diff options
| -rw-r--r-- | winsup/cygwin/ChangeLog | 8 | ||||
| -rw-r--r-- | winsup/cygwin/thread.cc | 23 | ||||
| -rw-r--r-- | winsup/cygwin/thread.h | 1 |
3 files changed, 28 insertions, 4 deletions
diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog index bc6703d91..f700246b2 100644 --- a/winsup/cygwin/ChangeLog +++ b/winsup/cygwin/ChangeLog @@ -1,3 +1,10 @@ +2001-12-26 Robert Collins <rbtcollins@hotmail.com> + + * thread.cc (pthread_cond::Signal): Use a separate flag for signal detection + and broadcast semantics. + (__pthread_cond_dowait): Ditto. + * thread.h (pthread_cond): New flag for testing when a waiter has woken. + 2001-12-26 Christopher Faylor <cgf@redhat.com> * Makefile.in: Quote arguments to shell scripts. @@ -116,6 +123,7 @@ * net.cc (cygwin_getsockopt): Dereference optlen pointer when passing to __check_null_invalid_struct_errno. +>>>>>>> 1.1060 2001-12-03 Christopher Faylor <cgf@redhat.com> * net.cc (cygwin_getsockopt): Allow NULL optval. diff --git a/winsup/cygwin/thread.cc b/winsup/cygwin/thread.cc index 8ca4820e8..ced5f6f80 100644 --- a/winsup/cygwin/thread.cc +++ b/winsup/cygwin/thread.cc @@ -499,24 +499,37 @@ pthread_cond::Signal () system_printf ("Failed to unlock condition variable access mutex, this %p", this); return; } + /* Prime the detection flag */ + ExitingWait = 1; + /* Signal any waiting thread */ PulseEvent (win32_obj_id); /* No one can start waiting until we release the condition access mutex */ /* The released thread will decrement waiting when it gets a time slice... without waiting for the access mutex + * InterLockedIncrement on 98 +, NT4 + returns the incremented value. + * On 95, nt 3.51 < it returns a sign correct number - 0=0, + for greater than 0, - + * for less than 0. + * Because of this we cannot spin on the waiting count, but rather we need a + * dedicated flag for a thread exiting the Wait function. + * Also not that Interlocked* sync CPU caches with memory. */ int spins = 10; - while (InterlockedIncrement (&waiting) != (temp - 1) && spins) + /* When ExitingWait is nonzero after a decrement, the leaving thread has + * done it's thing + */ + while (InterlockedDecrement (&ExitingWait) == 0 && spins) { - InterlockedDecrement (&waiting); + InterlockedIncrement (&ExitingWait); /* give up the cpu to force a context switch. */ Sleep (0); if (spins == 5) - /* we've had 5 timeslices, and the woekn thread still hasn't done it's + /* we've had 5 timeslices, and the woken thread still hasn't done it's * thing - maybe we raced it with the event? */ PulseEvent (win32_obj_id); spins--; } - InterlockedDecrement (&waiting); + if (waiting + 1 != temp) + system_printf ("Released too many threads - %d now %d originally", waiting, temp); if (pthread_mutex_unlock (&cond_access)) system_printf ("Failed to unlock condition variable access mutex, this %p", this); } @@ -1782,6 +1795,8 @@ __pthread_cond_dowait (pthread_cond_t *cond, pthread_mutex_t *mutex, bool last = false; if (InterlockedDecrement (&((*cond)->waiting)) == 0) last = true; + /* Tell Signal that we have been released */ + InterlockedDecrement (&((*cond)->ExitingWait)); (*themutex)->Lock (); if (last == true) (*cond)->mutex = NULL; diff --git a/winsup/cygwin/thread.h b/winsup/cygwin/thread.h index c1c0e1956..23aaa6860 100644 --- a/winsup/cygwin/thread.h +++ b/winsup/cygwin/thread.h @@ -306,6 +306,7 @@ class pthread_cond:public verifyable_object public: int shared; LONG waiting; + LONG ExitingWait; pthread_mutex *mutex; /* to allow atomic behaviour for cond_broadcast */ pthread_mutex_t cond_access; |