Function mi_page_init

3rd/mimalloc-2.0.9/src/page.c:649–695

Initialize a fresh page

// Initialize a fresh page
static void mi_page_init(mi_heap_t* heap, mi_page_t* page, size_t block_size, mi_tld_t* tld) {
  mi_assert(page != NULL);
  mi_segment_t* segment = _mi_page_segment(page);
  mi_assert(segment != NULL);
  mi_assert_internal(block_size > 0);
  // set fields
  mi_page_set_heap(page, heap);
  page->xblock_size = (block_size < MI_HUGE_BLOCK_SIZE ? (uint32_t)block_size : MI_HUGE_BLOCK_SIZE); // initialize before _mi_segment_page_start
  size_t page_size;
  const void* page_start = _mi_segment_page_start(segment, page, &page_size);
  MI_UNUSED(page_start);
  mi_track_mem_noaccess(page_start,page_size);
  mi_assert_internal(mi_page_block_size(page) <= page_size);
  mi_assert_internal(page_size <= page->slice_count*MI_SEGMENT_SLICE_SIZE);
  mi_assert_internal(page_size / block_size < (1L<<16));
  page->reserved = (uint16_t)(page_size / block_size);
  mi_assert_internal(page->reserved > 0);
  #ifdef MI_ENCODE_FREELIST
  page->keys[0] = _mi_heap_random_next(heap);
  page->keys[1] = _mi_heap_random_next(heap);
  #endif
  #if MI_DEBUG > 0
  page->is_zero = false; // ensure in debug mode we initialize with MI_DEBUG_UNINIT, see issue #501
  #else
  page->is_zero = page->is_zero_init;
  #endif

  mi_assert_internal(page->is_committed);
  mi_assert_internal(!page->is_reset);
  mi_assert_internal(page->capacity == 0);
  mi_assert_internal(page->free == NULL);
  mi_assert_internal(page->used == 0);
  mi_assert_internal(page->xthread_free == 0);
  mi_assert_internal(page->next == NULL);
  mi_assert_internal(page->prev == NULL);
  mi_assert_internal(page->retire_expire == 0);
  mi_assert_internal(!mi_page_has_aligned(page));
  #if (MI_ENCODE_FREELIST)
  mi_assert_internal(page->keys[0] != 0);
  mi_assert_internal(page->keys[1] != 0);
  #endif
  mi_assert_expensive(mi_page_is_valid_init(page));

  // initialize an initial free list
  mi_page_extend_free(heap,page,tld);
  mi_assert(mi_page_immediate_available(page));
}


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