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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E88D4C00140 for ; Fri, 12 Aug 2022 10:15:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236601AbiHLKPx (ORCPT ); Fri, 12 Aug 2022 06:15:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34708 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238210AbiHLKPY (ORCPT ); Fri, 12 Aug 2022 06:15:24 -0400 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BB4F8ABD6E; Fri, 12 Aug 2022 03:14:47 -0700 (PDT) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 5DAAF5C9AD; Fri, 12 Aug 2022 10:14:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1660299286; 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=ZbZXqZhVMx97LH/wfbkAQvfgc1/NDVE/NEBNZNQzYTU=; b=GiRwDUFguJx6UvwA2htp1tu/od4+/MgY/Ty7gEBk9JA03HG8yddGZJKVoyZfXc22LFyX/7 fsAhQ/NV/xEVrOr12UZ9Skp2vUueX3AnUd8NKHbZulNBtlMuqR83lmlBIZ3GzXWqC01Kwo Z8akVkNyRUB1+GfFYrb6Yvt6Q8gw02w= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id F310413305; Fri, 12 Aug 2022 10:14:45 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id dYwmOhUo9mJmVQAAMHmgww (envelope-from ); Fri, 12 Aug 2022 10:14:45 +0000 Date: Fri, 12 Aug 2022 12:14:44 +0200 From: Michal =?iso-8859-1?Q?Koutn=FD?= To: Chengming Zhou Cc: hannes@cmpxchg.org, tj@kernel.org, corbet@lwn.net, surenb@google.com, mingo@redhat.com, peterz@infradead.org, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, songmuchun@bytedance.com Subject: Re: [PATCH v2 09/10] sched/psi: per-cgroup PSI stats disable/re-enable interface Message-ID: References: <20220808110341.15799-1-zhouchengming@bytedance.com> <20220808110341.15799-10-zhouchengming@bytedance.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220808110341.15799-10-zhouchengming@bytedance.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Chengming. On Mon, Aug 08, 2022 at 07:03:40PM +0800, Chengming Zhou wrote: > diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst > index dd84e34bc051..ade40506ab80 100644 > --- a/Documentation/admin-guide/cgroup-v2.rst > +++ b/Documentation/admin-guide/cgroup-v2.rst > @@ -968,6 +968,13 @@ All cgroup core files are prefixed with "cgroup." > killing cgroups is a process directed operation, i.e. it affects > the whole thread-group. > > + cgroup.psi > + A read-write single value file that allowed values are "0" and "1". > + The default is "1". > + > + Writing "0" to the file will disable the cgroup PSI stats accounting. > + Writing "1" to the file will re-enable the cgroup PSI stats accounting. > + I'd suggest explaining here explicitely, this control attribute is not hierarchical (i.e. PSI accounting in a cgroup does not affect accounting in descendants and doesn't need pass enablement via ancestors from root). And the purpose that it "saves" cycles (where). Regards, Michal