From: Imran Khan imran.f.khan@oracle.com
[ Upstream commit 55df0933be74bd2e52aba0b67eb743ae0feabe7e ]
Currently show_workqueue_state shows the state of all workqueues and of all worker pools. In certain cases we may need to dump state of only a specific workqueue or worker pool. For example in destroy_workqueue we only need to show state of the workqueue which is getting destroyed.
So rename show_workqueue_state to show_all_workqueues(to signify it dumps state of all busy workqueues) and divide it into more granular functions (show_one_workqueue and show_one_worker_pool), that would show states of individual workqueues and worker pools and can be used in cases such as the one mentioned above.
Also, as mentioned earlier, make destroy_workqueue dump data pertaining to only the workqueue that is being destroyed and make user(s) of earlier interface(show_workqueue_state), use new interface (show_all_workqueues).
Signed-off-by: Imran Khan imran.f.khan@oracle.com Signed-off-by: Tejun Heo tj@kernel.org Stable-dep-of: 335a42ebb0ca ("workqueue: Fix hung time report of worker pools") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/tty/sysrq.c | 2 +- include/linux/workqueue.h | 3 +- kernel/power/process.c | 2 +- kernel/workqueue.c | 172 +++++++++++++++++++++----------------- 4 files changed, 100 insertions(+), 79 deletions(-)
diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c index 6b445ece83395..4ffed77f80018 100644 --- a/drivers/tty/sysrq.c +++ b/drivers/tty/sysrq.c @@ -301,7 +301,7 @@ static const struct sysrq_key_op sysrq_showregs_op = { static void sysrq_handle_showstate(int key) { show_state(); - show_workqueue_state(); + show_all_workqueues(); } static const struct sysrq_key_op sysrq_showstate_op = { .handler = sysrq_handle_showstate, diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h index 74d3c1efd9bb5..7fee9b6cfedef 100644 --- a/include/linux/workqueue.h +++ b/include/linux/workqueue.h @@ -469,7 +469,8 @@ extern bool workqueue_congested(int cpu, struct workqueue_struct *wq); extern unsigned int work_busy(struct work_struct *work); extern __printf(1, 2) void set_worker_desc(const char *fmt, ...); extern void print_worker_info(const char *log_lvl, struct task_struct *task); -extern void show_workqueue_state(void); +extern void show_all_workqueues(void); +extern void show_one_workqueue(struct workqueue_struct *wq); extern void wq_worker_comm(char *buf, size_t size, struct task_struct *task);
/** diff --git a/kernel/power/process.c b/kernel/power/process.c index ee78a39463e63..11b570fcf0494 100644 --- a/kernel/power/process.c +++ b/kernel/power/process.c @@ -94,7 +94,7 @@ static int try_to_freeze_tasks(bool user_only) todo - wq_busy, wq_busy);
if (wq_busy) - show_workqueue_state(); + show_all_workqueues();
if (!wakeup || pm_debug_messages_on) { read_lock(&tasklist_lock); diff --git a/kernel/workqueue.c b/kernel/workqueue.c index f5fa7be8d17ea..de6463b931762 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -375,6 +375,7 @@ EXPORT_SYMBOL_GPL(system_freezable_power_efficient_wq); static int worker_thread(void *__worker); static void workqueue_sysfs_unregister(struct workqueue_struct *wq); static void show_pwq(struct pool_workqueue *pwq); +static void show_one_worker_pool(struct worker_pool *pool);
#define CREATE_TRACE_POINTS #include <trace/events/workqueue.h> @@ -4454,7 +4455,7 @@ void destroy_workqueue(struct workqueue_struct *wq) raw_spin_unlock_irq(&pwq->pool->lock); mutex_unlock(&wq->mutex); mutex_unlock(&wq_pool_mutex); - show_workqueue_state(); + show_one_workqueue(wq); return; } raw_spin_unlock_irq(&pwq->pool->lock); @@ -4804,97 +4805,116 @@ static void show_pwq(struct pool_workqueue *pwq) }
/** - * show_workqueue_state - dump workqueue state - * - * Called from a sysrq handler or try_to_freeze_tasks() and prints out - * all busy workqueues and pools. + * show_one_workqueue - dump state of specified workqueue + * @wq: workqueue whose state will be printed */ -void show_workqueue_state(void) +void show_one_workqueue(struct workqueue_struct *wq) { - struct workqueue_struct *wq; - struct worker_pool *pool; + struct pool_workqueue *pwq; + bool idle = true; unsigned long flags; - int pi; - - rcu_read_lock();
