Home Home > GIT Browse > stable
summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorDavidlohr Bueso <dbueso@suse.de>2016-06-14 10:06:02 -0700
committerDavidlohr Bueso <dbueso@suse.de>2016-06-14 10:06:02 -0700
commit3b7e0ff02020f27fa5eb64b660176d743683bcba (patch)
treefd1aa251bc86454f74143a371c624f4814a8f134
parentda86a8061b12abee065f9f880c5fcf5edad3b2a2 (diff)
locking/mutex: Optimize mutex_trylock() fast-path (bsc#969756).rpm-4.4.13-46
-rw-r--r--arch/ia64/include/asm/mutex.h2
-rw-r--r--arch/powerpc/include/asm/mutex.h2
-rw-r--r--arch/x86/include/asm/mutex_32.h2
-rw-r--r--arch/x86/include/asm/mutex_64.h6
-rw-r--r--include/asm-generic/mutex-dec.h2
-rw-r--r--include/asm-generic/mutex-xchg.h6
6 files changed, 12 insertions, 8 deletions
diff --git a/arch/ia64/include/asm/mutex.h b/arch/ia64/include/asm/mutex.h
index f41e66d65e31..28cb819e0ff9 100644
--- a/arch/ia64/include/asm/mutex.h
+++ b/arch/ia64/include/asm/mutex.h
@@ -82,7 +82,7 @@ __mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *))
static inline int
__mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *))
{
- if (cmpxchg_acq(count, 1, 0) == 1)
+ if (atomic_read(count) == 1 && cmpxchg_acq(count, 1, 0) == 1)
return 1;
return 0;
}
diff --git a/arch/powerpc/include/asm/mutex.h b/arch/powerpc/include/asm/mutex.h
index 127ab23e1f6c..078155fa1189 100644
--- a/arch/powerpc/include/asm/mutex.h
+++ b/arch/powerpc/include/asm/mutex.h
@@ -124,7 +124,7 @@ __mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *))
static inline int
__mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *))
{
- if (likely(__mutex_cmpxchg_lock(count, 1, 0) == 1))
+ if (likely(atomic_read(count) == 1 && __mutex_cmpxchg_lock(count, 1, 0) == 1))
return 1;
return 0;
}
diff --git a/arch/x86/include/asm/mutex_32.h b/arch/x86/include/asm/mutex_32.h
index 85e6cda45a02..e9355a84fc67 100644
--- a/arch/x86/include/asm/mutex_32.h
+++ b/arch/x86/include/asm/mutex_32.h
@@ -101,7 +101,7 @@ static inline int __mutex_fastpath_trylock(atomic_t *count,
int (*fail_fn)(atomic_t *))
{
/* cmpxchg because it never induces a false contention state. */
- if (likely(atomic_cmpxchg(count, 1, 0) == 1))
+ if (likely(atomic_read(count) == 1 && atomic_cmpxchg(count, 1, 0) == 1))
return 1;
return 0;
diff --git a/arch/x86/include/asm/mutex_64.h b/arch/x86/include/asm/mutex_64.h
index 07537a44216e..d9850758464e 100644
--- a/arch/x86/include/asm/mutex_64.h
+++ b/arch/x86/include/asm/mutex_64.h
@@ -118,10 +118,10 @@ do { \
static inline int __mutex_fastpath_trylock(atomic_t *count,
int (*fail_fn)(atomic_t *))
{
- if (likely(atomic_cmpxchg(count, 1, 0) == 1))
+ if (likely(atomic_read(count) == 1 && atomic_cmpxchg(count, 1, 0) == 1))
return 1;
- else
- return 0;
+
+ return 0;
}
#endif /* _ASM_X86_MUTEX_64_H */
diff --git a/include/asm-generic/mutex-dec.h b/include/asm-generic/mutex-dec.h
index fd694cfd678a..c54829d3de37 100644
--- a/include/asm-generic/mutex-dec.h
+++ b/include/asm-generic/mutex-dec.h
@@ -80,7 +80,7 @@ __mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *))
static inline int
__mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *))
{
- if (likely(atomic_cmpxchg_acquire(count, 1, 0) == 1))
+ if (likely(atomic_read(count) == 1 && atomic_cmpxchg_acquire(count, 1, 0) == 1))
return 1;
return 0;
}
diff --git a/include/asm-generic/mutex-xchg.h b/include/asm-generic/mutex-xchg.h
index a6b4a7bd6ac9..3269ec4e195f 100644
--- a/include/asm-generic/mutex-xchg.h
+++ b/include/asm-generic/mutex-xchg.h
@@ -91,8 +91,12 @@ __mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *))
static inline int
__mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *))
{
- int prev = atomic_xchg_acquire(count, 0);
+ int prev;
+ if (atomic_read(count) != 1)
+ return 0;
+
+ prev = atomic_xchg_acquire(count, 0);
if (unlikely(prev < 0)) {
/*
* The lock was marked contended so we must restore that