Implement a FIO engine for testing cluster I/O

epoll_manager.cpp

@@ -0,0 +1,89 @@
+#include <sys/epoll.h>
+#include <sys/poll.h>
+#include <unistd.h>
+
+#include "epoll_manager.h"
+
+#define MAX_EPOLL_EVENTS 64
+
+epoll_manager_t::epoll_manager_t(ring_loop_t *ringloop)
+{
+    this->ringloop = ringloop;
+
+    epoll_fd = epoll_create(1);
+    if (epoll_fd < 0)
+    {
+        throw std::runtime_error(std::string("epoll_create: ") + strerror(errno));
+    }
+
+    tfd = new timerfd_manager_t([this](int fd, std::function<void(int, int)> handler) { set_fd_handler(fd, handler); });
+
+    handle_epoll_events();
+}
+
+epoll_manager_t::~epoll_manager_t()
+{
+    if (tfd)
+    {
+        delete tfd;
+        tfd = NULL;
+    }
+    close(epoll_fd);
+}
+
+void epoll_manager_t::set_fd_handler(int fd, std::function<void(int, int)> handler)
+{
+    if (handler != NULL)
+    {
+        bool exists = epoll_handlers.find(fd) != epoll_handlers.end();
+        epoll_event ev;
+        ev.data.fd = fd;
+        ev.events = EPOLLOUT | EPOLLIN | EPOLLRDHUP | EPOLLET;
+        if (epoll_ctl(epoll_fd, exists ? EPOLL_CTL_MOD : EPOLL_CTL_ADD, fd, &ev) < 0)
+        {
+            throw std::runtime_error(std::string("epoll_ctl: ") + strerror(errno));
+        }
+        epoll_handlers[fd] = handler;
+    }
+    else
+    {
+        if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, fd, NULL) < 0 && errno != ENOENT)
+        {
+            throw std::runtime_error(std::string("epoll_ctl: ") + strerror(errno));
+        }
+        epoll_handlers.erase(fd);
+    }
+}
+
+void epoll_manager_t::handle_epoll_events()
+{
+    io_uring_sqe *sqe = ringloop->get_sqe();
+    if (!sqe)
+    {
+        throw std::runtime_error("can't get SQE, will fall out of sync with EPOLLET");
+    }
+    ring_data_t *data = ((ring_data_t*)sqe->user_data);
+    my_uring_prep_poll_add(sqe, epoll_fd, POLLIN);
+    data->callback = [this](ring_data_t *data)
+    {
+        if (data->res < 0)
+        {
+            throw std::runtime_error(std::string("epoll failed: ") + strerror(-data->res));
+        }
+        handle_epoll_events();
+    };
+    ringloop->submit();
+    int nfds;
+    epoll_event events[MAX_EPOLL_EVENTS];
+restart:
+    nfds = epoll_wait(epoll_fd, events, MAX_EPOLL_EVENTS, 0);
+    for (int i = 0; i < nfds; i++)
+    {
+        auto & cb = epoll_handlers[events[i].data.fd];
+        cb(events[i].data.fd, events[i].events);
+    }
+    if (nfds == MAX_EPOLL_EVENTS)
+    {
+        goto restart;
+    }
+}