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Message-ID: <2542f908-0390-4f22-b2b2-293136087eee@meta.com>
Date: Fri, 9 Jan 2026 17:57:15 -0800
From: Vishwanath Seshagiri <vishs@...a.com>
To: Jason Wang <jasowang@...hat.com>
Cc: "Michael S . Tsirkin" <mst@...hat.com>,
Xuan Zhuo <xuanzhuo@...ux.alibaba.com>,
Eugenio Pérez
<eperezma@...hat.com>,
Andrew Lunn <andrew+netdev@...n.ch>,
"David S . Miller" <davem@...emloft.net>,
Eric Dumazet
<edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>, David Wei <dw@...idwei.uk>,
netdev@...r.kernel.org, virtualization@...ts.linux.dev,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] virtio_net: add page pool support for buffer
allocation
On 1/8/26 7:16 PM, Jason Wang wrote:
> On Thu, Jan 8, 2026 at 2:24 PM Vishwanath Seshagiri <vishs@...a.com> wrote:
>>
>> On 1/7/26 7:16 PM, Jason Wang wrote:
>>> On Wed, Jan 7, 2026 at 6:19 AM Vishwanath Seshagiri <vishs@...a.com> wrote:
>>>>
>>>> Use page_pool for RX buffer allocation in mergeable and small buffer
>>>> modes. skb_mark_for_recycle() enables page reuse.
>>>>
>>>> Big packets mode is unchanged because it uses page->private for linked
>>>> list chaining of multiple pages per buffer, which conflicts with
>>>> page_pool's internal use of page->private.
>>>>
>>>> Page pools are created in ndo_open and destroyed in remove (not
>>>> ndo_close). This follows existing driver behavior where RX buffers
>>>> remain in the virtqueue across open/close cycles and are only freed
>>>> on device removal.
>>>>
>>>> The rx_mode_work_enabled flag prevents virtnet_rx_mode_work() from
>>>> sending control virtqueue commands while ndo_close is tearing down
>>>> device state. With MEM_TYPE_PAGE_POOL, xdp_rxq_info_unreg() calls
>>>> page_pool_destroy() during close, and concurrent rx_mode_work can
>>>> cause virtqueue corruption. The check is after rtnl_lock() to
>>>> synchronize with ndo_close(), which sets the flag under the same lock.
>>>>
>>>> Signed-off-by: Vishwanath Seshagiri <vishs@...a.com>
>>>> ---
>>>> drivers/net/virtio_net.c | 246 ++++++++++++++++++++++++++++++++-------
>>>> 1 file changed, 205 insertions(+), 41 deletions(-)
>>>>
>>>> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
>>>> index 22d894101c01..c36663525c17 100644
>>>> --- a/drivers/net/virtio_net.c
>>>> +++ b/drivers/net/virtio_net.c
>>>> @@ -26,6 +26,7 @@
>>>> #include <net/netdev_rx_queue.h>
>>>> #include <net/netdev_queues.h>
>>>> #include <net/xdp_sock_drv.h>
>>>> +#include <net/page_pool/helpers.h>
>>>>
>>>> static int napi_weight = NAPI_POLL_WEIGHT;
>>>> module_param(napi_weight, int, 0444);
>>>> @@ -359,6 +360,8 @@ struct receive_queue {
>>>> /* Page frag for packet buffer allocation. */
>>>> struct page_frag alloc_frag;
>>>>
>>>> + struct page_pool *page_pool;
>>>> +
>>>> /* RX: fragments + linear part + virtio header */
>>>> struct scatterlist sg[MAX_SKB_FRAGS + 2];
>>>>
>>>> @@ -524,11 +527,13 @@ static int virtnet_xdp_handler(struct bpf_prog *xdp_prog, struct xdp_buff *xdp,
>>>> struct virtnet_rq_stats *stats);
>>>> static void virtnet_receive_done(struct virtnet_info *vi, struct receive_queue *rq,
