From 8578bdf835d6d6ece6718858d351456367b8a5cf Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Tue, 26 Sep 2006 10:52:32 +0200 Subject: [PATCH] [PATCH] Don't use lock section for mutexes and semaphores Lock sections cannot be handled by the dwarf2 unwinder. Disadvantage is a taken branch in the hot path. Signed-off-by: Andi Kleen --- include/asm-x86_64/mutex.h | 20 +++++------------ include/asm-x86_64/semaphore.h | 40 ++++++++++++---------------------- include/asm-x86_64/spinlock.h | 9 ++++---- 3 files changed, 24 insertions(+), 45 deletions(-) diff --git a/include/asm-x86_64/mutex.h b/include/asm-x86_64/mutex.h index 06fab6de2a88..16396b1de3e4 100644 --- a/include/asm-x86_64/mutex.h +++ b/include/asm-x86_64/mutex.h @@ -25,13 +25,9 @@ do { \ \ __asm__ __volatile__( \ LOCK_PREFIX " decl (%%rdi) \n" \ - " js 2f \n" \ - "1: \n" \ - \ - LOCK_SECTION_START("") \ - "2: call "#fail_fn" \n" \ - " jmp 1b \n" \ - LOCK_SECTION_END \ + " jns 1f \n" \ + " call "#fail_fn" \n" \ + "1:" \ \ :"=D" (dummy) \ : "D" (v) \ @@ -75,13 +71,9 @@ do { \ \ __asm__ __volatile__( \ LOCK_PREFIX " incl (%%rdi) \n" \ - " jle 2f \n" \ - "1: \n" \ - \ - LOCK_SECTION_START("") \ - "2: call "#fail_fn" \n" \ - " jmp 1b \n" \ - LOCK_SECTION_END \ + " jg 1f \n" \ + " call "#fail_fn" \n" \ + "1: " \ \ :"=D" (dummy) \ : "D" (v) \ diff --git a/include/asm-x86_64/semaphore.h b/include/asm-x86_64/semaphore.h index 064df08b9a0f..107bd90429e8 100644 --- a/include/asm-x86_64/semaphore.h +++ b/include/asm-x86_64/semaphore.h @@ -107,12 +107,9 @@ static inline void down(struct semaphore * sem) __asm__ __volatile__( "# atomic down operation\n\t" LOCK_PREFIX "decl %0\n\t" /* --sem->count */ - "js 2f\n" - "1:\n" - LOCK_SECTION_START("") - "2:\tcall __down_failed\n\t" - "jmp 1b\n" - LOCK_SECTION_END + "jns 1f\n\t" + "call __down_failed\n" + "1:" :"=m" (sem->count) :"D" (sem) :"memory"); @@ -130,14 +127,11 @@ static inline int down_interruptible(struct semaphore * sem) __asm__ __volatile__( "# atomic interruptible down operation\n\t" + "xorl %0,%0\n\t" LOCK_PREFIX "decl %1\n\t" /* --sem->count */ - "js 2f\n\t" - "xorl %0,%0\n" - "1:\n" - LOCK_SECTION_START("") - "2:\tcall __down_failed_interruptible\n\t" - "jmp 1b\n" - LOCK_SECTION_END + "jns 2f\n\t" + "call __down_failed_interruptible\n" + "2:\n" :"=a" (result), "=m" (sem->count) :"D" (sem) :"memory"); @@ -154,14 +148,11 @@ static inline int down_trylock(struct semaphore * sem) __asm__ __volatile__( "# atomic interruptible down operation\n\t" + "xorl %0,%0\n\t" LOCK_PREFIX "decl %1\n\t" /* --sem->count */ - "js 2f\n\t" - "xorl %0,%0\n" - "1:\n" - LOCK_SECTION_START("") - "2:\tcall __down_failed_trylock\n\t" - "jmp 1b\n" - LOCK_SECTION_END + "jns 2f\n\t" + "call __down_failed_trylock\n\t" + "2:\n" :"=a" (result), "=m" (sem->count) :"D" (sem) :"memory","cc"); @@ -179,12 +170,9 @@ static inline void up(struct semaphore * sem) __asm__ __volatile__( "# atomic up operation\n\t" LOCK_PREFIX "incl %0\n\t" /* ++sem->count */ - "jle 2f\n" - "1:\n" - LOCK_SECTION_START("") - "2:\tcall __up_wakeup\n\t" - "jmp 1b\n" - LOCK_SECTION_END + "jg 1f\n\t" + "call __up_wakeup\n" + "1:" :"=m" (sem->count) :"D" (sem) :"memory"); diff --git a/include/asm-x86_64/spinlock.h b/include/asm-x86_64/spinlock.h index a8e3d89f591f..1d0733b38a4b 100644 --- a/include/asm-x86_64/spinlock.h +++ b/include/asm-x86_64/spinlock.h @@ -22,14 +22,13 @@ #define __raw_spin_lock_string \ "\n1:\t" \ LOCK_PREFIX " ; decl %0\n\t" \ - "js 2f\n" \ - LOCK_SECTION_START("") \ - "2:\t" \ + "jns 2f\n" \ + "3:\n" \ "rep;nop\n\t" \ "cmpl $0,%0\n\t" \ - "jle 2b\n\t" \ + "jle 3b\n\t" \ "jmp 1b\n" \ - LOCK_SECTION_END + "2:\t" \ #define __raw_spin_lock_string_up \ "\n\tdecl %0" -- GitLab