Commit 55df0933 authored by Imran Khan's avatar Imran Khan Committed by Tejun Heo
Browse files

workqueue: Introduce show_one_worker_pool and show_one_workqueue. 



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: default avatarImran Khan <imran.f.khan@oracle.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent d25302e4

drivers/tty/sysrq.c

+1 −1
Original line number Diff line number Diff line
@@ -296,7 +296,7 @@ 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,

include/linux/workqueue.h

+2 −1
Original line number Diff line number Diff line
@@ -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);



/**

kernel/power/process.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

kernel/workqueue.c

+96 −76
Original line number Diff line number Diff line
@@ -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>
@@ -4447,7 +4448,7 @@ 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);
@@ -4797,25 +4798,14 @@ 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;

	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;

	unsigned long flags;



	for_each_pwq(pwq, wq) {

		if (pwq->nr_active || !list_empty(&pwq->inactive_works)) {
@@ -4823,8 +4813,8 @@ void show_workqueue_state(void) 
			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);
@@ -4843,16 +4833,23 @@ void show_workqueue_state(void) 
		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();

	}



}



	for_each_pool(pool, pi) {

/**

 * 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)
@@ -4882,12 +4879,35 @@ void show_workqueue_state(void) 
	raw_spin_unlock_irqrestore(&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_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();

}
@@ -5876,7 +5896,7 @@ 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);