* init.c (__pthread_initialize_minimal_internal): Check whether

	private futexes are available.
	* allocatestack.c (allocate_stack): Copy private_futex field from
	current thread into the new stack.
	* sysdeps/unix/sysv/linux/x86_64/libc-lowlevellock.S: Use private
	futexes if they are available.
	* sysdeps/unix/sysv/linux/i386/i486/libc-lowlevellock.S: Likewise
	* sysdeps/unix/sysv/linux/x86_64/lowlevellock.S: Adjust so that change
	in libc-lowlevellock.S allow using private futexes.
	* sysdeps/unix/sysv/linux/i386/i486/lowlevellock.S: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/lowlevellock.h: Define
	FUTEX_PRIVATE_FLAG.
	* sysdeps/unix/sysv/linux/i386/lowlevellock.h: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/pthread_once.S: Use private futexes
	if they are available.
	* sysdeps/unix/sysv/linux/i386/pthread_once.S: Likewise.
	* sysdeps/x86_64/tcb-offsets.sym: Add PRIVATE_FUTEX.
	* sysdeps/i386/tcb-offsets.sym: Likewise.
	* sysdeps/x86_64/tls.h (tcbhead_t): Add private_futex field.
	* sysdeps/i386/tls.h (tcbhead_t): Likewise.

4 files changed, 64 insertions, 19 deletions

diff --git a/nptl/sysdeps/unix/sysv/linux/x86_64/libc-lowlevellock.S b/nptl/sysdeps/unix/sysv/linux/x86_64/libc-lowlevellock.S
index 3621efa4fc..21bf58cbbd 100644
--- a/nptl/sysdeps/unix/sysv/linux/x86_64/libc-lowlevellock.S
+++ b/nptl/sysdeps/unix/sysv/linux/x86_64/libc-lowlevellock.S
@@ -1,4 +1,4 @@
-/* Copyright (C) 2002, 2003 Free Software Foundation, Inc.
+/* Copyright (C) 2002, 2003, 2007 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
 
@@ -17,6 +17,8 @@
    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
    02111-1307 USA.  */
 
+#include <kernel-features.h>
+
 /* In libc.so we do not unconditionally use the lock prefix.  Only if
    the application is using threads.  */
 #ifndef UP
@@ -27,4 +29,17 @@
 0:
 #endif
 
+/* All locks in libc are private.  Use the kernel feature if possible.  */
+#define FUTEX_PRIVATE_FLAG	128
+#ifdef __ASSUME_PRIVATE_FUTEX
+# define FUTEX_WAIT		(0 | FUTEX_PRIVATE_FLAG)
+# define FUTEX_WAKE		(1 | FUTEX_PRIVATE_FLAG)
+#else
+# define LOAD_FUTEX_WAIT(reg) \
+	movl	%fs:PRIVATE_FUTEX, reg
+# define LOAD_FUTEX_WAKE(reg) \
+	movl	%fs:PRIVATE_FUTEX, reg ; \
+	orl	$FUTEX_WAKE, reg
+#endif
+
 #include "lowlevellock.S"
diff --git a/nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S b/nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S
index 6724ded762..de70b1852c 100644
--- a/nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S
+++ b/nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S
@@ -31,8 +31,23 @@
 #endif
 
 #define SYS_futex		202
-#define FUTEX_WAIT		0
-#define FUTEX_WAKE		1
+#ifndef FUTEX_WAIT
+# define FUTEX_WAIT		0
+# define FUTEX_WAKE		1
+#endif
+
+#ifndef LOAD_FUTEX_WAIT
+# if FUTEX_WAIT == 0
+#  define LOAD_FUTEX_WAIT(reg) \
+	xorl	reg, reg
+# else
+#  define LOAD_FUTEX_WAIT(reg) \
+	movl	$FUTEX_WAIT, reg
+# endif
+# define LOAD_FUTEX_WAKE(reg) \
+	movl	$FUTEX_WAKE, reg
+#endif
+
 
