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[Qemu-devel] [PATCH 08/17] aio: add non-blocking variant of aio_wait
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH 08/17] aio: add non-blocking variant of aio_wait |
Date: |
Tue, 25 Sep 2012 14:55:54 +0200 |
This will be used when polling the GSource attached to an AioContext.
Signed-off-by: Paolo Bonzini <address@hidden>
---
aio.c | 16 ++++++++++++----
async.c | 2 +-
main-loop.c | 2 +-
qemu-aio.h | 21 +++++++++++++++------
4 file modificati, 29 inserzioni(+), 12 rimozioni(-)
diff --git a/aio.c b/aio.c
index c89f1e9..95ad467 100644
--- a/aio.c
+++ b/aio.c
@@ -93,13 +93,16 @@ void aio_set_event_notifier(AioContext *ctx,
(AioFlushHandler *)io_flush, notifier);
}
-bool aio_wait(AioContext *ctx)
+bool aio_poll(AioContext *ctx, bool blocking)
{
+ static struct timeval tv0;
AioHandler *node;
fd_set rdfds, wrfds;
int max_fd = -1;
int ret;
- bool busy;
+ bool busy, progress;
+
+ progress = false;
/*
* If there are callbacks left that have been queued, we need to call then.
@@ -107,6 +110,11 @@ bool aio_wait(AioContext *ctx)
* does not need a complete flush (as is the case for qemu_aio_wait loops).
*/
if (aio_bh_poll(ctx)) {
+ blocking = false;
+ progress = true;
+ }
+
+ if (progress && !blocking) {
return true;
}
@@ -142,11 +150,11 @@ bool aio_wait(AioContext *ctx)
/* No AIO operations? Get us out of here */
if (!busy) {
- return false;
+ return progress;
}
/* wait until next event */
- ret = select(max_fd, &rdfds, &wrfds, NULL, NULL);
+ ret = select(max_fd, &rdfds, &wrfds, NULL, blocking ? NULL : &tv0);
/* if we have any readable fds, dispatch event */
if (ret > 0) {
diff --git a/async.c b/async.c
index c99db79..513bdd7 100644
--- a/async.c
+++ b/async.c
@@ -144,5 +144,5 @@ AioContext *aio_context_new(void)
void aio_flush(AioContext *ctx)
{
- while (aio_wait(ctx));
+ while (aio_poll(ctx, true));
}
diff --git a/main-loop.c b/main-loop.c
index 8301fe9..67800fe 100644
--- a/main-loop.c
+++ b/main-loop.c
@@ -531,7 +531,7 @@ void qemu_aio_flush(void)
bool qemu_aio_wait(void)
{
- return aio_wait(qemu_aio_context);
+ return aio_poll(qemu_aio_context, true);
}
void qemu_aio_set_fd_handler(int fd,
diff --git a/qemu-aio.h b/qemu-aio.h
index f8a93d8..f19201e 100644
--- a/qemu-aio.h
+++ b/qemu-aio.h
@@ -133,13 +133,22 @@ void qemu_bh_delete(QEMUBH *bh);
* outstanding AIO operations have been completed or cancelled. */
void aio_flush(AioContext *ctx);
-/* Wait for a single AIO completion to occur. This function will wait
- * until a single AIO event has completed and it will ensure something
- * has moved before returning. This can issue new pending aio as
- * result of executing I/O completion or bh callbacks.
+/* Progress in completing AIO work to occur. This can issue new pending
+ * aio as a result of executing I/O completion or bh callbacks.
*
- * Return whether there is still any pending AIO operation. */
-bool aio_wait(AioContext *ctx);
+ * If there is no pending AIO operation or completion (bottom half),
+ * return false. If there are pending bottom halves, return true.
+ *
+ * If there are no pending bottom halves, but there are pending AIO
+ * operations, it may not be possible to make any progress without
+ * blocking. If @blocking is true, this function will wait until one
+ * or more AIO events have completed, to ensure something has moved
+ * before returning.
+ *
+ * If @blocking is false, this function will also return false if the
+ * function cannot make any progress without blocking.
+ */
+bool aio_poll(AioContext *ctx, bool blocking);
#ifdef CONFIG_POSIX
/* Returns 1 if there are still outstanding AIO requests; 0 otherwise */
--
1.7.12
- [Qemu-devel] [PATCH 03/17] event_notifier: add Win32 implementation, (continued)
- [Qemu-devel] [PATCH 03/17] event_notifier: add Win32 implementation, Paolo Bonzini, 2012/09/25
- [Qemu-devel] [PATCH 02/17] event_notifier: enable it to use pipes, Paolo Bonzini, 2012/09/25
- [Qemu-devel] [PATCH 04/17] aio: change qemu_aio_set_fd_handler to return void, Paolo Bonzini, 2012/09/25
- [Qemu-devel] [PATCH 06/17] aio: introduce AioContext, move bottom halves there, Paolo Bonzini, 2012/09/25
- [Qemu-devel] [PATCH 05/17] aio: provide platform-independent API, Paolo Bonzini, 2012/09/25
- [Qemu-devel] [PATCH 07/17] aio: add I/O handlers to the AioContext interface, Paolo Bonzini, 2012/09/25
- [Qemu-devel] [PATCH 08/17] aio: add non-blocking variant of aio_wait,
Paolo Bonzini <=
- [Qemu-devel] [PATCH 10/17] aio: add Win32 implementation, Paolo Bonzini, 2012/09/25
- [Qemu-devel] [PATCH 09/17] aio: prepare for introducing GSource-based dispatch, Paolo Bonzini, 2012/09/25
- [Qemu-devel] [PATCH 12/17] aio: add aio_notify, Paolo Bonzini, 2012/09/25
- [Qemu-devel] [PATCH 13/17] aio: call aio_notify after setting I/O handlers, Paolo Bonzini, 2012/09/25