Major update for pthreads, based in large part on improvements

from glibc 2.3.  This should make threads much more efficient.
 -Erik

1 files changed, 128 insertions, 31 deletions

diff --git a/libpthread/linuxthreads/semaphore.c b/libpthread/linuxthreads/semaphore.c
index 0297b3a1e..0038ddd2a 100644
--- a/libpthread/linuxthreads/semaphore.c
+++ b/libpthread/linuxthreads/semaphore.c
@@ -14,6 +14,8 @@
 
 /* Semaphores a la POSIX 1003.1b */
 
+#include <features.h>
+#define __USE_GNU
 #include <errno.h>
 #include "pthread.h"
 #include "semaphore.h"
@@ -32,7 +34,7 @@ int __new_sem_init(sem_t *sem, int pshared, unsigned int value)
     errno = ENOSYS;
     return -1;
   }
-  __pthread_init_lock((struct _pthread_fastlock *) &sem->__sem_lock);
+  __pthread_init_lock(&sem->__sem_lock);
   sem->__sem_value = value;
   sem->__sem_waiting = NULL;
   return 0;
@@ -47,9 +49,9 @@ static int new_sem_extricate_func(void *obj, pthread_descr th)
   sem_t *sem = obj;
   int did_remove = 0;
 
-  __pthread_lock((struct _pthread_fastlock *) &sem->__sem_lock, self);
+  __pthread_lock(&sem->__sem_lock, self);
   did_remove = remove_from_queue(&sem->__sem_waiting, th);
-  __pthread_unlock((struct _pthread_fastlock *) &sem->__sem_lock);
+  __pthread_unlock(&sem->__sem_lock);
 
   return did_remove;
 }
@@ -59,35 +61,50 @@ int __new_sem_wait(sem_t * sem)
   volatile pthread_descr self = thread_self();
   pthread_extricate_if extr;
   int already_canceled = 0;
+  int spurious_wakeup_count;
 
   /* Set up extrication interface */
   extr.pu_object = sem;
   extr.pu_extricate_func = new_sem_extricate_func;
 
-  __pthread_lock((struct _pthread_fastlock *) &sem->__sem_lock, self);
+  __pthread_lock(&sem->__sem_lock, self);
   if (sem->__sem_value > 0) {
     sem->__sem_value--;
-    __pthread_unlock((struct _pthread_fastlock *) &sem->__sem_lock);
+    __pthread_unlock(&sem->__sem_lock);
     return 0;
   }
   /* Register extrication interface */
-  __pthread_set_own_extricate_if(self, &extr); 
+  THREAD_SETMEM(self, p_sem_avail, 0);
+  __pthread_set_own_extricate_if(self, &extr);
   /* Enqueue only if not already cancelled. */
   if (!(THREAD_GETMEM(self, p_canceled)
       && THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE))
     enqueue(&sem->__sem_waiting, self);
   else
     already_canceled = 1;
-  __pthread_unlock((struct _pthread_fastlock *) &sem->__sem_lock);
+  __pthread_unlock(&sem->__sem_lock);
 
   if (already_canceled) {
-    __pthread_set_own_extricate_if(self, 0); 
+    __pthread_set_own_extricate_if(self, 0);
     pthread_exit(PTHREAD_CANCELED);
-  } 
+  }
 
   /* Wait for sem_post or cancellation, or fall through if already canceled */
-  suspend(self);
-  __pthread_set_own_extricate_if(self, 0); 
+  spurious_wakeup_count = 0;
+  while (1)
+    {
+      suspend(self);
+      if (THREAD_GETMEM(self, p_sem_avail) == 0
+	  && (THREAD_GETMEM(self, p_woken_by_cancel) == 0
+	      || THREAD_GETMEM(self, p_cancelstate) != PTHREAD_CANCEL_ENABLE))
+	{
+	  /* Count resumes that don't belong to us. */
+	  spurious_wakeup_count++;
+	  continue;
+	}
+      break;
+    }
+  __pthread_set_own_extricate_if(self, 0);
 
   /* Terminate only if the wakeup came from cancellation. */
   /* Otherwise ignore cancellation because we got the semaphore. */
@@ -105,7 +122,7 @@ int __new_sem_trywait(sem_t * sem)
 {
   int retval;
 
-  __pthread_lock((struct _pthread_fastlock *) &sem->__sem_lock, NULL);
+  __pthread_lock(&sem->__sem_lock, NULL);
   if (sem->__sem_value == 0) {
     errno = EAGAIN;
     retval = -1;
@@ -113,7 +130,7 @@ int __new_sem_trywait(sem_t * sem)
     sem->__sem_value--;
     retval = 0;
   }
-  __pthread_unlock((struct _pthread_fastlock *) &sem->__sem_lock);
+  __pthread_unlock(&sem->__sem_lock);
   return retval;
 }
 
