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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2011-09-12 13:06:17 +0200
committerIngo Molnar <mingo@elte.hu>2011-10-04 12:43:58 +0200
commitfa14ff4accfb24e59d2473f3d864d6648d80563b (patch)
treea2f3f5a16e1e740c6f96857e60c37826689d7b0b /kernel/sched.c
parent924f8f5af31423529cc3940cb2ae9fee736b7517 (diff)
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 <a.p.zijlstra@chello.nl> Cc: Huang Ying <ying.huang@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/1315836353.26517.42.camel@twins Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r--kernel/sched.c48
1 files changed, 10 insertions, 38 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index c5cf15e1eb5..1874c741831 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);
}