Function mi_segment_page_clear

3rd/mimalloc-2.0.9/src/segment.c:985–1015

note: can be called on abandoned pages

// note: can be called on abandoned pages
static mi_slice_t* mi_segment_page_clear(mi_page_t* page, mi_segments_tld_t* tld) {
  mi_assert_internal(page->xblock_size > 0);
  mi_assert_internal(mi_page_all_free(page));
  mi_segment_t* segment = _mi_ptr_segment(page);
  mi_assert_internal(segment->used > 0);
  
  size_t inuse = page->capacity * mi_page_block_size(page);
  _mi_stat_decrease(&tld->stats->page_committed, inuse);
  _mi_stat_decrease(&tld->stats->pages, 1);

  // reset the page memory to reduce memory pressure?
  if (!segment->mem_is_pinned && !page->is_reset && mi_option_is_enabled(mi_option_page_reset)) {
    size_t psize;
    uint8_t* start = _mi_page_start(segment, page, &psize);
    page->is_reset = true;
    _mi_os_reset(start, psize, tld->stats);
  }

  // zero the page data, but not the segment fields
  page->is_zero_init = false;
  ptrdiff_t ofs = offsetof(mi_page_t, capacity);
  memset((uint8_t*)page + ofs, 0, sizeof(*page) - ofs);
  page->xblock_size = 1;

  // and free it
  mi_slice_t* slice = mi_segment_span_free_coalesce(mi_page_to_slice(page), tld);  
  segment->used--;
  // cannot assert segment valid as it is called during reclaim
  // mi_assert_expensive(mi_segment_is_valid(segment, tld));
  return slice;
}

void _mi_segment_page_free(mi_page_t* page, bool force, mi_segments_tld_t* tld)
{