[Qemu-devel] [RFC] [PATCHv6 11/16] aio / timers: Convert aio_poll to use AioContext timers' deadline

[Alex Bligh <alex@alex.org.uk>]

Convert aio_poll to use deadline based on AioContext's timers.

aio_poll has been changed to return accurately whether progress
has occurred. Prior to this commit, aio_poll always returned
true if g_poll was entered, whether or not any progress was
made. This required a change to tests/test-aio.c where an
assert was backwards.

Signed-off-by: Alex Bligh <alex@alex.org.uk>
---
 aio-posix.c      |   20 +++++++++++++-------
 aio-win32.c      |   22 +++++++++++++++++++---
 tests/test-aio.c |    4 ++--
 3 files changed, 34 insertions(+), 12 deletions(-)

diff --git a/aio-posix.c b/aio-posix.c
index b68eccd..2ec419d 100644
--- a/aio-posix.c
+++ b/aio-posix.c
@@ -166,6 +166,10 @@ static bool aio_dispatch(AioContext *ctx)
             g_free(tmp);
         }
     }
+
+    /* Run our timers */
+    progress |= timerlistgroup_run_timers(ctx->tlg);
+
     return progress;
 }
 
@@ -232,9 +236,9 @@ bool aio_poll(AioContext *ctx, bool blocking)
     }
 
     /* wait until next event */
-    ret = g_poll((GPollFD *)ctx->pollfds->data,
-                 ctx->pollfds->len,
-                 blocking ? -1 : 0);
+    ret = qemu_poll_ns((GPollFD *)ctx->pollfds->data,
+                         ctx->pollfds->len,
+                         blocking ? timerlistgroup_deadline_ns(ctx->tlg) : 0);
 
     /* if we have any readable fds, dispatch event */
     if (ret > 0) {
@@ -245,11 +249,13 @@ bool aio_poll(AioContext *ctx, bool blocking)
                 node->pfd.revents = pfd->revents;
             }
         }
-        if (aio_dispatch(ctx)) {
-            progress = true;
-        }
+    }
+
+    /* Run dispatch even if there were no readable fds to run timers */
+    if (aio_dispatch(ctx)) {
+        progress = true;
     }
 
     assert(progress || busy);
-    return true;
+    return progress;
 }
diff --git a/aio-win32.c b/aio-win32.c
index 38723bf..acdc48a 100644
--- a/aio-win32.c
+++ b/aio-win32.c
@@ -98,6 +98,7 @@ bool aio_poll(AioContext *ctx, bool blocking)
     HANDLE events[MAXIMUM_WAIT_OBJECTS + 1];
     bool busy, progress;
     int count;
+    int timeout;
 
     progress = false;
 
@@ -111,6 +112,9 @@ bool aio_poll(AioContext *ctx, bool blocking)
         progress = true;
     }
 
+    /* Run timers */
+    progress |= timerlistgroup_run_timers(ctx->tlg);
+
     /*
      * Then dispatch any pending callbacks from the GSource.
      *
@@ -174,8 +178,11 @@ bool aio_poll(AioContext *ctx, bool blocking)
 
     /* wait until next event */
     while (count > 0) {
-        int timeout = blocking ? INFINITE : 0;
-        int ret = WaitForMultipleObjects(count, events, FALSE, timeout);
+        int ret;
+
+        timeout = blocking ?
+            qemu_timeout_ns_to_ms(timerlistgroup_deadline_ns(ctx->tlg)) : 0;
+        ret = WaitForMultipleObjects(count, events, FALSE, timeout);
 
         /* if we have any signaled events, dispatch event */
         if ((DWORD) (ret - WAIT_OBJECT_0) >= count) {
@@ -214,6 +221,15 @@ bool aio_poll(AioContext *ctx, bool blocking)
         events[ret - WAIT_OBJECT_0] = events[--count];
     }
 
+    if (blocking) {
+        /* Run the timers a second time. We do this because otherwise aio_wait
+         * will not note progress - and will stop a drain early - if we have
+         * a timer that was not ready to run entering g_poll but is ready
+         * after g_poll. This will only do anything if a timer has expired.
+         */
+        progress |= timerlistgroup_run_timers(ctx->tl);
+    }
+
     assert(progress || busy);
-    return true;
+    return progress;
 }
diff --git a/tests/test-aio.c b/tests/test-aio.c
index 2d7ec4c..eedf7f8 100644
--- a/tests/test-aio.c
+++ b/tests/test-aio.c
@@ -316,13 +316,13 @@ static void test_wait_event_notifier_noflush(void)
     event_notifier_set(&data.e);
     g_assert(aio_poll(ctx, false));
     g_assert_cmpint(data.n, ==, 1);
-    g_assert(aio_poll(ctx, false));
+    g_assert(!aio_poll(ctx, false));
     g_assert_cmpint(data.n, ==, 1);
 
     event_notifier_set(&data.e);
     g_assert(aio_poll(ctx, false));
     g_assert_cmpint(data.n, ==, 2);
-    g_assert(aio_poll(ctx, false));
+    g_assert(!aio_poll(ctx, false));
     g_assert_cmpint(data.n, ==, 2);
 
     event_notifier_set(&dummy.e);
-- 
1.7.9.5