Use page_pool for RX buffer allocation in mergeable and small buffer
modes to enable page recycling and avoid repeated page allocator calls.
skb_mark_for_recycle() enables page reuse in the network stack.
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.
Implement conditional DMA premapping using virtqueue_dma_dev():
- When non-NULL (vhost, virtio-pci): use PP_FLAG_DMA_MAP with page_pool
handling DMA mapping, submit via virtqueue_add_inbuf_premapped()
- When NULL (VDUSE, direct physical): page_pool handles allocation only,
submit via virtqueue_add_inbuf_ctx()
This preserves the DMA premapping optimization from commit 31f3cd4e5756b
("virtio-net: rq submits premapped per-buffer") while adding page_pool
support as a prerequisite for future zero-copy features (devmem TCP,
io_uring ZCRX).
Page pools are created in probe and destroyed in remove (not open/close),
following existing driver behavior where RX buffers remain in virtqueues
across interface state changes.
Signed-off-by: Vishwanath Seshagiri <vishs@meta.com>
---
drivers/net/Kconfig | 1 +
drivers/net/virtio_net.c | 360 ++++++++++++++++++++++-----------------
2 files changed, 206 insertions(+), 155 deletions(-)
diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index ac12eaf11755..f1e6b6b0a86f 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -450,6 +450,7 @@ config VIRTIO_NET
depends on VIRTIO
select NET_FAILOVER
select DIMLIB
+ select PAGE_POOL
help
This is the virtual network driver for virtio. It can be used with
QEMU based VMMs (like KVM or Xen). Say Y or M.
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index db88dcaefb20..52632361c1f8 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 +360,11 @@ struct receive_queue {
/* Page frag for packet buffer allocation. */
struct page_frag alloc_frag;
+ struct page_pool *page_pool;
+
+ /* True if page_pool handles DMA mapping via PP_FLAG_DMA_MAP */
+ bool use_page_pool_dma;
+
/* RX: fragments + linear part + virtio header */
struct scatterlist sg[MAX_SKB_FRAGS + 2];
@@ -521,11 +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,
@@ -706,15 +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 (page_pool_page_is_pp(page))
+ 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_rx_mode_work(struct virtnet_info *vi)
@@ -877,9 +894,12 @@ 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;
}
@@ -914,7 +934,10 @@ 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;
}
@@ -925,7 +948,7 @@ 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;
}
@@ -965,93 +988,10 @@ 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;
-}
-
-static void virtnet_rq_init_one_sg(struct receive_queue *rq, void *buf, u32 len)
-{
- struct virtnet_info *vi = rq->vq->vdev->priv;
- struct virtnet_rq_dma *dma;
- dma_addr_t addr;
- u32 offset;
- void *head;
-
- BUG_ON(vi->big_packets && !vi->mergeable_rx_bufs);
-
- head = page_address(rq->alloc_frag.page);
-
- offset = buf - head;
-
- dma = head;
-
- addr = dma->addr - sizeof(*dma) + offset;
-
- sg_init_table(rq->sg, 1);
- sg_fill_dma(rq->sg, addr, len);
-}
-
-static void *virtnet_rq_alloc(struct receive_queue *rq, u32 size, gfp_t gfp)
-{
- struct page_frag *alloc_frag = &rq->alloc_frag;
- struct virtnet_info *vi = rq->vq->vdev->priv;
- struct virtnet_rq_dma *dma;
- void *buf, *head;
- dma_addr_t addr;
BUG_ON(vi->big_packets && !vi->mergeable_rx_bufs);
- head = page_address(alloc_frag->page);
-
- dma = head;
-
- /* new pages */
- if (!alloc_frag->offset) {
- if (rq->last_dma) {
- /* Now, the new page is allocated, the last dma
- * will not be used. So the dma can be unmapped
- * if the ref is 0.
- */
- virtnet_rq_unmap(rq, rq->last_dma, 0);
- rq->last_dma = NULL;
- }
-
- dma->len = alloc_frag->size - sizeof(*dma);
-
- addr = virtqueue_map_single_attrs(rq->vq, dma + 1,
- dma->len, DMA_FROM_DEVICE, 0);
- if (virtqueue_map_mapping_error(rq->vq, addr))
- return NULL;
-
- dma->addr = addr;
- dma->need_sync = virtqueue_map_need_sync(rq->vq, addr);
-
- /* Add a reference to dma to prevent the entire dma from
- * being released during error handling. This reference
- * will be freed after the pages are no longer used.
