From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759239Ab1FWLVf (ORCPT ); Thu, 23 Jun 2011 07:21:35 -0400 Received: from e3.ny.us.ibm.com ([32.97.182.143]:49951 "EHLO e3.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756339Ab1FWLVd (ORCPT ); Thu, 23 Jun 2011 07:21:33 -0400 Message-ID: <4E0321AD.2080308@linux.vnet.ibm.com> Date: Thu, 23 Jun 2011 19:21:17 +0800 From: Cheng Xu User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.17) Gecko/20110516 Thunderbird/3.1.10 MIME-Version: 1.0 To: Yong Zhang CC: linux-kernel , Peter Zijlstra , Ingo Molnar , Mike Galbraith Subject: Re: [PATCH] sched: skip autogroup when looking for all rt sched groups References: In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/22/2011 01:22 PM, Yong Zhang wrote: > From: Yong Zhang > Subject: [PATCH] sched: skip autogroup when looking for all rt sched groups > > Since [commit ec514c48: sched: Fix rt_rq runtime leakage bug], > 'cat /proc/sched_debug' will print data of root_task_group.rt_rq > multi times, this is due to autogroup has no its own rt group, > instead rt group of autogroup is linked to root_task_group. > > So skip it when we are looking for all rt sched groups, and it > will also save some noop operation against root_task_group when > __disable_runtime()/__enable_runtime(). > > Signed-off-by: Yong Zhang > Cc: Ingo Molnar > Cc: Peter Zijlstra > Cc: Mike Galbraith > --- > > Since webmail may mangle the patch, attach it too. > > kernel/sched_autogroup.h | 1 + > kernel/sched_rt.c | 29 ++++++++++++++++++++++++----- > 2 files changed, 25 insertions(+), 5 deletions(-) > > diff --git a/kernel/sched_autogroup.h b/kernel/sched_autogroup.h > index 0557705..c2f0e72 100644 > --- a/kernel/sched_autogroup.h > +++ b/kernel/sched_autogroup.h > @@ -13,6 +13,7 @@ struct autogroup { > int nice; > }; > > +static inline bool task_group_is_autogroup(struct task_group *tg); > static inline struct task_group * > autogroup_task_group(struct task_struct *p, struct task_group *tg); > > diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c > index 10d0182..8edf487 100644 > --- a/kernel/sched_rt.c > +++ b/kernel/sched_rt.c > @@ -185,11 +185,30 @@ static inline u64 sched_rt_period(struct rt_rq *rt_rq) > > typedef struct task_group *rt_rq_iter_t; > > -#define for_each_rt_rq(rt_rq, iter, rq) \ > - for (iter = list_entry_rcu(task_groups.next, typeof(*iter), list); \ > - (&iter->list != &task_groups) && \ > - (rt_rq = iter->rt_rq[cpu_of(rq)]); \ > - iter = list_entry_rcu(iter->list.next, typeof(*iter), list)) > +/* autogroup is not related to rt group, skip it */ > +#define find_first_valid_task_group(iter) \ > + ({ \ > + list_for_each_entry_rcu(iter, &task_groups, list) \ > + if (!task_group_is_autogroup(iter)) \ > + break; \ > + iter; \ > + }) > + > +#define find_next_valid_task_group(iter) \ > + ({ \ > + do { \ > + iter = list_entry_rcu(iter->list.next, \ > + typeof(*iter), list); \ > + } while (&iter->list != &task_groups && \ > + task_group_is_autogroup(iter)); \ > + iter; \ > + }) > + > +#define for_each_rt_rq(rt_rq, iter, rq) \ > + for (find_first_valid_task_group(iter); \ > + (&iter->list != &task_groups) && \ > + (rt_rq = iter->rt_rq[cpu_of(rq)]); \ > + find_next_valid_task_group(iter)) > > static inline void list_add_leaf_rt_rq(struct rt_rq *rt_rq) > { This looks like it works, but seems we might be able to do that with less code... static inline struct task_group *next_task_group(struct task_group *tg) { do { tg = list_entry_rcu(tg->list.next, typeof(struct task_group), list); } while ((&tg->list != &task_groups) && (task_group_is_autogroup(tg))); if (&tg->list == &task_groups) tg = NULL; return tg; } #define for_each_rt_rq(rt_rq, iter, rq) \ for (iter = container_of(&task_groups, typeof(*iter), list); \ (iter = next_task_group(iter)) && \ (rt_rq = iter->rt_rq[cpu_of(rq)]);) Thanks, Cheng