>>>> struct sk_buff *skb, u8 flags);
>>>> -static struct sk_buff *virtnet_skb_append_frag(struct sk_buff *head_skb,
>>>> +static struct sk_buff *virtnet_skb_append_frag(struct receive_queue *rq,
>>>> + struct sk_buff *head_skb,
>>>> struct sk_buff *curr_skb,
>>>> struct page *page, void *buf,
>>>> int len, int truesize);
>>>> static void virtnet_xsk_completed(struct send_queue *sq, int num);
>>>> +static void free_unused_bufs(struct virtnet_info *vi);
>>>>
>>>> enum virtnet_xmit_type {
>>>> VIRTNET_XMIT_TYPE_SKB,
>>>> @@ -709,15 +714,24 @@ static struct page *get_a_page(struct receive_queue *rq, gfp_t gfp_mask)
>>>> return p;
>>>> }
>>>>
>>>> +static void virtnet_put_page(struct receive_queue *rq, struct page *page,
>>>> + bool allow_direct)
>>>> +{
>>>> + if (rq->page_pool)
>>>> + page_pool_put_page(rq->page_pool, page, -1, allow_direct);
>>>> + else
>>>> + put_page(page);
>>>> +}
>>>> +
>>>> static void virtnet_rq_free_buf(struct virtnet_info *vi,
>>>> struct receive_queue *rq, void *buf)
>>>> {
>>>> if (vi->mergeable_rx_bufs)
>>>> - put_page(virt_to_head_page(buf));
>>>> + virtnet_put_page(rq, virt_to_head_page(buf), false);
>>>> else if (vi->big_packets)
>>>> give_pages(rq, buf);
>>>> else
>>>> - put_page(virt_to_head_page(buf));
>>>> + virtnet_put_page(rq, virt_to_head_page(buf), false);
>>>> }
>>>>
>>>> static void enable_delayed_refill(struct virtnet_info *vi)
>>>> @@ -894,9 +908,11 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
>>>> if (unlikely(!skb))
>>>> return NULL;
>>>>
>>>> - page = (struct page *)page->private;
>>>> - if (page)
>>>> - give_pages(rq, page);
>>>> + if (!rq->page_pool) {
>>>> + page = (struct page *)page->private;
>>>> + if (page)
>>>> + give_pages(rq, page);
>>>> + }
>>>> goto ok;
>>>> }
>>>>
>>>> @@ -931,7 +947,10 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
>>>> skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page, offset,
>>>> frag_size, truesize);
>>>> len -= frag_size;
>>>> - page = (struct page *)page->private;
>>>> + if (!rq->page_pool)
>>>> + page = (struct page *)page->private;
>>>> + else
>>>> + page = NULL;
>>>> offset = 0;
>>>> }
>>>>
>>>> @@ -942,7 +961,7 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
>>>> hdr = skb_vnet_common_hdr(skb);
>>>> memcpy(hdr, hdr_p, hdr_len);
>>>> if (page_to_free)
>>>> - put_page(page_to_free);
>>>> + virtnet_put_page(rq, page_to_free, true);
>>>>
>>>> return skb;
>>>> }
>>>> @@ -982,15 +1001,10 @@ static void virtnet_rq_unmap(struct receive_queue *rq, void *buf, u32 len)
>>>> static void *virtnet_rq_get_buf(struct receive_queue *rq, u32 *len, void **ctx)
>>>> {
>>>> struct virtnet_info *vi = rq->vq->vdev->priv;
>>>> - void *buf;
>>>>
>>>> BUG_ON(vi->big_packets && !vi->mergeable_rx_bufs);
>>>>
>>>> - buf = virtqueue_get_buf_ctx(rq->vq, len, ctx);
>>>> - if (buf)
>>>> - virtnet_rq_unmap(rq, buf, *len);
>>>> -
>>>> - return buf;
>>>> + return virtqueue_get_buf_ctx(rq->vq, len, ctx);
>>>> }
>>>>
>>>> static void virtnet_rq_init_one_sg(struct receive_queue *rq, void *buf, u32 len)