- */
- get_page(alloc_frag->page);
- dma->ref = 1;
- alloc_frag->offset = sizeof(*dma);
-
- rq->last_dma = dma;
- }
-
- ++dma->ref;
-
- buf = head + alloc_frag->offset;
-
- get_page(alloc_frag->page);
- alloc_frag->offset += size;
-
- return buf;
+ return virtqueue_get_buf_ctx(rq->vq, len, ctx);
}
static void virtnet_rq_unmap_free_buf(struct virtqueue *vq, void *buf)
@@ -1067,9 +1007,6 @@ 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);
}
@@ -1335,7 +1272,7 @@ 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);
@@ -1771,7 +1708,7 @@ 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;
@@ -1781,7 +1718,7 @@ 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);
}
}
}
@@ -1873,7 +1810,7 @@ static struct page *xdp_linearize_page(struct net_device *dev,
if (page_off + *len + tailroom > PAGE_SIZE)
return NULL;
- page = alloc_page(GFP_ATOMIC);
+ page = page_pool_alloc_pages(rq->page_pool, GFP_ATOMIC);
if (!page)
return NULL;
@@ -1897,7 +1834,7 @@ 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;
}
@@ -1905,21 +1842,21 @@ 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 */
*len = page_off - XDP_PACKET_HEADROOM;
return page;
err_buf:
- __free_pages(page, 0);
+ page_pool_put_page(rq->page_pool, page, -1, true);
return NULL;
}
@@ -1962,7 +1899,7 @@ 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;
@@ -1996,7 +1933,7 @@ 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;
}
@@ -2028,13 +1965,15 @@ static struct sk_buff *receive_small_xdp(struct net_device *dev,
if (metasize)
skb_metadata_set(skb, metasize);
+ skb_mark_for_recycle(skb);
+
return skb;
err_xdp:
u64_stats_inc(&stats->xdp_drops);
err:
u64_stats_inc(&stats->drops);
- put_page(page);
+ virtnet_put_page(rq, page, true);
xdp_xmit:
return NULL;
}
@@ -2082,12 +2021,14 @@ 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)) {
+ skb_mark_for_recycle(skb);
return skb;
+ }
err:
u64_stats_inc(&stats->drops);
- put_page(page);
+ virtnet_put_page(rq, page, true);
return NULL;
}
@@ -2142,7 +2083,7 @@ 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);
}
}
@@ -2253,7 +2194,7 @@ 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;
}
@@ -2272,7 +2213,7 @@ 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;
}
@@ -2337,7 +2278,7 @@ static void *mergeable_xdp_get_buf(struct virtnet_info *vi,
if (*len + xdp_room > PAGE_SIZE)
return NULL;
- xdp_page = alloc_page(GFP_ATOMIC);
+ xdp_page = page_pool_alloc_pages(rq->page_pool, GFP_ATOMIC);
if (!xdp_page)
return NULL;
@@ -2347,7 +2288,7 @@ 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;
@@ -2393,6 +2334,8 @@ 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;
+
+ skb_mark_for_recycle(head_skb);
return head_skb;
case XDP_TX:
@@ -2403,10 +2346,10 @@ 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);
+ virtnet_put_page(rq, page, true);
mergeable_buf_free(rq, num_buf, dev, stats);
u64_stats_inc(&stats->xdp_drops);
@@ -2414,7 +2357,8 @@ 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)
@@ -2446,7 +2390,7 @@ 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 {
@@ -2499,6 +2443,8 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
if (unlikely(!curr_skb))
goto err_skb;
+
+ skb_mark_for_recycle(head_skb);
while (--num_buf) {
buf = virtnet_rq_get_buf(rq, &len, &ctx);
if (unlikely(!buf)) {
@@ -2517,7 +2463,7 @@ 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;
@@ -2527,7 +2473,7 @@ 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:
@@ -2666,32 +2612,42 @@ 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)
{
- char *buf;
