Update.

* sysdeps/unix/sysv/linux/kernel-posix-timers.h: Don't declare
	__timer_helper_thread.  Declare __start_helper_thread, __helper_once,
	and __helper_tid.
	(struct timer): Remove th and bar field.
	* sysdeps/unix/sysv/linux/timer_create.c (timer_create): Remove
	debugging code.  Create only one helper thread.
	* sysdeps/unix/sysv/linux/timer_delete.c (timer_delete): Don't kill
	helper thread.
	* sysdeps/unix/sysv/linux/timer_routines.c (timer_helper_thread):
	Renamed.  Define statically.  Use thread info from siginfo.
	(__helper_once): New variable.
	(__helper_tid): New variable.
	(__reset_helper_control): New function.
	(__start_helper_thread): New function.

nptl/ChangeLog

@@ -1,5 +1,20 @@
 2003-03-27  Ulrich Drepper  <drepper@redhat.com>
 
+	* sysdeps/unix/sysv/linux/kernel-posix-timers.h: Don't declare
+	__timer_helper_thread.  Declare __start_helper_thread, __helper_once,
+	and __helper_tid.
+	(struct timer): Remove th and bar field.
+	* sysdeps/unix/sysv/linux/timer_create.c (timer_create): Remove
+	debugging code.  Create only one helper thread.
+	* sysdeps/unix/sysv/linux/timer_delete.c (timer_delete): Don't kill
+	helper thread.
+	* sysdeps/unix/sysv/linux/timer_routines.c (timer_helper_thread):
+	Renamed.  Define statically.  Use thread info from siginfo.
+	(__helper_once): New variable.
+	(__helper_tid): New variable.
+	(__reset_helper_control): New function.
+	(__start_helper_thread): New function.
+
 	* pthread_create.c (start_thread): Don't use setjmp inside
 	__builtin_expect to work around gcc bug.
 

nptl/sysdeps/unix/sysv/linux/timer_create.c

@@ -26,6 +26,7 @@
 #include <sysdep.h>
 #include <kernel-features.h>
 #include <internaltypes.h>
+#include <nptl/pthreadP.h>
 #include "kernel-posix-timers.h"
 
 
@@ -138,12 +139,16 @@ timer_create (clock_id, evp, timerid)
 	  if (__no_posix_timers > 0)
 # endif
 	    {
-		  sigset_t ss;
-		  sigemptyset (&ss);
-		  sigaddset (&ss, TIMER_SIG);
-		  pthread_sigmask (SIG_BLOCK, &ss, NULL);
-	      struct timer *newp;
+	      /* Create the helper thread.  */
+	      pthread_once (&__helper_once, __start_helper_thread);
+	      if (__helper_tid == 0)
+		{
+		  /* No resources to start the helper thread.  */
+		  __set_errno (EAGAIN);
+		  return -1;
+		}
 
+	      struct timer *newp;
 	      newp = (struct timer *) malloc (sizeof (struct timer));
 	      if (newp == NULL)
 		return -1;
@@ -176,57 +181,29 @@ timer_create (clock_id, evp, timerid)
 	      (void) pthread_attr_setdetachstate (&newp->attr,
 						  PTHREAD_CREATE_DETACHED);
 
-	      /* Set up the barrier for sychronization.  */
-	      (void) pthread_barrier_init (&newp->bar, NULL, 2);
-
-	      /* The helper thread needs only very little resources
-		 and should go away automatically when canceled.  */
-	      pthread_attr_t attr;
-	      (void) pthread_attr_init (&attr);
-	      (void) pthread_attr_setdetachstate (&attr,
-						  PTHREAD_CREATE_DETACHED);
-	      (void) pthread_attr_setstacksize (&attr, PTHREAD_STACK_MIN);
-
-	      /* Create the helper thread for this timer.  */
-	      int res = pthread_create (&newp->th, &attr,
-					__timer_helper_thread, newp);
-	      if (res != 0)
-		goto err_out;
-
-	      /* No need for the attribute anymore.  */
-	      (void) pthread_attr_destroy (&attr);
-
 	      /* Create the event structure for the kernel timer.  */
 	      struct sigevent sev;
 	      sev.sigev_value.sival_ptr = newp;
-	      sev.sigev_signo = TIMER_SIG;
+	      sev.sigev_signo = SIGTIMER;
 	      sev.sigev_notify = SIGEV_SIGNAL | SIGEV_THREAD_ID;
 	      /* This is the thread ID of the helper thread.  */
-	      sev._sigev_un._pad[0] = ((struct pthread *) newp->th)->tid;
-
-	      /* Wait until the helper thread is set up.  */
-	      (void) pthread_barrier_wait (&newp->bar);
-
-	      /* No need for the barrier anymore.  */
-	      (void) pthread_barrier_destroy (&newp->bar);
+	      sev._sigev_un._pad[0] = __helper_tid;
 
