* sysdeps/unix/sysv/linux/sem_post.c: Only wake threads if old

value of semaphore was zero. * sysdeps/unix/sysv/linux/i386/i486/sem_post.S: Likewise. * sysdeps/unix/sysv/linux/powerpc/sem_post.c: Likewise. * sysdeps/unix/sysv/linux/sparc/sparc32/sem_post.c: Likewise. * sysdeps/unix/sysv/linux/x86_64/sem_post.S: Likewise. * sysdeps/unix/sysv/linux/x86_64/sem_wait.S: Remove unnecessary extra cancellation test. * sysdeps/unix/sysv/linux/x86_64/sem_timedwait.S: Likewise.
git-mirror · May 15, 2007 · 83d8791 · 83d8791
1 parent 1d47e92
commit 83d8791
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diff --git a/nptl/ChangeLog b/nptl/ChangeLog
@@ -1,3 +1,16 @@
+2007-05-14  Ulrich Drepper  <drepper@redhat.com>
+
+	* sysdeps/unix/sysv/linux/sem_post.c: Only wake threads if old
+	value of semaphore was zero.
+	* sysdeps/unix/sysv/linux/i386/i486/sem_post.S: Likewise.
+	* sysdeps/unix/sysv/linux/powerpc/sem_post.c: Likewise.
+	* sysdeps/unix/sysv/linux/sparc/sparc32/sem_post.c: Likewise.
+	* sysdeps/unix/sysv/linux/x86_64/sem_post.S: Likewise.
+
+	* sysdeps/unix/sysv/linux/x86_64/sem_wait.S: Remove unnecessary
+	extra cancellation test.
+	* sysdeps/unix/sysv/linux/x86_64/sem_timedwait.S: Likewise.
+
 2007-05-10  Ulrich Drepper  <drepper@redhat.com>
 
 	* descr.h (struct pthread): Rearrange members to fill hole in

diff --git a/nptl/sysdeps/unix/sysv/linux/i386/i486/sem_post.S b/nptl/sysdeps/unix/sysv/linux/i386/i486/sem_post.S
@@ -1,4 +1,4 @@
-/* Copyright (C) 2002, 2003, 2005 Free Software Foundation, Inc.
+/* Copyright (C) 2002, 2003, 2005, 2007 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
 
@@ -44,9 +44,12 @@ __new_sem_post:
 	LOCK
 	xaddl	%edx, (%ebx)
 
+	testl	%edx, %edx
+	jne	2f
+
 	movl	$SYS_futex, %eax
 	movl	$FUTEX_WAKE, %ecx
-	addl	$1, %edx
+	movl	$1, %edx
 	ENTER_KERNEL
 
 	testl	%eax, %eax

diff --git a/nptl/sysdeps/unix/sysv/linux/powerpc/sem_post.c b/nptl/sysdeps/unix/sysv/linux/powerpc/sem_post.c
@@ -1,5 +1,5 @@
 /* sem_post -- post to a POSIX semaphore.  Powerpc version.
-   Copyright (C) 2003, 2004 Free Software Foundation, Inc.
+   Copyright (C) 2003, 2004, 2007 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Paul Mackerras <paulus@au.ibm.com>, 2003.
 
@@ -32,12 +32,14 @@ __new_sem_post (sem_t *sem)
   int *futex = (int *) sem;
 
   __asm __volatile (__lll_rel_instr ::: "memory");
-  int nr = atomic_increment_val (futex);
-  int err = lll_futex_wake (futex, nr);
-  if (__builtin_expect (err, 0) < 0)
+  if (atomic_increment_val (futex) == 1)
     {
-      __set_errno (-err);
-      return -1;
+      int err = lll_futex_wake (futex, 1);
+      if (__builtin_expect (err, 0) < 0)
+	{
+	  __set_errno (-err);
+	  return -1;
+	}
     }
   return 0;
 }

diff --git a/nptl/sysdeps/unix/sysv/linux/sem_post.c b/nptl/sysdeps/unix/sysv/linux/sem_post.c
@@ -1,5 +1,5 @@
 /* sem_post -- post to a POSIX semaphore.  Generic futex-using version.
-   Copyright (C) 2003, 2004 Free Software Foundation, Inc.
+   Copyright (C) 2003, 2004, 2007 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Jakub Jelinek <jakub@redhat.com>, 2003.
 
