From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751377AbcEIOqT (ORCPT ); Mon, 9 May 2016 10:46:19 -0400 Received: from merlin.infradead.org ([205.233.59.134]:57341 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750998AbcEIOqS (ORCPT ); Mon, 9 May 2016 10:46:18 -0400 Date: Mon, 9 May 2016 16:46:11 +0200 From: Peter Zijlstra To: mingo@kernel.org, linux-kernel@vger.kernel.org Cc: clm@fb.com, matt@codeblueprint.co.uk, mgalbraith@suse.de, tglx@linutronix.de, fweisbec@gmail.com Subject: Re: [RFC][PATCH 2/7] sched: Restructure destroy_sched_domain() Message-ID: <20160509144611.GB3408@twins.programming.kicks-ass.net> References: <20160509104807.284575300@infradead.org> <20160509105210.506989560@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160509105210.506989560@infradead.org> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 09, 2016 at 12:48:09PM +0200, Peter Zijlstra wrote: > There is no point in doing a call_rcu() for each domain, only do a > callback for the root sched domain and clean up the entire set in one > go. > > Also make the entire call chain be called destroy_sched_domain*() to > remove confusion with the free_sched_domains() call, which does an > entirely different thing. > > Both cpu_attach_domain() callers of destroy_sched_domain() can live > without the call_rcu() because at those points the sched_domain hasn't > been published yet. > > Signed-off-by: Peter Zijlstra (Intel) > --- This one seems to work much better; so much for last minute 'cleanups'. --- kernel/sched/core.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5824,10 +5824,8 @@ static void free_sched_groups(struct sch } while (sg != first); } -static void free_sched_domain(struct rcu_head *rcu) +static void destroy_sched_domain(struct sched_domain *sd) { - struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu); - /* * If its an overlapping domain it has private groups, iterate and * nuke them all. @@ -5841,15 +5839,21 @@ static void free_sched_domain(struct rcu kfree(sd); } -static void destroy_sched_domain(struct sched_domain *sd) +static void destroy_sched_domains_rcu(struct rcu_head *rcu) { - call_rcu(&sd->rcu, free_sched_domain); + struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu); + + while (sd) { + struct sched_domain *parent = sd->parent; + destroy_sched_domain(sd); + sd = parent; + } } static void destroy_sched_domains(struct sched_domain *sd) { - for (; sd; sd = sd->parent) - destroy_sched_domain(sd); + if (sd) + call_rcu(&sd->rcu, destroy_sched_domains_rcu); } /*