unsigned int xdp_headroom = virtnet_get_headroom(vi);
void *ctx = (void *)(unsigned long)xdp_headroom;
int len = vi->hdr_len + VIRTNET_RX_PAD + GOOD_PACKET_LEN + xdp_headroom;
+ unsigned int offset;
+ struct page *page;
+ dma_addr_t addr;
+ char *buf;
int err;
len = SKB_DATA_ALIGN(len) +
SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
- if (unlikely(!skb_page_frag_refill(len, &rq->alloc_frag, gfp)))
- return -ENOMEM;
-
- buf = virtnet_rq_alloc(rq, len, gfp);
- if (unlikely(!buf))
+ 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;
- virtnet_rq_init_one_sg(rq, buf, vi->hdr_len + GOOD_PACKET_LEN);
+ if (rq->use_page_pool_dma) {
+ addr = page_pool_get_dma_addr(page) + offset;
+ addr += VIRTNET_RX_PAD + xdp_headroom;
- err = virtqueue_add_inbuf_premapped(rq->vq, rq->sg, 1, buf, ctx, gfp);
- if (err < 0) {
- virtnet_rq_unmap(rq, buf, 0);
- put_page(virt_to_head_page(buf));
+ sg_init_table(rq->sg, 1);
+ sg_fill_dma(rq->sg, addr, vi->hdr_len + GOOD_PACKET_LEN);
+ err = virtqueue_add_inbuf_premapped(rq->vq, rq->sg, 1,
+ buf, ctx, gfp);
+ } else {
+ sg_init_one(rq->sg, 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;
}
@@ -2764,13 +2720,15 @@ static unsigned int get_mergeable_buf_len(struct receive_queue *rq,
static int add_recvbuf_mergeable(struct virtnet_info *vi,
struct receive_queue *rq, gfp_t gfp)
{
- struct page_frag *alloc_frag = &rq->alloc_frag;
unsigned int headroom = virtnet_get_headroom(vi);
unsigned int tailroom = headroom ? sizeof(struct skb_shared_info) : 0;
unsigned int room = SKB_DATA_ALIGN(headroom + tailroom);
unsigned int len, hole;
- void *ctx;
+ unsigned int offset;
+ struct page *page;
+ dma_addr_t addr;
char *buf;
+ void *ctx;
int err;
/* Extra tailroom is needed to satisfy XDP's assumption. This
@@ -2779,18 +2737,14 @@ static int add_recvbuf_mergeable(struct virtnet_info *vi,
*/
len = get_mergeable_buf_len(rq, &rq->mrg_avg_pkt_len, room);
- if (unlikely(!skb_page_frag_refill(len + room, alloc_frag, gfp)))
- return -ENOMEM;
-
- if (!alloc_frag->offset && len + room + sizeof(struct virtnet_rq_dma) > alloc_frag->size)
- len -= sizeof(struct virtnet_rq_dma);
-
- buf = virtnet_rq_alloc(rq, len + room, gfp);
- if (unlikely(!buf))
+ 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 = alloc_frag->size - alloc_frag->offset;
+
+ 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
@@ -2800,18 +2754,27 @@ static int add_recvbuf_mergeable(struct virtnet_info *vi,
*/
if (!headroom)
len += hole;
- alloc_frag->offset += hole;
}
- virtnet_rq_init_one_sg(rq, buf, len);
-
ctx = mergeable_len_to_ctx(len + room, headroom);
- err = virtqueue_add_inbuf_premapped(rq->vq, rq->sg, 1, buf, ctx, gfp);
- if (err < 0) {
- virtnet_rq_unmap(rq, buf, 0);
- put_page(virt_to_head_page(buf));
+
+ if (rq->use_page_pool_dma) {
+ addr = page_pool_get_dma_addr(page) + offset;
+ addr += headroom;
+
+ sg_init_table(rq->sg, 1);
+ sg_fill_dma(rq->sg, addr, len);
+ err = virtqueue_add_inbuf_premapped(rq->vq, rq->sg, 1,
+ buf, ctx, gfp);
+ } else {
+ sg_init_one(rq->sg, 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;
}
@@ -3128,7 +3091,10 @@ 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;
@@ -3168,6 +3134,81 @@ 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->max_queue_pairs; i++) {
+ struct receive_queue *rq = &vi->rq[i];
+ struct page_pool_params pp_params = { 0 };
+ struct device *dma_dev;
+
+ 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.netdev = vi->dev;
+ pp_params.napi = &rq->napi;
+
+ /* Check if backend supports DMA API (e.g., vhost, virtio-pci).
