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 X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B4BE7C4338F for ; Fri, 30 Jul 2021 03:05:20 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 499E260E9B for ; Fri, 30 Jul 2021 03:05:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 499E260E9B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id C674C6B0036; Thu, 29 Jul 2021 23:05:19 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C17656B005D; Thu, 29 Jul 2021 23:05:19 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B05EF8D0001; Thu, 29 Jul 2021 23:05:19 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0116.hostedemail.com [216.40.44.116]) by kanga.kvack.org (Postfix) with ESMTP id 94F106B0036 for ; Thu, 29 Jul 2021 23:05:19 -0400 (EDT) Received: from smtpin14.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 2DC4A1840CAF1 for ; Fri, 30 Jul 2021 03:05:19 +0000 (UTC) X-FDA: 78417763158.14.C0CEFC0 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by imf07.hostedemail.com (Postfix) with ESMTP id 5687510000B8 for ; Fri, 30 Jul 2021 03:05:17 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10060"; a="192613816" X-IronPort-AV: E=Sophos;i="5.84,280,1620716400"; d="scan'208";a="192613816" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Jul 2021 20:05:07 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.84,280,1620716400"; d="scan'208";a="518685854" Received: from shbuild999.sh.intel.com (HELO localhost) ([10.239.146.151]) by fmsmga002.fm.intel.com with ESMTP; 29 Jul 2021 20:05:03 -0700 Date: Fri, 30 Jul 2021 11:05:02 +0800 From: Feng Tang To: Michal Hocko Cc: linux-mm@kvack.org, Andrew Morton , David Rientjes , Dave Hansen , Ben Widawsky , linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, Andrea Arcangeli , Mel Gorman , Mike Kravetz , Randy Dunlap , Vlastimil Babka , Andi Kleen , Dan Williams , ying.huang@intel.com, Dave Hansen Subject: Re: [PATCH v6 1/6] mm/mempolicy: Add MPOL_PREFERRED_MANY for multiple preferred nodes Message-ID: <20210730030502.GA87066@shbuild999.sh.intel.com> References: <1626077374-81682-1-git-send-email-feng.tang@intel.com> <1626077374-81682-2-git-send-email-feng.tang@intel.com> <20210728141156.GC43486@shbuild999.sh.intel.com> <20210729070918.GA96680@shbuild999.sh.intel.com> <20210729151242.GA42865@shbuild999.sh.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 5687510000B8 Authentication-Results: imf07.hostedemail.com; dkim=none; spf=none (imf07.hostedemail.com: domain of feng.tang@intel.com has no SPF policy when checking 192.55.52.136) smtp.mailfrom=feng.tang@intel.com; dmarc=fail reason="No valid SPF, No valid DKIM" header.from=intel.com (policy=none) X-Stat-Signature: 9mz3j6erz6tqsmeau4g4nhbicdzc5yh8 X-HE-Tag: 1627614317-958368 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 Thu, Jul 29, 2021 at 06:21:19PM +0200, Michal Hocko wrote: > On Thu 29-07-21 23:12:42, Feng Tang wrote: > > On Thu, Jul 29, 2021 at 03:38:44PM +0200, Michal Hocko wrote: > [...] > > > Also the > > > semantic to give nodes some ordering based on their numbers sounds > > > rather weird to me. > > > > I agree, and as I admitted in the first reply, this need to be fixed. > > OK. I was not really clear that we are on the same page here. > > > > The semantic I am proposing is to allocate from prefered nodes in > > > distance order starting from the local node. > > > > So the plan is: > > * if the local node is set in 'prefer-many's nodemask, then chose > > * otherwise chose the node with the shortest distance to local node > > ? > > Yes and what I am trying to say is that you will achieve that simply by > doing the following in policy_node: > if (policy->mode == MPOL_PREFERRED_MANY) > return nd; One thing is, it's possible that 'nd' is not set in the preferred nodemask. For policy_node(), most of its caller use the local node id as 'nd' parameter. For HBM and PMEM memory nodes, they are cpuless nodes, so they will not be a 'local node', but some use cases only prefer these nodes. Thanks, Feng > -- > Michal Hocko > SUSE Labs