From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936416AbXJSSp7 (ORCPT ); Fri, 19 Oct 2007 14:45:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1765935AbXJSSoV (ORCPT ); Fri, 19 Oct 2007 14:44:21 -0400 Received: from ms-smtp-02.nyroc.rr.com ([24.24.2.56]:57094 "EHLO ms-smtp-02.nyroc.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1765900AbXJSSoT (ORCPT ); Fri, 19 Oct 2007 14:44:19 -0400 Message-Id: <20071019184336.669654901@goodmis.org> References: <20071019184254.456160632@goodmis.org> User-Agent: quilt/0.46-1 Date: Fri, 19 Oct 2007 14:42:58 -0400 From: Steven Rostedt To: LKML , RT Cc: Linus Torvalds , Andrew Morton , Ingo Molnar , Thomas Gleixner , Gregory Haskins , Peter Zijlstra Subject: [patch 4/8] RT overloaded runqueues accounting Content-Disposition: inline; filename=rt-overload.patch Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org This patch adds an RT overload accounting system. When a runqueue has more than one RT task queued, it is marked as overloaded. That is that it is a candidate to have RT tasks pulled from it. Along with the rt_overload counter (number of overloaded runqueues) a bit mask of overloaded runqueues with RT tasks is set. Signed-off-by: Steven Rostedt --- kernel/sched_rt.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) Index: linux-test.git/kernel/sched_rt.c =================================================================== --- linux-test.git.orig/kernel/sched_rt.c 2007-10-19 12:34:46.000000000 -0400 +++ linux-test.git/kernel/sched_rt.c 2007-10-19 12:35:58.000000000 -0400 @@ -25,10 +25,23 @@ static void update_curr_rt(struct rq *rq curr->se.exec_start = rq->clock; } +#ifdef CONFIG_SMP +static __cacheline_aligned_in_smp atomic_t rt_overload; +static cpumask_t rto_cpumask; +#endif /* CONFIG_SMP*/ + static inline void inc_rt_tasks(struct task_struct *p, struct rq *rq) { if (rt_task(p)) rq->rt_nr_running++; +#ifdef CONFIG_SMP + if (rq->rt_nr_running == 2) { + cpu_set(rq->cpu, rto_cpumask); + /* Make sure this cpu is visible on rt_overloads */ + smp_wmb(); + atomic_inc(&rt_overload); + } +#endif } static inline void dec_rt_tasks(struct task_struct *p, struct rq *rq) @@ -37,6 +50,12 @@ static inline void dec_rt_tasks(struct t WARN_ON(!rq->rt_nr_running); rq->rt_nr_running--; } +#ifdef CONFIG_SMP + if (rq->rt_nr_running == 1) { + atomic_dec(&rt_overload); + cpu_clear(rq->cpu, rto_cpumask); + } +#endif } static void enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup) --