>>>> @@ -1084,9 +1098,6 @@ static void virtnet_rq_unmap_free_buf(struct virtqueue *vq, void *buf)
>>>> return;
>>>> }
>>>>
>>>> - if (!vi->big_packets || vi->mergeable_rx_bufs)
>>>> - virtnet_rq_unmap(rq, buf, 0);
>>>> -
>>>> virtnet_rq_free_buf(vi, rq, buf);
>>>> }
>>>>
>>>> @@ -1352,7 +1363,7 @@ static int xsk_append_merge_buffer(struct virtnet_info *vi,
>>>>
>>>> truesize = len;
>>>>
>>>> - curr_skb = virtnet_skb_append_frag(head_skb, curr_skb, page,
>>>> + curr_skb = virtnet_skb_append_frag(rq, head_skb, curr_skb, page,
>>>> buf, len, truesize);
>>>> if (!curr_skb) {
>>>> put_page(page);
>>>> @@ -1788,7 +1799,7 @@ static int virtnet_xdp_xmit(struct net_device *dev,
>>>> return ret;
>>>> }
>>>>
>>>> -static void put_xdp_frags(struct xdp_buff *xdp)
>>>> +static void put_xdp_frags(struct xdp_buff *xdp, struct receive_queue *rq)
>>>> {
>>>> struct skb_shared_info *shinfo;
>>>> struct page *xdp_page;
>>>> @@ -1798,7 +1809,7 @@ static void put_xdp_frags(struct xdp_buff *xdp)
>>>> shinfo = xdp_get_shared_info_from_buff(xdp);
>>>> for (i = 0; i < shinfo->nr_frags; i++) {
>>>> xdp_page = skb_frag_page(&shinfo->frags[i]);
>>>> - put_page(xdp_page);
>>>> + virtnet_put_page(rq, xdp_page, true);
>>>> }
>>>> }
>>>> }
>>>> @@ -1914,7 +1925,7 @@ static struct page *xdp_linearize_page(struct net_device *dev,
>>>> off = buf - page_address(p);
>>>>
>>>> if (check_mergeable_len(dev, ctx, buflen)) {
>>>> - put_page(p);
>>>> + virtnet_put_page(rq, p, true);
>>>> goto err_buf;
>>>> }
>>>>
>>>> @@ -1922,14 +1933,14 @@ static struct page *xdp_linearize_page(struct net_device *dev,
>>>> * is sending packet larger than the MTU.
>>>> */
>>>> if ((page_off + buflen + tailroom) > PAGE_SIZE) {
>>>> - put_page(p);
>>>> + virtnet_put_page(rq, p, true);
>>>> goto err_buf;
>>>> }
>>>>
>>>> memcpy(page_address(page) + page_off,
>>>> page_address(p) + off, buflen);
>>>> page_off += buflen;
>>>> - put_page(p);
>>>> + virtnet_put_page(rq, p, true);
>>>> }
>>>>
>>>> /* Headroom does not contribute to packet length */
>>>> @@ -1979,7 +1990,7 @@ static struct sk_buff *receive_small_xdp(struct net_device *dev,
>>>> unsigned int headroom = vi->hdr_len + header_offset;
>>>> struct virtio_net_hdr_mrg_rxbuf *hdr = buf + header_offset;
>>>> struct page *page = virt_to_head_page(buf);
>>>> - struct page *xdp_page;
>>>> + struct page *xdp_page = NULL;
>>>> unsigned int buflen;
>>>> struct xdp_buff xdp;
>>>> struct sk_buff *skb;
>>>> @@ -2013,7 +2024,7 @@ static struct sk_buff *receive_small_xdp(struct net_device *dev,
>>>> goto err_xdp;
>>>>
>>>> buf = page_address(xdp_page);
>>>> - put_page(page);
>>>> + virtnet_put_page(rq, page, true);
>>>> page = xdp_page;
>>>> }
>>>>
>>>> @@ -2045,13 +2056,19 @@ static struct sk_buff *receive_small_xdp(struct net_device *dev,
>>>> if (metasize)
>>>> skb_metadata_set(skb, metasize);
>>>>
>>>> + if (rq->page_pool && !xdp_page)
>>>> + skb_mark_for_recycle(skb);
>>>> +
>>>> return skb;
>>>>
>>>> err_xdp:
>>>> u64_stats_inc(&stats->xdp_drops);
>>>> err:
>>>> u64_stats_inc(&stats->drops);
>>>> - put_page(page);
>>>> + if (xdp_page)
>>>> + put_page(page);
>>>> + else
>>>> + virtnet_put_page(rq, page, true);
