneesh.kumar@linux.vnet.ibm.com, bsingharora@gmail.com, srikar@linux.vnet.ibm.com, haren@linux.vnet.ibm.com, jglisse@redhat.com, dave.hansen@intel.com, dan.j.williams@intel.com Subject: Re: [RFC] cpuset: Enable changing of top_cpuset's mems_allowed nodemask Message-ID: <20170131160029.ubt6fvw6oh2fgxpd@suse.de> References: <20170130203003.dm2ydoi3e6cbbwcj@suse.de> <20170131142237.27097-1-khandual@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20170131142237.27097-1-khandual@linux.vnet.ibm.com> User-Agent: Mutt/1.6.2 (2016-07-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 31, 2017 at 07:52:37PM +0530, Anshuman Khandual wrote: > At present, top_cpuset.mems_allowed is same as node_states[N_MEMORY] and it > cannot be changed at the runtime. Maximum possible node_states[N_MEMORY] > also gets reflected in top_cpuset.effective_mems interface. It prevents some > one from removing or restricting memory placement which will be applicable > system wide on a given memory node through cpuset mechanism which might be > limiting. This solves the problem by enabling update_nodemask() function to > accept changes to top_cpuset.mems_allowed as well. Once changed, it also > updates the value of top_cpuset.effective_mems. Updates all it's task's > mems_allowed nodemask as well. It calls cpuset_inc() to make sure cpuset > is accounted for in the buddy allocator through cpusets_enabled() check. > What's the point of allowing the root cpuset to be restricted? -- Mel Gorman SUSE Labs