On Mon, Dec 22, 2025 at 12:58:01PM +0100, Paolo Abeni wrote:
> On 12/21/25 2:42 PM, Michael S. Tsirkin wrote:
> > On Fri, Dec 19, 2025 at 12:03:29PM +0700, Bui Quang Minh wrote:
> >> On 12/17/25 09:58, Jason Wang wrote:
> >>> On Wed, Dec 17, 2025 at 12:23 AM Bui Quang Minh
> >>> <[email protected]> wrote:
> >>>> I think we can unconditionally schedule the delayed refill after
> >>>> enabling all the RX NAPIs (don't check the boolean schedule_refill
> >>>> anymore) to ensure that we will have refill work. We can still keep the
> >>>> try_fill_recv here to fill the receive buffer earlier in normal case.
> >>>> What do you think?
> >>> Or we can have a reill_pending
> >>
> >> Okay, let me implement this in the next version.
> >>
> >>> but basically I think we need something
> >>> that is much more simple. That is, using a per rq work instead of a
> >>> global one?
> >>
> >> I think we can leave this in a net-next patch later.
> >>
> >> Thanks,
> >> Quang Minh
> >
> > i am not sure per rq is not simpler than this pile of tricks.
> FWIW, I agree with Michael: the diffstat of the current patch is quite
> scaring, I don't think a per RQ work would be significantly larger, but
> should be significantly simpler to review and maintain.
>
> I suggest doing directly the per RQ work implementation.
>
> Thanks!
>
> Paolo
I mean a stupidly mechanical move of all refill to per RQ is
rather trivial (CB). Compiled only, feel free to reuse.
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 0369dda5ed60..4eb90b4e7b0f 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -379,6 +379,15 @@ struct receive_queue {
struct xdp_rxq_info xsk_rxq_info;
struct xdp_buff **xsk_buffs;
+
+ /* Work struct for delayed refilling if we run low on memory. */
+ struct delayed_work refill;
+
+ /* Is delayed refill enabled? */
+ bool refill_enabled;
+
+ /* The lock to synchronize the access to refill_enabled */
+ spinlock_t refill_lock;
};
#define VIRTIO_NET_RSS_MAX_KEY_SIZE 40
@@ -441,9 +450,6 @@ struct virtnet_info {
/* Packet virtio header size */
u8 hdr_len;
- /* Work struct for delayed refilling if we run low on memory. */
- struct delayed_work refill;
-
/* UDP tunnel support */
bool tx_tnl;
@@ -451,12 +457,6 @@ struct virtnet_info {
bool rx_tnl_csum;
- /* Is delayed refill enabled? */
- bool refill_enabled;
-
- /* The lock to synchronize the access to refill_enabled */
- spinlock_t refill_lock;
-
/* Work struct for config space updates */
struct work_struct config_work;
@@ -720,18 +720,11 @@ static void virtnet_rq_free_buf(struct virtnet_info *vi,
put_page(virt_to_head_page(buf));
}
-static void enable_delayed_refill(struct virtnet_info *vi)
+static void disable_delayed_refill(struct receive_queue *rq)
{
- spin_lock_bh(&vi->refill_lock);
- vi->refill_enabled = true;
- spin_unlock_bh(&vi->refill_lock);
-}
-
-static void disable_delayed_refill(struct virtnet_info *vi)
-{
- spin_lock_bh(&vi->refill_lock);
- vi->refill_enabled = false;
- spin_unlock_bh(&vi->refill_lock);
+ spin_lock_bh(&rq->refill_lock);
+ rq->refill_enabled = false;
+ spin_unlock_bh(&rq->refill_lock);
}
static void enable_rx_mode_work(struct virtnet_info *vi)
@@ -2935,38 +2928,20 @@ static void virtnet_napi_disable(struct receive_queue
*rq)
static void refill_work(struct work_struct *work)
{
- struct virtnet_info *vi =
- container_of(work, struct virtnet_info, refill.work);
+ struct receive_queue *rq = container_of(work, struct receive_queue,
+ refill.work);
+ struct virtnet_info *vi = rq->vq->vdev->priv;
bool still_empty;
- int i;
- for (i = 0; i < vi->curr_queue_pairs; i++) {
- struct receive_queue *rq = &vi->rq[i];
+ napi_disable(&rq->napi);
+ still_empty = !try_fill_recv(vi, rq, GFP_KERNEL);
+ virtnet_napi_do_enable(rq->vq, &rq->napi);
- /*
- * When queue API support is added in the future and the call
- * below becomes napi_disable_locked, this driver will need to
- * be refactored.