+ * If so, use page_pool's DMA mapping for premapped buffers.
+ * Otherwise (e.g., VDUSE), page_pool only handles allocation.
+ */
+ dma_dev = virtqueue_dma_dev(rq->vq);
+ if (dma_dev) {
+ pp_params.dev = dma_dev;
+ pp_params.flags = PP_FLAG_DMA_MAP;
+ pp_params.dma_dir = DMA_FROM_DEVICE;
+ rq->use_page_pool_dma = true;
+ } else {
+ pp_params.dev = vi->vdev->dev.parent;
+ pp_params.flags = 0;
+ rq->use_page_pool_dma = false;
+ }
+
+ 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);
@@ -3770,7 +3811,6 @@ static int virtnet_close(struct net_device *dev)
* open
*/
cancel_work_sync(&vi->config_work);
-
for (i = 0; i < vi->max_queue_pairs; i++) {
virtnet_disable_queue_pair(vi, i);
virtnet_cancel_dim(vi, &vi->rq[i].dim);
@@ -6442,9 +6482,6 @@ static int virtnet_find_vqs(struct virtnet_info *vi)
vi->sq[i].vq = vqs[txq2vq(i)];
}
- /* run here: ret == 0. */
-
-
err_find:
kfree(ctx);
err_ctx:
@@ -6945,6 +6982,14 @@ static int virtnet_probe(struct virtio_device *vdev)
goto free;
}
+ /* Create page pools for receive queues.
+ * Page pools are created at probe time so they can be used
+ * with premapped DMA addresses throughout the device lifetime.
+ */
+ err = virtnet_create_page_pools(vi);
+ if (err)
+ goto free_irq_moder;
+
#ifdef CONFIG_SYSFS
if (vi->mergeable_rx_bufs)
dev->sysfs_rx_queue_group = &virtio_net_mrg_rx_group;
@@ -6958,7 +7003,7 @@ static int virtnet_probe(struct virtio_device *vdev)
vi->failover = net_failover_create(vi->dev);
if (IS_ERR(vi->failover)) {
err = PTR_ERR(vi->failover);
- goto free_vqs;
+ goto free_page_pools;
}
}
@@ -7075,7 +7120,10 @@ static int virtnet_probe(struct virtio_device *vdev)
unregister_netdev(dev);
free_failover:
net_failover_destroy(vi->failover);
-free_vqs:
+free_page_pools:
+ virtnet_destroy_page_pools(vi);
+free_irq_moder:
+ virtnet_free_irq_moder(vi);
virtio_reset_device(vdev);
free_receive_page_frags(vi);
virtnet_del_vqs(vi);
@@ -7104,6 +7152,8 @@ static void remove_vq_common(struct virtnet_info *vi)
free_receive_page_frags(vi);
+ virtnet_destroy_page_pools(vi);
+
virtnet_del_vqs(vi);
}
--
2.47.3On Wed, Feb 4, 2026 at 7:10 AM Vishwanath Seshagiri <vishs@meta.com> wrote:
>
> Use page_pool for RX buffer allocation in mergeable and small buffer
> modes to enable page recycling and avoid repeated page allocator calls.
> skb_mark_for_recycle() enables page reuse in the network stack.
>
> 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.
>
> Implement conditional DMA premapping using virtqueue_dma_dev():
> - When non-NULL (vhost, virtio-pci): use PP_FLAG_DMA_MAP with page_pool
> handling DMA mapping, submit via virtqueue_add_inbuf_premapped()
> - When NULL (VDUSE, direct physical): page_pool handles allocation only,
> submit via virtqueue_add_inbuf_ctx()
>
> This preserves the DMA premapping optimization from commit 31f3cd4e5756b
> ("virtio-net: rq submits premapped per-buffer") while adding page_pool
> support as a prerequisite for future zero-copy features (devmem TCP,
> io_uring ZCRX).
