ceph/src/crimson/common/throttle.h

   1 // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:nil -*-
   2 // vim: ts=8 sw=2 smarttab
   3
   4 #pragma once
   5
   6 #include <seastar/core/condition-variable.hh>
   7 // pull seastar::timer<...>::timer definitions. FIX SEASTAR or reactor.hh
   8 // is obligatory and should be included everywhere?
   9 #include <seastar/core/reactor.hh>
  10
  11 #include "common/ThrottleInterface.h"
  12
  13 namespace crimson::common {
  14
  15 class Throttle final : public ThrottleInterface {
  16   size_t max = 0;
  17   size_t count = 0;
  18   size_t pending = 0;
  19   // we cannot change the "count" of seastar::semaphore after it is created,
  20   // so use condition_variable instead.
  21   seastar::condition_variable on_free_slots;
  22 public:
  23   explicit Throttle(size_t m)
  24     : max(m)
  25   {}
  26   int64_t take(int64_t c = 1) override;
  27   int64_t put(int64_t c = 1) override;
  28   seastar::future<> get(size_t c);
  29   size_t get_current() const {
  30     return count;
  31   }
  32   size_t get_max() const {
  33     return max;
  34   }
  35   size_t get_pending() const {
  36     return pending;
  37   }
  38   void reset_max(size_t m);
  39 private:
  40   bool _should_wait(size_t c) const;
  41 };
  42
  43 } // namespace crimson::common