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[Qemu-devel] [PULL 02/17] linux-aio: split processing events function
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PULL 02/17] linux-aio: split processing events function |
Date: |
Mon, 12 Sep 2016 15:08:39 +0100 |
From: Roman Pen <address@hidden>
Prepare processing events function to be called from ioq_submit(),
thus split function on two parts: the first harvests completed IO
requests, the second submits pending requests.
Signed-off-by: Roman Pen <address@hidden>
Message-id: address@hidden
Cc: Stefan Hajnoczi <address@hidden>
Cc: Paolo Bonzini <address@hidden>
Cc: address@hidden
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
block/linux-aio.c | 31 +++++++++++++++++++++----------
1 file changed, 21 insertions(+), 10 deletions(-)
diff --git a/block/linux-aio.c b/block/linux-aio.c
index 62ee1ea..252ebef 100644
--- a/block/linux-aio.c
+++ b/block/linux-aio.c
@@ -180,20 +180,20 @@ io_getevents_advance_and_peek(io_context_t ctx,
return io_getevents_peek(ctx, events);
}
-/* The completion BH fetches completed I/O requests and invokes their
- * callbacks.
+/**
+ * qemu_laio_process_completions:
+ * @s: AIO state
+ *
+ * Fetches completed I/O requests and invokes their callbacks.
*
* The function is somewhat tricky because it supports nested event loops, for
* example when a request callback invokes aio_poll(). In order to do this,
- * the completion events array and index are kept in LinuxAioState. The BH
- * reschedules itself as long as there are completions pending so it will
- * either be called again in a nested event loop or will be called after all
- * events have been completed. When there are no events left to complete, the
- * BH returns without rescheduling.
+ * indices are kept in LinuxAioState. Function schedules BH completion so it
+ * can be called again in a nested event loop. When there are no events left
+ * to complete the BH is being canceled.
*/
-static void qemu_laio_completion_bh(void *opaque)
+static void qemu_laio_process_completions(LinuxAioState *s)
{
- LinuxAioState *s = opaque;
struct io_event *events;
/* Reschedule so nested event loops see currently pending completions */
@@ -222,18 +222,29 @@ static void qemu_laio_completion_bh(void *opaque)
* own `for` loop. If we are the last all counters droped to zero. */
s->event_max = 0;
s->event_idx = 0;
+}
+static void qemu_laio_process_completions_and_submit(LinuxAioState *s)
+{
+ qemu_laio_process_completions(s);
if (!s->io_q.plugged && !QSIMPLEQ_EMPTY(&s->io_q.pending)) {
ioq_submit(s);
}
}
+static void qemu_laio_completion_bh(void *opaque)
+{
+ LinuxAioState *s = opaque;
+
+ qemu_laio_process_completions_and_submit(s);
+}
+
static void qemu_laio_completion_cb(EventNotifier *e)
{
LinuxAioState *s = container_of(e, LinuxAioState, e);
if (event_notifier_test_and_clear(&s->e)) {
- qemu_laio_completion_bh(s);
+ qemu_laio_process_completions_and_submit(s);
}
}
--
2.7.4
- [Qemu-devel] [PULL 00/17] Block patches, Stefan Hajnoczi, 2016/09/12
- [Qemu-devel] [PULL 01/17] linux-aio: consume events in userspace instead of calling io_getevents, Stefan Hajnoczi, 2016/09/12
- [Qemu-devel] [PULL 02/17] linux-aio: split processing events function,
Stefan Hajnoczi <=
- [Qemu-devel] [PULL 04/17] virtio-blk: rename virtio_device_info to virtio_blk_info, Stefan Hajnoczi, 2016/09/12
- [Qemu-devel] [PULL 03/17] linux-aio: process completions from ioq_submit(), Stefan Hajnoczi, 2016/09/12
- [Qemu-devel] [PULL 05/17] block: unblock backup operations in backing file, Stefan Hajnoczi, 2016/09/12
- [Qemu-devel] [PULL 06/17] Backup: clear all bitmap when doing block checkpoint, Stefan Hajnoczi, 2016/09/12
- [Qemu-devel] [PULL 07/17] Backup: export interfaces for extra serialization, Stefan Hajnoczi, 2016/09/12
- [Qemu-devel] [PULL 09/17] docs: block replication's description, Stefan Hajnoczi, 2016/09/12
- [Qemu-devel] [PULL 08/17] block: Link backup into block core, Stefan Hajnoczi, 2016/09/12
- [Qemu-devel] [PULL 10/17] mirror: auto complete active commit, Stefan Hajnoczi, 2016/09/12
- [Qemu-devel] [PULL 11/17] configure: support replication, Stefan Hajnoczi, 2016/09/12
- [Qemu-devel] [PULL 12/17] replication: Introduce new APIs to do replication operation, Stefan Hajnoczi, 2016/09/12