>
> Page pools are created in probe and destroyed in remove (not open/close),
> following existing driver behavior where RX buffers remain in virtqueues
> across interface state changes.
>
> Signed-off-by: Vishwanath Seshagiri <vishs@meta.com>
> ---
> drivers/net/Kconfig | 1 +
> drivers/net/virtio_net.c | 360 ++++++++++++++++++++++-----------------
> 2 files changed, 206 insertions(+), 155 deletions(-)
>
> diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
> index ac12eaf11755..f1e6b6b0a86f 100644
> --- a/drivers/net/Kconfig
> +++ b/drivers/net/Kconfig
> @@ -450,6 +450,7 @@ config VIRTIO_NET
> depends on VIRTIO
> select NET_FAILOVER
> select DIMLIB
> + select PAGE_POOL
> help
> This is the virtual network driver for virtio. It can be used with
> QEMU based VMMs (like KVM or Xen). Say Y or M.
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index db88dcaefb20..52632361c1f8 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 +360,11 @@ struct receive_queue {
> /* Page frag for packet buffer allocation. */
> struct page_frag alloc_frag;
>
> + struct page_pool *page_pool;
> +
> + /* True if page_pool handles DMA mapping via PP_FLAG_DMA_MAP */
> + bool use_page_pool_dma;
> +
> /* RX: fragments + linear part + virtio header */
> struct scatterlist sg[MAX_SKB_FRAGS + 2];
>
> @@ -521,11 +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,
> @@ -706,15 +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 (page_pool_page_is_pp(page))
> + 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_rx_mode_work(struct virtnet_info *vi)
> @@ -877,9 +894,12 @@ 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;
> }
>
> @@ -914,7 +934,10 @@ 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;
The check seems to be unnecessary as page_to_skb() will be only called
by big and mergeable. And we goto ok for mergeable before.
> offset = 0;
> }
>
> @@ -925,7 +948,7 @@ 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;
> }
> @@ -965,93 +988,10 @@ 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;
> -}
> -
> -static void virtnet_rq_init_one_sg(struct receive_queue *rq, void *buf, u32 len)
> -{
> - struct virtnet_info *vi = rq->vq->vdev->priv;
> - struct virtnet_rq_dma *dma;
> - dma_addr_t addr;
> - u32 offset;
> - void *head;
> -
> - BUG_ON(vi->big_packets && !vi->mergeable_rx_bufs);
> -
> - head = page_address(rq->alloc_frag.page);
> -
> - offset = buf - head;
> -
> - dma = head;
> -
> - addr = dma->addr - sizeof(*dma) + offset;
> -
> - sg_init_table(rq->sg, 1);
> - sg_fill_dma(rq->sg, addr, len);
> -}
> -
> -static void *virtnet_rq_alloc(struct receive_queue *rq, u32 size, gfp_t gfp)
> -{
> - struct page_frag *alloc_frag = &rq->alloc_frag;
> - struct virtnet_info *vi = rq->vq->vdev->priv;
> - struct virtnet_rq_dma *dma;
> - void *buf, *head;
> - dma_addr_t addr;
>
> BUG_ON(vi->big_packets && !vi->mergeable_rx_bufs);
>
> - head = page_address(alloc_frag->page);
> -
> - dma = head;
> -
> - /* new pages */
> - if (!alloc_frag->offset) {
> - if (rq->last_dma) {
> - /* Now, the new page is allocated, the last dma
> - * will not be used. So the dma can be unmapped
> - * if the ref is 0.
> - */
> - virtnet_rq_unmap(rq, rq->last_dma, 0);
> - rq->last_dma = NULL;
> - }
> -
> - dma->len = alloc_frag->size - sizeof(*dma);
> -
> - addr = virtqueue_map_single_attrs(rq->vq, dma + 1,
> - dma->len, DMA_FROM_DEVICE, 0);
> - if (virtqueue_map_mapping_error(rq->vq, addr))
> - return NULL;
> -
> - dma->addr = addr;
> - dma->need_sync = virtqueue_map_need_sync(rq->vq, addr);
> -
> - /* Add a reference to dma to prevent the entire dma from
> - * being released during error handling. This reference
> - * will be freed after the pages are no longer used.
