On 2/8/26 11:05 AM, Michael S. Tsirkin wrote:
On Sun, Feb 08, 2026 at 10:56:15AM -0800, Vishwanath Seshagiri wrote:On 2/8/26 10:42 AM, Michael S. Tsirkin wrote:On Sun, Feb 08, 2026 at 09:54:10AM -0800, Vishwanath Seshagiri 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 <[email protected]> --- Changes in v6: - Drop page_pool_frag_offset_add() helper and switch to page_pool_alloc_va(); page_pool_alloc_netmem() already handles internal fragmentation internally (Jakub Kicinski) - v5: https://lore.kernel.org/virtualization/[email protected]/ Benchmark results: Configuration: pktgen TX -> tap -> vhost-net | virtio-net RX -> XDP_DROP Small packets (64 bytes, mrg_rxbuf=off): 1Q: 853,493 -> 868,923 pps (+1.8%) 2Q: 1,655,793 -> 1,696,707 pps (+2.5%) 4Q: 3,143,375 -> 3,302,511 pps (+5.1%) 8Q: 6,082,590 -> 6,156,894 pps (+1.2%) Mergeable RX (64 bytes): 1Q: 766,168 -> 814,493 pps (+6.3%) 2Q: 1,384,871 -> 1,670,639 pps (+20.6%) 4Q: 2,773,081 -> 3,080,574 pps (+11.1%) 8Q: 5,600,615 -> 6,043,891 pps (+7.9%) Mergeable RX (1500 bytes): 1Q: 741,579 -> 785,442 pps (+5.9%) 2Q: 1,310,043 -> 1,534,554 pps (+17.1%) 4Q: 2,748,700 -> 2,890,582 pps (+5.2%) 8Q: 5,348,589 -> 5,618,664 pps (+5.0%) drivers/net/Kconfig | 1 + drivers/net/virtio_net.c | 434 +++++++++++++++++++-------------------- 2 files changed, 217 insertions(+), 218 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..5055df56e4a7 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); @@ -290,14 +291,6 @@ struct virtnet_interrupt_coalesce { u32 max_usecs; }; -/* The dma information of pages allocated at a time. */ -struct virtnet_rq_dma { - dma_addr_t addr; - u32 ref; - u16 len; - u16 need_sync; -}; - /* Internal representation of a send virtqueue */ struct send_queue { /* Virtqueue associated with this send _queue */ @@ -356,8 +349,10 @@ struct receive_queue { /* Average packet length for mergeable receive buffers. */ struct ewma_pkt_len mrg_avg_pkt_len; - /* 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]; @@ -370,9 +365,6 @@ struct receive_queue { struct xdp_rxq_info xdp_rxq; - /* Record the last dma info to free after new pages is allocated. */ - struct virtnet_rq_dma *last_dma; - struct xsk_buff_pool *xsk_pool; /* xdp rxq used by xsk */ @@ -521,11 +513,13 @@ 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 +700,24 @@ 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);equivalently: if (vi->big_packets && !vi->mergeable_rx_bufs) give_pages(rq, buf); else virtnet_put_page(rq, virt_to_head_page(buf), false); and then it matches the check we have like in 10 places in this file. maybe it's time for a helper that does vi->big_packets && !vi->mergeable_rx_bufs? maybe virtnet_no_page_pool()?Good idea. I will create the virtnet_no_page_pool() api and use that for making intent clear.} static void enable_rx_mode_work(struct virtnet_info *vi) @@ -876,10 +879,16 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi, skb = virtnet_build_skb(buf, truesize, p - buf, len); if (unlikely(!skb)) return NULL; + /* Big packets mode chains pages via page->private, which is + * incompatible with the way page_pool uses page->private. + * Currently, big packets mode doesn't use page pools. + */ + if (vi->big_packets && !vi->mergeable_rx_bufs) { + page = (struct page *)page->private; + if (page) + give_pages(rq, page); + } - page = (struct page *)page->private; - if (page) - give_pages(rq, page); goto ok; } @@ -925,133 +934,18 @@ 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; } -static void virtnet_rq_unmap(struct receive_queue *rq, void *buf, u32 len) -{ - struct virtnet_info *vi = rq->vq->vdev->priv; - struct page *page = virt_to_head_page(buf); - struct virtnet_rq_dma *dma; - void *head; - int offset; - - BUG_ON(vi->big_packets && !vi->mergeable_rx_bufs); - - head = page_address(page); - - dma = head; - - --dma->ref; - - if (dma->need_sync && len) { - offset = buf - (head + sizeof(*dma)); - - virtqueue_map_sync_single_range_for_cpu(rq->vq, dma->addr, - offset, len, - DMA_FROM_DEVICE); - } - - if (dma->ref) - return; - - virtqueue_unmap_single_attrs(rq->vq, dma->addr, dma->len, - DMA_FROM_DEVICE, DMA_ATTR_SKIP_CPU_SYNC); - put_page(page); -} - 