At Tue, 10 Jan 2012 16:01:17 +0800, Liu Yuan wrote: > > On 01/10/2012 03:52 PM, MORITA Kazutaka wrote: > > > At Sat, 7 Jan 2012 14:29:02 +0800, > > Liu Yuan wrote: > >> > >> From: Liu Yuan <[email protected]> > >> > >> We do nothing while we hold the mutex, then we don't need it. > >> > >> Signed-off-by: Liu Yuan <[email protected]> > >> --- > >> sheep/work.c | 4 ---- > >> 1 files changed, 0 insertions(+), 4 deletions(-) > >> > >> diff --git a/sheep/work.c b/sheep/work.c > >> index 789272e..de3f500 100644 > >> --- a/sheep/work.c > >> +++ b/sheep/work.c > >> @@ -194,10 +194,6 @@ static void *worker_routine(void *arg) > >> struct work *work; > >> eventfd_t value = 1; > >> > >> - pthread_mutex_lock(&wi->startup_lock); > >> - /* started this thread */ > >> - pthread_mutex_unlock(&wi->startup_lock); > >> - > > > > This lock is used to ensure that all worker threads are correctly > > started up. > > > > > Why we need mutex here to ensure correct start-up? We get the lock, do > nothing and then unlock, looks a null operation to me.
If we don't wait start-up here and pthread_create fails in init_work_queue(), a deadlock could happen. It is because init_work_queue() waits for the already running threads with pthread_join() but the threads would suspend with pthread_cond_wait(). If we can cleanly exit init_work_queue() in error cases, I think it is okay to remove the startup lock. Thanks, Kazutaka -- sheepdog mailing list [email protected] http://lists.wpkg.org/mailman/listinfo/sheepdog
