Messages in this thread Patch in this message | | | From | Lai Jiangshan <> | Subject | [PATCH 7/9 V3] workqueue: explicit way to wait for idles workers to finish | Date | Thu, 30 Aug 2012 00:51:58 +0800 |
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busy_worker_rebind_fn() can't return until all idle workers are rebound. This order is ensured by rebind_workers() currently.
We use mutex_lock(&worker->pool->manager_mutex) to wait for all idle workers to be rebound. this is an explicit way and it will ease the pain of the rebind_workers().
The sleeping mutex_lock(&worker->pool->manager_mutex) must be put in the top of busy_worker_rebind_fn(), because this busy worker thread can sleep before the WORKER_REBIND is cleared, but can't sleep after the WORKER_REBIND cleared.
It adds a small overhead to the unlikely path.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> --- kernel/workqueue.c | 8 +++++++- 1 files changed, 7 insertions(+), 1 deletions(-)
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index d88aa2e..719d6ec 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1376,9 +1376,15 @@ static void busy_worker_rebind_fn(struct work_struct *work) struct worker *worker = container_of(work, struct worker, rebind_work); struct global_cwq *gcwq = worker->pool->gcwq; + /* + * Waiting all idle workers are rebound by competing on + * pool->manager_mutex. + */ + mutex_lock(&worker->pool->manager_mutex); + if (worker_maybe_bind_and_lock(worker)) worker_clr_flags(worker, WORKER_REBIND); - + non_manager_role_manager_mutex_unlock(worker->pool); spin_unlock_irq(&gcwq->lock); } -- 1.7.4.4
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