> - */
> - get_page(alloc_frag->page);
> - dma->ref = 1;
> - alloc_frag->offset = sizeof(*dma);
> -
> - rq->last_dma = dma;
> - }
> -
> - ++dma->ref;
> -
> - buf = head + alloc_frag->offset;
> -
> - get_page(alloc_frag->page);
> - alloc_frag->offset += size;
> -
> - return buf;
> + return virtqueue_get_buf_ctx(rq->vq, len, ctx);
> }
>
> static void virtnet_rq_unmap_free_buf(struct virtqueue *vq, void *buf)
> @@ -1067,9 +1007,6 @@ 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);
> }
>
> @@ -1335,7 +1272,7 @@ 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);
> @@ -1771,7 +1708,7 @@ 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)
Nit: rq may come first to align with append_frags()?
> {
> struct skb_shared_info *shinfo;
> struct page *xdp_page;
> @@ -1781,7 +1718,7 @@ 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);
> }
> }
> }
> @@ -1873,7 +1810,7 @@ static struct page *xdp_linearize_page(struct net_device *dev,
> if (page_off + *len + tailroom > PAGE_SIZE)
> return NULL;
>
> - page = alloc_page(GFP_ATOMIC);
> + page = page_pool_alloc_pages(rq->page_pool, GFP_ATOMIC);
> if (!page)
> return NULL;
>
> @@ -1897,7 +1834,7 @@ 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;
> }
>
> @@ -1905,21 +1842,21 @@ 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 */
> *len = page_off - XDP_PACKET_HEADROOM;
> return page;
> err_buf:
> - __free_pages(page, 0);
> + page_pool_put_page(rq->page_pool, page, -1, true);
> return NULL;
> }
>
> @@ -1962,7 +1899,7 @@ 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;
This seems unnecessary.
> unsigned int buflen;
> struct xdp_buff xdp;
> struct sk_buff *skb;
> @@ -1996,7 +1933,7 @@ 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;
> }
>
> @@ -2028,13 +1965,15 @@ static struct sk_buff *receive_small_xdp(struct net_device *dev,
> if (metasize)
> skb_metadata_set(skb, metasize);
>
> + skb_mark_for_recycle(skb);
> +
> return skb;
>
> err_xdp:
> u64_stats_inc(&stats->xdp_drops);
> err:
> u64_stats_inc(&stats->drops);
> - put_page(page);
> + virtnet_put_page(rq, page, true);
> xdp_xmit:
> return NULL;
> }
> @@ -2082,12 +2021,14 @@ 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)) {
> + skb_mark_for_recycle(skb);
> return skb;
> + }
>
> err:
> u64_stats_inc(&stats->drops);
> - put_page(page);
> + virtnet_put_page(rq, page, true);
> return NULL;
> }
>
> @@ -2142,7 +2083,7 @@ 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);
> }
> }
>
> @@ -2253,7 +2194,7 @@ 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;
> }
>
> @@ -2272,7 +2213,7 @@ 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;
> }
>
> @@ -2337,7 +2278,7 @@ static void *mergeable_xdp_get_buf(struct virtnet_info *vi,
> if (*len + xdp_room > PAGE_SIZE)
> return NULL;
>
> - xdp_page = alloc_page(GFP_ATOMIC);
> + xdp_page = page_pool_alloc_pages(rq->page_pool, GFP_ATOMIC);
> if (!xdp_page)
> return NULL;
>
> @@ -2347,7 +2288,7 @@ 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;
>
> @@ -2393,6 +2334,8 @@ 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;
> +
> + skb_mark_for_recycle(head_skb);
> return head_skb;
>
> case XDP_TX:
> @@ -2403,10 +2346,10 @@ 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);
> + virtnet_put_page(rq, page, true);
> mergeable_buf_free(rq, num_buf, dev, stats);
>
> u64_stats_inc(&stats->xdp_drops);
> @@ -2414,7 +2357,8 @@ 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)
> @@ -2446,7 +2390,7 @@ 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 {
> @@ -2499,6 +2443,8 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
>
> if (unlikely(!curr_skb))
> goto err_skb;
> +
> + skb_mark_for_recycle(head_skb);
> while (--num_buf) {
> buf = virtnet_rq_get_buf(rq, &len, &ctx);
> if (unlikely(!buf)) {
> @@ -2517,7 +2463,7 @@ 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;
> @@ -2527,7 +2473,7 @@ 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:
