diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2017-03-17 22:44:45 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-03-23 10:54:41 +0300 |
| commit | e6790e4b5d5e97dc287f3496dd2cf2dbabdfdb35 (patch) | |
| tree | 70bb3495496bb4f41221119cc6c6acd954334457 /arch/x86/include/asm/atomic.h | |
| parent | b78c0d471255e99411d6c1b3975df21c3cd9f349 (diff) | |
| download | linux-e6790e4b5d5e97dc287f3496dd2cf2dbabdfdb35.tar.xz | |
locking/atomic/x86: Use atomic_try_cmpxchg()
Better code generation:
text data bss name
10665111 4530096 843776 defconfig-build/vmlinux.3
10655703 4530096 843776 defconfig-build/vmlinux.4
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/include/asm/atomic.h')
| -rw-r--r-- | arch/x86/include/asm/atomic.h | 27 |
1 files changed, 9 insertions, 18 deletions
diff --git a/arch/x86/include/asm/atomic.h b/arch/x86/include/asm/atomic.h index 8410377c6869..caa5798c92f4 100644 --- a/arch/x86/include/asm/atomic.h +++ b/arch/x86/include/asm/atomic.h @@ -207,16 +207,12 @@ static inline void atomic_##op(int i, atomic_t *v) \ } #define ATOMIC_FETCH_OP(op, c_op) \ -static inline int atomic_fetch_##op(int i, atomic_t *v) \ +static inline int atomic_fetch_##op(int i, atomic_t *v) \ { \ - int old, val = atomic_read(v); \ - for (;;) { \ - old = atomic_cmpxchg(v, val, val c_op i); \ - if (old == val) \ - break; \ - val = old; \ - } \ - return old; \ + int val = atomic_read(v); \ + do { \ + } while (!atomic_try_cmpxchg(v, &val, val c_op i)); \ + return val; \ } #define ATOMIC_OPS(op, c_op) \ @@ -242,16 +238,11 @@ ATOMIC_OPS(xor, ^) */ static __always_inline int __atomic_add_unless(atomic_t *v, int a, int u) { - int c, old; - c = atomic_read(v); - for (;;) { - if (unlikely(c == (u))) + int c = atomic_read(v); + do { + if (unlikely(c == u)) break; - old = atomic_cmpxchg((v), c, c + (a)); - if (likely(old == c)) - break; - c = old; - } + } while (!atomic_try_cmpxchg(v, &c, c + a)); return c; } |