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authorPaolo Bonzini <pbonzini@redhat.com>2015-07-21 16:07:50 +0200
committerStefan Hajnoczi <stefanha@redhat.com>2015-07-22 12:41:40 +0100
commit6493c975af75be5b8d9ade954239bdf5492b7911 (patch)
tree6e35d5d9140c7cae03f04d5f91750115b51859e9
parent12d69ac03b45156356b240424623719f15d8143e (diff)
downloadqemu-arm-6493c975af75be5b8d9ade954239bdf5492b7911.tar.gz
aio-win32: reorganize polling loop
Preparatory bugfixes and tweaks to the loop before the next patch: - disable dispatch optimization during aio_prepare. This fixes a bug. - do not modify "blocking" until after the first WaitForMultipleObjects call. This is needed in the next patch. - change the loop to do...while. This makes it obvious that the loop is always entered at least once. In the next patch this is important because the first iteration undoes the ctx->notify_me increment that happened before entering the loop. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Tested-by: Richard W.M. Jones <rjones@redhat.com> Message-id: 1437487673-23740-4-git-send-email-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
-rw-r--r--aio-win32.c21
1 files changed, 12 insertions, 9 deletions
diff --git a/aio-win32.c b/aio-win32.c
index 233d8f5d79..9268b5c9fc 100644
--- a/aio-win32.c
+++ b/aio-win32.c
@@ -284,11 +284,6 @@ bool aio_poll(AioContext *ctx, bool blocking)
int timeout;
aio_context_acquire(ctx);
- have_select_revents = aio_prepare(ctx);
- if (have_select_revents) {
- blocking = false;
- }
-
was_dispatching = ctx->dispatching;
progress = false;
@@ -304,6 +299,8 @@ bool aio_poll(AioContext *ctx, bool blocking)
*/
aio_set_dispatching(ctx, !blocking);
+ have_select_revents = aio_prepare(ctx);
+
ctx->walking_handlers++;
/* fill fd sets */
@@ -317,12 +314,18 @@ bool aio_poll(AioContext *ctx, bool blocking)
ctx->walking_handlers--;
first = true;
- /* wait until next event */
- while (count > 0) {
+ /* ctx->notifier is always registered. */
+ assert(count > 0);
+
+ /* Multiple iterations, all of them non-blocking except the first,
+ * may be necessary to process all pending events. After the first
+ * WaitForMultipleObjects call ctx->notify_me will be decremented.
+ */
+ do {
HANDLE event;
int ret;
- timeout = blocking
+ timeout = blocking && !have_select_revents
? qemu_timeout_ns_to_ms(aio_compute_timeout(ctx)) : 0;
if (timeout) {
aio_context_release(ctx);
@@ -351,7 +354,7 @@ bool aio_poll(AioContext *ctx, bool blocking)
blocking = false;
progress |= aio_dispatch_handlers(ctx, event);
- }
+ } while (count > 0);
progress |= timerlistgroup_run_timers(&ctx->tlg);