- *
- * One possible solution would be to:
- * - cancel refill_work with cancel_delayed_work (note:
- * non-sync)
- * - cancel refill_work with cancel_delayed_work_sync in
- * virtnet_remove after the netdev is unregistered
- * - wrap all of the work in a lock (perhaps the netdev
- * instance lock)
- * - check netif_running() and return early to avoid a race
- */
- napi_disable(&rq->napi);
- still_empty = !try_fill_recv(vi, rq, GFP_KERNEL);
- virtnet_napi_do_enable(rq->vq, &rq->napi);
-
- /* In theory, this can happen: if we don't get any buffers in
- * we will *never* try to fill again.
- */
- if (still_empty)
- schedule_delayed_work(&vi->refill, HZ/2);
- }
+ /* In theory, this can happen: if we don't get any buffers in
+ * we will *never* try to fill again.
+ */
+ if (still_empty)
+ schedule_delayed_work(&rq->refill, HZ / 2);
}
static int virtnet_receive_xsk_bufs(struct virtnet_info *vi,
@@ -3033,10 +3008,10 @@ static int virtnet_receive(struct receive_queue *rq,
int budget,
if (rq->vq->num_free > min((unsigned int)budget,
virtqueue_get_vring_size(rq->vq)) / 2) {
if (!try_fill_recv(vi, rq, GFP_ATOMIC)) {
- spin_lock(&vi->refill_lock);
- if (vi->refill_enabled)
- schedule_delayed_work(&vi->refill, 0);
- spin_unlock(&vi->refill_lock);
+ spin_lock(&rq->refill_lock);
+ if (rq->refill_enabled)
+ schedule_delayed_work(&rq->refill, 0);
+ spin_unlock(&rq->refill_lock);
}
}
@@ -3216,13 +3191,14 @@ static int virtnet_open(struct net_device *dev)
struct virtnet_info *vi = netdev_priv(dev);
int i, err;
- enable_delayed_refill(vi);
-
for (i = 0; i < vi->max_queue_pairs; i++) {
+ /* Enable refill work before enabling NAPI */
+ vi->rq[i].refill_enabled = true;
+
if (i < vi->curr_queue_pairs)
/* Make sure we have some buffers: if oom use wq. */
if (!try_fill_recv(vi, &vi->rq[i], GFP_KERNEL))
- schedule_delayed_work(&vi->refill, 0);
+ schedule_delayed_work(&vi->rq[i].refill, 0);
err = virtnet_enable_queue_pair(vi, i);
if (err < 0)
@@ -3241,11 +3217,10 @@ static int virtnet_open(struct net_device *dev)
return 0;
err_enable_qp:
- disable_delayed_refill(vi);
- cancel_delayed_work_sync(&vi->refill);
-
for (i--; i >= 0; i--) {
+ disable_delayed_refill(&vi->rq[i]);
virtnet_disable_queue_pair(vi, i);
+ cancel_delayed_work_sync(&vi->rq[i].refill);
virtnet_cancel_dim(vi, &vi->rq[i].dim);
}
@@ -3437,29 +3412,19 @@ static void __virtnet_rx_pause(struct virtnet_info *vi,
}
}
+static void virtnet_rx_pause(struct virtnet_info *vi, struct receive_queue *rq)
+{
+ disable_delayed_refill(rq);
+ cancel_delayed_work_sync(&rq->refill);
+ __virtnet_rx_pause(vi, rq);
+}
+
static void virtnet_rx_pause_all(struct virtnet_info *vi)
{
int i;
- /*
- * Make sure refill_work does not run concurrently to
- * avoid napi_disable race which leads to deadlock.
- */
- disable_delayed_refill(vi);
- cancel_delayed_work_sync(&vi->refill);
for (i = 0; i < vi->max_queue_pairs; i++)
- __virtnet_rx_pause(vi, &vi->rq[i]);
-}
-
-static void virtnet_rx_pause(struct virtnet_info *vi, struct receive_queue *rq)
-{
- /*
- * Make sure refill_work does not run concurrently to
- * avoid napi_disable race which leads to deadlock.
