Function mi_segment_os_free

3rd/mimalloc-2.0.9/src/segment.c:373–399

}

static void mi_segment_os_free(mi_segment_t* segment, mi_segments_tld_t* tld) {
  segment->thread_id = 0;
  _mi_segment_map_freed_at(segment);
  mi_segments_track_size(-((long)mi_segment_size(segment)),tld);
  if (MI_SECURE>0) {
    // _mi_os_unprotect(segment, mi_segment_size(segment)); // ensure no more guard pages are set
    // unprotect the guard pages; we cannot just unprotect the whole segment size as part may be decommitted
    size_t os_pagesize = _mi_os_page_size();
    _mi_os_unprotect((uint8_t*)segment + mi_segment_info_size(segment) - os_pagesize, os_pagesize);
    uint8_t* end = (uint8_t*)segment + mi_segment_size(segment) - os_pagesize;
    _mi_os_unprotect(end, os_pagesize);
  }

  // purge delayed decommits now? (no, leave it to the cache)
  // mi_segment_delayed_decommit(segment,true,tld->stats);
  
  // _mi_os_free(segment, mi_segment_size(segment), /*segment->memid,*/ tld->stats);
  const size_t size = mi_segment_size(segment);
  if (size != MI_SEGMENT_SIZE || segment->mem_align_offset != 0 || segment->kind == MI_SEGMENT_HUGE || // only push regular segments on the cache
       !_mi_segment_cache_push(segment, size, segment->memid, &segment->commit_mask, &segment->decommit_mask, segment->mem_is_large, segment->mem_is_pinned, tld->os)) 
  {
    const size_t csize = _mi_commit_mask_committed_size(&segment->commit_mask, size);
    if (csize > 0 && !segment->mem_is_pinned) _mi_stat_decrease(&_mi_stats_main.committed, csize);
    _mi_abandoned_await_readers();  // wait until safe to free
    _mi_arena_free(segment, mi_segment_size(segment), segment->mem_alignment, segment->mem_align_offset, segment->memid, segment->mem_is_pinned /* pretend not committed to not double count decommits */, tld->stats);
  }
}

// called by threads that are terminating 
void _mi_segment_thread_collect(mi_segments_tld_t* tld) {