update ceph source to reef 18.1.2

[ceph.git] / ceph / src / rocksdb / file / readahead_file_info.h

diff --git a/ceph/src/rocksdb/file/readahead_file_info.h b/ceph/src/rocksdb/file/readahead_file_info.h
new file mode 100644 (file)
index 0000000..f0208bf
--- /dev/null
+++ b/ceph/src/rocksdb/file/readahead_file_info.h
@@ -0,0 +1,33 @@
+// Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+#pragma once
+
+#include <cstddef>
+#include <cstdint>
+
+#include "rocksdb/rocksdb_namespace.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+// struct ReadaheadFileInfo contains readahead information that is passed from
+// one file to another file per level during iterations. This information helps
+// iterators to carry forward the internal automatic prefetching readahead value
+// to next file during sequential reads instead of starting from the scratch.
+
+struct ReadaheadFileInfo {
+  struct ReadaheadInfo {
+    size_t readahead_size = 0;
+    int64_t num_file_reads = 0;
+  };
+
+  // Used by Data block iterators to update readahead info.
+  ReadaheadInfo data_block_readahead_info;
+
+  // Used by Index block iterators to update readahead info.
+  ReadaheadInfo index_block_readahead_info;
+};
+
+}  // namespace ROCKSDB_NAMESPACE