@@ -31,12 +31,14 @@ __new_sem_post (sem_t *sem)
 {
   int *futex = (int *) sem;
 
-  int nr = atomic_increment_val (futex);
-  int err = lll_futex_wake (futex, nr);
-  if (__builtin_expect (err, 0) < 0)
+  if (atomic_increment_val (futex) == 1)
     {
-      __set_errno (-err);
-      return -1;
+      int err = lll_futex_wake (futex, 1);
+      if (__builtin_expect (err, 0) < 0)
+	{
+	  __set_errno (-err);
+	  return -1;
+	}
     }
   return 0;
 }

diff --git a/nptl/sysdeps/unix/sysv/linux/sparc/sparc32/sem_post.c b/nptl/sysdeps/unix/sysv/linux/sparc/sparc32/sem_post.c
@@ -1,5 +1,5 @@
 /* sem_post -- post to a POSIX semaphore.  SPARC version.
-   Copyright (C) 2003, 2004, 2006 Free Software Foundation, Inc.
+   Copyright (C) 2003, 2004, 2006, 2007 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Jakub Jelinek <jakub@redhat.com>, 2003.
 
@@ -39,11 +39,14 @@ __new_sem_post (sem_t *sem)
       nr = ++*futex;
       __sparc32_atomic_do_unlock24 (futex + 1);
     }
-  int err = lll_futex_wake (futex, nr);
-  if (__builtin_expect (err, 0) < 0)
+  if (nr == 1)
     {
-      __set_errno (-err);
-      return -1;
+      int err = lll_futex_wake (futex, 1);
+      if (__builtin_expect (err, 0) < 0)
+	{
+	  __set_errno (-err);
+	  return -1;
+	}
     }
   return 0;
 }

diff --git a/nptl/sysdeps/unix/sysv/linux/x86_64/sem_post.S b/nptl/sysdeps/unix/sysv/linux/x86_64/sem_post.S
@@ -1,4 +1,4 @@
-/* Copyright (C) 2002, 2003, 2005 Free Software Foundation, Inc.
+/* Copyright (C) 2002, 2003, 2005, 2007 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
 
@@ -41,15 +41,18 @@ sem_post:
 	LOCK
 	xaddl	%edx, (%rdi)
 
+	testl	%edx, %edx
+	jne	2f
+
 	movl	$SYS_futex, %eax
 	movl	$FUTEX_WAKE, %esi
-	incl	%edx
+	movl	$1, %edx
 	syscall
 
 	testq	%rax, %rax
 	js	1f
 
-	xorl	%eax, %eax
+2:	xorl	%eax, %eax
 	retq
 
 1:

diff --git a/nptl/sysdeps/unix/sysv/linux/x86_64/sem_timedwait.S b/nptl/sysdeps/unix/sysv/linux/x86_64/sem_timedwait.S
@@ -1,4 +1,4 @@
-/* Copyright (C) 2002, 2003, 2005 Free Software Foundation, Inc.
+/* Copyright (C) 2002, 2003, 2005, 2007 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
 
@@ -40,12 +40,6 @@
 	.align	16
 	cfi_startproc
 sem_timedwait:
-	/* First check for cancellation.  */
-	movl	%fs:CANCELHANDLING, %eax
-	andl	$0xfffffff9, %eax
-	cmpl	$8, %eax
-	je	11f
-
 	movl	(%rdi), %eax
 2:	testl	%eax, %eax
 	je	1f
@@ -160,16 +154,5 @@ sem_timedwait:
 
 	orl	$-1, %eax
 	jmp	10b
-	cfi_adjust_cfa_offset(-48)
-	cfi_restore(14)
-	cfi_restore(13)
-	cfi_restore(12)
-
-11:	/* Canceled.  */
-	movq	$0xffffffffffffffff, %fs:RESULT
-	LOCK
-	orl	$0x10, %fs:CANCELHANDLING
-	movq	%fs:CLEANUP_JMP_BUF, %rdi
-	jmp	HIDDEN_JUMPTARGET (__pthread_unwind)
 	cfi_endproc
 	.size	sem_timedwait,.-sem_timedwait
diff --git a/nptl/sysdeps/unix/sysv/linux/x86_64/sem_wait.S b/nptl/sysdeps/unix/sysv/linux/x86_64/sem_wait.S
@@ -1,4 +1,4 @@
-/* Copyright (C) 2002, 2003, 2005 Free Software Foundation, Inc.
+/* Copyright (C) 2002, 2003, 2005, 2007 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
 
@@ -37,12 +37,6 @@
 	.align	16
 	cfi_startproc
 sem_wait:
-	/* First check for cancellation.  */
-	movl	%fs:CANCELHANDLING, %eax
-	andl	$0xfffffff9, %eax
-	cmpl	$8, %eax
-	je	4f
-
 	pushq	%r12
 	cfi_adjust_cfa_offset(8)
 	cfi_offset(12, -16)
@@ -109,12 +103,5 @@ sem_wait:
 	cfi_restore(12)
 
 	retq
-
-4:	/* Canceled.  */
-	movq	$0xffffffffffffffff, %fs:RESULT
-	LOCK
-	orl	$0x10, %fs:CANCELHANDLING
-	movq	%fs:CLEANUP_JMP_BUF, %rdi
-	jmp	HIDDEN_JUMPTARGET (__pthread_unwind)
 	cfi_endproc
 	.size	sem_wait,.-sem_wait