Method DeleteArena

BeefRT/gperftools/src/base/low_level_alloc.cc:314–346

L < arena->mu, L < arena->arena->mu

// L < arena->mu, L < arena->arena->mu
bool LowLevelAlloc::DeleteArena(Arena *arena) {
  RAW_CHECK(arena != 0 && arena != &default_arena && arena != &unhooked_arena,
            "may not delete default arena");
  ArenaLock section(arena);
  bool empty = (arena->allocation_count == 0);
  section.Leave();
  if (empty) {
    while (arena->freelist.next[0] != 0) {
      AllocList *region = arena->freelist.next[0];
      size_t size = region->header.size;
      arena->freelist.next[0] = region->next[0];
      RAW_CHECK(region->header.magic ==
                Magic(kMagicUnallocated, &region->header),
                "bad magic number in DeleteArena()");
      RAW_CHECK(region->header.arena == arena,
                "bad arena pointer in DeleteArena()");
      RAW_CHECK(size % arena->pagesize == 0,
                "empty arena has non-page-aligned block size");
      RAW_CHECK(reinterpret_cast<intptr_t>(region) % arena->pagesize == 0,
                "empty arena has non-page-aligned block");
      int munmap_result;
      if ((arena->flags & LowLevelAlloc::kAsyncSignalSafe) == 0) {
        munmap_result = munmap(region, size);
      } else {
        munmap_result = MallocHook::UnhookedMUnmap(region, size);
      }
      RAW_CHECK(munmap_result == 0,
                "LowLevelAlloc::DeleteArena:  munmap failed address");
    }
    Free(arena);
  }
  return empty;
}

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