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if region overcommitting due to contention save it to a further slot

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daan 2019-08-19 21:20:24 -07:00
parent 2066e2797d
commit 48a7d64bdd
1 changed files with 19 additions and 3 deletions
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22
src/memory.c
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@ -128,6 +128,7 @@ static bool mi_region_commit_blocks(mem_region_t* region, size_t idx, size_t bit
size_t mask = mi_region_block_mask(blocks,bitidx); size_t mask = mi_region_block_mask(blocks,bitidx);
mi_assert_internal(mask != 0); mi_assert_internal(mask != 0);
mi_assert_internal((mask & mi_atomic_read(&region->map)) == mask); mi_assert_internal((mask & mi_atomic_read(&region->map)) == mask);
mi_assert_internal(&regions[idx] == region);
// ensure the region is reserved // ensure the region is reserved
void* start = mi_atomic_read_ptr(&region->start); void* start = mi_atomic_read_ptr(&region->start);
@ -142,6 +143,7 @@ static bool mi_region_commit_blocks(mem_region_t* region, size_t idx, size_t bit
} while (!mi_atomic_compare_exchange(&region->map, map & ~mask, map)); } while (!mi_atomic_compare_exchange(&region->map, map & ~mask, map));
return false; return false;
} }
Sleep(10);
// set the newly allocated region // set the newly allocated region
if (mi_atomic_compare_exchange_ptr(&region->start, start, NULL)) { if (mi_atomic_compare_exchange_ptr(&region->start, start, NULL)) {
@ -149,9 +151,23 @@ static bool mi_region_commit_blocks(mem_region_t* region, size_t idx, size_t bit
mi_atomic_increment(&regions_count); mi_atomic_increment(&regions_count);
} }
else { else {
// failed, another thread allocated just before us, free our allocated memory // failed, another thread allocated just before us!
// TODO: should we keep the allocated memory and assign it to some other region? // we assign it to a later slot instead (up to 4 tries).
_mi_os_free(start, MI_REGION_SIZE, tld->stats); // note: we don't need to increment the region count, this will happen on another allocation
for(size_t i = 1; i <= 4 && idx + i < MI_REGION_MAX; i++) {
void* s = mi_atomic_read_ptr(&regions[idx+i].start);
if (s == NULL) { // quick test
if (mi_atomic_compare_exchange_ptr(&regions[idx+i].start, start, s)) {
start = NULL;
break;
}
}
}
if (start != NULL) {
// free it if we didn't succeed to save it to some other region
_mi_os_free(start, MI_REGION_SIZE, tld->stats);
}
// and continue with the memory at our index
start = mi_atomic_read_ptr(&region->start); start = mi_atomic_read_ptr(&region->start);
} }
} }