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 +961,6 @@ 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 +1226,7 @@ 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 +1662,7 @@ 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 receive_queue *rq, struct xdp_buff *xdp) { struct skb_shared_info *shinfo; struct page *xdp_page; @@ -1781,7 +1672,7 @@ 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 +1764,7 @@ 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 +1788,7 @@ 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 +1796,21 @@ 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; } @@ -1969,6 +1860,12 @@ static struct sk_buff *receive_small_xdp(struct net_device *dev, unsigned int metasize = 0; u32 act; + if (rq->use_page_pool_dma) { + int off = buf - page_address(page); + + page_pool_dma_sync_for_cpu(rq->page_pool, page, off, len); + } +hmm no this is wrong i think: struct virtio_net_hdr_mrg_rxbuf *hdr = buf + header_offset; int off = buf - page_address(page); you should sync from hdr not from buf.Yeah, the sync offset should be from where device actually writes. I will add change it in v7.besides did not receive_small already sync? we do not need two syncs.Yes, 2 syncs are redundant. I will keep it in receive_small, so that two syncs do not happen.if (unlikely(hdr->hdr.gso_type)) goto err_xdp; @@ -1996,7 +1893,7 @@ 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 +1925,15 @@ 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; } @@ -2056,6 +1955,12 @@ static struct sk_buff *receive_small(struct net_device *dev, */ buf -= VIRTNET_RX_PAD + xdp_headroom; + if (rq->use_page_pool_dma) { + int offset = buf - page_address(page); + + page_pool_dma_sync_for_cpu(rq->page_pool, page, offset, len); + }similar issue I think. off by header len.ack. will change it in v7.+ len -= vi->hdr_len; u64_stats_add(&stats->bytes, len); @@ -2082,12 +1987,14 @@ 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 +2049,7 @@ 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 +2160,7 @@ 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 +2179,7 @@ static int virtnet_build_xdp_buff_mrg(struct net_device *dev, return 0; err: - put_xdp_frags(xdp); + put_xdp_frags(rq, xdp); return -EINVAL; } @@ -2337,7 +2244,7 @@ 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 +2254,7 @@ 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 +2300,8 @@ 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 +2312,10 @@ static struct sk_buff *receive_mergeable_xdp(struct net_device *dev, break; } - put_xdp_frags(&xdp); + put_xdp_frags(rq, &xdp); 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 +2323,8 @@ 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 +2356,7 @@ 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 { @@ -2475,6 +2385,10 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, unsigned int headroom = mergeable_ctx_to_headroom(ctx); head_skb = NULL; + + if (rq->use_page_pool_dma) + page_pool_dma_sync_for_cpu(rq->page_pool, page, offset, len); +nice but where is the sync for reset of buffers?u64_stats_add(&stats->bytes, len - vi->hdr_len); if (check_mergeable_len(dev, ctx, len)) @@ -2499,6 +2413,8 @@ 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);ok so we have recycling. I *think* that since below you set PP_FLAG_DMA_MAP, then page_pool does not sync_for_device on recycle; so CPU can write into packet data (e.g. XDP_PASS) and leave dirty cachelines. After reuse, on non-coherent DMA that can corrupt later packets unless you add PP_FLAG_DMA_SYNC_DEV (with max_len/offset) or do an explicit dma_sync_for_device before requeue. See Documentation/core-api/dma-api-howto.rst I agree it's annoying since maybe we did not touch it at all.Right. I initially left it out since dma_sync_for_device is a no-op on coherent platforms where virtio-net is typically deployed, but it's needed for correctness on non-coherent architectures. Will add PP_FLAG_DMA_SYNC_DEV with appropriate max_len/offset in v7.erm. pls document assumptions like this in the future.