> @@ -2666,32 +2612,42 @@ 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)
> {
> - char *buf;
> unsigned int xdp_headroom = virtnet_get_headroom(vi);
> void *ctx = (void *)(unsigned long)xdp_headroom;
> int len = vi->hdr_len + VIRTNET_RX_PAD + GOOD_PACKET_LEN + xdp_headroom;
> + unsigned int offset;
> + struct page *page;
> + dma_addr_t addr;
> + char *buf;
> int err;
>
> len = SKB_DATA_ALIGN(len) +
> SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
>
> - if (unlikely(!skb_page_frag_refill(len, &rq->alloc_frag, gfp)))
> - return -ENOMEM;
> -
> - buf = virtnet_rq_alloc(rq, len, gfp);
> - if (unlikely(!buf))
> + 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;
>
> - virtnet_rq_init_one_sg(rq, buf, vi->hdr_len + GOOD_PACKET_LEN);
> + if (rq->use_page_pool_dma) {
> + addr = page_pool_get_dma_addr(page) + offset;
> + addr += VIRTNET_RX_PAD + xdp_headroom;
>
> - err = virtqueue_add_inbuf_premapped(rq->vq, rq->sg, 1, buf, ctx, gfp);
> - if (err < 0) {
> - virtnet_rq_unmap(rq, buf, 0);
> - put_page(virt_to_head_page(buf));
> + sg_init_table(rq->sg, 1);
> + sg_fill_dma(rq->sg, addr, vi->hdr_len + GOOD_PACKET_LEN);
> + err = virtqueue_add_inbuf_premapped(rq->vq, rq->sg, 1,
> + buf, ctx, gfp);
> + } else {
> + sg_init_one(rq->sg, 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;
> }
>
> @@ -2764,13 +2720,15 @@ static unsigned int get_mergeable_buf_len(struct receive_queue *rq,
> static int add_recvbuf_mergeable(struct virtnet_info *vi,
> struct receive_queue *rq, gfp_t gfp)
> {
> - struct page_frag *alloc_frag = &rq->alloc_frag;
> unsigned int headroom = virtnet_get_headroom(vi);
> unsigned int tailroom = headroom ? sizeof(struct skb_shared_info) : 0;
> unsigned int room = SKB_DATA_ALIGN(headroom + tailroom);
> unsigned int len, hole;
> - void *ctx;
> + unsigned int offset;
> + struct page *page;
> + dma_addr_t addr;
> char *buf;
> + void *ctx;
> int err;
>
> /* Extra tailroom is needed to satisfy XDP's assumption. This
> @@ -2779,18 +2737,14 @@ static int add_recvbuf_mergeable(struct virtnet_info *vi,
> */
> len = get_mergeable_buf_len(rq, &rq->mrg_avg_pkt_len, room);
>
> - if (unlikely(!skb_page_frag_refill(len + room, alloc_frag, gfp)))
> - return -ENOMEM;
> -
> - if (!alloc_frag->offset && len + room + sizeof(struct virtnet_rq_dma) > alloc_frag->size)
> - len -= sizeof(struct virtnet_rq_dma);
> -
> - buf = virtnet_rq_alloc(rq, len + room, gfp);
> - if (unlikely(!buf))
> + 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 = alloc_frag->size - alloc_frag->offset;
> +
> + 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
> @@ -2800,18 +2754,27 @@ static int add_recvbuf_mergeable(struct virtnet_info *vi,
> */
> if (!headroom)
> len += hole;
> - alloc_frag->offset += hole;
> }
>
> - virtnet_rq_init_one_sg(rq, buf, len);
> -
> ctx = mergeable_len_to_ctx(len + room, headroom);
> - err = virtqueue_add_inbuf_premapped(rq->vq, rq->sg, 1, buf, ctx, gfp);
> - if (err < 0) {
> - virtnet_rq_unmap(rq, buf, 0);
> - put_page(virt_to_head_page(buf));
> +
> + if (rq->use_page_pool_dma) {
> + addr = page_pool_get_dma_addr(page) + offset;
> + addr += headroom;
> +
> + sg_init_table(rq->sg, 1);
> + sg_fill_dma(rq->sg, addr, len);
> + err = virtqueue_add_inbuf_premapped(rq->vq, rq->sg, 1,
> + buf, ctx, gfp);
> + } else {
> + sg_init_one(rq->sg, 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;
> }
>
> @@ -3128,7 +3091,10 @@ 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;
>
> @@ -3168,6 +3134,81 @@ 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->max_queue_pairs; i++) {
> + struct receive_queue *rq = &vi->rq[i];
> + struct page_pool_params pp_params = { 0 };
> + struct device *dma_dev;
> +
> + if (rq->page_pool)
> + continue;
> +
> + if (rq->xsk_pool)
> + continue;
> +
> + if (!vi->mergeable_rx_bufs && vi->big_packets)
> + continue;
This check could be moved out of the loop.
