diff options
| -rw-r--r-- | include/linux/sched.h | 1 | ||||
| -rw-r--r-- | kernel/sched.c | 31 |
2 files changed, 16 insertions, 16 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index 5d3c9900943..3b0ca66bd6c 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -190,6 +190,7 @@ extern unsigned long long time_sync_thresh; /* in tsk->state again */ #define TASK_DEAD 64 #define TASK_WAKEKILL 128 +#define TASK_WAKING 256 /* Convenience macros for the sake of set_task_state */ #define TASK_KILLABLE (TASK_WAKEKILL | TASK_UNINTERRUPTIBLE) diff --git a/kernel/sched.c b/kernel/sched.c index 32b7a81230c..fc6fda881d2 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2310,7 +2310,6 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync) { int cpu, orig_cpu, this_cpu, success = 0; unsigned long flags; - long old_state; struct rq *rq; if (!sched_feat(SYNC_WAKEUPS)) @@ -2332,11 +2331,12 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync) } #endif + this_cpu = get_cpu(); + smp_wmb(); rq = task_rq_lock(p, &flags); update_rq_clock(rq); - old_state = p->state; - if (!(old_state & state)) + if (!(p->state & state)) goto out; if (p->se.on_rq) @@ -2344,27 +2344,25 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync) cpu = task_cpu(p); orig_cpu = cpu; - this_cpu = smp_processor_id(); #ifdef CONFIG_SMP if (unlikely(task_running(rq, p))) goto out_activate; + /* + * In order to handle concurrent wakeups and release the rq->lock + * we put the task in TASK_WAKING state. + */ + p->state = TASK_WAKING; + task_rq_unlock(rq, &flags); + cpu = p->sched_class->select_task_rq(p, SD_BALANCE_WAKE, sync); - if (cpu != orig_cpu) { + if (cpu != orig_cpu) set_task_cpu(p, cpu); - task_rq_unlock(rq, &flags); - /* might preempt at this point */ - rq = task_rq_lock(p, &flags); - old_state = p->state; - if (!(old_state & state)) - goto out; - if (p->se.on_rq) - goto out_running; - this_cpu = smp_processor_id(); - cpu = task_cpu(p); - } + rq = task_rq_lock(p, &flags); + WARN_ON(p->state != TASK_WAKING); + cpu = task_cpu(p); #ifdef CONFIG_SCHEDSTATS schedstat_inc(rq, ttwu_count); @@ -2422,6 +2420,7 @@ out_running: #endif out: task_rq_unlock(rq, &flags); + put_cpu(); return success; } |