On Sun, Apr 27, 2014 at 12:08:56PM +0800, Lai Jiangshan wrote: > 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 <la...@cn.fujitsu.com> ... > @@ -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 either @pool->manager_mutex.
Please drop "either" from the sentence. > @@ -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); W/ locking updated, we can simply assign the pointer on idr_alloc() instead of doing split alloc/replace. I'm a bit on the fence about this patch. It does simplify the code a bit but then we lose the ability to iterate workers without grabbing the manager_mutex, which would come handy when, for example, implementing better workqueue info reporting during oops which we'll prolly need to add sooner or later. Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
