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authorPaolo Bonzini <pbonzini@redhat.com>2012-03-20 10:49:19 +0100
committerBlue Swirl <blauwirbel@gmail.com>2012-04-07 08:34:16 +0000
commitd3385eb448e38f828c78f8f68ec5d79c66a58b5d (patch)
tree86d8bd988391e96e5b0b835e0af7220a33819b50 /main-loop.c
parent15455536df5ef652759ccf465d5e6f73acb493df (diff)
downloadqemu-arm-d3385eb448e38f828c78f8f68ec5d79c66a58b5d.tar.gz
main-loop: interrupt wait when data arrives on a socket
Right now, the main loop is not interrupted when data arrives on a socket. To fix this, register each socket to interrupt the main loop with WSAEventSelect. This does not replace select, it only communicates a change in socket state that requires a select call. Since the interrupt fires only once per recv call, or only once after a send call returns EWOULDBLOCK we can activate it on all events unconditionally. If QEMU is momentarily uninterested on some condition, the main loop will not busy wait. Instead, it may get one extra wakeup, but then it will ignore the condition until progress occurs and/or qemu_set_fd_handler is called to set a callback. At this point the condition will be tested via select and the callback will be invoked even if it is still disabled on the event. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Diffstat (limited to 'main-loop.c')
-rw-r--r--main-loop.c69
1 files changed, 44 insertions, 25 deletions
diff --git a/main-loop.c b/main-loop.c
index dc6bdb591f..7364074c56 100644
--- a/main-loop.c
+++ b/main-loop.c
@@ -392,10 +392,18 @@ void qemu_del_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
}
}
+void qemu_fd_register(int fd)
+{
+ WSAEventSelect(fd, qemu_event_handle, FD_READ | FD_ACCEPT | FD_CLOSE |
+ FD_CONNECT | FD_WRITE | FD_OOB);
+}
+
static int os_host_main_loop_wait(int timeout)
{
int ret, ret2, i;
PollingEntry *pe;
+ int err;
+ WaitObjects *w = &wait_objects;
static struct timeval tv0;
/* XXX: need to suppress polling by better using win32 events */
@@ -403,38 +411,49 @@ static int os_host_main_loop_wait(int timeout)
for (pe = first_polling_entry; pe != NULL; pe = pe->next) {
ret |= pe->func(pe->opaque);
}
- if (ret == 0) {
- int err;
- WaitObjects *w = &wait_objects;
+ if (ret != 0) {
+ return ret;
+ }
- qemu_mutex_unlock_iothread();
- ret = WaitForMultipleObjects(w->num, w->events, FALSE, timeout);
- qemu_mutex_lock_iothread();
- if (WAIT_OBJECT_0 + 0 <= ret && ret <= WAIT_OBJECT_0 + w->num - 1) {
- if (w->func[ret - WAIT_OBJECT_0]) {
- w->func[ret - WAIT_OBJECT_0](w->opaque[ret - WAIT_OBJECT_0]);
- }
+ if (nfds >= 0) {
+ ret = select(nfds + 1, &rfds, &wfds, &xfds, &tv0);
+ if (ret != 0) {
+ timeout = 0;
+ }
+ }
- /* Check for additional signaled events */
- for (i = (ret - WAIT_OBJECT_0 + 1); i < w->num; i++) {
- /* Check if event is signaled */
- ret2 = WaitForSingleObject(w->events[i], 0);
- if (ret2 == WAIT_OBJECT_0) {
- if (w->func[i]) {
- w->func[i](w->opaque[i]);
- }
- } else if (ret2 != WAIT_TIMEOUT) {
- err = GetLastError();
- fprintf(stderr, "WaitForSingleObject error %d %d\n", i, err);
+ qemu_mutex_unlock_iothread();
+ ret = WaitForMultipleObjects(w->num, w->events, FALSE, timeout);
+ qemu_mutex_lock_iothread();
+ if (WAIT_OBJECT_0 + 0 <= ret && ret <= WAIT_OBJECT_0 + w->num - 1) {
+ if (w->func[ret - WAIT_OBJECT_0]) {
+ w->func[ret - WAIT_OBJECT_0](w->opaque[ret - WAIT_OBJECT_0]);
+ }
+
+ /* Check for additional signaled events */
+ for (i = (ret - WAIT_OBJECT_0 + 1); i < w->num; i++) {
+ /* Check if event is signaled */
+ ret2 = WaitForSingleObject(w->events[i], 0);
+ if (ret2 == WAIT_OBJECT_0) {
+ if (w->func[i]) {
+ w->func[i](w->opaque[i]);
}
+ } else if (ret2 != WAIT_TIMEOUT) {
+ err = GetLastError();
+ fprintf(stderr, "WaitForSingleObject error %d %d\n", i, err);
}
- } else if (ret != WAIT_TIMEOUT) {
- err = GetLastError();
- fprintf(stderr, "WaitForMultipleObjects error %d %d\n", ret, err);
}
+ } else if (ret != WAIT_TIMEOUT) {
+ err = GetLastError();
+ fprintf(stderr, "WaitForMultipleObjects error %d %d\n", ret, err);
}
- ret = select(nfds + 1, &rfds, &wfds, &xfds, &tv0);
+
+ /* 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.
+ */
+
return ret;
}
#endif