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workqueue: convert worker_idr to worker_ida

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We no longer iterate workers via worker_idr and worker_idr is used
only for allocating/freeing ID, so we can convert it to worker_ida.

By using ida_simple_get/remove(), worker_ida doesn't require external
synchronization, so we don't need manager_mutex to protect it and the
ID-removal code is allowed to be moved out from
worker_detach_from_pool().

In a later patch, worker_detach_from_pool() will be used in rescuers
which don't have IDs, so we move the ID-removal code out from
worker_detach_from_pool() into worker_thread().

tj: Minor description updates.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Lai Jiangshan 2014-05-20 17:46:32 +08:00 committed by Tejun Heo
parent da028469ba
commit 7cda9aae05
1 changed files with 8 additions and 12 deletions
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20
kernel/workqueue.c
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@ -161,10 +161,11 @@ struct worker_pool {
/* see manage_workers() for details on the two manager mutexes */ /* see manage_workers() for details on the two manager mutexes */
struct mutex manager_arb; /* manager arbitration */ struct mutex manager_arb; /* manager arbitration */
struct mutex manager_mutex; /* manager exclusion */ struct mutex manager_mutex; /* manager exclusion */
struct idr worker_idr; /* M: worker IDs */
struct list_head workers; /* M: attached workers */ struct list_head workers; /* M: attached workers */
struct completion *detach_completion; /* all workers detached */ struct completion *detach_completion; /* all workers detached */
struct ida worker_ida; /* worker IDs for task name */
struct workqueue_attrs *attrs; /* I: worker attributes */ struct workqueue_attrs *attrs; /* I: worker attributes */
struct hlist_node hash_node; /* PL: unbound_pool_hash node */ struct hlist_node hash_node; /* PL: unbound_pool_hash node */
int refcnt; /* PL: refcnt for unbound pools */ int refcnt; /* PL: refcnt for unbound pools */
@ -1696,7 +1697,6 @@ static void worker_detach_from_pool(struct worker *worker,
struct completion *detach_completion = NULL; struct completion *detach_completion = NULL;
mutex_lock(&pool->manager_mutex); mutex_lock(&pool->manager_mutex);
idr_remove(&pool->worker_idr, worker->id);
list_del(&worker->node); list_del(&worker->node);
if (list_empty(&pool->workers)) if (list_empty(&pool->workers))
detach_completion = pool->detach_completion; detach_completion = pool->detach_completion;
@ -1727,11 +1727,8 @@ static struct worker *create_worker(struct worker_pool *pool)
lockdep_assert_held(&pool->manager_mutex); lockdep_assert_held(&pool->manager_mutex);
/* /* ID is needed to determine kthread name */
* ID is needed to determine kthread name. Allocate ID first id = ida_simple_get(&pool->worker_ida, 0, 0, GFP_KERNEL);
* without installing the pointer.
*/
id = idr_alloc(&pool->worker_idr, NULL, 0, 0, GFP_KERNEL);
if (id < 0) if (id < 0)
goto fail; goto fail;
@ -1772,8 +1769,6 @@ static struct worker *create_worker(struct worker_pool *pool)
if (pool->flags & POOL_DISASSOCIATED) if (pool->flags & POOL_DISASSOCIATED)
worker->flags |= WORKER_UNBOUND; worker->flags |= WORKER_UNBOUND;
/* successful, commit the pointer to idr */
idr_replace(&pool->worker_idr, worker, worker->id);
/* successful, attach the worker to the pool */ /* successful, attach the worker to the pool */
list_add_tail(&worker->node, &pool->workers); list_add_tail(&worker->node, &pool->workers);
@ -1781,7 +1776,7 @@ static struct worker *create_worker(struct worker_pool *pool)
fail: fail:
if (id >= 0) if (id >= 0)
idr_remove(&pool->worker_idr, id); ida_simple_remove(&pool->worker_ida, id);
kfree(worker); kfree(worker);
return NULL; return NULL;
} }
@ -2250,6 +2245,7 @@ woke_up:
worker->task->flags &= ~PF_WQ_WORKER; worker->task->flags &= ~PF_WQ_WORKER;
set_task_comm(worker->task, "kworker/dying"); set_task_comm(worker->task, "kworker/dying");
ida_simple_remove(&pool->worker_ida, worker->id);
worker_detach_from_pool(worker, pool); worker_detach_from_pool(worker, pool);
kfree(worker); kfree(worker);
return 0; return 0;
@ -3486,9 +3482,9 @@ static int init_worker_pool(struct worker_pool *pool)
mutex_init(&pool->manager_arb); mutex_init(&pool->manager_arb);
mutex_init(&pool->manager_mutex); mutex_init(&pool->manager_mutex);
idr_init(&pool->worker_idr);
INIT_LIST_HEAD(&pool->workers); INIT_LIST_HEAD(&pool->workers);
ida_init(&pool->worker_ida);
INIT_HLIST_NODE(&pool->hash_node); INIT_HLIST_NODE(&pool->hash_node);
pool->refcnt = 1; pool->refcnt = 1;
@ -3503,7 +3499,7 @@ static void rcu_free_pool(struct rcu_head *rcu)
{ {
struct worker_pool *pool = container_of(rcu, struct worker_pool, rcu); struct worker_pool *pool = container_of(rcu, struct worker_pool, rcu);
idr_destroy(&pool->worker_idr); ida_destroy(&pool->worker_ida);
free_workqueue_attrs(pool->attrs); free_workqueue_attrs(pool->attrs);
kfree(pool); kfree(pool);
} }