ceph/src/crimson/thread/Throttle.cc

   1 #include "Throttle.h"
   2
   3 namespace ceph::thread {
   4
   5 int64_t Throttle::take(int64_t c)
   6 {
   7   if (!max) {
   8     return 0;
   9   }
  10   count += c;
  11   return count;
  12 }
  13
  14 int64_t Throttle::put(int64_t c)
  15 {
  16   if (!max) {
  17     return 0;
  18   }
  19   if (!c) {
  20     return count;
  21   }
  22   on_free_slots.signal();
  23   count -= c;
  24   return count;
  25 }
  26
  27 seastar::future<> Throttle::get(size_t c)
  28 {
  29   if (!max) {
  30     return seastar::now();
  31   }
  32   return on_free_slots.wait([this, c] {
  33     return !_should_wait(c);
  34   }).then([this, c] {
  35     count += c;
  36     return seastar::now();
  37   });
  38 }
  39
  40 void Throttle::reset_max(size_t m) {
  41   if (max == m) {
  42     return;
  43   }
  44
  45   if (m > max) {
  46     on_free_slots.signal();
  47   }
  48   max = m;
  49 }
  50
  51 bool Throttle::_should_wait(size_t c) const {
  52   if (!max) {
  53     return false;
  54   }
  55   return ((c <= max && count + c > max) || // normally stay under max
  56           (c >= max && count > max));      // except for large c
  57 }
  58
  59 } // namespace ceph::thread::seastar