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ck: Use relaxed memory order if possible

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In uniprocessor configurations we can use a relaxed memory order and
compiler memory barriers should be sufficient.

Update #3472.
This commit is contained in:
Sebastian Huber 2018-09-17 07:38:32 +02:00
parent 1af372a5ee
commit be6515d2c1
1 changed files with 25 additions and 10 deletions
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27
freebsd/sys/contrib/ck/include/gcc/ck_pr.h
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@ -32,6 +32,11 @@
#endif
#include <ck_cc.h>
#ifdef RTEMS_SMP
#define CK_PR_ATOMIC_ORDER __ATOMIC_SEQ_CST
#else
#define CK_PR_ATOMIC_ORDER __ATOMIC_RELAXED
#endif
CK_CC_INLINE static void
ck_pr_barrier(void)
@ -122,12 +127,21 @@ ck_pr_stall(void)
/*
* Load and store fences are equivalent to full fences in the GCC port.
*/
#ifdef RTEMS_SMP
#define CK_PR_FENCE(T) \
CK_CC_INLINE static void \
ck_pr_fence_strict_##T(void) \
{ \
__atomic_thread_fence(__ATOMIC_SEQ_CST);\
__atomic_thread_fence(CK_PR_ATOMIC_ORDER); \
}
#else
#define CK_PR_FENCE(T) \
CK_CC_INLINE static void \
ck_pr_fence_strict_##T(void) \
{ \
__asm__ __volatile__("" ::: "memory"); \
}
#endif
CK_PR_FENCE(atomic)
CK_PR_FENCE(atomic_atomic)
@ -159,7 +173,7 @@ CK_PR_FENCE(unlock)
{ \
bool z; \
z = __atomic_compare_exchange_n((T *)target, &compare, set, \
false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST); \
false, CK_PR_ATOMIC_ORDER, CK_PR_ATOMIC_ORDER); \
return z; \
}
@ -186,7 +200,7 @@ ck_pr_cas_ptr_value(void *target, void *compare, void *set, void *v)
{
*(void **)v = compare;
return __atomic_compare_exchange_n((void **)target, v, set, false,
__ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
CK_PR_ATOMIC_ORDER, CK_PR_ATOMIC_ORDER);
}
#define CK_PR_CAS_O(S, T) \
@ -195,7 +209,7 @@ ck_pr_cas_ptr_value(void *target, void *compare, void *set, void *v)
{ \
*v = compare; \
return __atomic_compare_exchange_n(target, v, set, \
false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST); \
false, CK_PR_ATOMIC_ORDER, CK_PR_ATOMIC_ORDER); \
}
CK_PR_CAS_O(char, char)
@ -216,7 +230,7 @@ CK_PR_CAS_O(8, uint8_t)
ck_pr_faa_##S(M *target, T d) \
{ \
d = __atomic_fetch_add((T *)target, d, \
__ATOMIC_SEQ_CST); \
CK_PR_ATOMIC_ORDER); \
return (d); \
}
@ -243,7 +257,7 @@ CK_PR_FAA_S(8, uint8_t)
ck_pr_##K##_##S(M *target, T d) \
{ \
d = __atomic_fetch_##K((T *)target, d, \
__ATOMIC_SEQ_CST); \
CK_PR_ATOMIC_ORDER); \
return; \
}
@ -296,5 +310,6 @@ CK_PR_UNARY_S(8, uint8_t)
#undef CK_PR_UNARY_S
#undef CK_PR_UNARY
#undef CK_PR_ATOMIC_ORDER
#endif /* !CK_F_PR */
#endif /* CK_PR_GCC_H */