Function mi_segment_perhaps_decommit

3rd/mimalloc-2.0.9/src/segment.c:509–546

}

static void mi_segment_perhaps_decommit(mi_segment_t* segment, uint8_t* p, size_t size, mi_stats_t* stats) {
  if (!segment->allow_decommit) return;
  if (mi_option_get(mi_option_decommit_delay) == 0) {
    mi_segment_commitx(segment, false, p, size, stats);
  }
  else {
    // register for future decommit in the decommit mask
    uint8_t* start = NULL;
    size_t   full_size = 0;
    mi_commit_mask_t mask; 
    mi_segment_commit_mask(segment, true /*conservative*/, p, size, &start, &full_size, &mask);
    if (mi_commit_mask_is_empty(&mask) || full_size==0) return;
    
    // update delayed commit
    mi_assert_internal(segment->decommit_expire > 0 || mi_commit_mask_is_empty(&segment->decommit_mask));      
    mi_commit_mask_t cmask;
    mi_commit_mask_create_intersect(&segment->commit_mask, &mask, &cmask);  // only decommit what is committed; span_free may try to decommit more
    mi_commit_mask_set(&segment->decommit_mask, &cmask);
    mi_msecs_t now = _mi_clock_now();    
    if (segment->decommit_expire == 0) {
      // no previous decommits, initialize now
      segment->decommit_expire = now + mi_option_get(mi_option_decommit_delay);
    }
    else if (segment->decommit_expire <= now) {
      // previous decommit mask already expired
      if (segment->decommit_expire + mi_option_get(mi_option_decommit_extend_delay) <= now) {
        mi_segment_delayed_decommit(segment, true, stats);
      }
      else {
        segment->decommit_expire = now + mi_option_get(mi_option_decommit_extend_delay); // (mi_option_get(mi_option_decommit_delay) / 8); // wait a tiny bit longer in case there is a series of free's
      }
    }
    else {
      // previous decommit mask is not yet expired, increase the expiration by a bit.
      segment->decommit_expire += mi_option_get(mi_option_decommit_extend_delay);
    }
  }  
}

static void mi_segment_delayed_decommit(mi_segment_t* segment, bool force, mi_stats_t* stats) {
  if (!segment->allow_decommit || mi_commit_mask_is_empty(&segment->decommit_mask)) return;