 	      /* Create the timer.  */
 	      INTERNAL_SYSCALL_DECL (err);
-	      res = INTERNAL_SYSCALL (timer_create, err, 3, clock_id, &sev,
-				      &newp->ktimerid);
+	      int res = INTERNAL_SYSCALL (timer_create, err, 3, clock_id, &sev,
+					  &newp->ktimerid);
 	      if (! INTERNAL_SYSCALL_ERROR_P (res, err))
 		{
 		  *timerid = (timer_t) newp;
 		  return 0;
 		}
 
-	      /* Something went wrong.  Kill the thread.  */
-	      pthread_cancel (newp->th);
 	      /* Free the resources.  */
-	      res = INTERNAL_SYSCALL_ERRNO (res, err);
-	    err_out:
 	      free (newp);
-	      __set_errno (res);
+
+	      __set_errno (INTERNAL_SYSCALL_ERRNO (res, err));
+
 	      return -1;
 	    }
 	}

nptl/sysdeps/unix/sysv/linux/timer_delete.c

@@ -58,10 +58,6 @@ timer_delete (timerid)
 	  __no_posix_timers = 1;
 # endif
 
-	  /* We have to get rid of the helper thread if we created one.  */
-	  if (kt->sigev_notify == SIGEV_THREAD)
-	    (void) pthread_cancel (kt->th);
-
 	  /* Free the memory.  */
 	  (void) free (kt);
 

nptl/sysdeps/unix/sysv/linux/timer_routines.c

@@ -22,6 +22,7 @@
 #include <stdbool.h>
 #include <sysdep.h>
 #include <kernel-features.h>
+#include <nptl/pthreadP.h>
 #include "kernel-posix-timers.h"
 
 
@@ -40,24 +41,14 @@ timer_sigev_thread (void *arg)
 
 
 /* Helper function to support starting threads for SIGEV_THREAD.  */
-void *
-attribute_hidden
-__timer_helper_thread (void *arg)
+static void *
+timer_helper_thread (void *arg)
 {
-  /* Block all signals.  */
+  /* Block all signals.  We will only wait for the signal the kernel
+     will send.  */
   sigset_t ss;
-
-  sigfillset (&ss);
-  (void) pthread_sigmask (SIG_BLOCK, &ss, NULL);
-
-  struct timer *tk = (struct timer *) arg;
-
-  /* Synchronize with the parent.  */
-  (void) pthread_barrier_wait (&tk->bar);
-
-  /* We will only wait for the signal the kernel will send.  */
   sigemptyset (&ss);
-  sigaddset (&ss, TIMER_SIG);
+  sigaddset (&ss, SIGTIMER);
 
   /* Endless loop of waiting for signals.  The loop is only ended when
      the thread is canceled.  */
@@ -65,15 +56,60 @@ __timer_helper_thread (void *arg)
     {
       siginfo_t si;
 
-      if (sigwaitinfo (&ss, &si) > 0 && si.si_timerid == tk->ktimerid)
+      if (sigwaitinfo (&ss, &si) > 0 && si.si_code == SI_TIMER)
 	{
+
+	  struct timer *tk = (struct timer *) si.si_ptr;
+
 	  /* That the signal we are waiting for.  */
 	  pthread_t th;
-	  (void) pthread_create (&th, &tk->attr, timer_sigev_thread, arg);
+	  (void) pthread_create (&th, &tk->attr, timer_sigev_thread, tk);
 	}
     }
 }
 
+
+/* Control variable for helper thread creation.  */
+pthread_once_t __helper_once attribute_hidden;
+
+
+/* TID of the helper thread.  */
+pid_t __helper_tid attribute_hidden;
+
+
+/* Reset variables so that after a fork a new helper thread gets started.  */
+static void
+reset_helper_control (void)
+{
+  __helper_once = PTHREAD_ONCE_INIT;
+  __helper_tid = 0;
+}
+
+
+void
+attribute_hidden
+__start_helper_thread (void)
+{
+  /* The helper thread needs only very little resources
+     and should go away automatically when canceled.  */
+  pthread_attr_t attr;
+  (void) pthread_attr_init (&attr);
+  (void) pthread_attr_setstacksize (&attr, PTHREAD_STACK_MIN);
+
+  /* Create the helper thread for this timer.  */
+  pthread_t th;
+  int res = pthread_create (&th, &attr, timer_helper_thread, NULL);
+  if (res == 0)
+    /* We managed to start the helper thread.  */
+    __helper_tid = ((struct pthread *) th)->tid;
+
+  /* No need for the attribute anymore.  */
+  (void) pthread_attr_destroy (&attr);
+
+  /* We have to make sure that after fork()ing a new helper thread can
+     be created.  */
+  pthread_atfork (NULL, NULL, reset_helper_control);
+}
 #endif
 
 #ifndef __ASSUME_POSIX_TIMERS