> +
> + 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.netdev = vi->dev;
> + pp_params.napi = &rq->napi;
> +
> + /* Check if backend supports DMA API (e.g., vhost, virtio-pci).
> + * If so, use page_pool's DMA mapping for premapped buffers.
> + * Otherwise (e.g., VDUSE), page_pool only handles allocation.
> + */
> + dma_dev = virtqueue_dma_dev(rq->vq);
> + if (dma_dev) {
> + pp_params.dev = dma_dev;
> + pp_params.flags = PP_FLAG_DMA_MAP;
> + pp_params.dma_dir = DMA_FROM_DEVICE;
> + rq->use_page_pool_dma = true;
> + } else {
> + pp_params.dev = vi->vdev->dev.parent;
> + pp_params.flags = 0;
> + rq->use_page_pool_dma = false;
> + }
> +
> + 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);
> @@ -3770,7 +3811,6 @@ static int virtnet_close(struct net_device *dev)
> * open
> */
> cancel_work_sync(&vi->config_work);
> -
Unnecessary changes.
> for (i = 0; i < vi->max_queue_pairs; i++) {
> virtnet_disable_queue_pair(vi, i);
> virtnet_cancel_dim(vi, &vi->rq[i].dim);
> @@ -6442,9 +6482,6 @@ static int virtnet_find_vqs(struct virtnet_info *vi)
> vi->sq[i].vq = vqs[txq2vq(i)];
> }
>
> - /* run here: ret == 0. */
> -
> -
Seems some leftovers of some temporary change.
> err_find:
> kfree(ctx);
> err_ctx:
> @@ -6945,6 +6982,14 @@ static int virtnet_probe(struct virtio_device *vdev)
> goto free;
> }
>
> + /* Create page pools for receive queues.
> + * Page pools are created at probe time so they can be used
> + * with premapped DMA addresses throughout the device lifetime.
> + */
> + err = virtnet_create_page_pools(vi);
> + if (err)
> + goto free_irq_moder;
> +
> #ifdef CONFIG_SYSFS
> if (vi->mergeable_rx_bufs)
> dev->sysfs_rx_queue_group = &virtio_net_mrg_rx_group;
> @@ -6958,7 +7003,7 @@ static int virtnet_probe(struct virtio_device *vdev)
> vi->failover = net_failover_create(vi->dev);
> if (IS_ERR(vi->failover)) {
> err = PTR_ERR(vi->failover);
> - goto free_vqs;
> + goto free_page_pools;
> }
> }
>
> @@ -7075,7 +7120,10 @@ static int virtnet_probe(struct virtio_device *vdev)
> unregister_netdev(dev);
> free_failover:
> net_failover_destroy(vi->failover);
> -free_vqs:
> +free_page_pools:
> + virtnet_destroy_page_pools(vi);
> +free_irq_moder:
> + virtnet_free_irq_moder(vi);
> virtio_reset_device(vdev);
> free_receive_page_frags(vi);
> virtnet_del_vqs(vi);
> @@ -7104,6 +7152,8 @@ static void remove_vq_common(struct virtnet_info *vi)
>
> free_receive_page_frags(vi);
>
> + virtnet_destroy_page_pools(vi);
> +
> virtnet_del_vqs(vi);
> }
>
> --
> 2.47.3
>
Thanks
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