 /* For the calculation see asm/vsyscall.h.  */
 #define VSYSCALL_ADDR_vgettimeofday	0xffffffffff600000
@@ -52,11 +67,7 @@ __lll_mutex_lock_wait:
 	cfi_offset(%rdx, -24)
 	xorq	%r10, %r10	/* No timeout.  */
 	movl	$2, %edx
-#if FUTEX_WAIT == 0
-	xorl	%esi, %esi
-#else
-	movl	$FUTEX_WAIT, %esi
-#endif
+	LOAD_FUTEX_WAIT (%esi)
 
 	cmpl	%edx, %eax	/* NB:	 %edx == 2 */
 	jne	2f
@@ -151,11 +162,7 @@ __lll_mutex_timedlock_wait:
 	je	8f
 
 	movq	%rsp, %r10
-#if FUTEX_WAIT == 0
-	xorl	%esi, %esi
-#else
-	movl	$FUTEX_WAIT, %esi
-#endif
+	LOAD_FUTEX_WAIT (%esi)
 	movq	%r12, %rdi
 	movl	$SYS_futex, %eax
 	syscall
@@ -247,7 +254,7 @@ __lll_mutex_unlock_wake:
 	cfi_offset(%rdx, -24)
 
 	movl	$0, (%rdi)
-	movl	$FUTEX_WAKE, %esi
+	LOAD_FUTEX_WAKE (%esi)
 	movl	$1, %edx	/* Wake one thread.  */
 	movl	$SYS_futex, %eax
 	syscall
@@ -311,6 +318,8 @@ __lll_timedwait_tid:
 	jz	4f
 
 	movq	%rsp, %r10
+	/* XXX The kernel so far uses global futex for the wakeup at
+	   all times.  */
 #if FUTEX_WAIT == 0
 	xorl	%esi, %esi
 #else
diff --git a/nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.h b/nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.h
index bb988f3b2b..fbe48b37aa 100644
--- a/nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.h
+++ b/nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.h
@@ -39,6 +39,7 @@
 #define FUTEX_LOCK_PI		6
 #define FUTEX_UNLOCK_PI		7
 #define FUTEX_TRYLOCK_PI	8
+#define FUTEX_PRIVATE_FLAG	128
 
 
 /* Initializer for compatibility lock.  */
diff --git a/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_once.S b/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_once.S
index 9db5516913..7740c599d1 100644
--- a/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_once.S
+++ b/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_once.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.
 
@@ -17,14 +17,19 @@
    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
    02111-1307 USA.  */
 
+#include <kernel-features.h>
+#include <tcb-offsets.h>
+
 #ifndef UP
 # define LOCK lock
 #else
 # define LOCK
 #endif
 
-#define SYS_futex	202
-#define FUTEX_WAKE	1
+#define SYS_futex		202
+#define FUTEX_WAIT		0
+#define FUTEX_WAKE		1
+#define FUTEX_PRIVATE_FLAG	128
 
 	.comm	__fork_generation, 4, 4
 
@@ -74,10 +79,15 @@ __pthread_once:
 	jnz	3f	/* Different for generation -> run initializer.  */
 
 	/* Somebody else got here first.  Wait.  */
-#if FUTEX_WAIT == 0
-	xorl	%esi, %esi
+#ifdef __ASSUME_PRIVATE_FUTEX
+	movl	$FUTEX_WAIT|FUTEX_PRIVATE_FLAG, %esi
 #else
+# if FUTEX_WAIT == 0
+	movl	%fs:PRIVATE_FUTEX, %esi
+# else
 	movl	$FUTEX_WAIT, %esi
+	orl	%fs:PRIVATE_FUTEX, %esi
+# endif
 #endif
 	movl	$SYS_futex, %eax
 	syscall
@@ -106,7 +116,12 @@ __pthread_once:
 
 	/* Wake up all other threads.  */
 	movl	$0x7fffffff, %edx
+#ifdef __ASSUME_PRIVATE_FUTEX
+	movl	$FUTEX_WAKE|FUTEX_PRIVATE_FLAG, %esi
+#else
 	movl	$FUTEX_WAKE, %esi
+	orl	%fs:PRIVATE_FUTEX, %esi
+#endif
 	movl	$SYS_futex, %eax
 	syscall
 
@@ -133,7 +148,12 @@ clear_once_control:
 	movl	$0, (%rdi)
 
 	movl	$0x7fffffff, %edx
+#ifdef __ASSUME_PRIVATE_FUTEX
+	movl	$FUTEX_WAKE|FUTEX_PRIVATE_FLAG, %esi
+#else
 	movl	$FUTEX_WAKE, %esi
+	orl	%fs:PRIVATE_FUTEX, %esi
+#endif
 	movl	$SYS_futex, %eax
 	syscall