>>>> xdp_xmit:
>>>> return NULL;
>>>> }
>>>> @@ -2099,12 +2116,15 @@ static struct sk_buff *receive_small(struct net_device *dev,
>>>> }
>>>>
>>>> skb = receive_small_build_skb(vi, xdp_headroom, buf, len);
>>>> - if (likely(skb))
>>>> + if (likely(skb)) {
>>>> + if (rq->page_pool)
>>>> + skb_mark_for_recycle(skb);
>>>> return skb;
>>>> + }
>>>>
>>>> err:
>>>> u64_stats_inc(&stats->drops);
>>>> - put_page(page);
>>>> + virtnet_put_page(rq, page, true);
>>>> return NULL;
>>>> }
>>>>
>>>> @@ -2159,7 +2179,7 @@ static void mergeable_buf_free(struct receive_queue *rq, int num_buf,
>>>> }
>>>> u64_stats_add(&stats->bytes, len);
>>>> page = virt_to_head_page(buf);
>>>> - put_page(page);
>>>> + virtnet_put_page(rq, page, true);
>>>> }
>>>> }
>>>>
>>>> @@ -2270,7 +2290,7 @@ static int virtnet_build_xdp_buff_mrg(struct net_device *dev,
>>>> offset = buf - page_address(page);
>>>>
>>>> if (check_mergeable_len(dev, ctx, len)) {
>>>> - put_page(page);
>>>> + virtnet_put_page(rq, page, true);
>>>> goto err;
>>>> }
>>>>
>>>> @@ -2289,7 +2309,7 @@ static int virtnet_build_xdp_buff_mrg(struct net_device *dev,
>>>> return 0;
>>>>
>>>> err:
>>>> - put_xdp_frags(xdp);
>>>> + put_xdp_frags(xdp, rq);
>>>> return -EINVAL;
>>>> }
>>>>
>>>> @@ -2364,7 +2384,7 @@ static void *mergeable_xdp_get_buf(struct virtnet_info *vi,
>>>>
>>>> *frame_sz = PAGE_SIZE;
>>>>
>>>> - put_page(*page);
>>>> + virtnet_put_page(rq, *page, true);
>>>>
>>>> *page = xdp_page;
>>>>
>>>> @@ -2386,6 +2406,7 @@ static struct sk_buff *receive_mergeable_xdp(struct net_device *dev,
>>>> struct page *page = virt_to_head_page(buf);
>>>> int offset = buf - page_address(page);
>>>> unsigned int xdp_frags_truesz = 0;
>>>> + struct page *org_page = page;
>>>> struct sk_buff *head_skb;
>>>> unsigned int frame_sz;
>>>> struct xdp_buff xdp;
>>>> @@ -2410,6 +2431,8 @@ static struct sk_buff *receive_mergeable_xdp(struct net_device *dev,
>>>> head_skb = build_skb_from_xdp_buff(dev, vi, &xdp, xdp_frags_truesz);
>>>> if (unlikely(!head_skb))
>>>> break;
>>>> + if (rq->page_pool && page == org_page)
>>>> + skb_mark_for_recycle(head_skb);
>>>> return head_skb;
>>>>
>>>> case XDP_TX:
>>>> @@ -2420,10 +2443,13 @@ static struct sk_buff *receive_mergeable_xdp(struct net_device *dev,
>>>> break;
>>>> }
>>>>
>>>> - put_xdp_frags(&xdp);
>>>> + put_xdp_frags(&xdp, rq);
>>>>
>>>> err_xdp:
>>>> - put_page(page);
>>>> + if (page != org_page)
>>>> + put_page(page);
>>>> + else
>>>> + virtnet_put_page(rq, page, true);
>>>> mergeable_buf_free(rq, num_buf, dev, stats);
>>>>
>>>> u64_stats_inc(&stats->xdp_drops);
>>>> @@ -2431,7 +2457,8 @@ static struct sk_buff *receive_mergeable_xdp(struct net_device *dev,
>>>> return NULL;
>>>> }
>>>>
>>>> -static struct sk_buff *virtnet_skb_append_frag(struct sk_buff *head_skb,
>>>> +static struct sk_buff *virtnet_skb_append_frag(struct receive_queue *rq,
>>>> + struct sk_buff *head_skb,
>>>> struct sk_buff *curr_skb,
>>>> struct page *page, void *buf,
>>>> int len, int truesize)
>>>> @@ -2463,7 +2490,7 @@ static struct sk_buff *virtnet_skb_append_frag(struct sk_buff *head_skb,