- pr_info("Showing busy workqueues and worker pools:\n"); - - list_for_each_entry_rcu(wq, &workqueues, list) { - struct pool_workqueue *pwq; - bool idle = true; - - for_each_pwq(pwq, wq) { - if (pwq->nr_active || !list_empty(&pwq->inactive_works)) { - idle = false; - break; - } + for_each_pwq(pwq, wq) { + if (pwq->nr_active || !list_empty(&pwq->inactive_works)) { + idle = false; + break; } - if (idle) - continue; + } + if (idle) /* Nothing to print for idle workqueue */ + return;
- pr_info("workqueue %s: flags=0x%x\n", wq->name, wq->flags); + pr_info("workqueue %s: flags=0x%x\n", wq->name, wq->flags);
- for_each_pwq(pwq, wq) { - raw_spin_lock_irqsave(&pwq->pool->lock, flags); - if (pwq->nr_active || !list_empty(&pwq->inactive_works)) { - /* - * Defer printing to avoid deadlocks in console - * drivers that queue work while holding locks - * also taken in their write paths. - */ - printk_deferred_enter(); - show_pwq(pwq); - printk_deferred_exit(); - } - raw_spin_unlock_irqrestore(&pwq->pool->lock, flags); + for_each_pwq(pwq, wq) { + raw_spin_lock_irqsave(&pwq->pool->lock, flags); + if (pwq->nr_active || !list_empty(&pwq->inactive_works)) { /* - * We could be printing a lot from atomic context, e.g. - * sysrq-t -> show_workqueue_state(). Avoid triggering - * hard lockup. + * Defer printing to avoid deadlocks in console + * drivers that queue work while holding locks + * also taken in their write paths. */ - touch_nmi_watchdog(); - } - } - - for_each_pool(pool, pi) { - struct worker *worker; - bool first = true; - - raw_spin_lock_irqsave(&pool->lock, flags); - if (pool->nr_workers == pool->nr_idle) - goto next_pool; - /* - * Defer printing to avoid deadlocks in console drivers that - * queue work while holding locks also taken in their write - * paths. - */ - printk_deferred_enter(); - pr_info("pool %d:", pool->id); - pr_cont_pool_info(pool); - pr_cont(" hung=%us workers=%d", - jiffies_to_msecs(jiffies - pool->watchdog_ts) / 1000, - pool->nr_workers); - if (pool->manager) - pr_cont(" manager: %d", - task_pid_nr(pool->manager->task)); - list_for_each_entry(worker, &pool->idle_list, entry) { - pr_cont(" %s%d", first ? "idle: " : "", - task_pid_nr(worker->task)); - first = false; + printk_deferred_enter(); + show_pwq(pwq); + printk_deferred_exit(); } - pr_cont("\n"); - printk_deferred_exit(); - next_pool: - raw_spin_unlock_irqrestore(&pool->lock, flags); + raw_spin_unlock_irqrestore(&pwq->pool->lock, flags); /* * We could be printing a lot from atomic context, e.g. - * sysrq-t -> show_workqueue_state(). Avoid triggering + * sysrq-t -> show_all_workqueues(). Avoid triggering * hard lockup. */ touch_nmi_watchdog(); }
+} + +/** + * show_one_worker_pool - dump state of specified worker pool + * @pool: worker pool whose state will be printed + */ +static void show_one_worker_pool(struct worker_pool *pool) +{ + struct worker *worker; + bool first = true; + unsigned long flags; + + raw_spin_lock_irqsave(&pool->lock, flags); + if (pool->nr_workers == pool->nr_idle) + goto next_pool; + /* + * Defer printing to avoid deadlocks in console drivers that + * queue work while holding locks also taken in their write + * paths. + */ + printk_deferred_enter(); + pr_info("pool %d:", pool->id); + pr_cont_pool_info(pool); + pr_cont(" hung=%us workers=%d", + jiffies_to_msecs(jiffies - pool->watchdog_ts) / 1000, + pool->nr_workers); + if (pool->manager) + pr_cont(" manager: %d", + task_pid_nr(pool->manager->task)); + list_for_each_entry(worker, &pool->idle_list, entry) { + pr_cont(" %s%d", first ? "idle: " : "", + task_pid_nr(worker->task)); + first = false; + } + pr_cont("\n"); + printk_deferred_exit(); +next_pool: + raw_spin_unlock_irqrestore(&pool->lock, flags); + /* + * We could be printing a lot from atomic context, e.g. + * sysrq-t -> show_all_workqueues(). Avoid triggering + * hard lockup. + */ + touch_nmi_watchdog(); + +} + +/** + * show_all_workqueues - dump workqueue state + * + * Called from a sysrq handler or try_to_freeze_tasks() and prints out + * all busy workqueues and pools. + */ +void show_all_workqueues(void) +{ + struct workqueue_struct *wq; + struct worker_pool *pool; + int pi; + + rcu_read_lock(); + + pr_info("Showing busy workqueues and worker pools:\n"); + + list_for_each_entry_rcu(wq, &workqueues, list) + show_one_workqueue(wq); + + for_each_pool(pool, pi) + show_one_worker_pool(pool); + rcu_read_unlock(); }
@@ -5883,7 +5903,7 @@ static void wq_watchdog_timer_fn(struct timer_list *unused) rcu_read_unlock();
if (lockup_detected) - show_workqueue_state(); + show_all_workqueues();
wq_watchdog_reset_touched(); mod_timer(&wq_watchdog_timer, jiffies + thresh);