Messages in this thread | | | Date | Fri, 3 Jul 2009 11:24:38 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCHv5 2/2] memory barrier: adding smp_mb__after_lock |
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* Eric Dumazet <eric.dumazet@gmail.com> wrote:
> Ingo Molnar a écrit : > > * Jiri Olsa <jolsa@redhat.com> wrote: > > > >> +++ b/arch/x86/include/asm/spinlock.h > >> @@ -302,4 +302,7 @@ static inline void __raw_write_unlock(raw_rwlock_t *rw) > >> #define _raw_read_relax(lock) cpu_relax() > >> #define _raw_write_relax(lock) cpu_relax() > >> > >> +/* The {read|write|spin}_lock() on x86 are full memory barriers. */ > >> +#define smp_mb__after_lock() do { } while (0) > > > > Two small stylistic comments, please make this an inline function: > > > > static inline void smp_mb__after_lock(void) { } > > #define smp_mb__after_lock > > > > (untested) > > > >> +/* The lock does not imply full memory barrier. */ > >> +#ifndef smp_mb__after_lock > >> +#define smp_mb__after_lock() smp_mb() > >> +#endif > > > > ditto. > > > > Ingo > > This was following existing implementations of various smp_mb__??? helpers : > > # grep -4 smp_mb__before_clear_bit include/asm-generic/bitops.h > > /* > * clear_bit may not imply a memory barrier > */ > #ifndef smp_mb__before_clear_bit > #define smp_mb__before_clear_bit() smp_mb() > #define smp_mb__after_clear_bit() smp_mb() > #endif
Did i mention that those should be fixed too? :-)
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