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, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 3316FC433ED for ; Thu, 15 Apr 2021 12:16:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F361061152 for ; Thu, 15 Apr 2021 12:16:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232921AbhDOMQt (ORCPT ); Thu, 15 Apr 2021 08:16:49 -0400 Received: from foss.arm.com ([217.140.110.172]:44844 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232889AbhDOMQp (ORCPT ); Thu, 15 Apr 2021 08:16:45 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 1358A106F; Thu, 15 Apr 2021 05:16:22 -0700 (PDT) Received: from [192.168.178.6] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 93C1C3F73B; Thu, 15 Apr 2021 05:16:19 -0700 (PDT) Subject: Re: [PATCH v2 7/9] sched,debug: Convert sysctl sched_domains to debugfs To: Peter Zijlstra , Valentin Schneider Cc: mingo@kernel.org, mgorman@suse.de, juri.lelli@redhat.com, vincent.guittot@linaro.org, rostedt@goodmis.org, bsegall@google.com, bristot@redhat.com, joshdon@google.com, linux-kernel@vger.kernel.org, greg@kroah.com, linux@rasmusvillemoes.dk References: <20210412101421.609526370@infradead.org> <20210412102001.485107586@infradead.org> <87lf9mmdyk.mognet@arm.com> From: Dietmar Eggemann Message-ID: Date: Thu, 15 Apr 2021 14:16:14 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 15/04/2021 11:06, Peter Zijlstra wrote: > On Tue, Apr 13, 2021 at 03:55:15PM +0100, Valentin Schneider wrote: >> On 12/04/21 12:14, Peter Zijlstra wrote: >>> Stop polluting sysctl, move to debugfs for SCHED_DEBUG stuff. >>> >>> Signed-off-by: Peter Zijlstra (Intel) >>> Reviewed-by: Dietmar Eggemann >> >> On my Juno (2+4 big.LITTLE), sys/kernel/debug/sched/domains/ is now empty. >> >> I think that's because of unregister_sched_domain_sysctl() - >> debugfs_remove() is recursive, and I do get a case where we rebuild the >> domains but no CPU has been added or removed (we rebuild the domains when >> cpufreq kicks in, it's part of the big.LITTLE ponies). >> >> Do we actually still need that unregister? From a brief glance it looks >> like we could throw it out. > > Yeah, I can't think of anything either. AFAICT it hasn't done anything > useful since that cpumask optimization. Consider it gone. > > I'll let it soak for another day or so, but then I was planning on > merging this series. > > Updated patch has been in queue.git/sched/debug since yesterday. Had to check since v1 was working fine on Juno. So it was this __cpumask_clear_cpu() in register_sched_domain_sysctl() introduced in v2 which let the files under /sys/kernel/debug/sched/domains disapear. With {un,}register_sched_domain_sysctl() removed from partition_sched_domains_locked() they're there again. Looks like now register_sched_domain_sysctl() can be made static in kernel/sched/debug.c. [...]