Commit a2be943b authored by Marco Crivellari's avatar Marco Crivellari Committed by Tejun Heo
Browse files

workqueue: replace use of system_wq with system_percpu_wq 



Currently if a user enqueue a work item using schedule_delayed_work() the
used wq is "system_wq" (per-cpu wq) while queue_delayed_work() use
WORK_CPU_UNBOUND (used when a cpu is not specified). The same applies to
schedule_work() that is using system_wq and queue_work(), that makes use
again of WORK_CPU_UNBOUND.

This lack of consistentcy cannot be addressed without refactoring the API.

system_wq is a per-CPU worqueue, yet nothing in its name tells about that
CPU affinity constraint, which is very often not required by users. Make
it clear by adding a system_percpu_wq.

queue_work() / queue_delayed_work() mod_delayed_work() will now use the
new per-cpu wq: whether the user still stick on the old name a warn will
be printed along a wq redirect to the new one.

This patch add the new system_percpu_wq except for mm, fs and net
subsystem, whom are handled in separated patches.

The old wq will be kept for a few release cylces.

Suggested-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarMarco Crivellari <marco.crivellari@suse.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent f6cfa602

include/linux/workqueue.h

+11 −11
Original line number Diff line number Diff line
@@ -434,10 +434,10 @@ enum wq_consts { 
 * short queue flush time.  Don't queue works which can run for too

 * long.

 *

 * system_highpri_wq is similar to system_wq but for work items which

 * system_highpri_wq is similar to system_percpu_wq but for work items which

 * require WQ_HIGHPRI.

 *

 * system_long_wq is similar to system_wq but may host long running

 * system_long_wq is similar to system_percpu_wq but may host long running

 * works.  Queue flushing might take relatively long.

 *

 * system_dfl_wq is unbound workqueue.  Workers are not bound to
@@ -445,13 +445,13 @@ enum wq_consts { 
 * executed immediately as long as max_active limit is not reached and

 * resources are available.

 *

 * system_freezable_wq is equivalent to system_wq except that it's

 * system_freezable_wq is equivalent to system_percpu_wq except that it's

 * freezable.

 *

 * *_power_efficient_wq are inclined towards saving power and converted

 * into WQ_UNBOUND variants if 'wq_power_efficient' is enabled; otherwise,

 * they are same as their non-power-efficient counterparts - e.g.

 * system_power_efficient_wq is identical to system_wq if

 * system_power_efficient_wq is identical to system_percpu_wq if

 * 'wq_power_efficient' is disabled.  See WQ_POWER_EFFICIENT for more info.

 *

 * system_bh[_highpri]_wq are convenience interface to softirq. BH work items
@@ -708,7 +708,7 @@ static inline bool mod_delayed_work(struct workqueue_struct *wq, 
 */

static inline bool schedule_work_on(int cpu, struct work_struct *work)

{

	return queue_work_on(cpu, system_wq, work);

	return queue_work_on(cpu, system_percpu_wq, work);

}



/**
@@ -727,7 +727,7 @@ static inline bool schedule_work_on(int cpu, struct work_struct *work) 
 */

static inline bool schedule_work(struct work_struct *work)

{

	return queue_work(system_wq, work);

	return queue_work(system_percpu_wq, work);

}



/**
@@ -770,15 +770,15 @@ extern void __warn_flushing_systemwide_wq(void) 
#define flush_scheduled_work()						\

({									\

	__warn_flushing_systemwide_wq();				\

	__flush_workqueue(system_wq);					\

	__flush_workqueue(system_percpu_wq);					\

})



#define flush_workqueue(wq)						\

({									\

	struct workqueue_struct *_wq = (wq);				\

									\

	if ((__builtin_constant_p(_wq == system_wq) &&			\

	     _wq == system_wq) ||					\

	if ((__builtin_constant_p(_wq == system_percpu_wq) &&			\

	     _wq == system_percpu_wq) ||					\

	    (__builtin_constant_p(_wq == system_highpri_wq) &&		\

	     _wq == system_highpri_wq) ||				\

	    (__builtin_constant_p(_wq == system_long_wq) &&		\
@@ -807,7 +807,7 @@ extern void __warn_flushing_systemwide_wq(void) 
static inline bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork,

					    unsigned long delay)

{

	return queue_delayed_work_on(cpu, system_wq, dwork, delay);

	return queue_delayed_work_on(cpu, system_percpu_wq, dwork, delay);

}



/**
@@ -821,7 +821,7 @@ static inline bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork, 
static inline bool schedule_delayed_work(struct delayed_work *dwork,

					 unsigned long delay)

{

	return queue_delayed_work(system_wq, dwork, delay);

	return queue_delayed_work(system_percpu_wq, dwork, delay);

}



#ifndef CONFIG_SMP

kernel/workqueue.c

+1 −1
Original line number Diff line number Diff line
@@ -7668,7 +7668,7 @@ static int wq_watchdog_param_set_thresh(const char *val, 
	if (ret)

		return ret;



	if (system_wq)

	if (system_percpu_wq)

		wq_watchdog_set_thresh(thresh);

	else

		wq_watchdog_thresh = thresh;