static AioContext *qemu_aio_context;
+AioContext *qemu_get_aio_context(void)
+{
+ return qemu_aio_context;
+}
+
void qemu_notify_event(void)
{
if (!qemu_aio_context) {
return 0;
}
-static fd_set rfds, wfds, xfds;
-static int nfds;
-static GPollFD poll_fds[1024 * 2]; /* this is probably overkill */
-static int n_poll_fds;
static int max_priority;
-/* Load rfds/wfds/xfds into gpollfds. Will be removed a few commits later. */
-static void gpollfds_from_select(void)
-{
- int fd;
- for (fd = 0; fd <= nfds; fd++) {
- int events = 0;
- if (FD_ISSET(fd, &rfds)) {
- events |= G_IO_IN | G_IO_HUP | G_IO_ERR;
- }
- if (FD_ISSET(fd, &wfds)) {
- events |= G_IO_OUT | G_IO_ERR;
- }
- if (FD_ISSET(fd, &xfds)) {
- events |= G_IO_PRI;
- }
- if (events) {
- GPollFD pfd = {
- .fd = fd,
- .events = events,
- };
- g_array_append_val(gpollfds, pfd);
- }
- }
-}
-
-/* Store gpollfds revents into rfds/wfds/xfds. Will be removed a few commits
- * later.
- */
-static void gpollfds_to_select(int ret)
-{
- int i;
-
- FD_ZERO(&rfds);
- FD_ZERO(&wfds);
- FD_ZERO(&xfds);
-
- if (ret <= 0) {
- return;
- }
-
- for (i = 0; i < gpollfds->len; i++) {
- int fd = g_array_index(gpollfds, GPollFD, i).fd;
- int revents = g_array_index(gpollfds, GPollFD, i).revents;
-
- if (revents & (G_IO_IN | G_IO_HUP | G_IO_ERR)) {
- FD_SET(fd, &rfds);
- }
- if (revents & (G_IO_OUT | G_IO_ERR)) {
- FD_SET(fd, &wfds);
- }
- if (revents & G_IO_PRI) {
- FD_SET(fd, &xfds);
- }
- }
-}
-
#ifndef _WIN32
-static void glib_select_fill(int *max_fd, fd_set *rfds, fd_set *wfds,
- fd_set *xfds, uint32_t *cur_timeout)
+static int glib_pollfds_idx;
+static int glib_n_poll_fds;
+
+static void glib_pollfds_fill(uint32_t *cur_timeout)
{
GMainContext *context = g_main_context_default();
- int i;
int timeout = 0;
+ int n;
g_main_context_prepare(context, &max_priority);
- n_poll_fds = g_main_context_query(context, max_priority, &timeout,
- poll_fds, ARRAY_SIZE(poll_fds));
- g_assert(n_poll_fds <= ARRAY_SIZE(poll_fds));
-
- for (i = 0; i < n_poll_fds; i++) {
- GPollFD *p = &poll_fds[i];
-
- if ((p->events & G_IO_IN)) {
- FD_SET(p->fd, rfds);
- *max_fd = MAX(*max_fd, p->fd);
- }
- if ((p->events & G_IO_OUT)) {
- FD_SET(p->fd, wfds);
- *max_fd = MAX(*max_fd, p->fd);
- }
- if ((p->events & G_IO_ERR)) {
- FD_SET(p->fd, xfds);
- *max_fd = MAX(*max_fd, p->fd);
- }
- }
+ glib_pollfds_idx = gpollfds->len;
+ n = glib_n_poll_fds;
+ do {
+ GPollFD *pfds;
+ glib_n_poll_fds = n;
+ g_array_set_size(gpollfds, glib_pollfds_idx + glib_n_poll_fds);
+ pfds = &g_array_index(gpollfds, GPollFD, glib_pollfds_idx);
+ n = g_main_context_query(context, max_priority, &timeout, pfds,
+ glib_n_poll_fds);
+ } while (n != glib_n_poll_fds);
if (timeout >= 0 && timeout < *cur_timeout) {
*cur_timeout = timeout;
}
}
-static void glib_select_poll(fd_set *rfds, fd_set *wfds, fd_set *xfds,
- bool err)
+static void glib_pollfds_poll(void)
{
GMainContext *context = g_main_context_default();
+ GPollFD *pfds = &g_array_index(gpollfds, GPollFD, glib_pollfds_idx);
- if (!err) {
- int i;
-
- for (i = 0; i < n_poll_fds; i++) {
- GPollFD *p = &poll_fds[i];
-
- if ((p->events & G_IO_IN) && FD_ISSET(p->fd, rfds)) {
- p->revents |= G_IO_IN;
- }
- if ((p->events & G_IO_OUT) && FD_ISSET(p->fd, wfds)) {
- p->revents |= G_IO_OUT;
- }
- if ((p->events & G_IO_ERR) && FD_ISSET(p->fd, xfds)) {
- p->revents |= G_IO_ERR;
- }
- }
- }
-
- if (g_main_context_check(context, max_priority, poll_fds, n_poll_fds)) {
+ if (g_main_context_check(context, max_priority, pfds, glib_n_poll_fds)) {
g_main_context_dispatch(context);
}
}
+#define MAX_MAIN_LOOP_SPIN (1000)
+
static int os_host_main_loop_wait(uint32_t timeout)
{
int ret;
+ static int spin_counter;
+
+ glib_pollfds_fill(&timeout);
+
+ /* If the I/O thread is very busy or we are incorrectly busy waiting in
+ * the I/O thread, this can lead to starvation of the BQL such that the
+ * VCPU threads never run. To make sure we can detect the later case,
+ * print a message to the screen. If we run into this condition, create
+ * a fake timeout in order to give the VCPU threads a chance to run.
