From 19fcec84d8d7d21e796c7624e521b60d28ee21ed Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Sun, 7 Apr 2024 20:45:59 +0200
Subject: Adding upstream version 16.2.11+ds.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 src/rocksdb/util/rate_limiter.h | 113 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 113 insertions(+)
 create mode 100644 src/rocksdb/util/rate_limiter.h

(limited to 'src/rocksdb/util/rate_limiter.h')

diff --git a/src/rocksdb/util/rate_limiter.h b/src/rocksdb/util/rate_limiter.h
new file mode 100644
index 000000000..5f047a567
--- /dev/null
+++ b/src/rocksdb/util/rate_limiter.h
@@ -0,0 +1,113 @@
+//  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).
+//
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+
+#pragma once
+
+#include <algorithm>
+#include <atomic>
+#include <chrono>
+#include <deque>
+#include "port/port.h"
+#include "rocksdb/env.h"
+#include "rocksdb/rate_limiter.h"
+#include "util/mutexlock.h"
+#include "util/random.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+class GenericRateLimiter : public RateLimiter {
+ public:
+  GenericRateLimiter(int64_t refill_bytes, int64_t refill_period_us,
+                     int32_t fairness, RateLimiter::Mode mode, Env* env,
+                     bool auto_tuned);
+
+  virtual ~GenericRateLimiter();
+
+  // This API allows user to dynamically change rate limiter's bytes per second.
+  virtual void SetBytesPerSecond(int64_t bytes_per_second) override;
+
+  // Request for token to write bytes. If this request can not be satisfied,
+  // the call is blocked. Caller is responsible to make sure
+  // bytes <= GetSingleBurstBytes()
+  using RateLimiter::Request;
+  virtual void Request(const int64_t bytes, const Env::IOPriority pri,
+                       Statistics* stats) override;
+
+  virtual int64_t GetSingleBurstBytes() const override {
+    return refill_bytes_per_period_.load(std::memory_order_relaxed);
+  }
+
+  virtual int64_t GetTotalBytesThrough(
+      const Env::IOPriority pri = Env::IO_TOTAL) const override {
+    MutexLock g(&request_mutex_);
+    if (pri == Env::IO_TOTAL) {
+      return total_bytes_through_[Env::IO_LOW] +
+             total_bytes_through_[Env::IO_HIGH];
+    }
+    return total_bytes_through_[pri];
+  }
+
+  virtual int64_t GetTotalRequests(
+      const Env::IOPriority pri = Env::IO_TOTAL) const override {
+    MutexLock g(&request_mutex_);
+    if (pri == Env::IO_TOTAL) {
+      return total_requests_[Env::IO_LOW] + total_requests_[Env::IO_HIGH];
+    }
+    return total_requests_[pri];
+  }
+
+  virtual int64_t GetBytesPerSecond() const override {
+    return rate_bytes_per_sec_;
+  }
+
+ private:
+  void Refill();
+  int64_t CalculateRefillBytesPerPeriod(int64_t rate_bytes_per_sec);
+  Status Tune();
+
+  uint64_t NowMicrosMonotonic(Env* env) {
+    return env->NowNanos() / std::milli::den;
+  }
+
+  // This mutex guard all internal states
+  mutable port::Mutex request_mutex_;
+
+  const int64_t kMinRefillBytesPerPeriod = 100;
+
+  const int64_t refill_period_us_;
+
+  int64_t rate_bytes_per_sec_;
+  // This variable can be changed dynamically.
+  std::atomic<int64_t> refill_bytes_per_period_;
+  Env* const env_;
+
+  bool stop_;
+  port::CondVar exit_cv_;
+  int32_t requests_to_wait_;
+
+  int64_t total_requests_[Env::IO_TOTAL];
+  int64_t total_bytes_through_[Env::IO_TOTAL];
+  int64_t available_bytes_;
+  int64_t next_refill_us_;
+
+  int32_t fairness_;
+  Random rnd_;
+
+  struct Req;
+  Req* leader_;
+  std::deque<Req*> queue_[Env::IO_TOTAL];
+
+  bool auto_tuned_;
+  int64_t num_drains_;
+  int64_t prev_num_drains_;
+  const int64_t max_bytes_per_sec_;
+  std::chrono::microseconds tuned_time_;
+};
+
+}  // namespace ROCKSDB_NAMESPACE
-- 
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