tcg/optimize: fix setcond2 optimization

[qemu.git] / main-loop.c

diff --git a/main-loop.c b/main-loop.c
index c2ede99632d1582eb0608636b8b1b445b77b2440..f46aece8b86b7fc27698521aa319afb1bf69f228 100644 (file)
--- a/main-loop.c
+++ b/main-loop.c
@@ -109,6 +109,11 @@ static int qemu_signal_init(void)
 
 static AioContext *qemu_aio_context;
 
+AioContext *qemu_get_aio_context(void)
+{
+    return qemu_aio_context;
+}
+
 void qemu_notify_event(void)
 {
     if (!qemu_aio_context) {
@@ -143,66 +148,8 @@ int qemu_init_main_loop(void)
     return 0;
 }
 
-static fd_set rfds, wfds, xfds;
-static int nfds;
 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 int glib_pollfds_idx;
 static int glib_n_poll_fds;
@@ -241,25 +188,43 @@ static void glib_pollfds_poll(void)
     }
 }
 
+#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;
+        }
+
+        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();
     }
@@ -417,6 +382,8 @@ static int os_host_main_loop_wait(uint32_t timeout)
     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;
@@ -463,10 +430,6 @@ static int os_host_main_loop_wait(uint32_t timeout)
      * 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);
@@ -480,7 +443,6 @@ static int os_host_main_loop_wait(uint32_t timeout)
             pollfds_poll(gpollfds, nfds, &rfds, &wfds, &xfds);
         }
     }
-    gpollfds_to_select(select_ret);
 
     return select_ret || g_poll_ret;
 }
@@ -498,20 +460,15 @@ int main_loop_wait(int nonblocking)
     /* 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();