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=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 0BE7EC432BE for ; Wed, 28 Jul 2021 12:31:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DC6D860F9D for ; Wed, 28 Jul 2021 12:31:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235076AbhG1MbI (ORCPT ); Wed, 28 Jul 2021 08:31:08 -0400 Received: from smtp-out1.suse.de ([195.135.220.28]:48438 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234881AbhG1MbG (ORCPT ); Wed, 28 Jul 2021 08:31:06 -0400 Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out1.suse.de (Postfix) with ESMTP id 6277922314; Wed, 28 Jul 2021 12:31:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1627475464; 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=npMFGiRKpe9E2NAzxS4y+5J6eprtxsqTY9vAsITRMUg=; b=grWfSWG5enS6L02jqEBUn/cVF8gY3gQ3BR/4ugX8P8YwDZw4VnyA+reyvLfcyqIgY4MIpT 0MJ3wYrCYgUP+x91sRjSi6f5dMTVuwsiNqWRFiTLidGMb7HGnVyjgfrQgLS49ehsYtzyir CmoaE91Mp8qa0YNxL6qXl30SHvYJJHE= 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 1EE79A3B81; Wed, 28 Jul 2021 12:31:04 +0000 (UTC) Date: Wed, 28 Jul 2021 14:31:03 +0200 From: Michal Hocko To: Feng Tang 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: References: <1626077374-81682-1-git-send-email-feng.tang@intel.com> <1626077374-81682-2-git-send-email-feng.tang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1626077374-81682-2-git-send-email-feng.tang@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [Sorry for a late review] On Mon 12-07-21 16:09:29, Feng Tang wrote: [...] > @@ -1887,7 +1909,8 @@ nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *policy) > /* Return the node id preferred by the given mempolicy, or the given id */ > static int policy_node(gfp_t gfp, struct mempolicy *policy, int nd) > { > - if (policy->mode == MPOL_PREFERRED) { > + if (policy->mode == MPOL_PREFERRED || > + policy->mode == MPOL_PREFERRED_MANY) { > nd = first_node(policy->nodes); > } else { > /* Do we really want to have the preferred node to be always the first node in the node mask? Shouldn't that strive for a locality as well? Existing callers already prefer numa_node_id() - aka local node - and I belive we shouldn't just throw that away here. > @@ -1931,6 +1954,7 @@ unsigned int mempolicy_slab_node(void) > > switch (policy->mode) { > case MPOL_PREFERRED: > + case MPOL_PREFERRED_MANY: > return first_node(policy->nodes); Similarly here but I am not really familiar with the slab numa code enough to have strong opinions here. > @@ -2173,10 +2198,12 @@ struct page *alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma, > * node and don't fall back to other nodes, as the cost of > * remote accesses would likely offset THP benefits. > * > - * If the policy is interleave, or does not allow the current > - * node in its nodemask, we allocate the standard way. > + * If the policy is interleave or multiple preferred nodes, or > + * does not allow the current node in its nodemask, we allocate > + * the standard way. > */ > - if (pol->mode == MPOL_PREFERRED) > + if ((pol->mode == MPOL_PREFERRED || > + pol->mode == MPOL_PREFERRED_MANY)) > hpage_node = first_node(pol->nodes); Same here. > @@ -2451,6 +2479,9 @@ int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long > break; > > case MPOL_PREFERRED: > + case MPOL_PREFERRED_MANY: > + if (node_isset(curnid, pol->nodes)) > + goto out; > polnid = first_node(pol->nodes); > break; I do not follow what is the point of using first_node here. Either the node is in the mask or it is misplaced. What are you trying to achieve here? -- Michal Hocko SUSE Labs