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Commit 35b6bb63 authored by Tejun Heo's avatar Tejun Heo
Browse files

workqueue: make GCWQ_FREEZING a pool flag 



Make GCWQ_FREEZING a pool flag POOL_FREEZING.  This patch doesn't
change locking - FREEZING on both pools of a CPU are set or clear
together while holding gcwq->lock.  It shouldn't cause any functional
difference.

This leaves gcwq->flags w/o any flags.  Removed.

While at it, convert BUG_ON()s in freeze_workqueue_begin() and
thaw_workqueues() to WARN_ON_ONCE().

This is part of an effort to remove global_cwq and make worker_pool
the top level abstraction, which in turn will help implementing worker
pools with user-specified attributes.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Reviewed-by: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
parent 24647570

kernel/workqueue.c

+15 −13
Original line number Diff line number Diff line
@@ -46,11 +46,6 @@ 
#include "workqueue_internal.h"



enum {

	/*

	 * global_cwq flags

	 */

	GCWQ_FREEZING		= 1 << 1,	/* freeze in progress */



	/*

	 * worker_pool flags

	 *
@@ -70,6 +65,7 @@ enum { 
	POOL_MANAGE_WORKERS	= 1 << 0,	/* need to manage workers */

	POOL_MANAGING_WORKERS   = 1 << 1,       /* managing workers */

	POOL_DISASSOCIATED	= 1 << 2,	/* cpu can't serve workers */

	POOL_FREEZING		= 1 << 3,	/* freeze in progress */



	/* worker flags */

	WORKER_STARTED		= 1 << 0,	/* started */
@@ -152,7 +148,6 @@ struct worker_pool { 
struct global_cwq {

	spinlock_t		lock;		/* the gcwq lock */

	unsigned int		cpu;		/* I: the associated cpu */

	unsigned int		flags;		/* L: GCWQ_* flags */



	/* workers are chained either in busy_hash or pool idle_list */

	DECLARE_HASHTABLE(busy_hash, BUSY_WORKER_HASH_ORDER);
@@ -3380,13 +3375,15 @@ void workqueue_set_max_active(struct workqueue_struct *wq, int max_active) 
	wq->saved_max_active = max_active;



	for_each_cwq_cpu(cpu, wq) {

		struct global_cwq *gcwq = get_gcwq(cpu);

		struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);

		struct worker_pool *pool = cwq->pool;

		struct global_cwq *gcwq = pool->gcwq;



		spin_lock_irq(&gcwq->lock);



		if (!(wq->flags & WQ_FREEZABLE) ||

		    !(gcwq->flags & GCWQ_FREEZING))

			cwq_set_max_active(get_cwq(gcwq->cpu, wq), max_active);

		    !(pool->flags & POOL_FREEZING))

			cwq_set_max_active(cwq, max_active);



		spin_unlock_irq(&gcwq->lock);

	}
@@ -3676,12 +3673,15 @@ void freeze_workqueues_begin(void) 


	for_each_gcwq_cpu(cpu) {

		struct global_cwq *gcwq = get_gcwq(cpu);

		struct worker_pool *pool;

		struct workqueue_struct *wq;



		spin_lock_irq(&gcwq->lock);



		BUG_ON(gcwq->flags & GCWQ_FREEZING);

		gcwq->flags |= GCWQ_FREEZING;

		for_each_worker_pool(pool, gcwq) {

			WARN_ON_ONCE(pool->flags & POOL_FREEZING);

			pool->flags |= POOL_FREEZING;

		}



		list_for_each_entry(wq, &workqueues, list) {

			struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
@@ -3767,8 +3767,10 @@ void thaw_workqueues(void) 


		spin_lock_irq(&gcwq->lock);



		BUG_ON(!(gcwq->flags & GCWQ_FREEZING));

		gcwq->flags &= ~GCWQ_FREEZING;

		for_each_worker_pool(pool, gcwq) {

			WARN_ON_ONCE(!(pool->flags & POOL_FREEZING));

			pool->flags &= ~POOL_FREEZING;

		}



		list_for_each_entry(wq, &workqueues, list) {

			struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);