On Sat, Jan 10, 2026 at 9:58 AM Vishwanath Seshagiri <[email protected]> wrote:
>
>
>
> On 1/8/26 7:16 PM, Jason Wang wrote:
> > On Thu, Jan 8, 2026 at 2:24 PM Vishwanath Seshagiri <[email protected]> wrote:
> >>
> >> On 1/7/26 7:16 PM, Jason Wang wrote:
> >>> On Wed, Jan 7, 2026 at 6:19 AM Vishwanath Seshagiri <[email protected]>
> >>> 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 <[email protected]>
> >>>> ---
> >>>> 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?
Works for me.
Thanks
>
>
> >
> >> 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
> >
>
