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[Qemu-devel] [PATCH 2/3] atomics: Use __atomic_*_n() variant primitives
From: |
Pranith Kumar |
Subject: |
[Qemu-devel] [PATCH 2/3] atomics: Use __atomic_*_n() variant primitives |
Date: |
Wed, 24 Aug 2016 16:44:22 -0400 |
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 <address@hidden>
---
include/qemu/atomic.h | 16 +++++-----------
1 file changed, 5 insertions(+), 11 deletions(-)
diff --git a/include/qemu/atomic.h b/include/qemu/atomic.h
index d313e6b..fc2309f 100644
--- a/include/qemu/atomic.h
+++ b/include/qemu/atomic.h
@@ -103,8 +103,7 @@
#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 +128,7 @@
#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 +151,8 @@
#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 +166,7 @@
#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
@@ -179,9 +175,7 @@
#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 */
--
2.9.3