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sched: Convert to struct llist

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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>
This commit is contained in:
Peter Zijlstra 2011-09-12 13:06:17 +02:00 committed by Ingo Molnar
parent 924f8f5af3
commit fa14ff4acc
2 changed files with 12 additions and 39 deletions
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3
include/linux/sched.h
View file

@ -90,6 +90,7 @@ struct sched_param {
#include <linux/task_io_accounting.h>
#include <linux/latencytop.h>
#include <linux/cred.h>
#include <linux/llist.h>
#include <asm/processor.h>
@ -1225,7 +1226,7 @@ struct task_struct {
unsigned int ptrace;
#ifdef CONFIG_SMP
struct task_struct *wake_entry;
struct llist_node wake_entry;
int on_cpu;
#endif
int on_rq;

48
kernel/sched.c
View file

@ -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);
}