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[Qemu-devel] [PATCH v3 2/7] virtio-blk: multiqueue batch notify
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PATCH v3 2/7] virtio-blk: multiqueue batch notify |
Date: |
Tue, 7 Jun 2016 17:28:26 +0100 |
The batch notification BH needs to know which virtqueues to notify when
multiqueue is enabled. Use a bitmap to track the virtqueues with
pending notifications.
At this point there is only one virtqueue so hard-code virtqueue index
0. A later patch will switch to real virtqueue indices.
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
hw/block/dataplane/virtio-blk.c | 29 +++++++++++++++++++++++------
1 file changed, 23 insertions(+), 6 deletions(-)
diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
index 3cb97c9..4439c7b 100644
--- a/hw/block/dataplane/virtio-blk.c
+++ b/hw/block/dataplane/virtio-blk.c
@@ -34,8 +34,8 @@ struct VirtIOBlockDataPlane {
VirtIODevice *vdev;
VirtQueue *vq; /* virtqueue vring */
- EventNotifier *guest_notifier; /* irq */
QEMUBH *bh; /* bh for guest notification */
+ unsigned long *batch_notify_vqs;
Notifier insert_notifier, remove_notifier;
@@ -54,18 +54,34 @@ struct VirtIOBlockDataPlane {
/* Raise an interrupt to signal guest, if necessary */
void virtio_blk_data_plane_notify(VirtIOBlockDataPlane *s)
{
+ set_bit(0, s->batch_notify_vqs);
qemu_bh_schedule(s->bh);
}
static void notify_guest_bh(void *opaque)
{
VirtIOBlockDataPlane *s = opaque;
+ unsigned nvqs = s->conf->num_queues;
+ unsigned long bitmap[BITS_TO_LONGS(nvqs)];
+ unsigned j;
- if (!virtio_should_notify(s->vdev, s->vq)) {
- return;
+ memcpy(bitmap, s->batch_notify_vqs, sizeof(bitmap));
+ memset(s->batch_notify_vqs, 0, sizeof(bitmap));
+
+ for (j = 0; j < nvqs; j += BITS_PER_LONG) {
+ unsigned long bits = bitmap[j];
+
+ while (bits != 0) {
+ unsigned i = j + ctzl(bits);
+ VirtQueue *vq = virtio_get_queue(s->vdev, i);
+
+ if (virtio_should_notify(s->vdev, vq)) {
+ event_notifier_set(virtio_queue_get_guest_notifier(vq));
+ }
+
+ bits &= bits - 1; /* clear right-most bit */
+ }
}
-
- event_notifier_set(s->guest_notifier);
}
static void data_plane_set_up_op_blockers(VirtIOBlockDataPlane *s)
@@ -157,6 +173,7 @@ void virtio_blk_data_plane_create(VirtIODevice *vdev,
VirtIOBlkConf *conf,
}
s->ctx = iothread_get_aio_context(s->iothread);
s->bh = aio_bh_new(s->ctx, notify_guest_bh, s);
+ s->batch_notify_vqs = bitmap_new(conf->num_queues);
s->insert_notifier.notify = data_plane_blk_insert_notifier;
s->remove_notifier.notify = data_plane_blk_remove_notifier;
@@ -179,6 +196,7 @@ void virtio_blk_data_plane_destroy(VirtIOBlockDataPlane *s)
data_plane_remove_op_blockers(s);
notifier_remove(&s->insert_notifier);
notifier_remove(&s->remove_notifier);
+ g_free(s->batch_notify_vqs);
qemu_bh_delete(s->bh);
object_unref(OBJECT(s->iothread));
g_free(s);
@@ -217,7 +235,6 @@ void virtio_blk_data_plane_start(VirtIOBlockDataPlane *s)
"ensure -enable-kvm is set\n", r);
goto fail_guest_notifiers;
}
- s->guest_notifier = virtio_queue_get_guest_notifier(s->vq);
/* Set up virtqueue notify */
r = k->set_host_notifier(qbus->parent, 0, true);
--
2.5.5
- [Qemu-devel] [PATCH v3 0/7] virtio-blk: multiqueue support, Stefan Hajnoczi, 2016/06/08
- [Qemu-devel] [PATCH v3 3/7] virtio-blk: tell dataplane which vq to notify, Stefan Hajnoczi, 2016/06/08
- [Qemu-devel] [PATCH v3 4/7] virtio-blk: associate request with a virtqueue, Stefan Hajnoczi, 2016/06/08
- [Qemu-devel] [PATCH v3 2/7] virtio-blk: multiqueue batch notify,
Stefan Hajnoczi <=
- [Qemu-devel] [PATCH v3 1/7] virtio-blk: add VirtIOBlockConf->num_queues, Stefan Hajnoczi, 2016/06/08
- [Qemu-devel] [PATCH v3 5/7] virtio-blk: live migrate s->rq with multiqueue, Stefan Hajnoczi, 2016/06/08
- [Qemu-devel] [PATCH v3 6/7] virtio-blk: dataplane multiqueue support, Stefan Hajnoczi, 2016/06/08
- [Qemu-devel] [PATCH v3 7/7] virtio-blk: add num-queues device property, Stefan Hajnoczi, 2016/06/08
- Re: [Qemu-devel] [PATCH v3 0/7] virtio-blk: multiqueue support, Stefan Hajnoczi, 2016/06/20