From fa14ff4accfb24e59d2473f3d864d6648d80563b Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 12 Sep 2011 13:06:17 +0200 Subject: sched: Convert to struct llist Use the generic llist primitives. We had a private lockless list implementation in the scheduler in the wake-list code, now that we have a generic llist implementation that provides all required operations, switch to it. This patch is not expected to change any behavior. Signed-off-by: Peter Zijlstra Cc: Huang Ying Cc: Andrew Morton Link: http://lkml.kernel.org/r/1315836353.26517.42.camel@twins Signed-off-by: Ingo Molnar --- kernel/sched.c | 48 ++++++++++-------------------------------------- 1 file changed, 10 insertions(+), 38 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index c5cf15e1eb57..1874c7418319 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -702,7 +702,7 @@ struct rq { #endif #ifdef CONFIG_SMP - struct task_struct *wake_list; + struct llist_head wake_list; #endif }; @@ -2698,42 +2698,26 @@ static int ttwu_remote(struct task_struct *p, int wake_flags) } #ifdef CONFIG_SMP -static void sched_ttwu_do_pending(struct task_struct *list) +static void sched_ttwu_pending(void) { struct rq *rq = this_rq(); + struct llist_node *llist = llist_del_all(&rq->wake_list); + struct task_struct *p; raw_spin_lock(&rq->lock); - while (list) { - struct task_struct *p = list; - list = list->wake_entry; + while (llist) { + p = llist_entry(llist, struct task_struct, wake_entry); + llist = llist_next(llist); ttwu_do_activate(rq, p, 0); } raw_spin_unlock(&rq->lock); } -#ifdef CONFIG_HOTPLUG_CPU - -static void sched_ttwu_pending(void) -{ - struct rq *rq = this_rq(); - struct task_struct *list = xchg(&rq->wake_list, NULL); - - if (!list) - return; - - sched_ttwu_do_pending(list); -} - -#endif /* CONFIG_HOTPLUG_CPU */ - void scheduler_ipi(void) { - struct rq *rq = this_rq(); - struct task_struct *list = xchg(&rq->wake_list, NULL); - - if (!list) + if (llist_empty(&this_rq()->wake_list)) return; /* @@ -2750,25 +2734,13 @@ void scheduler_ipi(void) * somewhat pessimize the simple resched case. */ irq_enter(); - sched_ttwu_do_pending(list); + sched_ttwu_pending(); irq_exit(); } static void ttwu_queue_remote(struct task_struct *p, int cpu) { - struct rq *rq = cpu_rq(cpu); - struct task_struct *next = rq->wake_list; - - for (;;) { - struct task_struct *old = next; - - p->wake_entry = next; - next = cmpxchg(&rq->wake_list, old, p); - if (next == old) - break; - } - - if (!next) + if (llist_add(&p->wake_entry, &cpu_rq(cpu)->wake_list)) smp_send_reschedule(cpu); } -- cgit v1.2.3-59-g8ed1b