Fix bookkeeping in mutex when using requeue_pi.

git-mirror · Jul 28, 2009 · b0948ff · b0948ff
1 parent e73e694
commit b0948ff
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Showing 9 changed files with 83 additions and 24 deletions.
diff --git a/nptl/ChangeLog b/nptl/ChangeLog
@@ -1,3 +1,20 @@
+2009-07-28  Ulrich Drepper  <drepper@redhat.com>
+
+	* pthread_mutex_lock.c [NO_INCR] (__pthread_mutex_cond_lock_adjust):
+	New function.
+	* pthreadP.h: Declare __pthread_mutex_cond_lock_adjust.
+	* sysdeps/unix/sysv/linux/pthread-pi-defines.sym: Add ROBUST_BIT.
+	* sysdeps/unix/sysv/linux/x86_64/pthread_cond_broadcast.S: Don't use
+	requeue_pi for robust mutexes.
+	* sysdeps/unix/sysv/linux/x86_64/pthread_cond_signal.S: Likewise.
+	* sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S: Likewise.
+	Don't only skip __pthread_mutex_cond_lock.  Call instead
+	__pthread_mutex_cond_lock_adjust.
+	* sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S: Likewise.
+
+	* pthread_mutex_unlock.c (__pthread_mutex_unlock_full): Minor
+	optimization of PI mutex handling.
+
 2009-07-27  Ulrich Drepper  <drepper@redhat.com>
 
 	[BZ #10418]

diff --git a/nptl/pthreadP.h b/nptl/pthreadP.h
@@ -418,6 +418,8 @@ extern int __pthread_mutex_lock_internal (pthread_mutex_t *__mutex)
      attribute_hidden;
 extern int __pthread_mutex_cond_lock (pthread_mutex_t *__mutex)
      attribute_hidden internal_function;
+extern void __pthread_mutex_cond_lock_adjust (pthread_mutex_t *__mutex)
+     attribute_hidden internal_function;
 extern int __pthread_mutex_unlock (pthread_mutex_t *__mutex);
 extern int __pthread_mutex_unlock_internal (pthread_mutex_t *__mutex)
      attribute_hidden;

diff --git a/nptl/pthread_mutex_lock.c b/nptl/pthread_mutex_lock.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2002-2007, 2008 Free Software Foundation, Inc.
+/* Copyright (C) 2002-2007, 2008, 2009 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
 
@@ -473,3 +473,22 @@ __pthread_mutex_lock_full (pthread_mutex_t *mutex)
 strong_alias (__pthread_mutex_lock, pthread_mutex_lock)
 strong_alias (__pthread_mutex_lock, __pthread_mutex_lock_internal)
 #endif
+
+
+#ifdef NO_INCR
+void
+__pthread_mutex_cond_lock_adjust (mutex)
+     pthread_mutex_t *mutex;
+{
+  assert ((mutex->__data.__kind & PTHREAD_MUTEX_PRIO_INHERIT_NP) != 0);
+  assert ((mutex->__data.__kind & PTHREAD_MUTEX_ROBUST_NORMAL_NP) == 0);
+  assert ((mutex->__data.__kind & PTHREAD_MUTEX_PSHARED_BIT) == 0);
+
+  /* Record the ownership.  */
+  pid_t id = THREAD_GETMEM (THREAD_SELF, tid);
+  mutex->__data.__owner = id;
+
+  if (mutex->__data.__kind == PTHREAD_MUTEX_PI_RECURSIVE_NP)
+    ++mutex->__data.__count;
+}
+#endif
diff --git a/nptl/pthread_mutex_unlock.c b/nptl/pthread_mutex_unlock.c
@@ -150,7 +150,7 @@ __pthread_mutex_unlock_full (pthread_mutex_t *mutex, int decr)
       if (--mutex->__data.__count != 0)
 	/* We still hold the mutex.  */
 	return 0;
-      goto continue_pi;
+      goto continue_pi_non_robust;
 
     case PTHREAD_MUTEX_PI_ROBUST_RECURSIVE_NP:
       /* Recursive mutex.  */
@@ -173,7 +173,7 @@ __pthread_mutex_unlock_full (pthread_mutex_t *mutex, int decr)
 	/* We still hold the mutex.  */
 	return 0;
 
-      goto continue_pi;
+      goto continue_pi_robust;
 
     case PTHREAD_MUTEX_PI_ERRORCHECK_NP:
     case PTHREAD_MUTEX_PI_NORMAL_NP:
@@ -195,9 +195,9 @@ __pthread_mutex_unlock_full (pthread_mutex_t *mutex, int decr)
       pi_notrecoverable:
        newowner = PTHREAD_MUTEX_NOTRECOVERABLE;
 
-    continue_pi:
       if ((mutex->__data.__kind & PTHREAD_MUTEX_ROBUST_NORMAL_NP) != 0)
 	{
+	continue_pi_robust:
 	  /* Remove mutex from the list.
 	     Note: robust PI futexes are signaled by setting bit 0.  */
 	  THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending,
@@ -206,6 +206,7 @@ __pthread_mutex_unlock_full (pthread_mutex_t *mutex, int decr)
 	  DEQUEUE_MUTEX (mutex);
 	}
 
+    continue_pi_non_robust:
       mutex->__data.__owner = newowner;
       if (decr)
 	/* One less user.  */

diff --git a/nptl/sysdeps/unix/sysv/linux/pthread-pi-defines.sym b/nptl/sysdeps/unix/sysv/linux/pthread-pi-defines.sym
@@ -3,5 +3,6 @@
 -- These PI macros are used by assembly code.
 
