func ReadAt(fd int, off int64, size int) ([]byte, error) {
idx := <-idle_event
retch := aio_result_map[idx]
defer func() { idle_event <- idx }()
var cb *C.struct_iocb = &cbs[idx]
var read_buf unsafe.Pointer
C.posix_memalign(&read_buf, pagesize, C.size_t(size))
defer C.free(read_buf)
C.io_prep_pread(cb, C.int(fd), read_buf, C.size_t(size), C.longlong(off))
cbs[idx].data = unsafe.Pointer(&idx)
aio_lock.Lock()
rt := C.io_submit(ctx, 1, &cb)
if int(rt) < 0 {
aio_lock.Unlock()
return nil, errors.New("io submit failed")
}
aiocount++
aio_lock.Unlock()
select {
case have_aio_event <- 0:
default:
}
ret := <-retch
return ret.buf, ret.err
}
func (sch *aioScheduler) Read(fd int, buf []byte, off uint64) (int, error) {
iocb := &C.iocb_t{}
sh := *(*reflect.SliceHeader)(unsafe.Pointer(&buf))
C.io_prep_pread(iocb, C.int(fd), unsafe.Pointer(sh.Data), C.size_t(sh.Len), C.longlong(off))
ev, err := sch.submit(iocb)
if err != nil {
return 0, err
}
return int(ev.wait()), nil
}