vitastor/src/timerfd_manager.cpp

178 行
4.4 KiB
C++

// Copyright (c) Vitaliy Filippov, 2019+
// License: VNPL-1.1 or GNU GPL-2.0+ (see README.md for details)
#include <sys/timerfd.h>
#include <sys/poll.h>
#include <sys/epoll.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <string>
#include <stdexcept>
#include "timerfd_manager.h"
timerfd_manager_t::timerfd_manager_t(std::function<void(int, bool, std::function<void(int, int)>)> set_fd_handler)
{
this->set_fd_handler = set_fd_handler;
wait_state = 0;
timerfd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK);
if (timerfd < 0)
{
throw std::runtime_error(std::string("timerfd_create: ") + strerror(errno));
}
set_fd_handler(timerfd, false, [this](int fd, int events)
{
handle_readable();
});
}
timerfd_manager_t::~timerfd_manager_t()
{
set_fd_handler(timerfd, false, NULL);
close(timerfd);
}
void timerfd_manager_t::inc_timer(timerfd_timer_t & t)
{
t.next.tv_sec += t.micros/1000000;
t.next.tv_nsec += (t.micros%1000000)*1000;
if (t.next.tv_nsec > 1000000000)
{
t.next.tv_sec++;
t.next.tv_nsec -= 1000000000;
}
}
int timerfd_manager_t::set_timer(uint64_t millis, bool repeat, std::function<void(int)> callback)
{
return set_timer_us(millis*1000, repeat, callback);
}
int timerfd_manager_t::set_timer_us(uint64_t micros, bool repeat, std::function<void(int)> callback)
{
int timer_id = id++;
timespec start;
clock_gettime(CLOCK_MONOTONIC, &start);
timers.push_back({
.id = timer_id,
.micros = micros,
.start = start,
.next = start,
.repeat = repeat,
.callback = callback,
});
inc_timer(timers[timers.size()-1]);
set_nearest();
return timer_id;
}
void timerfd_manager_t::clear_timer(int timer_id)
{
for (int i = 0; i < timers.size(); i++)
{
if (timers[i].id == timer_id)
{
timers.erase(timers.begin()+i, timers.begin()+i+1);
if (nearest == i)
{
nearest = -1;
wait_state = wait_state & ~1;
}
else if (nearest > i)
{
nearest--;
}
set_nearest();
break;
}
}
}
void timerfd_manager_t::set_nearest()
{
if (onstack > 0)
{
// Prevent re-entry
return;
}
onstack++;
again:
if (!timers.size())
{
nearest = -1;
itimerspec exp = {};
if (timerfd_settime(timerfd, 0, &exp, NULL))
{
throw std::runtime_error(std::string("timerfd_settime: ") + strerror(errno));
}
wait_state = wait_state & ~1;
}
else
{
nearest = 0;
for (int i = 1; i < timers.size(); i++)
{
if (timers[i].next.tv_sec < timers[nearest].next.tv_sec ||
timers[i].next.tv_sec == timers[nearest].next.tv_sec &&
timers[i].next.tv_nsec < timers[nearest].next.tv_nsec)
{
nearest = i;
}
}
timespec now;
clock_gettime(CLOCK_MONOTONIC, &now);
itimerspec exp = {
.it_interval = { 0 },
.it_value = timers[nearest].next,
};
exp.it_value.tv_sec -= now.tv_sec;
exp.it_value.tv_nsec -= now.tv_nsec;
if (exp.it_value.tv_nsec < 0)
{
exp.it_value.tv_sec--;
exp.it_value.tv_nsec += 1000000000;
}
if (exp.it_value.tv_sec < 0 || exp.it_value.tv_sec == 0 && exp.it_value.tv_nsec <= 0)
{
// It already happened
// FIXME: Postpone to setImmediate/BH to avoid reenterability problems
trigger_nearest();
goto again;
}
if (timerfd_settime(timerfd, 0, &exp, NULL))
{
throw std::runtime_error(std::string("timerfd_settime: ") + strerror(errno));
}
wait_state = wait_state | 1;
}
onstack--;
}
void timerfd_manager_t::handle_readable()
{
uint64_t n;
size_t res = read(timerfd, &n, 8);
if (res == 8 && nearest >= 0)
{
trigger_nearest();
}
wait_state = 0;
set_nearest();
}
void timerfd_manager_t::trigger_nearest()
{
int nearest_id = timers[nearest].id;
auto cb = timers[nearest].callback;
if (timers[nearest].repeat)
{
inc_timer(timers[nearest]);
}
else
{
timers.erase(timers.begin()+nearest, timers.begin()+nearest+1);
}
nearest = -1;
cb(nearest_id);
}