On 02/20/2014 08:11 AM, Tejun Heo wrote: > Hello, Lai. > > On Wed, Feb 19, 2014 at 11:47:58AM +0800, Lai Jiangshan wrote: >> If a worker is wokenup unexpectedly, it will start to work incorretly. >> Although it hardly happen, we should catch it and wait for being started >> if it does happen. > > Can this actually happen? If so, how?
I don't think it can happen. It depends on the system outside of workqueue. I'm afraid someone see the task and wake up it. workqueue protect itself. > >> Signed-off-by: Lai Jiangshan <[email protected]> >> --- >> kernel/workqueue.c | 6 ++++++ >> 1 files changed, 6 insertions(+), 0 deletions(-) >> >> diff --git a/kernel/workqueue.c b/kernel/workqueue.c >> index 82ef9f3..bee5fe1 100644 >> --- a/kernel/workqueue.c >> +++ b/kernel/workqueue.c >> @@ -2284,6 +2284,12 @@ static int worker_thread(void *__worker) >> struct worker *worker = __worker; >> struct worker_pool *pool = worker->pool; >> >> + if (WARN_ON_ONCE(!(worker->flags & WORKER_STARTED))) { > > And if this is something which can legitimately happen, why are we > triggering WARN on it? If it happens, it means there is something wrong in the system. > >> + /* The worker is wokenup unexpectedly before started */ >> + mutex_lock(&pool->manager_mutex); >> + mutex_unlock(&pool->manager_mutex); > > And what does these mutex cycling achieve (they need comment)? Synchronize the manager to finish. > > Thanks. > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
