diff options
Diffstat (limited to 'nptl/pthread_cond_signal.c')
| -rw-r--r-- | nptl/pthread_cond_signal.c | 33 |
1 files changed, 28 insertions, 5 deletions
diff --git a/nptl/pthread_cond_signal.c b/nptl/pthread_cond_signal.c index 908a2acfaf..102d0b380c 100644 --- a/nptl/pthread_cond_signal.c +++ b/nptl/pthread_cond_signal.c @@ -47,12 +47,35 @@ __pthread_cond_signal (cond) ++cond->__data.__wakeup_seq; ++cond->__data.__futex; - /* Wake one. */ - if (! __builtin_expect (lll_futex_wake_unlock (&cond->__data.__futex, 1, - 1, &cond->__data.__lock, - pshared), 0)) - return 0; +#if (defined lll_futex_cmp_requeue_pi \ + && defined __ASSUME_REQUEUE_PI) + int pi_flag = PTHREAD_MUTEX_PRIO_INHERIT_NP | PTHREAD_MUTEX_ROBUST_NP; + pthread_mutex_t *mut = cond->__data.__mutex; + /* Do not use requeue for pshared condvars. */ + if (mut != (void *) ~0l) + pi_flag &= mut->__data.__kind; + + if (__builtin_expect (pi_flag == PTHREAD_MUTEX_PRIO_INHERIT_NP, 0) + /* This can only really fail with a ENOSYS, since nobody can modify + futex while we have the cond_lock. */ + && lll_futex_cmp_requeue_pi (&cond->__data.__futex, 1, 0, + &mut->__data.__lock, + cond->__data.__futex, pshared) == 0) + { + lll_unlock (cond->__data.__lock, pshared); + return 0; + } + else +#endif + /* Wake one. */ + if (! __builtin_expect (lll_futex_wake_unlock (&cond->__data.__futex, + 1, 1, + &cond->__data.__lock, + pshared), 0)) + return 0; + + /* Fallback if neither of them work. */ lll_futex_wake (&cond->__data.__futex, 1, pshared); } |