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| author | Guo Ren <guoren@linux.alibaba.com> | 2020-12-20 07:10:23 +0000 |
|---|---|---|
| committer | Guo Ren <guoren@linux.alibaba.com> | 2021-01-12 09:52:40 +0800 |
| commit | c38425df20371ea977c38809cb1ebe8586171caf (patch) | |
| tree | 8e3dcbd47112c76da5f4b2e4c9358966d6c69abd /arch | |
| parent | d6c5cb9f8c7584e961a5b04fa2553659e1b2cce7 (diff) | |
| download | linux-stable-c38425df20371ea977c38809cb1ebe8586171caf.tar.gz linux-stable-c38425df20371ea977c38809cb1ebe8586171caf.tar.bz2 linux-stable-c38425df20371ea977c38809cb1ebe8586171caf.zip | |
csky: Fixup asm/cmpxchg.h with correct ordering barrier
Optimize the performance of cmpxchg by using more fine-grained
acquire/release barriers.
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/csky/include/asm/cmpxchg.h | 27 |
1 files changed, 17 insertions, 10 deletions
diff --git a/arch/csky/include/asm/cmpxchg.h b/arch/csky/include/asm/cmpxchg.h index 89224530a0ee..dabc8e46ce7b 100644 --- a/arch/csky/include/asm/cmpxchg.h +++ b/arch/csky/include/asm/cmpxchg.h @@ -3,12 +3,12 @@ #ifndef __ASM_CSKY_CMPXCHG_H #define __ASM_CSKY_CMPXCHG_H -#ifdef CONFIG_CPU_HAS_LDSTEX +#ifdef CONFIG_SMP #include <asm/barrier.h> extern void __bad_xchg(void); -#define __xchg(new, ptr, size) \ +#define __xchg_relaxed(new, ptr, size) \ ({ \ __typeof__(ptr) __ptr = (ptr); \ __typeof__(new) __new = (new); \ @@ -16,7 +16,6 @@ extern void __bad_xchg(void); unsigned long tmp; \ switch (size) { \ case 4: \ - smp_mb(); \ asm volatile ( \ "1: ldex.w %0, (%3) \n" \ " mov %1, %2 \n" \ @@ -25,7 +24,6 @@ extern void __bad_xchg(void); : "=&r" (__ret), "=&r" (tmp) \ : "r" (__new), "r"(__ptr) \ :); \ - smp_mb(); \ break; \ default: \ __bad_xchg(); \ @@ -33,9 +31,10 @@ extern void __bad_xchg(void); __ret; \ }) -#define xchg(ptr, x) (__xchg((x), (ptr), sizeof(*(ptr)))) +#define xchg_relaxed(ptr, x) \ + (__xchg_relaxed((x), (ptr), sizeof(*(ptr)))) -#define __cmpxchg(ptr, old, new, size) \ +#define __cmpxchg_relaxed(ptr, old, new, size) \ ({ \ __typeof__(ptr) __ptr = (ptr); \ __typeof__(new) __new = (new); \ @@ -44,7 +43,6 @@ extern void __bad_xchg(void); __typeof__(*(ptr)) __ret; \ switch (size) { \ case 4: \ - smp_mb(); \ asm volatile ( \ "1: ldex.w %0, (%3) \n" \ " cmpne %0, %4 \n" \ @@ -56,7 +54,6 @@ extern void __bad_xchg(void); : "=&r" (__ret), "=&r" (__tmp) \ : "r" (__new), "r"(__ptr), "r"(__old) \ :); \ - smp_mb(); \ break; \ default: \ __bad_xchg(); \ @@ -64,8 +61,18 @@ extern void __bad_xchg(void); __ret; \ }) -#define cmpxchg(ptr, o, n) \ - (__cmpxchg((ptr), (o), (n), sizeof(*(ptr)))) +#define cmpxchg_relaxed(ptr, o, n) \ + (__cmpxchg_relaxed((ptr), (o), (n), sizeof(*(ptr)))) + +#define cmpxchg(ptr, o, n) \ +({ \ + __typeof__(*(ptr)) __ret; \ + __smp_release_fence(); \ + __ret = cmpxchg_relaxed(ptr, o, n); \ + __smp_acquire_fence(); \ + __ret; \ +}) + #else #include <asm-generic/cmpxchg.h> #endif |