From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936457AbXJSSqb (ORCPT ); Fri, 19 Oct 2007 14:46:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932415AbXJSSoX (ORCPT ); Fri, 19 Oct 2007 14:44:23 -0400 Received: from ms-smtp-01.nyroc.rr.com ([24.24.2.55]:56981 "EHLO ms-smtp-01.nyroc.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1765895AbXJSSoT (ORCPT ); Fri, 19 Oct 2007 14:44:19 -0400 Message-Id: <20071019184336.349767581@goodmis.org> References: <20071019184254.456160632@goodmis.org> User-Agent: quilt/0.46-1 Date: Fri, 19 Oct 2007 14:42:56 -0400 From: Steven Rostedt To: LKML , RT Cc: Linus Torvalds , Andrew Morton , Ingo Molnar , Thomas Gleixner , Gregory Haskins , Peter Zijlstra Subject: [patch 2/8] track highest prio queued on runqueue Content-Disposition: inline; filename=add-rq-highest-prio.patch Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org This patch adds accounting to each runqueue to keep track of the highest prio task queued on the run queue. We only care about RT tasks, so if the run queue does not contain any active RT tasks its priority will be considered MAX_RT_PRIO. This information will be used for later patches. Signed-off-by: Steven Rostedt --- kernel/sched.c | 7 +++++++ kernel/sched_rt.c | 25 +++++++++++++++++++++++++ 2 files changed, 32 insertions(+) Index: linux-test.git/kernel/sched.c =================================================================== --- linux-test.git.orig/kernel/sched.c 2007-10-19 12:33:09.000000000 -0400 +++ linux-test.git/kernel/sched.c 2007-10-19 12:34:32.000000000 -0400 @@ -324,6 +324,8 @@ struct rq { int push_cpu; /* cpu of this runqueue: */ int cpu; + /* highest queued rt task prio */ + int highest_prio; struct task_struct *migration_thread; struct list_head migration_queue; @@ -972,6 +974,8 @@ static void activate_task(struct rq *rq, enqueue_task(rq, p, wakeup); inc_nr_running(p, rq); + + rq_prio_add_task(rq, p); } /* @@ -984,6 +988,8 @@ static void deactivate_task(struct rq *r dequeue_task(rq, p, sleep); dec_nr_running(p, rq); + + rq_prio_remove_task(rq, p); } /** @@ -6619,6 +6625,7 @@ void __init sched_init(void) rq->cpu = i; rq->migration_thread = NULL; INIT_LIST_HEAD(&rq->migration_queue); + rq->highest_prio = MAX_RT_PRIO; #endif atomic_set(&rq->nr_iowait, 0); Index: linux-test.git/kernel/sched_rt.c =================================================================== --- linux-test.git.orig/kernel/sched_rt.c 2007-10-19 12:33:09.000000000 -0400 +++ linux-test.git/kernel/sched_rt.c 2007-10-19 12:33:23.000000000 -0400 @@ -110,6 +110,31 @@ static struct task_struct *pick_next_tas return next; } +#ifdef CONFIG_SMP +static inline void rq_prio_add_task(struct rq *rq, struct task_struct *p) +{ + if (unlikely(rt_task(p)) && p->prio < rq->highest_prio) + rq->highest_prio = p->prio; +} + +static inline void rq_prio_remove_task(struct rq *rq, struct task_struct *p) +{ + struct rt_prio_array *array; + + if (unlikely(rt_task(p))) { + if (rq->rt_nr_running) { + if (p->prio >= rq->highest_prio) { + /* recalculate */ + array = &rq->rt.active; + rq->highest_prio = + sched_find_first_bit(array->bitmap); + } /* otherwise leave rq->highest prio alone */ + } else + rq->highest_prio = MAX_RT_PRIO; + } +} +#endif /* CONFIG_SMP */ + static void put_prev_task_rt(struct rq *rq, struct task_struct *p) { update_curr_rt(rq); --