*/
#include "qemu-common.h"
-#include "qemu-timer.h"
+#include "qemu/timer.h"
#include "slirp/slirp.h"
-#include "main-loop.h"
-#include "qemu-aio.h"
+#include "qemu/main-loop.h"
+#include "block/aio.h"
#ifndef _WIN32
-#include "compatfd.h"
+#include "qemu/compatfd.h"
/* If we have signalfd, we mask out the signals we want to handle and then
* use signalfd to listen for them. We rely on whatever the current signal
static AioContext *qemu_aio_context;
+AioContext *qemu_get_aio_context(void)
+{
+ return qemu_aio_context;
+}
+
void qemu_notify_event(void)
{
if (!qemu_aio_context) {
aio_notify(qemu_aio_context);
}
+static GArray *gpollfds;
+
int qemu_init_main_loop(void)
{
int ret;
GSource *src;
init_clocks();
- init_timer_alarm();
+ if (init_timer_alarm() < 0) {
+ fprintf(stderr, "could not initialize alarm timer\n");
+ exit(1);
+ }
- qemu_mutex_lock_iothread();
ret = qemu_signal_init();
if (ret) {
return ret;
}
+ gpollfds = g_array_new(FALSE, FALSE, sizeof(GPollFD));
qemu_aio_context = aio_context_new();
src = aio_get_g_source(qemu_aio_context);
g_source_attach(src, NULL);
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;
#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)
{
- struct timeval tv, *tvarg = NULL;
int ret;
+ static int spin_counter;
- glib_select_fill(&nfds, &rfds, &wfds, &xfds, &timeout);
+ glib_pollfds_fill(&timeout);
- if (timeout < UINT32_MAX) {
- tvarg = &tv;
- tv.tv_sec = timeout / 1000;
- tv.tv_usec = (timeout % 1000) * 1000;
+ /* 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;
+ }
+
+ timeout = 1;
}
if (timeout > 0) {
+ spin_counter = 0;
qemu_mutex_unlock_iothread();
+ } else {
+ spin_counter++;
}
- ret = select(nfds + 1, &rfds, &wfds, &xfds, tvarg);
+ ret = g_poll((GPollFD *)gpollfds->data, gpollfds->len, timeout);
if (timeout > 0) {
qemu_mutex_lock_iothread();
}
- glib_select_poll(&rfds, &wfds, &xfds, (ret < 0));
+ glib_pollfds_poll();
return ret;
}
#else
FD_CONNECT | FD_WRITE | FD_OOB);
}
+static int pollfds_fill(GArray *pollfds, fd_set *rfds, fd_set *wfds,
+ fd_set *xfds)
+{
+ int nfds = -1;
+ int i;
+
+ for (i = 0; i < pollfds->len; i++) {
+ GPollFD *pfd = &g_array_index(pollfds, GPollFD, i);
+ int fd = pfd->fd;
+ int events = pfd->events;
+ if (events & (G_IO_IN | G_IO_HUP | G_IO_ERR)) {
+ FD_SET(fd, rfds);
+ nfds = MAX(nfds, fd);
+ }
+ if (events & (G_IO_OUT | G_IO_ERR)) {
+ FD_SET(fd, wfds);
+ nfds = MAX(nfds, fd);
+ }
+ if (events & G_IO_PRI) {
+ FD_SET(fd, xfds);
+ nfds = MAX(nfds, fd);
+ }
+ }
+ return nfds;
+}
+
+static void pollfds_poll(GArray *pollfds, int nfds, fd_set *rfds,
+ fd_set *wfds, fd_set *xfds)
+{
+ int i;
+
+ for (i = 0; i < pollfds->len; i++) {
+ GPollFD *pfd = &g_array_index(pollfds, GPollFD, i);
+ int fd = pfd->fd;
+ int revents = 0;
+
+ if (FD_ISSET(fd, rfds)) {
+ revents |= G_IO_IN | G_IO_HUP | G_IO_ERR;
+ }
+ if (FD_ISSET(fd, wfds)) {
+ revents |= G_IO_OUT | G_IO_ERR;
+ }
+ if (FD_ISSET(fd, xfds)) {
+ revents |= G_IO_PRI;
+ }
+ pfd->revents = revents & pfd->events;
+ }
+}
+
static int os_host_main_loop_wait(uint32_t timeout)
{
GMainContext *context = g_main_context_default();
- int ret, i;
+ GPollFD poll_fds[1024 * 2]; /* this is probably overkill */
+ int select_ret = 0;
+ 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;
return ret;
}
- if (nfds >= 0) {
- ret = select(nfds + 1, &rfds, &wfds, &xfds, &tv0);
- if (ret != 0) {
- timeout = 0;
- }
- }
-
g_main_context_prepare(context, &max_priority);
n_poll_fds = g_main_context_query(context, max_priority, &poll_timeout,
poll_fds, ARRAY_SIZE(poll_fds));
}
qemu_mutex_unlock_iothread();
- ret = g_poll(poll_fds, n_poll_fds + w->num, poll_timeout);
+ g_poll_ret = g_poll(poll_fds, n_poll_fds + w->num, poll_timeout);
qemu_mutex_lock_iothread();
- if (ret > 0) {
+ if (g_poll_ret > 0) {
for (i = 0; i < w->num; i++) {
w->revents[i] = poll_fds[n_poll_fds + i].revents;
}
g_main_context_dispatch(context);
}
- /* If an edge-triggered socket event occurred, select will return a
- * positive result on the next iteration. We do not need to do anything
- * here.
+ /* Call select after g_poll to avoid a useless iteration and therefore
+ * improve socket latency.
*/
- return ret;
+ FD_ZERO(&rfds);
+ FD_ZERO(&wfds);
+ FD_ZERO(&xfds);
+ nfds = pollfds_fill(gpollfds, &rfds, &wfds, &xfds);
+ if (nfds >= 0) {
+ select_ret = select(nfds + 1, &rfds, &wfds, &xfds, &tv0);
+ if (select_ret != 0) {
+ timeout = 0;
+ }
+ if (select_ret > 0) {
+ pollfds_poll(gpollfds, nfds, &rfds, &wfds, &xfds);
+ }
+ }
+
+ return select_ret || g_poll_ret;
}
#endif
}
/* 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();
return aio_bh_new(qemu_aio_context, cb, opaque);
}
-void qemu_aio_flush(void)
-{
- aio_flush(qemu_aio_context);
-}
-
bool qemu_aio_wait(void)
{
return aio_poll(qemu_aio_context, true);
projects / qemu.git / blobdiff