>>>>
>>>> offset = buf - page_address(page);
>>>> if (skb_can_coalesce(curr_skb, num_skb_frags, page, offset)) {
>>>> - put_page(page);
>>>> + virtnet_put_page(rq, page, true);
>>>> skb_coalesce_rx_frag(curr_skb, num_skb_frags - 1,
>>>> len, truesize);
>>>> } else {
>>>> @@ -2512,10 +2539,13 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
>>>> }
>>>>
>>>> head_skb = page_to_skb(vi, rq, page, offset, len, truesize, headroom);
>>>> + if (unlikely(!head_skb))
>>>> + goto err_skb;
>>>> +
>>>> curr_skb = head_skb;
>>>>
>>>> - if (unlikely(!curr_skb))
>>>> - goto err_skb;
>>>> + if (rq->page_pool)
>>>> + skb_mark_for_recycle(head_skb);
>>>> while (--num_buf) {
>>>> buf = virtnet_rq_get_buf(rq, &len, &ctx);
>>>> if (unlikely(!buf)) {
>>>> @@ -2534,7 +2564,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
>>>> goto err_skb;
>>>>
>>>> truesize = mergeable_ctx_to_truesize(ctx);
>>>> - curr_skb = virtnet_skb_append_frag(head_skb, curr_skb, page,
>>>> + curr_skb = virtnet_skb_append_frag(rq, head_skb, curr_skb, page,
>>>> buf, len, truesize);
>>>> if (!curr_skb)
>>>> goto err_skb;
>>>> @@ -2544,7 +2574,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
>>>> return head_skb;
>>>>
>>>> err_skb:
>>>> - put_page(page);
>>>> + virtnet_put_page(rq, page, true);
>>>> mergeable_buf_free(rq, num_buf, dev, stats);
>>>>
>>>> err_buf:
>>>> @@ -2683,6 +2713,8 @@ static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
>>>> static int add_recvbuf_small(struct virtnet_info *vi, struct receive_queue *rq,
>>>> gfp_t gfp)
>>>> {
>>>> + unsigned int offset;
>>>> + struct page *page;
>>>> char *buf;
>>>> unsigned int xdp_headroom = virtnet_get_headroom(vi);
>>>> void *ctx = (void *)(unsigned long)xdp_headroom;
>>>> @@ -2692,6 +2724,24 @@ static int add_recvbuf_small(struct virtnet_info *vi, struct receive_queue *rq,
>>>> len = SKB_DATA_ALIGN(len) +
>>>> SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
>>>>
>>>> + if (rq->page_pool) {
>>>
>>> I think it would be a burden if we maintain two different data paths.
>>
>> I will move it to probe in v2.
>>
>>> And what's more, I see this patch doesn't require DMA mapping for the
>>> page pool. This basically defeats the pre mapping logic introduced in
>>> 31f3cd4e5756b("virtio-net: rq submits premapped per-buffer"). Lastly,
>>> it seems we should make VIRTIO_NET select PAGE_POOL.
>>
>> I intentionally used flags=0 and virtqueue_add_inbuf_ctx() to keep the
>> initial patch simple, following the pattern of xen-netfront which also
>> used flags=0 due to its custom DMA mechanism (grant tables).
>>
>> My concern was that virtio has its own DMA abstraction
>> vdev->map->map_page() (used by VDUSE), and I wasn't sure if page_pool's
>> standard dma_map_page() would be compatible with all virtio backends.
>
> You are right, DMA is unware about virtio mappings, so we can't use that.
>
>>
>> To preserve the premapping optimization, I see two options:
>> 1. Use PP_FLAG_DMA_MAP with virtqueue_dma_dev() as the DMA device. This
>> is simpler but uses the standard DMA API, which may not work corerctly
>> with VDUSE.
