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linux-aio: split processing events function

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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 <roman.penyaev@profitbricks.com>
Message-id: 1468931263-32667-3-git-send-email-roman.penyaev@profitbricks.com
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: qemu-devel@nongnu.org
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Roman Pen 2016-07-19 14:27:42 +02:00 committed by Stefan Hajnoczi
parent 9e909a5829
commit 3407de572b
1 changed files with 21 additions and 10 deletions
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31
block/linux-aio.c
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@ -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);
}
}