Files
scylladb/utils/rate_limiter.cc
Duarte Nunes fa2b0384d2 Replace std::experimental types with C++17 std version.
Replace stdx::optional and stdx::string_view with the C++ std
counterparts.

Some instances of boost::variant were also replaced with std::variant,
namely those that called seastar::visit.

Scylla now requires GCC 8 to compile.

Signed-off-by: Duarte Nunes <duarte@scylladb.com>
Message-Id: <20190108111141.5369-1-duarte@scylladb.com>
2019-01-08 13:16:36 +02:00

51 lines
1.5 KiB
C++

/*
* Copyright (C) 2015 ScyllaDB
*/
/*
* This file is part of Scylla.
*
* Scylla is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Scylla is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Scylla. If not, see <http://www.gnu.org/licenses/>.
*/
#include "rate_limiter.hh"
utils::rate_limiter::rate_limiter(size_t rate)
: _units_per_s(rate) {
if (_units_per_s != 0) {
_timer.set_callback(std::bind(&rate_limiter::on_timer, this));
_timer.arm(lowres_clock::now() + std::chrono::seconds(1),
std::optional<lowres_clock::duration> {
std::chrono::seconds(1) });
}
}
void utils::rate_limiter::on_timer() {
_sem.signal(_units_per_s - _sem.current());
}
future<> utils::rate_limiter::reserve(size_t u) {
if (_units_per_s == 0) {
return make_ready_future<>();
}
if (u <= _units_per_s) {
return _sem.wait(u);
}
auto n = std::min(u, _units_per_s);
auto r = u - n;
return _sem.wait(n).then([this, r] {
return reserve(r);
});
}