>> 2. Integrate page_pool allocation with virtio's existing DMA infra -
>> allocate pages from page_pool, but DMA map using
>> virtqueue_map_single_attrs(), then use virtqueue_add_inbuf_premapped().
>> This preserves the compatibility but requires tracking DMA mapping per
>> page.
>>
>> Which would be better? Or, is there anything simpler that I'm missing?
>>
>
> 2 would be better.
Thanks for confirming. For v2, I'll check virtqueue_dma_dev() at probe
time to select the DMA strategy:
1. When virtqueue_dma_dev() != NULL i.e. standard virtio backends:
- Create page_pool with PP_FLAG_DMA_MAP, dev = virtqueue_dma_dev()
- Page pool handles the DMA mapping, and pages stay mapped across
recycling
- Submit it using virtqueue_add_inbuf_premapped()
2. When it is NULL i.e. VDUSE, direct physical:
- Create page_pool with flags = 0
- Manually map using vitqueue_map_single_attrs()
- Submit using virtqueue_add_inbuf_premapped()
- Unmap on recycle via virtqueue_unmap_single_attrs()
Does this sound good?
>
>> Will add PAGE_POOL in kConfig for VIRTIO_NET in v2.
>>
>>>
>>>> + page = page_pool_alloc_frag(rq->page_pool, &offset, len, gfp);
>>>> + if (unlikely(!page))
>>>> + return -ENOMEM;
>>>> +
>>>> + buf = page_address(page) + offset;
>>>> + buf += VIRTNET_RX_PAD + xdp_headroom;
>>>> +
>>>> + sg_init_table(rq->sg, 1);
>>>> + sg_set_buf(&rq->sg[0], buf, vi->hdr_len + GOOD_PACKET_LEN);
>>>> +
>>>> + err = virtqueue_add_inbuf_ctx(rq->vq, rq->sg, 1, buf, ctx, gfp);
>>>> + if (err < 0)
>>>> + page_pool_put_page(rq->page_pool,
>>>> + virt_to_head_page(buf), -1, false);
>>>> + return err;
>>>> + }
>>>> +
>>>> if (unlikely(!skb_page_frag_refill(len, &rq->alloc_frag, gfp)))
>>>> return -ENOMEM;
>>>>
>>>> @@ -2786,6 +2836,8 @@ static int add_recvbuf_mergeable(struct virtnet_info *vi,
>>>> unsigned int tailroom = headroom ? sizeof(struct skb_shared_info) : 0;
>>>> unsigned int room = SKB_DATA_ALIGN(headroom + tailroom);
>>>> unsigned int len, hole;
>>>> + unsigned int offset;
>>>> + struct page *page;
>>>> void *ctx;
>>>> char *buf;
>>>> int err;
>>>> @@ -2796,6 +2848,39 @@ static int add_recvbuf_mergeable(struct virtnet_info *vi,
>>>> */
>>>> len = get_mergeable_buf_len(rq, &rq->mrg_avg_pkt_len, room);
>>>>
>>>> + if (rq->page_pool) {
>>>> + page = page_pool_alloc_frag(rq->page_pool, &offset,
>>>> + len + room, gfp);
>>>> + if (unlikely(!page))
>>>> + return -ENOMEM;
>>>> +
>>>> + buf = page_address(page) + offset;
>>>> + buf += headroom; /* advance address leaving hole at front of pkt */
>>>> +
>>>> + hole = PAGE_SIZE - (offset + len + room);
>>>> + if (hole < len + room) {
>>>> + /* To avoid internal fragmentation, if there is very likely not
>>>> + * enough space for another buffer, add the remaining space to
>>>> + * the current buffer.
>>>> + * XDP core assumes that frame_size of xdp_buff and the length
>>>> + * of the frag are PAGE_SIZE, so we disable the hole mechanism.
