Method ShardedCache

be/src/kudu/util/cache.cc:548–564

class ShardedCache : public Cache {
 public:
  explicit ShardedCache(size_t capacity, const string& id)
        : shard_bits_(DetermineShardBits()) {
    // A cache is often a singleton, so:
    // 1. We reuse its MemTracker if one already exists, and
    // 2. It is directly parented to the root MemTracker.
    mem_tracker_ = MemTracker::FindOrCreateGlobalTracker(
        -1, strings::Substitute("$0-sharded_$1_cache", id, ToString(policy)));

    int num_shards = 1 << shard_bits_;
    const size_t per_shard = (capacity + (num_shards - 1)) / num_shards;
    for (int s = 0; s < num_shards; s++) {
      unique_ptr<CacheShard<policy>> shard(
          new CacheShard<policy>(mem_tracker_.get()));
      shard->SetCapacity(per_shard);
      shards_.push_back(shard.release());
    }
  }

  virtual ~ShardedCache() {
    STLDeleteElements(&shards_);