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MINOR: threads: Introduce double-width CAS on x86_64 and arm.

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Introduce double-width compare-and-swap on arches that support it, right now
x86_64, arm, and aarch64.
Also introduce functions to do memory barriers.
This commit is contained in:
Olivier Houchard 2017-12-21 17:13:05 +01:00 committed by Willy Tarreau
parent 928fbfa8b7
commit f61f0cb95f
1 changed files with 151 additions and 0 deletions
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151
include/common/hathreads.h
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@ -89,6 +89,18 @@ extern THREAD_LOCAL unsigned long tid_bit; /* The bit corresponding to the threa
#define HA_RWLOCK_TRYRDLOCK(lbl, l) ({ 0; })
#define HA_RWLOCK_RDUNLOCK(lbl, l) do { /* do nothing */ } while(0)
static inline void __ha_barrier_load(void)
{
}
static inline void __ha_barrier_store(void)
{
}
static inline void __ha_barrier_full(void)
{
}
#else /* USE_THREAD */
#include <stdio.h>
@ -668,6 +680,145 @@ static inline void __spin_unlock(enum lock_label lbl, struct ha_spinlock *l,
#endif /* DEBUG_THREAD */
#ifdef __x86_64__
#define HA_HAVE_CAS_DW 1
#define HA_CAS_IS_8B
static __inline int
__ha_cas_dw(void *target, void *compare, const void *set)
{
char ret;
__asm __volatile("lock cmpxchg16b %0; setz %3"
: "+m" (*(void **)target),
"=a" (((void **)compare)[0]),
"=d" (((void **)compare)[1]),
"=q" (ret)
: "a" (((void **)compare)[0]),
"d" (((void **)compare)[1]),
"b" (((const void **)set)[0]),
"c" (((const void **)set)[1])
: "memory", "cc");
return (ret);
}
static __inline void
__ha_barrier_load(void)
{
__asm __volatile("lfence" ::: "memory");
}
static __inline void
__ha_barrier_store(void)
{
__asm __volatile("sfence" ::: "memory");
}
static __inline void
__ha_barrier_full(void)
{
__asm __volatile("mfence" ::: "memory");
}
#elif defined(__arm__) && (defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__))
#define HA_HAVE_CAS_DW 1
static __inline void
__ha_barrier_load(void)
{
__asm __volatile("dmb" ::: "memory");
}
static __inline void
__ha_barrier_store(void)
{
__asm __volatile("dsb" ::: "memory");
}
static __inline void
__ha_barrier_full(void)
{
__asm __volatile("dmb" ::: "memory");
}
static __inline int __ha_cas_dw(void *target, void *compare, void *set)
{
uint64_t previous;
int tmp;
__asm __volatile("1:"
"ldrexd %0, [%4];"
"cmp %Q0, %Q2;"
"ittt eq;"
"cmpeq %R0, %R2;"
"strexdeq %1, %3, [%4];"
"cmpeq %1, #1;"
"beq 1b;"
: "=&r" (previous), "=&r" (tmp)
: "r" (compare), "r" (set), "r" (target)
: "memory", "cc");
tmp = (previous == *(uint64_t *)compare);
*(uint64_t *)compare = previous;
return (tmp);
}
#elif defined (__aarch64__)
#define HA_HAVE_CAS_DW 1
#define HA_CAS_IS_8B
static __inline void
__ha_barrier_load(void)
{
__asm __volatile("dmb ishld" ::: "memory");
}
static __inline void
__ha_barrier_store(void)
{
__asm __volatile("dmb ishst" ::: "memory");
}
static __inline void
__ha_barrier_full(void)
{
__asm __volatile("dmb ish" ::: "memory");
}
static __inline int __ha_cas_dw(void *target, void *compare, void *set)
{
void *value[2];
uint64_t tmp1, tmp2;
__asm__ __volatile__("1:"
"ldxp %0, %1, [%4];"
"mov %2, %0;"
"mov %3, %1;"
"eor %0, %0, %5;"
"eor %1, %1, %6;"
"orr %1, %0, %1;"
"mov %w0, #0;"
"cbnz %1, 2f;"
"stxp %w0, %7, %8, [%4];"
"cbnz %w0, 1b;"
"mov %w0, #1;"
"2:"
: "=&r" (tmp1), "=&r" (tmp2), "=&r" (value[0]), "=&r" (value[1])
: "r" (target), "r" (((void **)(compare))[0]), "r" (((void **)(compare))[1]), "r" (((void **)(set))[0]), "r" (((void **)(set))[1])
: "cc", "memory");
memcpy(compare, &value, sizeof(value));
return (tmp1);
}
#else
#define __ha_barrier_load __sync_synchronize
#define __ha_barrier_store __sync_synchronize
#define __ha_barrier_full __sync_synchronize
#endif
#endif /* USE_THREAD */
static inline void __ha_compiler_barrier(void)
{
__asm __volatile("" ::: "memory");
}
#endif /* _COMMON_HATHREADS_H */