Function mi_segments_page_alloc

3rd/mimalloc-2.0.9/src/segment.c:1489–1513

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static mi_page_t* mi_segments_page_alloc(mi_heap_t* heap, mi_page_kind_t page_kind, size_t required, size_t block_size, mi_segments_tld_t* tld, mi_os_tld_t* os_tld)
{
  mi_assert_internal(required <= MI_LARGE_OBJ_SIZE_MAX && page_kind <= MI_PAGE_LARGE);

  // find a free page
  size_t page_size = _mi_align_up(required, (required > MI_MEDIUM_PAGE_SIZE ? MI_MEDIUM_PAGE_SIZE : MI_SEGMENT_SLICE_SIZE));
  size_t slices_needed = page_size / MI_SEGMENT_SLICE_SIZE;
  mi_assert_internal(slices_needed * MI_SEGMENT_SLICE_SIZE == page_size);
  mi_page_t* page = mi_segments_page_find_and_allocate(slices_needed, heap->arena_id, tld); //(required <= MI_SMALL_SIZE_MAX ? 0 : slices_needed), tld);
  if (page==NULL) {
    // no free page, allocate a new segment and try again
    if (mi_segment_reclaim_or_alloc(heap, slices_needed, block_size, tld, os_tld) == NULL) {
      // OOM or reclaimed a good page in the heap
      return NULL;  
    }
    else {
      // otherwise try again
      return mi_segments_page_alloc(heap, page_kind, required, block_size, tld, os_tld);
    }
  }
  mi_assert_internal(page != NULL && page->slice_count*MI_SEGMENT_SLICE_SIZE == page_size);
  mi_assert_internal(_mi_ptr_segment(page)->thread_id == _mi_thread_id());
  mi_segment_delayed_decommit(_mi_ptr_segment(page), false, tld->stats);
  return page;
}