#define _GNU_SOURCE
#define __STDC_FORMAT_MACROS
#include <sys/epoll.h>
#include <stdio.h> /* for perror() */
#include <unistd.h> /* for syscall() */
#include <sys/syscall.h> /* for __NR_* definitions */
#include <linux/aio_abi.h> /* for AIO types and constants */
#include <fcntl.h> /* O_RDWR */
#include <string.h> /* memset() */
#include <inttypes.h> /* uint64_t */
#include <stdlib.h>
#define TEST_FILE "aio_test_file"
#define TEST_FILE_SIZE (128 * 1024)
#define NUM_EVENTS 128
#define ALIGN_SIZE 512
#define RD_WR_SIZE 1024
inline int io_setup(unsigned nr, aio_context_t *ctxp)
{
return syscall(__NR_io_setup, nr, ctxp);
}
inline int io_submit(aio_context_t ctx, long nr, struct iocb **iocbpp)
{
return syscall(__NR_io_submit, ctx, nr, iocbpp);
}
inline int io_getevents(aio_context_t ctx, long min_nr, long max_nr,
struct io_event *events, struct timespec *timeout)
{
return syscall(__NR_io_getevents, ctx, min_nr, max_nr, events, timeout);
}
inline int io_destroy(aio_context_t ctx)
{
return syscall(__NR_io_destroy, ctx);
}
inline int eventfd2(unsigned int initval, int flags)
{
return syscall(__NR_eventfd2, initval, flags);
}
struct custom_iocb
{
struct iocb iocb;
int nth_request;
};
typedef void io_callback_t(aio_context_t ctx, struct iocb *iocb, long res, long res2);
void aio_callback(aio_context_t ctx, struct iocb *iocb, long res, long res2)
{
struct custom_iocb *iocbp = (struct custom_iocb *)iocb;
printf("nth_request: %d, request_type: %s, offset: %lld, length: %lu, res: %ld, res2: %ld\n",
iocbp->nth_request, (iocb->aio_lio_opcode == IOCB_CMD_PREAD) ? "READ" : "WRITE",
iocb->aio_offset, iocb->aio_nbytes, res, res2);
}
int main(int argc, char *argv[])
{
int efd, fd, epfd;
aio_context_t ctx;
struct timespec tms;
struct io_event events[NUM_EVENTS];
struct custom_iocb iocbs[NUM_EVENTS];
struct iocb *iocbps[NUM_EVENTS];
struct custom_iocb *iocbp;
int i, j, r;
void *buf;
void *aio_buf;
struct epoll_event epevent;
efd = eventfd2(0, O_NONBLOCK | O_CLOEXEC);
if (efd == -1) {
perror("eventfd2");
return 2;
}
fd = open(TEST_FILE, O_RDWR | O_CREAT | O_DIRECT, 0644);
if (fd == -1) {
perror("open");
return 3;
}
ftruncate(fd, TEST_FILE_SIZE);
ctx = 0;
if (io_setup(NUM_EVENTS, &ctx)) {
perror("io_setup");
return 4;
}
if (posix_memalign(&buf, ALIGN_SIZE, RD_WR_SIZE * NUM_EVENTS)) {
perror("posix_memalign");
return 5;
}
printf("buf: %p\n", buf);
for (i = 0, iocbp = iocbs; i < NUM_EVENTS; ++i, ++iocbp) {
aio_buf = (void *)((char *)buf + (i*RD_WR_SIZE));
memset(aio_buf, 0, RD_WR_SIZE);
iocbp->iocb.aio_fildes = fd;
iocbp->iocb.aio_lio_opcode = IOCB_CMD_PREAD;
iocbp->iocb.aio_buf = (uint64_t)aio_buf;
iocbp->iocb.aio_offset = i * RD_WR_SIZE;
iocbp->iocb.aio_nbytes = RD_WR_SIZE;
iocbp->iocb.aio_flags = IOCB_FLAG_RESFD;
iocbp->iocb.aio_resfd = efd;
iocbp->iocb.aio_data = (__u64)aio_callback;
iocbp->nth_request = i + 1;
iocbps[i] = &iocbp->iocb;
}
if (io_submit(ctx, NUM_EVENTS, iocbps) != NUM_EVENTS) {
perror("io_submit");
return 6;
}
epfd = epoll_create(1);
if (epfd == -1) {
perror("epoll_create");
return 7;
}
epevent.events = EPOLLIN | EPOLLET;
epevent.data.ptr = NULL;
if (epoll_ctl(epfd, EPOLL_CTL_ADD, efd, &epevent)) {
perror("epoll_ctl");
return 8;
}
i = 0;
while (i < NUM_EVENTS) {
uint64_t finished_aio;
if (epoll_wait(epfd, &epevent, 1, -1) != 1) {
perror("epoll_wait");
return 9;
}
if (read(efd, &finished_aio, sizeof(finished_aio)) != sizeof(finished_aio)) {
perror("read");
return 10;
}
printf("finished io number: %"PRIu64"\n", finished_aio);
while (finished_aio > 0) {
tms.tv_sec = 0;
tms.tv_nsec = 0;
r = io_getevents(ctx, 1, NUM_EVENTS, events, &tms);
if (r > 0) {
for (j = 0; j < r; ++j) {
((io_callback_t *)(events[j].data))(ctx, (struct iocb *)events[j].obj, events[j].res, events[j].res2);
}
i += r;
finished_aio -= r;
}
}
}
close(epfd);
free(buf);
io_destroy(ctx);
close(fd);
close(efd);
remove(TEST_FILE);
return 0;
}
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