Function mi_page_malloc_zero

system/lib/mimalloc/src/alloc.c:32–44

Fast allocation in a page: just pop from the free list. Fall back to generic allocation only if the list is empty. Note: in release mode the (inlined) routine is about 7 instructions with a single test.

// Fall back to generic allocation only if the list is empty.
// Note: in release mode the (inlined) routine is about 7 instructions with a single test.
static mi_decl_forceinline void* mi_page_malloc_zero(mi_theap_t* theap, mi_page_t* page, size_t size, bool zero, size_t* usable) mi_attr_noexcept
{
  if (page->block_size != 0) { // not the empty theap
    mi_assert_internal(mi_page_block_size(page) >= size);
    mi_assert_internal(_mi_is_aligned(mi_page_slice_start(page), MI_PAGE_ALIGN));
    mi_assert_internal(_mi_ptr_page(mi_page_start(page))==page);
  }

  // check the free list
  mi_block_t* const block = page->free;
  if mi_unlikely(block == NULL) {
    return _mi_malloc_generic(theap, size, (zero ? 1 : 0), usable);
  }
  mi_assert_internal(block != NULL && _mi_ptr_page(block) == page);
  if (usable != NULL) { *usable = mi_page_usable_block_size(page); };