diff --git a/aio-posix.c b/aio-posix.c
index c6adddbd8262d00254cc88298f2fd738425b253d..5216d82290f96125c4737c997963facbb4ee9820 100644
--- a/aio-posix.c
+++ b/aio-posix.c
@@ -30,6 +30,8 @@ struct AioHandler
IOHandler *io_read;
IOHandler *io_write;
AioPollFn *io_poll;
+ IOHandler *io_poll_begin;
+ IOHandler *io_poll_end;
int deleted;
void *opaque;
bool is_external;
@@ -270,6 +272,20 @@ void aio_set_fd_handler(AioContext *ctx,
}
}
+void aio_set_fd_poll(AioContext *ctx, int fd,
+ IOHandler *io_poll_begin,
+ IOHandler *io_poll_end)
+{
+ AioHandler *node = find_aio_handler(ctx, fd);
+
+ if (!node) {
+ return;
+ }
+
+ node->io_poll_begin = io_poll_begin;
+ node->io_poll_end = io_poll_end;
+}
+
void aio_set_event_notifier(AioContext *ctx,
EventNotifier *notifier,
bool is_external,
@@ -280,8 +296,53 @@ void aio_set_event_notifier(AioContext *ctx,
(IOHandler *)io_read, NULL, io_poll, notifier);
}
+void aio_set_event_notifier_poll(AioContext *ctx,
+ EventNotifier *notifier,
+ EventNotifierHandler *io_poll_begin,
+ EventNotifierHandler *io_poll_end)
+{
+ aio_set_fd_poll(ctx, event_notifier_get_fd(notifier),
+ (IOHandler *)io_poll_begin,
+ (IOHandler *)io_poll_end);
+}
+
+static void poll_set_started(AioContext *ctx, bool started)
+{
+ AioHandler *node;
+
+ if (started == ctx->poll_started) {
+ return;
+ }
+
+ ctx->poll_started = started;
+
+ ctx->walking_handlers++;
+ QLIST_FOREACH(node, &ctx->aio_handlers, node) {
+ IOHandler *fn;
+
+ if (node->deleted) {
+ continue;
+ }
+
+ if (started) {
+ fn = node->io_poll_begin;
+ } else {
+ fn = node->io_poll_end;
+ }
+
+ if (fn) {
+ fn(node->opaque);
+ }
+ }
+ ctx->walking_handlers--;
+}
+
+
bool aio_prepare(AioContext *ctx)
{
+ /* Poll mode cannot be used with glib's event loop, disable it. */
+ poll_set_started(ctx, false);
+
return false;
}
@@ -422,6 +483,23 @@ static void add_pollfd(AioHandler *node)
npfd++;
}
+static bool run_poll_handlers_once(AioContext *ctx)
+{
+ bool progress = false;
+ AioHandler *node;
+
+ QLIST_FOREACH(node, &ctx->aio_handlers, node) {
+ if (!node->deleted && node->io_poll &&
+ node->io_poll(node->opaque)) {
+ progress = true;
+ }
+
+ /* Caller handles freeing deleted nodes. Don't do it here. */
+ }
+
+ return progress;
+}
+
/* run_poll_handlers:
* @ctx: the AioContext
* @max_ns: maximum time to poll for, in nanoseconds
@@ -437,7 +515,7 @@ static void add_pollfd(AioHandler *node)
*/
static bool run_poll_handlers(AioContext *ctx, int64_t max_ns)
{
- bool progress = false;
+ bool progress;
int64_t end_time;
assert(ctx->notify_me);
@@ -449,16 +527,7 @@ static bool run_poll_handlers(AioContext *ctx, int64_t max_ns)
end_time = qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + max_ns;
do {
- AioHandler *node;
-
- QLIST_FOREACH(node, &ctx->aio_handlers, node) {
- if (!node->deleted && node->io_poll &&
- node->io_poll(node->opaque)) {
- progress = true;
- }
-
- /* Caller handles freeing deleted nodes. Don't do it here. */
- }
+ progress = run_poll_handlers_once(ctx);
} while (!progress && qemu_clock_get_ns(QEMU_CLOCK_REALTIME) < end_time);
trace_run_poll_handlers_end(ctx, progress);
@@ -468,10 +537,9 @@ static bool run_poll_handlers(AioContext *ctx, int64_t max_ns)
/* try_poll_mode:
* @ctx: the AioContext
- * @blocking: polling is only attempted when blocking is true
+ * @blocking: busy polling is only attempted when blocking is true
*
- * If blocking is true then ctx->notify_me must be non-zero so this function
- * can detect aio_notify().
