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| author | Uros Bizjak <ubizjak@gmail.com> | 2024-04-10 08:29:33 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2024-04-10 15:04:54 +0200 |
| commit | 276b893049e4cdc2f33c009706a75ec18a114485 (patch) | |
| tree | 8ff543384b7089401d1adb7bddafcaf03f8c6b66 | |
| parent | aef95dac9ce4f271cc43195ffc175114ed934cbe (diff) | |
| download | linux-276b893049e4cdc2f33c009706a75ec18a114485.tar.gz linux-276b893049e4cdc2f33c009706a75ec18a114485.tar.bz2 linux-276b893049e4cdc2f33c009706a75ec18a114485.zip | |
locking/atomic/x86: Introduce arch_atomic64_try_cmpxchg() to x86_32
Introduce arch_atomic64_try_cmpxchg() for 32-bit targets to use
optimized target specific implementation instead of a generic one.
This implementation eliminates dual-word compare after
cmpxchg8b instruction and improves generated asm code from:
2273: f0 0f c7 0f lock cmpxchg8b (%edi)
2277: 8b 74 24 2c mov 0x2c(%esp),%esi
227b: 89 d3 mov %edx,%ebx
227d: 89 c2 mov %eax,%edx
227f: 89 5c 24 10 mov %ebx,0x10(%esp)
2283: 8b 7c 24 30 mov 0x30(%esp),%edi
2287: 89 44 24 1c mov %eax,0x1c(%esp)
228b: 31 f2 xor %esi,%edx
228d: 89 d0 mov %edx,%eax
228f: 89 da mov %ebx,%edx
2291: 31 fa xor %edi,%edx
2293: 09 d0 or %edx,%eax
2295: 0f 85 a5 00 00 00 jne 2340 <...>
to:
2270: f0 0f c7 0f lock cmpxchg8b (%edi)
2274: 0f 85 a6 00 00 00 jne 2320 <...>
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20240410062957.322614-1-ubizjak@gmail.com
| -rw-r--r-- | arch/x86/include/asm/atomic64_32.h | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/arch/x86/include/asm/atomic64_32.h b/arch/x86/include/asm/atomic64_32.h index 3486d91b8595..ec217aaf41eb 100644 --- a/arch/x86/include/asm/atomic64_32.h +++ b/arch/x86/include/asm/atomic64_32.h @@ -61,12 +61,18 @@ ATOMIC64_DECL(add_unless); #undef __ATOMIC64_DECL #undef ATOMIC64_EXPORT -static __always_inline s64 arch_atomic64_cmpxchg(atomic64_t *v, s64 o, s64 n) +static __always_inline s64 arch_atomic64_cmpxchg(atomic64_t *v, s64 old, s64 new) { - return arch_cmpxchg64(&v->counter, o, n); + return arch_cmpxchg64(&v->counter, old, new); } #define arch_atomic64_cmpxchg arch_atomic64_cmpxchg +static __always_inline bool arch_atomic64_try_cmpxchg(atomic64_t *v, s64 *old, s64 new) +{ + return arch_try_cmpxchg64(&v->counter, old, new); +} +#define arch_atomic64_try_cmpxchg arch_atomic64_try_cmpxchg + static __always_inline s64 arch_atomic64_xchg(atomic64_t *v, s64 n) { s64 o; |