ack. will add these assumptions it into v7.
if (unlikely(!buf)) { @@ -2517,7 +2433,7 @@ 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 +2443,7 @@ 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 +2582,41 @@ 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 len = vi->hdr_len + VIRTNET_RX_PAD + GOOD_PACKET_LEN + xdp_headroom; + 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); + buf = page_pool_alloc_va(rq->page_pool, &len, gfp); if (unlikely(!buf)) return -ENOMEM; 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) { + page = virt_to_head_page(buf); + addr = page_pool_get_dma_addr(page) + + (buf - (char *)page_address(page)); - 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 +2689,14 @@ 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 len, alloc_len; + struct page *page; + dma_addr_t addr; char *buf; + void *ctx; int err; /* Extra tailroom is needed to satisfy XDP's assumption. This @@ -2779,39 +2705,36 @@ 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); + alloc_len = len + room; + buf = page_pool_alloc_va(rq->page_pool, &alloc_len, gfp); if (unlikely(!buf)) return -ENOMEM; buf += headroom; /* advance address leaving hole at front of pkt */ - hole = alloc_frag->size - alloc_frag->offset; - 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; - alloc_frag->offset += hole; - } - virtnet_rq_init_one_sg(rq, buf, len); + if (!headroom) + len = alloc_len - room; 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) { + page = virt_to_head_page(buf); + addr = page_pool_get_dma_addr(page) + + (buf - (char *)page_address(page)); + + 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 +3051,10 @@ 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 +3094,81 @@ 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; + + if (!vi->mergeable_rx_bufs && vi->big_packets) + return 0; + + 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; + + 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); @@ -6287,17 +6288,6 @@ static void free_receive_bufs(struct virtnet_info *vi) rtnl_unlock(); } -static void free_receive_page_frags(struct virtnet_info *vi) -{ - int i; - for (i = 0; i < vi->max_queue_pairs; i++) - if (vi->rq[i].alloc_frag.page) { - if (vi->rq[i].last_dma) - virtnet_rq_unmap(&vi->rq[i], vi->rq[i].last_dma, 0); - put_page(vi->rq[i].alloc_frag.page); - } -} - static void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf) { struct virtnet_info *vi = vq->vdev->priv; @@ -6441,10 +6431,8 @@ static int virtnet_find_vqs(struct virtnet_info *vi) vi->rq[i].min_buf_len = mergeable_min_buf_len(vi, vi->rq[i].vq); vi->sq[i].vq = vqs[txq2vq(i)]; } - /* run here: ret == 0. */ - err_find: kfree(ctx); err_ctx: @@ -6945,6 +6933,14 @@ 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 +6954,7 @@ 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; } } @@ -7075,9 +7071,11 @@ 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); free: free_netdev(dev); @@ -7102,7 +7100,7 @@ static void remove_vq_common(struct virtnet_info *vi) free_receive_bufs(vi); - free_receive_page_frags(vi); + virtnet_destroy_page_pools(vi); virtnet_del_vqs(vi); } -- 2.47.3
