diff options
Diffstat (limited to '')
| -rw-r--r-- | include/qemu/atomic.h | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/include/qemu/atomic.h b/include/qemu/atomic.h index 96db6e9db5..7a590969b5 100644 --- a/include/qemu/atomic.h +++ b/include/qemu/atomic.h @@ -67,13 +67,23 @@ __atomic_store(ptr, &_val, __ATOMIC_RELAXED); \ } while(0) -/* Atomic RCU operations imply weak memory barriers */ +/* See above: most compilers currently treat consume and acquire the + * same, but this slows down atomic_rcu_read unnecessarily. + */ +#ifdef __SANITIZE_THREAD__ +#define atomic_rcu_read__nocheck(ptr, valptr) \ + __atomic_load(ptr, valptr, __ATOMIC_CONSUME); +#else +#define atomic_rcu_read__nocheck(ptr, valptr) \ + __atomic_load(ptr, valptr, __ATOMIC_RELAXED); \ + smp_read_barrier_depends(); +#endif #define atomic_rcu_read(ptr) \ ({ \ QEMU_BUILD_BUG_ON(sizeof(*ptr) > sizeof(void *)); \ typeof(*ptr) _val; \ - __atomic_load(ptr, &_val, __ATOMIC_CONSUME); \ + atomic_rcu_read__nocheck(ptr, &_val); \ _val; \ }) |