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authorLai Jiangshan <laijs@cn.fujitsu.com>2014-05-20 17:46:27 +0800
committerTejun Heo <tj@kernel.org>2014-05-20 10:59:30 -0400
commit9625ab1727743f6a164df26b7b1eeeced7380b42 (patch)
treed3da8ffc218ca3077ebbc140eb7f345a2bae38f1 /kernel/workqueue.c
parentcf416171e7e1d966111f53bdae82f51af05e7bf8 (diff)
workqueue: use manager lock only to protect worker_idr
worker_idr is highly bound to managers and is always/only accessed in manager lock context. So we don't need pool->lock for it. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/workqueue.c')
-rw-r--r--kernel/workqueue.c34
1 files changed, 6 insertions, 28 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index c8411085466..910d963f6b7 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -124,8 +124,7 @@ enum {
* cpu or grabbing pool->lock is enough for read access. If
* POOL_DISASSOCIATED is set, it's identical to L.
*
- * MG: pool->manager_mutex and pool->lock protected. Writes require both
- * locks. Reads can happen under either lock.
+ * M: pool->manager_mutex protected.
*
* PL: wq_pool_mutex protected.
*
@@ -164,7 +163,7 @@ struct worker_pool {
/* see manage_workers() for details on the two manager mutexes */
struct mutex manager_arb; /* manager arbitration */
struct mutex manager_mutex; /* manager exclusion */
- struct idr worker_idr; /* MG: worker IDs and iteration */
+ struct idr worker_idr; /* M: worker IDs and iteration */
struct workqueue_attrs *attrs; /* I: worker attributes */
struct hlist_node hash_node; /* PL: unbound_pool_hash node */
@@ -340,16 +339,6 @@ static void copy_workqueue_attrs(struct workqueue_attrs *to,
lockdep_is_held(&wq->mutex), \
"sched RCU or wq->mutex should be held")
-#ifdef CONFIG_LOCKDEP
-#define assert_manager_or_pool_lock(pool) \
- WARN_ONCE(debug_locks && \
- !lockdep_is_held(&(pool)->manager_mutex) && \
- !lockdep_is_held(&(pool)->lock), \
- "pool->manager_mutex or ->lock should be held")
-#else
-#define assert_manager_or_pool_lock(pool) do { } while (0)
-#endif
-
#define for_each_cpu_worker_pool(pool, cpu) \
for ((pool) = &per_cpu(cpu_worker_pools, cpu)[0]; \
(pool) < &per_cpu(cpu_worker_pools, cpu)[NR_STD_WORKER_POOLS]; \
@@ -378,14 +367,14 @@ static void copy_workqueue_attrs(struct workqueue_attrs *to,
* @wi: integer used for iteration
* @pool: worker_pool to iterate workers of
*
- * This must be called with either @pool->manager_mutex or ->lock held.
+ * This must be called with @pool->manager_mutex.
*
* The if/else clause exists only for the lockdep assertion and can be
* ignored.
*/
#define for_each_pool_worker(worker, wi, pool) \
idr_for_each_entry(&(pool)->worker_idr, (worker), (wi)) \
- if (({ assert_manager_or_pool_lock((pool)); false; })) { } \
+ if (({ lockdep_assert_held(&pool->manager_mutex); false; })) { } \
else
/**
@@ -1725,13 +1714,7 @@ static struct worker *create_worker(struct worker_pool *pool)
* ID is needed to determine kthread name. Allocate ID first
* without installing the pointer.
*/
- idr_preload(GFP_KERNEL);
- spin_lock_irq(&pool->lock);
-
- id = idr_alloc(&pool->worker_idr, NULL, 0, 0, GFP_NOWAIT);
-
- spin_unlock_irq(&pool->lock);
- idr_preload_end();
+ id = idr_alloc(&pool->worker_idr, NULL, 0, 0, GFP_KERNEL);
if (id < 0)
goto fail;
@@ -1773,18 +1756,13 @@ static struct worker *create_worker(struct worker_pool *pool)
worker->flags |= WORKER_UNBOUND;
/* successful, commit the pointer to idr */
- spin_lock_irq(&pool->lock);
idr_replace(&pool->worker_idr, worker, worker->id);
- spin_unlock_irq(&pool->lock);
return worker;
fail:
- if (id >= 0) {
- spin_lock_irq(&pool->lock);
+ if (id >= 0)
idr_remove(&pool->worker_idr, id);
- spin_unlock_irq(&pool->lock);
- }
kfree(worker);
return NULL;
}