- */
- disable_delayed_refill(vi);
- cancel_delayed_work_sync(&vi->refill);
- __virtnet_rx_pause(vi, rq);
+ virtnet_rx_pause(vi, &vi->rq[i]);
}
static void __virtnet_rx_resume(struct virtnet_info *vi,
@@ -3474,15 +3439,17 @@ static void __virtnet_rx_resume(struct virtnet_info *vi,
if (running)
virtnet_napi_enable(rq);
+ spin_lock_bh(&rq->refill_lock);
+ rq->refill_enabled = true;
if (schedule_refill)
- schedule_delayed_work(&vi->refill, 0);
+ schedule_delayed_work(&rq->refill, 0);
+ spin_unlock_bh(&rq->refill_lock);
}
static void virtnet_rx_resume_all(struct virtnet_info *vi)
{
int i;
- enable_delayed_refill(vi);
for (i = 0; i < vi->max_queue_pairs; i++) {
if (i < vi->curr_queue_pairs)
__virtnet_rx_resume(vi, &vi->rq[i], true);
@@ -3493,7 +3460,6 @@ static void virtnet_rx_resume_all(struct virtnet_info *vi)
static void virtnet_rx_resume(struct virtnet_info *vi, struct receive_queue
*rq)
{
- enable_delayed_refill(vi);
__virtnet_rx_resume(vi, rq, true);
}
@@ -3768,6 +3734,7 @@ static int virtnet_set_queues(struct virtnet_info *vi,
u16 queue_pairs)
struct virtio_net_rss_config_trailer old_rss_trailer;
struct net_device *dev = vi->dev;
struct scatterlist sg;
+ int i;
if (!vi->has_cvq || !virtio_has_feature(vi->vdev, VIRTIO_NET_F_MQ))
return 0;
@@ -3821,10 +3788,14 @@ static int virtnet_set_queues(struct virtnet_info *vi,
u16 queue_pairs)
succ:
vi->curr_queue_pairs = queue_pairs;
/* virtnet_open() will refill when device is going to up. */
- spin_lock_bh(&vi->refill_lock);
- if (dev->flags & IFF_UP && vi->refill_enabled)
- schedule_delayed_work(&vi->refill, 0);
- spin_unlock_bh(&vi->refill_lock);
+ if (dev->flags & IFF_UP) {
+ for (i = 0; i < vi->curr_queue_pairs; i++) {
+ spin_lock_bh(&vi->rq[i].refill_lock);
+ if (vi->rq[i].refill_enabled)
+ schedule_delayed_work(&vi->rq[i].refill, 0);
+ spin_unlock_bh(&vi->rq[i].refill_lock);
+ }
+ }
return 0;
}
@@ -3834,10 +3805,6 @@ static int virtnet_close(struct net_device *dev)
struct virtnet_info *vi = netdev_priv(dev);
int i;
- /* Make sure NAPI doesn't schedule refill work */
- disable_delayed_refill(vi);
- /* Make sure refill_work doesn't re-enable napi! */
- cancel_delayed_work_sync(&vi->refill);
/* Prevent the config change callback from changing carrier
* after close
*/
@@ -3848,7 +3815,9 @@ static int virtnet_close(struct net_device *dev)
cancel_work_sync(&vi->config_work);
for (i = 0; i < vi->max_queue_pairs; i++) {
+ disable_delayed_refill(&vi->rq[i]);
virtnet_disable_queue_pair(vi, i);
+ cancel_delayed_work_sync(&vi->rq[i].refill);
virtnet_cancel_dim(vi, &vi->rq[i].dim);
}
@@ -5793,7 +5762,6 @@ static int virtnet_restore_up(struct virtio_device *vdev)
virtio_device_ready(vdev);
- enable_delayed_refill(vi);
enable_rx_mode_work(vi);
if (netif_running(vi->dev)) {
@@ -6550,7 +6518,6 @@ static int virtnet_alloc_queues(struct virtnet_info *vi)
if (!vi->rq)
goto err_rq;
- INIT_DELAYED_WORK(&vi->refill, refill_work);
for (i = 0; i < vi->max_queue_pairs; i++) {
vi->rq[i].pages = NULL;
netif_napi_add_config(vi->dev, &vi->rq[i].napi, virtnet_poll,
@@ -6567,6 +6534,8 @@ static int virtnet_alloc_queues(struct virtnet_info *vi)
u64_stats_init(&vi->rq[i].stats.syncp);
u64_stats_init(&vi->sq[i].stats.syncp);
mutex_init(&vi->rq[i].dim_lock);
+ INIT_DELAYED_WORK(&vi->rq[i].refill, refill_work);
+ spin_lock_init(&vi->rq[i].refill_lock);
}
return 0;
@@ -6892,7 +6861,6 @@ static int virtnet_probe(struct virtio_device *vdev)
INIT_WORK(&vi->config_work, virtnet_config_changed_work);
INIT_WORK(&vi->rx_mode_work, virtnet_rx_mode_work);
- spin_lock_init(&vi->refill_lock);
if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF)) {
vi->mergeable_rx_bufs = true;
@@ -7156,7 +7124,8 @@ static int virtnet_probe(struct virtio_device *vdev)
net_failover_destroy(vi->failover);
free_vqs:
virtio_reset_device(vdev);
- cancel_delayed_work_sync(&vi->refill);
+ for (i = 0; i < vi->max_queue_pairs; i++)
+ cancel_delayed_work_sync(&vi->rq[i].refill);
free_receive_page_frags(vi);
virtnet_del_vqs(vi);
free:
