From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932344AbdBHRTC (ORCPT ); Wed, 8 Feb 2017 12:19:02 -0500 Received: from mx2.suse.de ([195.135.220.15]:58027 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753869AbdBHRSd (ORCPT ); Wed, 8 Feb 2017 12:18:33 -0500 Subject: Re: [PATCH 3/3] mm: Enable Buddy allocation isolation for CDM nodes To: Anshuman Khandual , linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20170208140148.16049-1-khandual@linux.vnet.ibm.com> <20170208140148.16049-4-khandual@linux.vnet.ibm.com> Cc: mhocko@suse.com, mgorman@suse.de, 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 From: Vlastimil Babka Message-ID: <8ef1de25-d4fd-482c-c55e-df93d0730484@suse.cz> Date: Wed, 8 Feb 2017 18:18:09 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.0 MIME-Version: 1.0 In-Reply-To: <20170208140148.16049-4-khandual@linux.vnet.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/08/2017 03:01 PM, Anshuman Khandual wrote: > This implements allocation isolation for CDM nodes in buddy allocator by > discarding CDM memory zones all the time except in the cases where the gfp > flag has got __GFP_THISNODE or the nodemask contains CDM nodes in cases > where it is non NULL (explicit allocation request in the kernel or user > process MPOL_BIND policy based requests). > > Signed-off-by: Anshuman Khandual > --- > mm/page_alloc.c | 19 +++++++++++++++++++ > 1 file changed, 19 insertions(+) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 40908de..7d8c82a 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -64,6 +64,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -2908,6 +2909,24 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags, > struct page *page; > unsigned long mark; > > + /* > + * CDM nodes get skipped if the requested gfp flag > + * does not have __GFP_THISNODE set or the nodemask > + * does not have any CDM nodes in case the nodemask > + * is non NULL (explicit allocation requests from > + * kernel or user process MPOL_BIND policy which has > + * CDM nodes). > + */ > + if (is_cdm_node(zone->zone_pgdat->node_id)) { > + if (!(gfp_mask & __GFP_THISNODE)) { > + if (!ac->nodemask) > + continue; > + > + if (!nodemask_has_cdm(*ac->nodemask)) > + continue; nodemask_has_cdm() looks quite expensive, combined with the loop here that's O(n^2). But I don't understand why you need it. If there is no cdm node in the nodemask, then we never reach this code with a cdm node, because the zonelist iterator already checks the nodemask? Am I missing something? > + } > + } > + > if (cpusets_enabled() && > (alloc_flags & ALLOC_CPUSET) && > !__cpuset_zone_allowed(zone, gfp_mask)) >