+ */
+ if (spin_counter > MAX_MAIN_LOOP_SPIN) {
+ static bool notified;
+
+ if (!notified) {
+ fprintf(stderr,
+ "main-loop: WARNING: I/O thread spun for %d iterations\n",
+ MAX_MAIN_LOOP_SPIN);
+ notified = true;
+ }
- glib_select_fill(&nfds, &rfds, &wfds, &xfds, &timeout);
+ timeout = 1;
+ }
if (timeout > 0) {
+ spin_counter = 0;
qemu_mutex_unlock_iothread();
+ } else {
+ spin_counter++;
}
- /* We'll eventually drop fd_set completely. But for now we still have
- * *_fill() and *_poll() functions that use rfds/wfds/xfds.
- */
- gpollfds_from_select();
-
ret = g_poll((GPollFD *)gpollfds->data, gpollfds->len, timeout);
- gpollfds_to_select(ret);
-
if (timeout > 0) {
qemu_mutex_lock_iothread();
}
- glib_select_poll(&rfds, &wfds, &xfds, (ret < 0));
+ glib_pollfds_poll();
return ret;
}
#else
static int os_host_main_loop_wait(uint32_t timeout)
{
GMainContext *context = g_main_context_default();
+ GPollFD poll_fds[1024 * 2]; /* this is probably overkill */
int select_ret = 0;
- int g_poll_ret, ret, i;
+ int g_poll_ret, ret, i, n_poll_fds;
PollingEntry *pe;
WaitObjects *w = &wait_objects;
gint poll_timeout;
static struct timeval tv0;
+ fd_set rfds, wfds, xfds;
+ int nfds;
/* XXX: need to suppress polling by better using win32 events */
ret = 0;
* improve socket latency.
*/
- /* This back-and-forth between GPollFDs and select(2) is temporary. We'll
- * drop it in a couple of patches, I promise :).
- */
- gpollfds_from_select();
FD_ZERO(&rfds);
FD_ZERO(&wfds);
FD_ZERO(&xfds);
pollfds_poll(gpollfds, nfds, &rfds, &wfds, &xfds);
}
}
- gpollfds_to_select(select_ret);
return select_ret || g_poll_ret;
}
/* poll any events */
g_array_set_size(gpollfds, 0); /* reset for new iteration */
/* XXX: separate device handlers from system ones */
- nfds = -1;
- FD_ZERO(&rfds);
- FD_ZERO(&wfds);
- FD_ZERO(&xfds);
-
#ifdef CONFIG_SLIRP
slirp_update_timeout(&timeout);
- slirp_select_fill(&nfds, &rfds, &wfds, &xfds);
+ slirp_pollfds_fill(gpollfds);
#endif
- qemu_iohandler_fill(&nfds, &rfds, &wfds, &xfds);
+ qemu_iohandler_fill(gpollfds);
ret = os_host_main_loop_wait(timeout);
- qemu_iohandler_poll(&rfds, &wfds, &xfds, ret);
+ qemu_iohandler_poll(gpollfds, ret);
#ifdef CONFIG_SLIRP
- slirp_select_poll(&rfds, &wfds, &xfds, (ret < 0));
+ slirp_pollfds_poll(gpollfds, (ret < 0));
#endif
qemu_run_all_timers();
projects / qemu.git / blobdiff