success = 1; /* we're going to change ->state */
cpu = task_cpu(p);
+ /*
+ * Ensure we load p->on_rq _after_ p->state, otherwise it would
+ * be possible to, falsely, observe p->on_rq == 0 and get stuck
+ * in smp_cond_load_acquire() below.
+ *
+ * sched_ttwu_pending() try_to_wake_up()
+ * [S] p->on_rq = 1; [L] P->state
+ * UNLOCK rq->lock -----.
+ * \
+ * +--- RMB
+ * schedule() /
+ * LOCK rq->lock -----'
+ * UNLOCK rq->lock
+ *
+ * [task p]
+ * [S] p->state = UNINTERRUPTIBLE [L] p->on_rq
+ *
+ * Pairs with the UNLOCK+LOCK on rq->lock from the
+ * last wakeup of our task and the schedule that got our task
+ * current.
+ */
+ smp_rmb();
if (p->on_rq && ttwu_remote(p, wake_flags))
goto stat;
*/
int wake_up_process(struct task_struct *p)
{
- WARN_ON(task_is_stopped_or_traced(p));
return try_to_wake_up(p, TASK_NORMAL, 0);
}
EXPORT_SYMBOL(wake_up_process);
static unsigned long
calc_load(unsigned long load, unsigned long exp, unsigned long active)
{
- load *= exp;
- load += active * (FIXED_1 - exp);
- load += 1UL << (FSHIFT - 1);
- return load >> FSHIFT;
+ unsigned long newload;
+
+ newload = load * exp + active * (FIXED_1 - exp);
+ if (active >= load)
+ newload += FIXED_1-1;
+
+ return newload / FIXED_1;
}
#ifdef CONFIG_NO_HZ
/*
* reset the NMI-timeout, listing all files on a slow
* console might take a lot of time:
+ * Also, reset softlockup watchdogs on all CPUs, because
+ * another CPU might be blocked waiting for us to process
+ * an IPI.
*/
touch_nmi_watchdog();
+ touch_all_softlockup_watchdogs();
if (!state_filter || (p->state & state_filter))
sched_show_task(p);
} while_each_thread(g, p);
- touch_all_softlockup_watchdogs();
-
#ifdef CONFIG_SCHED_DEBUG
sysrq_sched_debug_show();
#endif
{
memset(rd, 0, sizeof(*rd));
- if (!alloc_cpumask_var(&rd->span, GFP_KERNEL))
+ if (!zalloc_cpumask_var(&rd->span, GFP_KERNEL))
goto out;
- if (!alloc_cpumask_var(&rd->online, GFP_KERNEL))
+ if (!zalloc_cpumask_var(&rd->online, GFP_KERNEL))
goto free_span;
- if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))
+ if (!zalloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))
goto free_online;
if (cpupri_init(&rd->cpupri) != 0)