@@ -124,19 +141,21 @@ int __new_sem_post(sem_t * sem)
   struct pthread_request request;
 
   if (THREAD_GETMEM(self, p_in_sighandler) == NULL) {
-    __pthread_lock((struct _pthread_fastlock *) &sem->__sem_lock, self);
+    __pthread_lock(&sem->__sem_lock, self);
     if (sem->__sem_waiting == NULL) {
       if (sem->__sem_value >= SEM_VALUE_MAX) {
         /* Overflow */
         errno = ERANGE;
-        __pthread_unlock((struct _pthread_fastlock *) &sem->__sem_lock);
+        __pthread_unlock(&sem->__sem_lock);
         return -1;
       }
       sem->__sem_value++;
-      __pthread_unlock((struct _pthread_fastlock *) &sem->__sem_lock);
+      __pthread_unlock(&sem->__sem_lock);
     } else {
       th = dequeue(&sem->__sem_waiting);
-      __pthread_unlock((struct _pthread_fastlock *) &sem->__sem_lock);
+      __pthread_unlock(&sem->__sem_lock);
+      th->p_sem_avail = 1;
+      WRITE_MEMORY_BARRIER();
       restart(th);
     }
   } else {
@@ -150,8 +169,8 @@ int __new_sem_post(sem_t * sem)
     }
     request.req_kind = REQ_POST;
     request.req_args.post = sem;
-    __libc_write(__pthread_manager_request,
-                 (char *) &request, sizeof(request));
+    TEMP_FAILURE_RETRY(__libc_write(__pthread_manager_request,
+				    (char *) &request, sizeof(request)));
   }
   return 0;
 }
@@ -189,21 +208,99 @@ int sem_unlink(const char *name)
   return -1;
 }
 
-#if defined PIC && DO_VERSIONING
-default_symbol_version (__new_sem_init, sem_init, GLIBC_2.1);
-default_symbol_version (__new_sem_wait, sem_wait, GLIBC_2.1);
-default_symbol_version (__new_sem_trywait, sem_trywait, GLIBC_2.1);
-default_symbol_version (__new_sem_post, sem_post, GLIBC_2.1);
-default_symbol_version (__new_sem_getvalue, sem_getvalue, GLIBC_2.1);
-default_symbol_version (__new_sem_destroy, sem_destroy, GLIBC_2.1);
-#else
-# ifdef weak_alias
+int sem_timedwait(sem_t *sem, const struct timespec *abstime)
+{
+  pthread_descr self = thread_self();
+  pthread_extricate_if extr;
+  int already_canceled = 0;
+  int spurious_wakeup_count;
+
+  __pthread_lock(&sem->__sem_lock, self);
+  if (sem->__sem_value > 0) {
+    --sem->__sem_value;
+    __pthread_unlock(&sem->__sem_lock);
+    return 0;
+  }
+
+  if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000) {
+    /* The standard requires that if the function would block and the
+       time value is illegal, the function returns with an error.  */
+    __pthread_unlock(&sem->__sem_lock);
+    return EINVAL;
+  }
+
+  /* Set up extrication interface */
+  extr.pu_object = sem;
+  extr.pu_extricate_func = new_sem_extricate_func;
+
+  /* Register extrication interface */
+  THREAD_SETMEM(self, p_sem_avail, 0);
+  __pthread_set_own_extricate_if(self, &extr);
+  /* Enqueue only if not already cancelled. */
+  if (!(THREAD_GETMEM(self, p_canceled)
+      && THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE))
+    enqueue(&sem->__sem_waiting, self);
+  else
+    already_canceled = 1;
+  __pthread_unlock(&sem->__sem_lock);
+
+  if (already_canceled) {
+    __pthread_set_own_extricate_if(self, 0);
+    pthread_exit(PTHREAD_CANCELED);
+  }
+
+  spurious_wakeup_count = 0;
+  while (1)
+    {
+      if (timedsuspend(self, abstime) == 0) {
+	int was_on_queue;
+
+	/* __pthread_lock will queue back any spurious restarts that
+	   may happen to it. */
+
+	__pthread_lock(&sem->__sem_lock, self);
+	was_on_queue = remove_from_queue(&sem->__sem_waiting, self);
+	__pthread_unlock(&sem->__sem_lock);
+
+	if (was_on_queue) {
+	  __pthread_set_own_extricate_if(self, 0);
+	  return ETIMEDOUT;
+	}
+
+	/* Eat the outstanding restart() from the signaller */
+	suspend(self);
+      }
+
+      if (THREAD_GETMEM(self, p_sem_avail) == 0
+	  && (THREAD_GETMEM(self, p_woken_by_cancel) == 0
+	      || THREAD_GETMEM(self, p_cancelstate) != PTHREAD_CANCEL_ENABLE))
+	{
+	  /* Count resumes that don't belong to us. */
+	  spurious_wakeup_count++;
+	  continue;
+	}
+      break;
+    }
+
+ __pthread_set_own_extricate_if(self, 0);
+
+  /* Terminate only if the wakeup came from cancellation. */
+  /* Otherwise ignore cancellation because we got the semaphore. */
+
+  if (THREAD_GETMEM(self, p_woken_by_cancel)
+      && THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE) {
+    THREAD_SETMEM(self, p_woken_by_cancel, 0);
+    pthread_exit(PTHREAD_CANCELED);
+  }
+  /* We got the semaphore */
+  return 0;
+}
+
+
 weak_alias (__new_sem_init, sem_init)
 weak_alias (__new_sem_wait, sem_wait)
 weak_alias (__new_sem_trywait, sem_trywait)
 weak_alias (__new_sem_post, sem_post)
 weak_alias (__new_sem_getvalue, sem_getvalue)
 weak_alias (__new_sem_destroy, sem_destroy)
-# endif
-#endif
-    
+