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=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT 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 2C561C2BB54 for ; Tue, 7 Apr 2020 13:14:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0CB9420719 for ; Tue, 7 Apr 2020 13:14:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728866AbgDGNOF (ORCPT ); Tue, 7 Apr 2020 09:14:05 -0400 Received: from freundtech.com ([78.47.86.165]:48150 "EHLO freundtech.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728152AbgDGNOE (ORCPT ); Tue, 7 Apr 2020 09:14:04 -0400 X-Greylist: delayed 514 seconds by postgrey-1.27 at vger.kernel.org; Tue, 07 Apr 2020 09:14:03 EDT Received: from arch-desktop.local (unknown [IPv6:2a02:8071:2bb9:5f00::120]) by freundtech.com (Postfix) with ESMTPSA id 7D0621E0347; Tue, 7 Apr 2020 15:05:27 +0200 (CEST) From: Adrian Freund To: linux-doc@vger.kernel.org Cc: corbet@lwn.net, peterz@infradead.org, Adrian Freund Subject: [PATCH] Documentation: scheduler: fix outdated information on sched groups Date: Tue, 7 Apr 2020 15:05:25 +0200 Message-Id: <20200407130525.76663-1-adrian@freund.io> X-Mailer: git-send-email 2.26.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org The documentation claims that two sched groups must not overlap. This is no longer true, as overlapping sched groups are used on NUMA systems. This change has been introduced by commit e3589f6c81e47 and was documented by an in-code comment in commit 35a566e6e8a18. Signed-off-by: Adrian Freund --- Documentation/scheduler/sched-domains.rst | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/Documentation/scheduler/sched-domains.rst b/Documentation/scheduler/sched-domains.rst index f7504226f445..5c4b7f4f0062 100644 --- a/Documentation/scheduler/sched-domains.rst +++ b/Documentation/scheduler/sched-domains.rst @@ -19,10 +19,12 @@ CPUs". Each scheduling domain must have one or more CPU groups (struct sched_group) which are organised as a circular one way linked list from the ->groups pointer. The union of cpumasks of these groups MUST be the same as the -domain's span. The intersection of cpumasks from any two of these groups -MUST be the empty set. The group pointed to by the ->groups pointer MUST -contain the CPU to which the domain belongs. Groups may be shared among -CPUs as they contain read only data after they have been set up. +domain's span. The group pointed to by the ->groups pointer MUST contain the CPU +to which the domain belongs. Groups may be shared among CPUs as they contain +read only data after they have been set up. The intersection of cpumasks from +any two of these groups may be non empty. If this is the case the SD_OVERLAP +flag is set on the corresponding scheduling domain and its groups may not be +shared between CPUs. Balancing within a sched domain occurs between groups. That is, each group is treated as one entity. The load of a group is defined as the sum of the -- 2.26.0