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| author | Pranith Kumar <bobby.prani@gmail.com> | 2016-08-29 13:17:01 -0400 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2016-09-13 19:09:44 +0200 |
| commit | 89943de17c4e276f2c47f05b4604e8816a6a636c (patch) | |
| tree | 658abe8cd074bb6a9b7a6ff6b0695342a58cfbfd | |
| parent | 705ac1ca539ba05ab52c3290ccb45f9e47aa7c5e (diff) | |
| download | focaccia-qemu-89943de17c4e276f2c47f05b4604e8816a6a636c.tar.gz focaccia-qemu-89943de17c4e276f2c47f05b4604e8816a6a636c.zip | |
atomics: Use __atomic_*_n() variant primitives
Use the __atomic_*_n() primitives which take the value as argument. It is not necessary to store the value locally before calling the primitive, hence saving us a stack store and load. Signed-off-by: Pranith Kumar <bobby.prani@gmail.com> Message-Id: <20160829171701.14025-1-bobby.prani@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| -rw-r--r-- | include/qemu/atomic.h | 24 |
1 files changed, 8 insertions, 16 deletions
diff --git a/include/qemu/atomic.h b/include/qemu/atomic.h index 8348eccadb..0cce246ea9 100644 --- a/include/qemu/atomic.h +++ b/include/qemu/atomic.h @@ -96,15 +96,12 @@ #define atomic_read(ptr) \ ({ \ QEMU_BUILD_BUG_ON(sizeof(*ptr) > sizeof(void *)); \ - typeof_strip_qual(*ptr) _val; \ - __atomic_load(ptr, &_val, __ATOMIC_RELAXED); \ - _val; \ + __atomic_load_n(ptr, __ATOMIC_RELAXED); \ }) #define atomic_set(ptr, i) do { \ QEMU_BUILD_BUG_ON(sizeof(*ptr) > sizeof(void *)); \ - typeof(*ptr) _val = (i); \ - __atomic_store(ptr, &_val, __ATOMIC_RELAXED); \ + __atomic_store_n(ptr, i, __ATOMIC_RELAXED); \ } while(0) /* See above: most compilers currently treat consume and acquire the @@ -129,8 +126,7 @@ #define atomic_rcu_set(ptr, i) do { \ QEMU_BUILD_BUG_ON(sizeof(*ptr) > sizeof(void *)); \ - typeof(*ptr) _val = (i); \ - __atomic_store(ptr, &_val, __ATOMIC_RELEASE); \ + __atomic_store_n(ptr, i, __ATOMIC_RELEASE); \ } while(0) /* atomic_mb_read/set semantics map Java volatile variables. They are @@ -153,9 +149,8 @@ #define atomic_mb_set(ptr, i) do { \ QEMU_BUILD_BUG_ON(sizeof(*ptr) > sizeof(void *)); \ - typeof(*ptr) _val = (i); \ smp_wmb(); \ - __atomic_store(ptr, &_val, __ATOMIC_RELAXED); \ + __atomic_store_n(ptr, i, __ATOMIC_RELAXED); \ smp_mb(); \ } while(0) #else @@ -169,8 +164,7 @@ #define atomic_mb_set(ptr, i) do { \ QEMU_BUILD_BUG_ON(sizeof(*ptr) > sizeof(void *)); \ - typeof(*ptr) _val = (i); \ - __atomic_store(ptr, &_val, __ATOMIC_SEQ_CST); \ + __atomic_store_n(ptr, i, __ATOMIC_SEQ_CST); \ } while(0) #endif @@ -179,17 +173,15 @@ #define atomic_xchg(ptr, i) ({ \ QEMU_BUILD_BUG_ON(sizeof(*ptr) > sizeof(void *)); \ - typeof_strip_qual(*ptr) _new = (i), _old; \ - __atomic_exchange(ptr, &_new, &_old, __ATOMIC_SEQ_CST); \ - _old; \ + __atomic_exchange_n(ptr, i, __ATOMIC_SEQ_CST); \ }) /* Returns the eventual value, failed or not */ #define atomic_cmpxchg(ptr, old, new) \ ({ \ QEMU_BUILD_BUG_ON(sizeof(*ptr) > sizeof(void *)); \ - typeof_strip_qual(*ptr) _old = (old), _new = (new); \ - __atomic_compare_exchange(ptr, &_old, &_new, false, \ + typeof_strip_qual(*ptr) _old = (old); \ + __atomic_compare_exchange_n(ptr, &_old, new, false, \ __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST); \ _old; \ }) |