Function _mi_segment_cache_push

3rd/mimalloc-2.0.9/src/segment-cache.c:206–263

}

mi_decl_noinline bool _mi_segment_cache_push(void* start, size_t size, size_t memid, const mi_commit_mask_t* commit_mask, const mi_commit_mask_t* decommit_mask, bool is_large, bool is_pinned, mi_os_tld_t* tld)
{
#ifdef MI_CACHE_DISABLE
  return false;
#else

  // only for normal segment blocks
  if (size != MI_SEGMENT_SIZE || ((uintptr_t)start % MI_SEGMENT_ALIGN) != 0) return false;

  // numa node determines start field
  int numa_node = _mi_os_numa_node(NULL);
  size_t start_field = 0;
  if (numa_node > 0) {
    start_field = (MI_CACHE_FIELDS / _mi_os_numa_node_count())*numa_node;
    if (start_field >= MI_CACHE_FIELDS) start_field = 0;
  }

  // purge expired entries
  mi_segment_cache_purge(false /* limit purges to a constant N */, false /* don't force unexpired */, tld);

  // find an available slot
  mi_bitmap_index_t bitidx;
  bool claimed = _mi_bitmap_try_find_from_claim(cache_inuse, MI_CACHE_FIELDS, start_field, 1, &bitidx);
  if (!claimed) return false;

  mi_assert_internal(_mi_bitmap_is_claimed(cache_available, MI_CACHE_FIELDS, 1, bitidx));
  mi_assert_internal(_mi_bitmap_is_claimed(cache_available_large, MI_CACHE_FIELDS, 1, bitidx));
#if MI_DEBUG>1
  if (is_pinned || is_large) {
    mi_assert_internal(mi_commit_mask_is_full(commit_mask));
  }
#endif

  // set the slot
  mi_cache_slot_t* slot = &cache[mi_bitmap_index_bit(bitidx)];
  slot->p = start;
  slot->memid = memid;
  slot->is_pinned = is_pinned;
  mi_atomic_storei64_relaxed(&slot->expire,(mi_msecs_t)0);
  slot->commit_mask = *commit_mask;
  slot->decommit_mask = *decommit_mask;
  if (!mi_commit_mask_is_empty(commit_mask) && !is_large && !is_pinned && mi_option_is_enabled(mi_option_allow_decommit)) {
    long delay = mi_option_get(mi_option_segment_decommit_delay);
    if (delay == 0) {
      _mi_abandoned_await_readers(); // wait until safe to decommit
      mi_commit_mask_decommit(&slot->commit_mask, start, MI_SEGMENT_SIZE, tld->stats);
      mi_commit_mask_create_empty(&slot->decommit_mask);
    }
    else {
      mi_atomic_storei64_release(&slot->expire, _mi_clock_now() + delay);
    }
  }

  // make it available
  _mi_bitmap_unclaim((is_large ? cache_available_large : cache_available), MI_CACHE_FIELDS, 1, bitidx);
  return true;
#endif
}