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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 10DD7C433DB for ; Mon, 18 Jan 2021 10:59:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BB03022252 for ; Mon, 18 Jan 2021 10:59:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389827AbhARK7E (ORCPT ); Mon, 18 Jan 2021 05:59:04 -0500 Received: from mx2.suse.de ([195.135.220.15]:55342 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389410AbhARK6l (ORCPT ); Mon, 18 Jan 2021 05:58:41 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id F3588B1C1; Mon, 18 Jan 2021 10:57:59 +0000 (UTC) Date: Mon, 18 Jan 2021 10:57:57 +0000 From: Mel Gorman To: Imran Khan Cc: mingo@redhat.com, peterz@infradead.org, vincent.guittot@linaro.org, juri.lelli@redhat.com, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, bristot@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH] Remove redundant sched_numa_balancing check. Message-ID: <20210118105757.GA20777@suse.de> References: <20210118103218.204373-1-imran.f.khan@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20210118103218.204373-1-imran.f.khan@oracle.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 18, 2021 at 09:32:18PM +1100, Imran Khan wrote: > task_numa_fault is invoked from do_numa_page/do_huge_pmd_numa_page, > for task_numa_work induced memory faults. task_numa_work is scheduled > from task_tick_numa which is invoked only if sched_numa_balancing > is true. > > So task_numa_fault will not get invoked if sched_numa_balancing is > false and hence we can avoid checking it again in task_numa_fault. > > Signed-off-by: Imran Khan If NUMA balancing is disabled at runtime, there may still be PTEs that are marked for NUMA balancing. While these still get handled at fault, there is no point tracking the fault information in task_numa_fault and this function can still get called after sched_numa_balancing is disabled. -- Mel Gorman SUSE Labs