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Optionally use a thread-local cache for valid memory

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When libunwind is compiled with per-thread-caches, then also
make the cache of valid memory addresses thread-local.
This commit is contained in:
Milian Wolff 2018-05-04 21:55:52 +02:00
parent 3d473e183d
commit cd8c5d70d4
1 changed files with 39 additions and 1 deletions
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40
src/x86_64/Ginit.c
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@ -174,8 +174,45 @@ tdep_init_mem_validate (void)
}
/* Cache of already validated addresses */
#if HAVE_ATOMIC_OPS_H
#if defined(HAVE___THREAD) && HAVE___THREAD
#define NLGA 4
// thread-local variant
static __thread unw_word_t last_good_addr[NLGA];
static __thread int lga_victim;
static int
is_cached_valid_mem(unw_word_t addr)
{
int i;
for (i = 0; i < NLGA; i++)
{
if (addr == &last_good_addr[i])
return 1;
}
return 0;
}
static void
cache_valid_mem(unw_word_t addr)
{
int i, victim;
victim = lga_victim;
for (i = 0; i < NLGA; i++) {
if (last_good_addr[victim] == 0) {
last_good_addr[victim] = addr;
return;
}
victim = (victim + 1) % NLGA;
}
/* All slots full. Evict the victim. */
last_good_addr[victim] = addr;
victim = (victim + 1) % NLGA;
lga_victim = victim;
}
#elif HAVE_ATOMIC_OPS_H
// global, thread safe variant
static AO_T last_good_addr[NLGA];
static AO_T lga_victim;
@ -209,6 +246,7 @@ cache_valid_mem(unw_word_t addr)
AO_store(&lga_victim, victim);
}
#else
// disabled, no cache
static int
is_cached_valid_mem(unw_word_t addr UNUSED)
{