if region overcommitting due to contention save it to a further slot
@@ -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);
mi_assert_internal(mask != 0);
mi_assert_internal((mask & mi_atomic_read(&region->map)) == mask);
+ mi_assert_internal(&regions[idx] == region);
// ensure the region is reserved
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));
return false;
}
+ Sleep(10);
// set the newly allocated region
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);
}
else {
- // failed, another thread allocated just before us, free our allocated memory
- // TODO: should we keep the allocated memory and assign it to some other region?
+ // failed, another thread allocated just before us!
+ // we assign it to a later slot instead (up to 4 tries).
+ // 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);
}
}
