Author: hselasky Date: Sun Feb 18 18:46:56 2018 New Revision: 329524 URL: https://svnweb.freebsd.org/changeset/base/329524
Log:
Optimise xchg() to use atomic_swap_32() and atomic_swap_64().
Suggested by: kib@
MFC after: 1 week
Sponsored by: Mellanox Technologies
Modified:
head/sys/compat/linuxkpi/common/include/asm/atomic.h
Modified: head/sys/compat/linuxkpi/common/include/asm/atomic.h
==============================================================================
--- head/sys/compat/linuxkpi/common/include/asm/atomic.h Sun Feb 18
17:37:23 2018 (r329523)
+++ head/sys/compat/linuxkpi/common/include/asm/atomic.h Sun Feb 18
18:46:56 2018 (r329524)
@@ -205,31 +205,31 @@ atomic_cmpxchg(atomic_t *v, int old, int new)
u16 u16[0]; \
u32 u32[0]; \
u64 u64[0]; \
- } __ret = { .val = READ_ONCE(*ptr) }, __new = { .val = (new) }; \
+ } __ret, __new = { .val = (new) }; \
\
CTASSERT(sizeof(__ret.val) == 1 || sizeof(__ret.val) == 2 || \
sizeof(__ret.val) == 4 || sizeof(__ret.val) == 8); \
\
switch (sizeof(__ret.val)) { \
case 1: \
+ __ret.val = READ_ONCE(*ptr); \
while (!atomic_fcmpset_8((volatile u8 *)(ptr), \
__ret.u8, __new.u8[0])) \
; \
break; \
case 2: \
+ __ret.val = READ_ONCE(*ptr); \
while (!atomic_fcmpset_16((volatile u16 *)(ptr), \
__ret.u16, __new.u16[0])) \
; \
break; \
case 4: \
- while (!atomic_fcmpset_32((volatile u32 *)(ptr), \
- __ret.u32, __new.u32[0])) \
- ; \
+ __ret.u32[0] = atomic_swap_32((volatile u32 *)(ptr), \
+ __new.u32[0]); \
break; \
case 8: \
- while (!atomic_fcmpset_64((volatile u64 *)(ptr), \
- __ret.u64, __new.u64[0])) \
- ; \
+ __ret.u64[0] = atomic_swap_64((volatile u64 *)(ptr), \
+ __new.u64[0]); \
break; \
} \
__ret.val; \
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