Commit 3407de57 authored by Roman Pen's avatar Roman Pen Committed by Stefan Hajnoczi
Browse files

linux-aio: split processing events function 



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: default avatarRoman 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: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent 9e909a58

block/linux-aio.c

+21 −10
Original line number Diff line number Diff line
@@ -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);

    }

}