Function ExtractStats

BeefRT/gperftools/src/tcmalloc.cc:319–354

Get stats into "r". Also, if class_count != NULL, class_count[k] will be set to the total number of objects of size class k in the central cache, transfer cache, and per-thread caches. If small_spans is non-NULL, it is filled. Same for large_spans.

// central cache, transfer cache, and per-thread caches. If small_spans
// is non-NULL, it is filled.  Same for large_spans.
static void ExtractStats(TCMallocStats* r, uint64_t* class_count,
                         PageHeap::SmallSpanStats* small_spans,
                         PageHeap::LargeSpanStats* large_spans) {
  r->central_bytes = 0;
  r->transfer_bytes = 0;
  for (int cl = 0; cl < kNumClasses; ++cl) {
    const int length = Static::central_cache()[cl].length();
    const int tc_length = Static::central_cache()[cl].tc_length();
    const size_t cache_overhead = Static::central_cache()[cl].OverheadBytes();
    const size_t size = static_cast<uint64_t>(
        Static::sizemap()->ByteSizeForClass(cl));
    r->central_bytes += (size * length) + cache_overhead;
    r->transfer_bytes += (size * tc_length);
    if (class_count) {
      // Sum the lengths of all per-class freelists, except the per-thread
      // freelists, which get counted when we call GetThreadStats(), below.
      class_count[cl] = length + tc_length;
    }

  }

  // Add stats from per-thread heaps
  r->thread_bytes = 0;
  { // scope
    SpinLockHolder h(Static::pageheap_lock());
    ThreadCache::GetThreadStats(&r->thread_bytes, class_count);
    r->metadata_bytes = TCMALLOC_NAMESPACE::metadata_system_bytes();
    r->pageheap = Static::pageheap()->stats();
    if (small_spans != NULL) {
      Static::pageheap()->GetSmallSpanStats(small_spans);
    }
    if (large_spans != NULL) {
      Static::pageheap()->GetLargeSpanStats(large_spans);
    }
  }
}

static double PagesToMiB(uint64_t pages) {
  return (pages << kPageShift) / 1048576.0;