diff options
Diffstat (limited to 'kernel/workqueue.c')
| -rw-r--r-- | kernel/workqueue.c | 39 |
1 files changed, 35 insertions, 4 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index b77119d71641..c6ea96d5b716 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1849,8 +1849,20 @@ static void unplug_oldest_pwq(struct workqueue_struct *wq) raw_spin_lock_irq(&pwq->pool->lock); if (pwq->plugged) { pwq->plugged = false; - if (pwq_activate_first_inactive(pwq, true)) + if (pwq_activate_first_inactive(pwq, true)) { + /* + * While plugged, queueing skips activation which + * includes bumping the nr_active count and adding the + * pwq to nna->pending_pwqs if the count can't be + * obtained. We need to restore both for the pwq being + * unplugged. The first call activates the first + * inactive work item and the second, if there are more + * inactive, puts the pwq on pending_pwqs. + */ + pwq_activate_first_inactive(pwq, false); + kick_pool(pwq->pool); + } } raw_spin_unlock_irq(&pwq->pool->lock); } @@ -7699,8 +7711,29 @@ static void wq_watchdog_timer_fn(struct timer_list *unused) else ts = touched; - /* did we stall? */ + /* + * Did we stall? + * + * Do a lockless check first to do not disturb the system. + * + * Prevent false positives by double checking the timestamp + * under pool->lock. The lock makes sure that the check reads + * an updated pool->last_progress_ts when this CPU saw + * an already updated pool->worklist above. It seems better + * than adding another barrier into __queue_work() which + * is a hotter path. + */ if (time_after(now, ts + thresh)) { + scoped_guard(raw_spinlock_irqsave, &pool->lock) { + pool_ts = pool->last_progress_ts; + if (time_after(pool_ts, touched)) + ts = pool_ts; + else + ts = touched; + } + if (!time_after(now, ts + thresh)) + continue; + lockup_detected = true; stall_time = jiffies_to_msecs(now - pool_ts) / 1000; max_stall_time = max(max_stall_time, stall_time); @@ -7712,8 +7745,6 @@ static void wq_watchdog_timer_fn(struct timer_list *unused) pr_cont_pool_info(pool); pr_cont(" stuck for %us!\n", stall_time); } - - } if (lockup_detected) |