diff options
Diffstat (limited to 'include/qemu/atomic.h')
| -rw-r--r-- | include/qemu/atomic.h | 17 |
1 files changed, 5 insertions, 12 deletions
diff --git a/include/qemu/atomic.h b/include/qemu/atomic.h index f85834ee8b..d95612f7a0 100644 --- a/include/qemu/atomic.h +++ b/include/qemu/atomic.h @@ -259,24 +259,17 @@ # define smp_mb__after_rmw() smp_mb() #endif -/* qatomic_mb_read/set semantics map Java volatile variables. They are - * less expensive on some platforms (notably POWER) than fully - * sequentially consistent operations. - * - * As long as they are used as paired operations they are safe to - * use. See docs/devel/atomics.rst for more discussion. +/* + * On some architectures, qatomic_set_mb is more efficient than a store + * plus a fence. */ -#define qatomic_mb_read(ptr) \ - qatomic_load_acquire(ptr) - #if !defined(QEMU_SANITIZE_THREAD) && \ (defined(__i386__) || defined(__x86_64__) || defined(__s390x__)) -/* This is more efficient than a store plus a fence. */ -# define qatomic_mb_set(ptr, i) \ +# define qatomic_set_mb(ptr, i) \ ({ (void)qatomic_xchg(ptr, i); smp_mb__after_rmw(); }) #else -# define qatomic_mb_set(ptr, i) \ +# define qatomic_set_mb(ptr, i) \ ({ qatomic_store_release(ptr, i); smp_mb(); }) #endif |