revert (remove empty page removal on search): this is not generally valid when concurrent frees do not always add to thread_delayed_free.
@@ -659,7 +659,9 @@ static void mi_page_init(mi_heap_t* heap, mi_page_t* page, size_t block_size, mi
static mi_page_t* mi_page_queue_find_free_ex(mi_heap_t* heap, mi_page_queue_t* pq)
{
// search through the pages in "next fit" order
+ mi_page_t* rpage = NULL;
size_t count = 0;
+ size_t page_free_count = 0;
mi_page_t* page = pq->first;
while( page != NULL)
{
@@ -671,8 +673,21 @@ static mi_page_t* mi_page_queue_find_free_ex(mi_heap_t* heap, mi_page_queue_t* p
// 1. if the page contains free blocks, we are done
if (mi_page_immediate_available(page)) {
+ // If all blocks are free, we might retire this page instead.
+ // do this at most 8 times to bound allocation time.
+ // (note: this can happen if a page was earlier not retired due
+ // to having neighbours that were mostly full or due to concurrent frees)
+ if (page_free_count < 8 && mi_page_all_free(page)) {
+ page_free_count++;
+ if (rpage != NULL) _mi_page_free(rpage,pq,false);
+ rpage = page;
+ page = next;
+ continue; // and keep looking
+ }
+ else {
break; // pick this one
}
+ }
// 2. Try to extend
if (page->capacity < page->reserved) {
@@ -691,6 +706,14 @@ static mi_page_t* mi_page_queue_find_free_ex(mi_heap_t* heap, mi_page_queue_t* p
mi_stat_counter_increase(heap->tld->stats.searches,count);
+ if (page == NULL) {
+ page = rpage;
+ rpage = NULL;
+ }
+ if (rpage != NULL) {
+ _mi_page_free(rpage,pq,false);
+ }
+
if (page == NULL) {
page = mi_page_fresh(heap, pq);
}