>>>> + */
>>>> + if (!headroom)
>>>> + len += hole;
>>>> + }
>>>> +
>>>> + ctx = mergeable_len_to_ctx(len + room, headroom);
>>>> +
>>>> + sg_init_table(rq->sg, 1);
>>>> + sg_set_buf(&rq->sg[0], buf, len);
>>>> +
>>>> + err = virtqueue_add_inbuf_ctx(rq->vq, rq->sg, 1, buf, ctx, gfp);
>>>> + if (err < 0)
>>>> + page_pool_put_page(rq->page_pool,
>>>> + virt_to_head_page(buf), -1, false);
>>>> + return err;
>>>> + }
>>>> +
>>>> if (unlikely(!skb_page_frag_refill(len + room, alloc_frag, gfp)))
>>>> return -ENOMEM;
>>>>
>>>> @@ -3181,7 +3266,10 @@ static int virtnet_enable_queue_pair(struct virtnet_info *vi, int qp_index)
>>>> return err;
>>>>
>>>> err = xdp_rxq_info_reg_mem_model(&vi->rq[qp_index].xdp_rxq,
>>>> - MEM_TYPE_PAGE_SHARED, NULL);
>>>> + vi->rq[qp_index].page_pool ?
>>>> + MEM_TYPE_PAGE_POOL :
>>>> + MEM_TYPE_PAGE_SHARED,
>>>> + vi->rq[qp_index].page_pool);
>>>> if (err < 0)
>>>> goto err_xdp_reg_mem_model;
>>>>
>>>> @@ -3221,11 +3309,77 @@ static void virtnet_update_settings(struct virtnet_info *vi)
>>>> vi->duplex = duplex;
>>>> }
>>>>
>>>> +static int virtnet_create_page_pools(struct virtnet_info *vi)
>>>> +{
>>>> + int i, err;
>>>> +
>>>> + for (i = 0; i < vi->curr_queue_pairs; i++) {
>>>> + struct receive_queue *rq = &vi->rq[i];
>>>> + struct page_pool_params pp_params = { 0 };
>>>> +
>>>> + if (rq->page_pool)
>>>> + continue;
>>>> +
>>>> + if (rq->xsk_pool)
>>>> + continue;
>>>> +
>>>> + if (!vi->mergeable_rx_bufs && vi->big_packets)
>>>> + continue;
>>>> +
>>>> + pp_params.order = 0;
>>>> + pp_params.pool_size = virtqueue_get_vring_size(rq->vq);
>>>> + pp_params.nid = dev_to_node(vi->vdev->dev.parent);
>>>> + pp_params.dev = vi->vdev->dev.parent;
>>>> + pp_params.netdev = vi->dev;
>>>> + pp_params.napi = &rq->napi;
>>>> + pp_params.flags = 0;
>>>> +
>>>> + rq->page_pool = page_pool_create(&pp_params);
>>>> + if (IS_ERR(rq->page_pool)) {
>>>> + err = PTR_ERR(rq->page_pool);
>>>> + rq->page_pool = NULL;
>>>> + goto err_cleanup;
>>>> + }
>>>> + }
>>>> + return 0;
>>>> +
>>>> +err_cleanup:
>>>> + while (--i >= 0) {
>>>> + struct receive_queue *rq = &vi->rq[i];
>>>> +
>>>> + if (rq->page_pool) {
>>>> + page_pool_destroy(rq->page_pool);
>>>> + rq->page_pool = NULL;
>>>> + }
>>>> + }
>>>> + return err;
>>>> +}
>>>> +
>>>> +static void virtnet_destroy_page_pools(struct virtnet_info *vi)
>>>> +{
>>>> + int i;
>>>> +
>>>> + for (i = 0; i < vi->max_queue_pairs; i++) {
>>>> + struct receive_queue *rq = &vi->rq[i];
>>>> +
>>>> + if (rq->page_pool) {
>>>> + page_pool_destroy(rq->page_pool);
>>>> + rq->page_pool = NULL;
>>>> + }
>>>> + }
>>>> +}
>>>> +
>>>> static int virtnet_open(struct net_device *dev)
>>>> {
>>>> struct virtnet_info *vi = netdev_priv(dev);
>>>> int i, err;
>>>>
>>>> + err = virtnet_create_page_pools(vi);
>>>
>>> Any reason those page pools were not created during the probe?
>>
>> No good reason. I will add it in v2.
>>
>
> Thanks
>
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