@@ -481,7 +481,7 @@ static void posix_aio_read(void *opaque)
PosixAioState *s = opaque;
ssize_t len;
- /* read all bytes from signal pipe */
+ /* read all bytes from eventfd or signal pipe */
for (;;) {
char bytes[16];
@@ -506,10 +506,14 @@ static PosixAioState *posix_aio_state;
static void posix_aio_notify_event(void)
{
- char byte = 0;
+ /* Write 8 bytes to be compatible with eventfd. */
+ static const uint64_t val = 1;
ssize_t ret;
- ret = write(posix_aio_state->wfd, &byte, sizeof(byte));
+ do {
+ ret = write(posix_aio_state->wfd, &val, sizeof(val));
+ } while (ret < 0 && errno == EINTR);
+
if (ret < 0 && errno != EAGAIN)
die("write()");
}
@@ -623,7 +627,7 @@ int paio_init(void)
s = g_malloc(sizeof(PosixAioState));
s->first_aio = NULL;
- if (qemu_pipe(fds) == -1) {
+ if (qemu_eventfd(fds) == -1) {
fprintf(stderr, "failed to create pipe\n");
g_free(s);
return -1;
Use qemu_eventfd for signaling POSIX AIO completions. If native eventfd suport is available, this avoids multiple read accesses to drain multiple pending signals. As before we use a pipe if eventfd is not supported. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> --- posix-aio-compat.c | 12 ++++++++---- 1 files changed, 8 insertions(+), 4 deletions(-)