[Qemu-devel] [PULL 24/42] aio / timers: Convert mainloop to use timeout

[Stefan Hajnoczi <stefanha@redhat.com>]

From: Alex Bligh <alex@alex.org.uk>

Convert mainloop to use timeout from default timerlist group
(i.e. the current 3 static timers)

main-loop.c produces a (possibly spurious) warning about
multiple iterations. Adapt the way this works for a signed
timeout and make the warning a bit safer.

Signed-off-by: Alex Bligh <alex@alex.org.uk>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 main-loop.c | 51 +++++++++++++++++++++++++++++++++++++--------------
 1 file changed, 37 insertions(+), 14 deletions(-)

diff --git a/main-loop.c b/main-loop.c
index 2d9774e..2866d95 100644
--- a/main-loop.c
+++ b/main-loop.c
@@ -155,10 +155,11 @@ static int max_priority;
 static int glib_pollfds_idx;
 static int glib_n_poll_fds;
 
-static void glib_pollfds_fill(uint32_t *cur_timeout)
+static void glib_pollfds_fill(int64_t *cur_timeout)
 {
     GMainContext *context = g_main_context_default();
     int timeout = 0;
+    int64_t timeout_ns;
     int n;
 
     g_main_context_prepare(context, &max_priority);
@@ -174,9 +175,13 @@ static void glib_pollfds_fill(uint32_t *cur_timeout)
                                  glib_n_poll_fds);
     } while (n != glib_n_poll_fds);
 
-    if (timeout >= 0 && timeout < *cur_timeout) {
-        *cur_timeout = timeout;
+    if (timeout < 0) {
+        timeout_ns = -1;
+    } else {
+        timeout_ns = (int64_t)timeout * (int64_t)SCALE_MS;
     }
+
+    *cur_timeout = qemu_soonest_timeout(timeout_ns, *cur_timeout);
 }
 
 static void glib_pollfds_poll(void)
@@ -191,7 +196,7 @@ static void glib_pollfds_poll(void)
 
 #define MAX_MAIN_LOOP_SPIN (1000)
 
-static int os_host_main_loop_wait(uint32_t timeout)
+static int os_host_main_loop_wait(int64_t timeout)
 {
     int ret;
     static int spin_counter;
@@ -204,7 +209,7 @@ static int os_host_main_loop_wait(uint32_t timeout)
      * 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) {
+    if (!timeout && (spin_counter > MAX_MAIN_LOOP_SPIN)) {
         static bool notified;
 
         if (!notified) {
@@ -214,19 +219,19 @@ static int os_host_main_loop_wait(uint32_t timeout)
             notified = true;
         }
 
-        timeout = 1;
+        timeout = SCALE_MS;
     }
 
-    if (timeout > 0) {
+    if (timeout) {
         spin_counter = 0;
         qemu_mutex_unlock_iothread();
     } else {
         spin_counter++;
     }
 
-    ret = g_poll((GPollFD *)gpollfds->data, gpollfds->len, timeout);
+    ret = qemu_poll_ns((GPollFD *)gpollfds->data, gpollfds->len, timeout);
 
-    if (timeout > 0) {
+    if (timeout) {
         qemu_mutex_lock_iothread();
     }
 
@@ -373,7 +378,7 @@ static void pollfds_poll(GArray *pollfds, int nfds, fd_set *rfds,
     }
 }
 
-static int os_host_main_loop_wait(uint32_t timeout)
+static int os_host_main_loop_wait(int64_t timeout)
 {
     GMainContext *context = g_main_context_default();
     GPollFD poll_fds[1024 * 2]; /* this is probably overkill */
@@ -382,6 +387,7 @@ static int os_host_main_loop_wait(uint32_t timeout)
     PollingEntry *pe;
     WaitObjects *w = &wait_objects;
     gint poll_timeout;
+    int64_t poll_timeout_ns;
     static struct timeval tv0;
     fd_set rfds, wfds, xfds;
     int nfds;
@@ -419,12 +425,17 @@ static int os_host_main_loop_wait(uint32_t timeout)
         poll_fds[n_poll_fds + i].events = G_IO_IN;
     }
 
-    if (poll_timeout < 0 || timeout < poll_timeout) {
-        poll_timeout = timeout;
+    if (poll_timeout < 0) {
+        poll_timeout_ns = -1;
+    } else {
+        poll_timeout_ns = (int64_t)poll_timeout * (int64_t)SCALE_MS;
     }
 
+    poll_timeout_ns = qemu_soonest_timeout(poll_timeout_ns, timeout);
+
     qemu_mutex_unlock_iothread();
-    g_poll_ret = g_poll(poll_fds, n_poll_fds + w->num, poll_timeout);
+    g_poll_ret = qemu_poll_ns(poll_fds, n_poll_fds + w->num, poll_timeout_ns);
+
     qemu_mutex_lock_iothread();
     if (g_poll_ret > 0) {
         for (i = 0; i < w->num; i++) {
@@ -449,6 +460,7 @@ int main_loop_wait(int nonblocking)
 {
     int ret;
     uint32_t timeout = UINT32_MAX;
+    int64_t timeout_ns;
 
     if (nonblocking) {
         timeout = 0;
@@ -462,7 +474,18 @@ int main_loop_wait(int nonblocking)
     slirp_pollfds_fill(gpollfds);
 #endif
     qemu_iohandler_fill(gpollfds);
-    ret = os_host_main_loop_wait(timeout);
+
+    if (timeout == UINT32_MAX) {
+        timeout_ns = -1;
+    } else {
+        timeout_ns = (uint64_t)timeout * (int64_t)(SCALE_MS);
+    }
+
+    timeout_ns = qemu_soonest_timeout(timeout_ns,
+                                      timerlistgroup_deadline_ns(
+                                          &main_loop_tlg));
+
+    ret = os_host_main_loop_wait(timeout_ns);
     qemu_iohandler_poll(gpollfds, ret);
 #ifdef CONFIG_SLIRP
     slirp_pollfds_poll(gpollfds, (ret < 0));
-- 
1.8.3.1