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virtio-net: fix TX timer with tx_burst

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When virtio_net_flush_tx() reaches the tx_burst value all
the queue is not flushed and nothing restart the timer.

Fix that by doing for TX timer as we do for bottom half TX:
rearming the timer if we find any packet to send during the
virtio_net_flush_tx() call.

Fixes: e3f30488e5 ("virtio-net: Limit number of packets sent per TX flush")
Cc: alex.williamson@redhat.com
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
This commit is contained in:
Laurent Vivier 2022-10-20 11:58:46 +02:00 • committed by Jason Wang
parent df8d070817
commit 7550a82259
1 changed files with 41 additions and 9 deletions
Download patch file Download diff file Expand all files Collapse all files

50
hw/net/virtio-net.c
View file

@ -2536,14 +2536,19 @@ static void virtio_net_tx_complete(NetClientState *nc, ssize_t len)
virtio_queue_set_notification(q->tx_vq, 1); virtio_queue_set_notification(q->tx_vq, 1);
ret = virtio_net_flush_tx(q); ret = virtio_net_flush_tx(q);
if (q->tx_bh && ret >= n->tx_burst) { if (ret >= n->tx_burst) {
/* /*
* the flush has been stopped by tx_burst * the flush has been stopped by tx_burst
* we will not receive notification for the * we will not receive notification for the
* remainining part, so re-schedule * remainining part, so re-schedule
*/ */
virtio_queue_set_notification(q->tx_vq, 0); virtio_queue_set_notification(q->tx_vq, 0);
qemu_bh_schedule(q->tx_bh); if (q->tx_bh) {
qemu_bh_schedule(q->tx_bh);
} else {
timer_mod(q->tx_timer,
qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + n->tx_timeout);
}
q->tx_waiting = 1; q->tx_waiting = 1;
} }
} }
@ -2644,6 +2649,8 @@ drop:
return num_packets; return num_packets;
} }
static void virtio_net_tx_timer(void *opaque);
static void virtio_net_handle_tx_timer(VirtIODevice *vdev, VirtQueue *vq) static void virtio_net_handle_tx_timer(VirtIODevice *vdev, VirtQueue *vq)
{ {
VirtIONet *n = VIRTIO_NET(vdev); VirtIONet *n = VIRTIO_NET(vdev);
@ -2661,15 +2668,13 @@ static void virtio_net_handle_tx_timer(VirtIODevice *vdev, VirtQueue *vq)
} }
if (q->tx_waiting) { if (q->tx_waiting) {
virtio_queue_set_notification(vq, 1); /* We already have queued packets, immediately flush */
timer_del(q->tx_timer); timer_del(q->tx_timer);
q->tx_waiting = 0; virtio_net_tx_timer(q);
if (virtio_net_flush_tx(q) == -EINVAL) {
return;
}
} else { } else {
/* re-arm timer to flush it (and more) on next tick */
timer_mod(q->tx_timer, timer_mod(q->tx_timer,
qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + n->tx_timeout); qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + n->tx_timeout);
q->tx_waiting = 1; q->tx_waiting = 1;
virtio_queue_set_notification(vq, 0); virtio_queue_set_notification(vq, 0);
} }
@ -2702,6 +2707,8 @@ static void virtio_net_tx_timer(void *opaque)
VirtIONetQueue *q = opaque; VirtIONetQueue *q = opaque;
VirtIONet *n = q->n; VirtIONet *n = q->n;
VirtIODevice *vdev = VIRTIO_DEVICE(n); VirtIODevice *vdev = VIRTIO_DEVICE(n);
int ret;
/* This happens when device was stopped but BH wasn't. */ /* This happens when device was stopped but BH wasn't. */
if (!vdev->vm_running) { if (!vdev->vm_running) {
/* Make sure tx waiting is set, so we'll run when restarted. */ /* Make sure tx waiting is set, so we'll run when restarted. */
@ -2716,8 +2723,33 @@ static void virtio_net_tx_timer(void *opaque)
return; return;
} }
ret = virtio_net_flush_tx(q);
if (ret == -EBUSY || ret == -EINVAL) {
return;
}
/*
* If we flush a full burst of packets, assume there are
* more coming and immediately rearm
*/
if (ret >= n->tx_burst) {
q->tx_waiting = 1;
timer_mod(q->tx_timer,
qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + n->tx_timeout);
return;
}
/*
* If less than a full burst, re-enable notification and flush
* anything that may have come in while we weren't looking. If
* we find something, assume the guest is still active and rearm
*/
virtio_queue_set_notification(q->tx_vq, 1); virtio_queue_set_notification(q->tx_vq, 1);
virtio_net_flush_tx(q); ret = virtio_net_flush_tx(q);
if (ret > 0) {
virtio_queue_set_notification(q->tx_vq, 0);
q->tx_waiting = 1;
timer_mod(q->tx_timer,
qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + n->tx_timeout);
}
} }
static void virtio_net_tx_bh(void *opaque) static void virtio_net_tx_bh(void *opaque)