Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753310AbaKRClm (ORCPT ); Mon, 17 Nov 2014 21:41:42 -0500 Received: from mga02.intel.com ([134.134.136.20]:46093 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751213AbaKRCll (ORCPT ); Mon, 17 Nov 2014 21:41:41 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.07,407,1413270000"; d="scan'208";a="609498556" Date: Tue, 18 Nov 2014 10:21:13 +0800 From: Wanpeng Li To: Juri Lelli Cc: Ingo Molnar , Peter Zijlstra , Kirill Tkhai , linux-kernel@vger.kernel.org, Wanpeng Li Subject: Re: [PATCH] sched/rt: fix rt runtime corrupt when dl refuse a smaller bandwidth Message-ID: <20141118022113.GA10673@kernel> Reply-To: Wanpeng Li References: <1415868459-7043-1-git-send-email-wanpeng.li@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1415868459-7043-1-git-send-email-wanpeng.li@linux.intel.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ping Juri, ;-) On Thu, Nov 13, 2014 at 04:47:39PM +0800, Wanpeng Li wrote: >Dl class will refuse the bandwidth being set to some value smaller >than the currently allocated bandwidth in any of the root_domains >through sched_rt_runtime_us and sched_rt_period_us. RT runtime will >be set according to sched_rt_runtime_us before dl class verify if >the new bandwidth is suitable in the case of !CONFIG_RT_GROUP_SCHED. > >However, rt runtime will be corrupt if dl refuse the new bandwidth >since there is no undo to reset the rt runtime to the old value. > >This patch fix it by setting rt runtime after all kinds of rational >checking in the case of !CONFIG_RT_GROUP_SCHED. > >Signed-off-by: Wanpeng Li >--- > kernel/sched/core.c | 30 ++++++++++++++++-------------- > 1 file changed, 16 insertions(+), 14 deletions(-) > >diff --git a/kernel/sched/core.c b/kernel/sched/core.c >index 2e7578a..355dde3 100644 >--- a/kernel/sched/core.c >+++ b/kernel/sched/core.c >@@ -7795,20 +7795,7 @@ static int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk) > #else /* !CONFIG_RT_GROUP_SCHED */ > static int sched_rt_global_constraints(void) > { >- unsigned long flags; >- int i, ret = 0; >- >- raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags); >- for_each_possible_cpu(i) { >- struct rt_rq *rt_rq = &cpu_rq(i)->rt; >- >- raw_spin_lock(&rt_rq->rt_runtime_lock); >- rt_rq->rt_runtime = global_rt_runtime(); >- raw_spin_unlock(&rt_rq->rt_runtime_lock); >- } >- raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags); >- >- return ret; >+ return 0; > } > #endif /* CONFIG_RT_GROUP_SCHED */ > >@@ -7890,6 +7877,21 @@ static int sched_rt_global_validate(void) > > static void sched_rt_do_global(void) > { >+#ifndef CONFIG_RT_GROUP_SCHED >+ unsigned long flags; >+ int i; >+ >+ raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags); >+ for_each_possible_cpu(i) { >+ struct rt_rq *rt_rq = &cpu_rq(i)->rt; >+ >+ raw_spin_lock(&rt_rq->rt_runtime_lock); >+ rt_rq->rt_runtime = global_rt_runtime(); >+ raw_spin_unlock(&rt_rq->rt_runtime_lock); >+ } >+ raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags); >+#endif >+ > def_rt_bandwidth.rt_runtime = global_rt_runtime(); > def_rt_bandwidth.rt_period = ns_to_ktime(global_rt_period()); > } >-- >1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/