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Be conservative and always perform an mb after an atomic_cmpset operation.

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John Baldwin 2001-06-22 21:13:20 +00:00
parent 6d541bf1ae
commit 49f886f5d3
1 changed files with 2 additions and 0 deletions
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2
sys/alpha/include/atomic.h
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@ -361,6 +361,7 @@ atomic_cmpset_32(volatile u_int32_t* p, u_int32_t cmpval, u_int32_t newval)
"mov %3, %0\n\t" /* value to store */
"stl_c %0, %1\n\t" /* attempt to store */
"beq %0, 3f\n\t" /* if it failed, spin */
"mb\n\t" /* drain to memory */
"2:\n" /* done */
".section .text3,\"ax\"\n" /* improve branch prediction */
"3:\tbr 1b\n" /* try again */
@ -389,6 +390,7 @@ atomic_cmpset_64(volatile u_int64_t* p, u_int64_t cmpval, u_int64_t newval)
"mov %3, %0\n\t" /* value to store */
"stq_c %0, %1\n\t" /* attempt to store */
"beq %0, 3f\n\t" /* if it failed, spin */
"mb\n\t" /* drain to memory */
"2:\n" /* done */
".section .text3,\"ax\"\n" /* improve branch prediction */
"3:\tbr 1b\n" /* try again */