+ * ctx->notify_me must be non-zero so this function can detect aio_notify().
*
* Note that the caller must have incremented ctx->walking_handlers.
*
@@ -485,13 +553,20 @@ static bool try_poll_mode(AioContext *ctx, bool blocking)
(uint64_t)ctx->poll_max_ns);
if (max_ns) {
+ poll_set_started(ctx, true);
+
if (run_poll_handlers(ctx, max_ns)) {
return true;
}
}
}
- return false;
+ poll_set_started(ctx, false);
+
+ /* Even if we don't run busy polling, try polling once in case it can make
+ * progress and the caller will be able to avoid ppoll(2)/epoll_wait(2).
+ */
+ return run_poll_handlers_once(ctx);
}
bool aio_poll(AioContext *ctx, bool blocking)
diff --git a/aio-win32.c b/aio-win32.c
index 0a6e91b0c37799d4b0f272aad8f59d31cfdd24e4..d0e40a854c1088c7c9ffc16fb6647e8236464175 100644
--- a/aio-win32.c
+++ b/aio-win32.c
@@ -102,6 +102,13 @@ void aio_set_fd_handler(AioContext *ctx,
aio_notify(ctx);
}
+void aio_set_fd_poll(AioContext *ctx, int fd,
+ IOHandler *io_poll_begin,
+ IOHandler *io_poll_end)
+{
+ /* Not implemented */
+}
+
void aio_set_event_notifier(AioContext *ctx,
EventNotifier *e,
bool is_external,
@@ -153,6 +160,14 @@ void aio_set_event_notifier(AioContext *ctx,
aio_notify(ctx);
}
+void aio_set_event_notifier_poll(AioContext *ctx,
+ EventNotifier *notifier,
+ EventNotifierHandler *io_poll_begin,
+ EventNotifierHandler *io_poll_end)
+{
+ /* Not implemented */
+}
+
bool aio_prepare(AioContext *ctx)
{
static struct timeval tv0;
diff --git a/include/block/aio.h b/include/block/aio.h
index 349143f6d9a783a7fc95e590e005557955eaeced..3817d179fd04275a87e3092a84fe1a09c22f5688 100644
--- a/include/block/aio.h
+++ b/include/block/aio.h
@@ -137,6 +137,9 @@ struct AioContext {
/* Maximum polling time in nanoseconds */
int64_t poll_max_ns;
+ /* Are we in polling mode or monitoring file descriptors? */
+ bool poll_started;
+
/* epoll(7) state used when built with CONFIG_EPOLL */
int epollfd;
bool epoll_enabled;
@@ -339,6 +342,14 @@ void aio_set_fd_handler(AioContext *ctx,
AioPollFn *io_poll,
void *opaque);
+/* Set polling begin/end callbacks for a file descriptor that has already been
+ * registered with aio_set_fd_handler. Do nothing if the file descriptor is
+ * not registered.
+ */
+void aio_set_fd_poll(AioContext *ctx, int fd,
+ IOHandler *io_poll_begin,
+ IOHandler *io_poll_end);
+
/* Register an event notifier and associated callbacks. Behaves very similarly
* to event_notifier_set_handler. Unlike event_notifier_set_handler, these callbacks
* will be invoked when using aio_poll().
@@ -352,6 +363,15 @@ void aio_set_event_notifier(AioContext *ctx,
EventNotifierHandler *io_read,
AioPollFn *io_poll);
+/* Set polling begin/end callbacks for an event notifier that has already been
+ * registered with aio_set_event_notifier. Do nothing if the event notifier is
+ * not registered.
+ */
+void aio_set_event_notifier_poll(AioContext *ctx,
+ EventNotifier *notifier,
+ EventNotifierHandler *io_poll_begin,
+ EventNotifierHandler *io_poll_end);
+
/* Return a GSource that lets the main loop poll the file descriptors attached
* to this AioContext.
*/