1 files changed, 126 insertions, 0 deletions
diff --git a/src/rocksdb/monitoring/instrumented_mutex.h b/src/rocksdb/monitoring/instrumented_mutex.h
new file mode 100644
index 000000000..e5aae34df
--- /dev/null
+++ b/src/rocksdb/monitoring/instrumented_mutex.h
@@ -0,0 +1,126 @@
+//  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 "monitoring/statistics.h"
+#include "port/port.h"
+#include "rocksdb/statistics.h"
+#include "rocksdb/system_clock.h"
+#include "rocksdb/thread_status.h"
+#include "util/stop_watch.h"
+
+namespace ROCKSDB_NAMESPACE {
+class InstrumentedCondVar;
+
+// A wrapper class for port::Mutex that provides additional layer
+// for collecting stats and instrumentation.
+class InstrumentedMutex {
+ public:
+  explicit InstrumentedMutex(bool adaptive = false)
+      : mutex_(adaptive), stats_(nullptr), clock_(nullptr), stats_code_(0) {}
+
+  explicit InstrumentedMutex(SystemClock* clock, bool adaptive = false)
+      : mutex_(adaptive), stats_(nullptr), clock_(clock), stats_code_(0) {}
+
+  InstrumentedMutex(Statistics* stats, SystemClock* clock, int stats_code,
+                    bool adaptive = false)
+      : mutex_(adaptive),
+        stats_(stats),
+        clock_(clock),
+        stats_code_(stats_code) {}
+
+#ifdef COERCE_CONTEXT_SWITCH
+  InstrumentedMutex(Statistics* stats, SystemClock* clock, int stats_code,
+                    InstrumentedCondVar* bg_cv, bool adaptive = false)
+      : mutex_(adaptive),
+        stats_(stats),
+        clock_(clock),
+        stats_code_(stats_code),
+        bg_cv_(bg_cv) {}
+#endif
+
+  void Lock();
+
+  void Unlock() { mutex_.Unlock(); }
+
+  void AssertHeld() { mutex_.AssertHeld(); }
+
+ private:
+  void LockInternal();
+  friend class InstrumentedCondVar;
+  port::Mutex mutex_;
+  Statistics* stats_;
+  SystemClock* clock_;
+  int stats_code_;
+#ifdef COERCE_CONTEXT_SWITCH
+  InstrumentedCondVar* bg_cv_ = nullptr;
+#endif
+};
+
+class ALIGN_AS(CACHE_LINE_SIZE) CacheAlignedInstrumentedMutex
+    : public InstrumentedMutex {
+  using InstrumentedMutex::InstrumentedMutex;
+};
+static_assert(alignof(CacheAlignedInstrumentedMutex) != CACHE_LINE_SIZE ||
+              sizeof(CacheAlignedInstrumentedMutex) % CACHE_LINE_SIZE == 0);
+
+// RAII wrapper for InstrumentedMutex
+class InstrumentedMutexLock {
+ public:
+  explicit InstrumentedMutexLock(InstrumentedMutex* mutex) : mutex_(mutex) {
+    mutex_->Lock();
+  }
+
+  ~InstrumentedMutexLock() { mutex_->Unlock(); }
+
+ private:
+  InstrumentedMutex* const mutex_;
+  InstrumentedMutexLock(const InstrumentedMutexLock&) = delete;
+  void operator=(const InstrumentedMutexLock&) = delete;
+};
+
+// RAII wrapper for temporary releasing InstrumentedMutex inside
+// InstrumentedMutexLock
+class InstrumentedMutexUnlock {
+ public:
+  explicit InstrumentedMutexUnlock(InstrumentedMutex* mutex) : mutex_(mutex) {
+    mutex_->Unlock();
+  }
+
+  ~InstrumentedMutexUnlock() { mutex_->Lock(); }
+
+ private:
+  InstrumentedMutex* const mutex_;
+  InstrumentedMutexUnlock(const InstrumentedMutexUnlock&) = delete;
+  void operator=(const InstrumentedMutexUnlock&) = delete;
+};
+
+class InstrumentedCondVar {
+ public:
+  explicit InstrumentedCondVar(InstrumentedMutex* instrumented_mutex)
+      : cond_(&(instrumented_mutex->mutex_)),
+        stats_(instrumented_mutex->stats_),
+        clock_(instrumented_mutex->clock_),
+        stats_code_(instrumented_mutex->stats_code_) {}
+
+  void Wait();
+
+  bool TimedWait(uint64_t abs_time_us);
+
+  void Signal() { cond_.Signal(); }
+
+  void SignalAll() { cond_.SignalAll(); }
+
+ private:
+  void WaitInternal();
+  bool TimedWaitInternal(uint64_t abs_time_us);
+  port::CondVar cond_;
+  Statistics* stats_;
+  SystemClock* clock_;
+  int stats_code_;
+};
+
+}  // namespace ROCKSDB_NAMESPACE