On Mon, May 5, 2014 at 9:13 PM, Tejun Heo <t...@kernel.org> wrote: > Hello, > > On Sun, Apr 27, 2014 at 12:08:57PM +0800, Lai Jiangshan wrote: >> @@ -1692,9 +1691,8 @@ static struct worker *alloc_worker(void) >> * create_worker - create a new workqueue worker >> * @pool: pool the new worker will belong to >> * >> - * Create a new worker which is bound to @pool. The returned worker >> - * can be started by calling start_worker() or destroyed using >> - * destroy_worker(). >> + * Create a new worker which is bound to @pool. >> + * The new worker should be started and enter idle by start_worker(). > > Hmm... we used to have a path where a worker is created and then > destroyed without being started. IIRC, it was on the CPU online > failure path. A worker was created for the CPU coming online and if > the online operation failed the created worker was shut down without > being started. Right, we no longer shutdown per-cpu pools on offline > so this doesn't matter anymore. Might worthwhile to note in the patch > description tho. > >> @@ -1815,6 +1812,7 @@ static int create_and_start_worker(struct worker_pool >> *pool) >> * @worker: worker to be destroyed >> * >> * Destroy @worker and adjust @pool stats accordingly. >> + * The worker should be idle(WORKER_IDLE). > > Just write "The worker should be idle." Also, in general, can you > please put a space before opening parenthesis? > >> * >> * CONTEXT: >> * spin_lock_irq(pool->lock) which is released and regrabbed. >> @@ -1828,13 +1826,13 @@ static void destroy_worker(struct worker *worker) >> >> /* sanity check frenzy */ >> if (WARN_ON(worker->current_work) || >> - WARN_ON(!list_empty(&worker->scheduled))) >> + WARN_ON(!list_empty(&worker->scheduled)) || >> + WARN_ON(!(worker->flags & WORKER_IDLE)) || >> + WARN_ON(pool->nr_workers == 1 && !list_empty(&pool->worklist))) > > I'm not sure about the pool condition check. It's kinda overreaching > to check for it from worker destruction.
"pool->nr_workers == 1", it is the last worker of the pool, so I add this check. I will remove it. > >> @@ -3589,6 +3587,7 @@ static void put_unbound_pool(struct worker_pool *pool) >> mutex_lock(&pool->manager_mutex); >> spin_lock_irq(&pool->lock); >> >> + WARN_ON(pool->nr_workers != pool->nr_idle); > > Does this condition detect anything new from the condition below? It is already ensured that all workers are idle since pool->ref==0 and manager_arb is held. This additional WARN_ON() does double check. It tells the reviewers that destroying all workers on idle_list equals to destroying all workers of the pool. I can remove this WARN_ON(). > >> while ((worker = first_worker(pool))) >> destroy_worker(worker); >> WARN_ON(pool->nr_workers || pool->nr_idle); > > 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/ -- 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/