 MUTEX_KIND	offsetof (pthread_mutex_t, __data.__kind)
+ROBUST_BIT	PTHREAD_MUTEX_ROBUST_NORMAL_NP
 PI_BIT		PTHREAD_MUTEX_PRIO_INHERIT_NP
 PS_BIT		PTHREAD_MUTEX_PSHARED_BIT
diff --git a/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_broadcast.S b/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_broadcast.S
@@ -75,8 +75,10 @@ __pthread_cond_broadcast:
 	jne	9f
 
 	/* Requeue to a PI mutex if the PI bit is set.  */
-	testl	$PI_BIT, MUTEX_KIND(%r8)
-	jne	81f
+	movl	MUTEX_KIND(%r8), %eax
+	andl	$(ROBUST_BIT|PI_BIT), %eax
+	cmpl	$PI_BIT, %eax
+	je	81f
 
 	/* Wake up all threads.  */
 #ifdef __ASSUME_PRIVATE_FUTEX

diff --git a/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_signal.S b/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_signal.S
@@ -64,8 +64,10 @@ __pthread_cond_signal:
 
 	/* Get the address of the mutex used.  */
 	movq    dep_mutex(%r8), %rcx
-	testl	$PI_BIT, MUTEX_KIND(%rcx)
-	jne	9f
+	movl	MUTEX_KIND(%rcx), %eax
+	andl	$(ROBUST_BIT|PI_BIT), %eax
+	cmpl	$PI_BIT, %eax
+	je	9f
 
 #ifdef __ASSUME_PRIVATE_FUTEX
 	movl	$(FUTEX_WAKE_OP|FUTEX_PRIVATE_FLAG), %esi

diff --git a/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S b/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S
@@ -165,9 +165,12 @@ __pthread_cond_timedwait:
 	je	60f
 
 	movq	dep_mutex(%rdi), %r8
-	/* Requeue to a PI mutex if the PI bit is set.  */
-	testl	$PI_BIT, MUTEX_KIND(%r8)
-	je	61f
+	/* Requeue to a non-robust PI mutex if the PI bit is set and
+	the robust bit is not set.  */
+	movl	MUTEX_KIND(%r8), %eax
+	andl	$(ROBUST_BIT|PI_BIT), %eax
+	cmpl	$PI_BIT, %eax
+	jne	61f
 
 	movl	$(FUTEX_WAIT_REQUEUE_PI|FUTEX_PRIVATE_FLAG), %esi
 	xorl	%eax, %eax
@@ -289,11 +292,10 @@ __pthread_cond_timedwait:
 
 	/* If requeue_pi is used the kernel performs the locking of the
 	   mutex. */
-41:	xorl	%eax, %eax
+41:	movq	16(%rsp), %rdi
 	testl	%r15d, %r15d
-	jnz	63f
+	jnz	64f
 
-	movq	16(%rsp), %rdi
 	callq	__pthread_mutex_cond_lock
 
 63:	testq	%rax, %rax
@@ -316,12 +318,18 @@ __pthread_cond_timedwait:
 
 	retq
 
-	/* Initial locking failed.  */
-31:	cfi_adjust_cfa_offset(4 * 8 + FRAME_SIZE)
+	cfi_adjust_cfa_offset(4 * 8 + FRAME_SIZE)
 	cfi_rel_offset(%r12, FRAME_SIZE + 24)
 	cfi_rel_offset(%r13, FRAME_SIZE + 16)
 	cfi_rel_offset(%r14, FRAME_SIZE + 8)
 	cfi_rel_offset(%r15, FRAME_SIZE)
+
+64:	callq	__pthread_mutex_cond_lock_adjust
+	movq	%r14, %rax
+	jmp	48b
+
+	/* Initial locking failed.  */
+31:
 #if cond_lock != 0
 	addq	$cond_lock, %rdi
 #endif

diff --git a/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S b/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S
@@ -134,9 +134,12 @@ __pthread_cond_wait:
 	je	60f
 
 	movq	dep_mutex-cond_futex(%rdi), %r8
-	/* Requeue to a PI mutex if the PI bit is set.  */
-	testl	$PI_BIT, MUTEX_KIND(%r8)
-	je	61f
+	/* Requeue to a non-robust PI mutex if the PI bit is set and
+	the robust bit is not set.  */
+	movl	MUTEX_KIND(%r8), %eax
+	andl	$(ROBUST_BIT|PI_BIT), %eax
+	cmpl	$PI_BIT, %eax
+	jne	61f
 
 	movl	$(FUTEX_WAIT_REQUEUE_PI|FUTEX_PRIVATE_FLAG), %esi
 	movl	$SYS_futex, %eax
@@ -234,11 +237,10 @@ __pthread_cond_wait:
 
 	/* If requeue_pi is used the kernel performs the locking of the
 	   mutex. */
-11:	xorl	%eax, %eax
+11:	movq	16(%rsp), %rdi
 	testl	%r13d, %r13d
-	jnz	14f
+	jnz	18f
 
-	movq	16(%rsp), %rdi
 	callq	__pthread_mutex_cond_lock
 
 14:	addq	$FRAME_SIZE, %rsp
@@ -254,11 +256,16 @@ __pthread_cond_wait:
 	/* We return the result of the mutex_lock operation.  */
 	retq
 
-	/* Initial locking failed.  */
-1:
 	cfi_adjust_cfa_offset(16 + FRAME_SIZE)
 	cfi_rel_offset(%r12, FRAME_SIZE + 8)
 	cfi_rel_offset(%r13, FRAME_SIZE)
+
+18:	callq	__pthread_mutex_cond_lock_adjust
+	xorl	%eax, %eax
+	jmp	14b
+
+	/* Initial locking failed.  */
+1:
 #if cond_lock != 0
 	addq	$cond_lock, %rdi
 #endif