NACK: [SRU][k/gcp][PATCH] gve: Reduce alloc and copy costs in the GQ rx path
Andrei Gherzan
andrei.gherzan at canonical.com
Tue May 30 15:04:49 UTC 2023
On 23/05/30 10:51AM, Khalid Elmously wrote:
> From: Shailend Chand <shailend at google.com>
>
> BugLink: https://bugs.launchpad.net/bugs/2021830
>
> Previously, even if just one of the many fragments of a 9k packet
> required a copy, we'd copy the whole packet into a freshly-allocated
> 9k-sized linear SKB, and this led to performance issues.
>
> By having a pool of pages to copy into, each fragment can be
> independently handled, leading to a reduced incidence of
> allocation and copy.
>
> Signed-off-by: Shailend Chand <shailend at google.com>
> Signed-off-by: David S. Miller <davem at davemloft.net>
> (cherry picked from commit 82fd151d38d9fda714c5bb2e9e79ecd6bdc72da6)
> Signed-off-by: Khalid Elmously <khalid.elmously at canonical.com>
> ---
> drivers/net/ethernet/google/gve/gve.h | 26 +-
> drivers/net/ethernet/google/gve/gve_ethtool.c | 2 +
> drivers/net/ethernet/google/gve/gve_rx.c | 542 ++++++++++--------
> drivers/net/ethernet/google/gve/gve_rx_dqo.c | 2 +-
> drivers/net/ethernet/google/gve/gve_utils.c | 30 +-
> drivers/net/ethernet/google/gve/gve_utils.h | 2 +-
> 6 files changed, 338 insertions(+), 266 deletions(-)
>
> diff --git a/drivers/net/ethernet/google/gve/gve.h b/drivers/net/ethernet/google/gve/gve.h
> index 160735484465..5655da9cd236 100644
> --- a/drivers/net/ethernet/google/gve/gve.h
> +++ b/drivers/net/ethernet/google/gve/gve.h
> @@ -60,7 +60,8 @@ struct gve_rx_slot_page_info {
> void *page_address;
> u32 page_offset; /* offset to write to in page */
> int pagecnt_bias; /* expected pagecnt if only the driver has a ref */
> - u8 can_flip;
> + u16 pad; /* adjustment for rx padding */
> + u8 can_flip; /* tracks if the networking stack is using the page */
> };
>
> /* A list of pages registered with the device during setup and used by a queue
> @@ -149,10 +150,17 @@ struct gve_rx_ctx {
> /* head and tail of skb chain for the current packet or NULL if none */
> struct sk_buff *skb_head;
> struct sk_buff *skb_tail;
> - u16 total_expected_size;
> - u8 expected_frag_cnt;
> - u8 curr_frag_cnt;
> - u8 reuse_frags;
> + u32 total_size;
> + u8 frag_cnt;
> + bool drop_pkt;
> +};
> +
> +struct gve_rx_cnts {
> + u32 ok_pkt_bytes;
> + u16 ok_pkt_cnt;
> + u16 total_pkt_cnt;
> + u16 cont_pkt_cnt;
> + u16 desc_err_pkt_cnt;
> };
>
> /* Contains datapath state used to represent an RX queue. */
> @@ -167,6 +175,10 @@ struct gve_rx_ring {
> /* threshold for posting new buffs and descs */
> u32 db_threshold;
> u16 packet_buffer_size;
> +
> + u32 qpl_copy_pool_mask;
> + u32 qpl_copy_pool_head;
> + struct gve_rx_slot_page_info *qpl_copy_pool;
> };
>
> /* DQO fields. */
> @@ -216,7 +228,9 @@ struct gve_rx_ring {
> u64 rx_desc_err_dropped_pkt; /* free-running count of packets dropped by descriptor error */
> u64 rx_cont_packet_cnt; /* free-running multi-fragment packets received */
> u64 rx_frag_flip_cnt; /* free-running count of rx segments where page_flip was used */
> - u64 rx_frag_copy_cnt; /* free-running count of rx segments copied into skb linear portion */
> + u64 rx_frag_copy_cnt; /* free-running count of rx segments copied */
> + u64 rx_frag_alloc_cnt; /* free-running count of rx page allocations */
> +
> u32 q_num; /* queue index */
> u32 ntfy_id; /* notification block index */
> struct gve_queue_resources *q_resources; /* head and tail pointer idx */
> diff --git a/drivers/net/ethernet/google/gve/gve_ethtool.c b/drivers/net/ethernet/google/gve/gve_ethtool.c
> index 7b9a2d9d9624..e7e4ba99c20e 100644
> --- a/drivers/net/ethernet/google/gve/gve_ethtool.c
> +++ b/drivers/net/ethernet/google/gve/gve_ethtool.c
> @@ -45,6 +45,7 @@ static const char gve_gstrings_main_stats[][ETH_GSTRING_LEN] = {
> static const char gve_gstrings_rx_stats[][ETH_GSTRING_LEN] = {
> "rx_posted_desc[%u]", "rx_completed_desc[%u]", "rx_consumed_desc[%u]", "rx_bytes[%u]",
> "rx_cont_packet_cnt[%u]", "rx_frag_flip_cnt[%u]", "rx_frag_copy_cnt[%u]",
> + "rx_frag_alloc_cnt[%u]",
> "rx_dropped_pkt[%u]", "rx_copybreak_pkt[%u]", "rx_copied_pkt[%u]",
> "rx_queue_drop_cnt[%u]", "rx_no_buffers_posted[%u]",
> "rx_drops_packet_over_mru[%u]", "rx_drops_invalid_checksum[%u]",
> @@ -271,6 +272,7 @@ gve_get_ethtool_stats(struct net_device *netdev,
> data[i++] = rx->rx_cont_packet_cnt;
> data[i++] = rx->rx_frag_flip_cnt;
> data[i++] = rx->rx_frag_copy_cnt;
> + data[i++] = rx->rx_frag_alloc_cnt;
> /* rx dropped packets */
> data[i++] = tmp_rx_skb_alloc_fail +
> tmp_rx_buf_alloc_fail +
> diff --git a/drivers/net/ethernet/google/gve/gve_rx.c b/drivers/net/ethernet/google/gve/gve_rx.c
> index 021bbf308d68..e2f4494c65fb 100644
> --- a/drivers/net/ethernet/google/gve/gve_rx.c
> +++ b/drivers/net/ethernet/google/gve/gve_rx.c
> @@ -35,6 +35,12 @@ static void gve_rx_unfill_pages(struct gve_priv *priv, struct gve_rx_ring *rx)
> rx->data.page_info[i].pagecnt_bias - 1);
> gve_unassign_qpl(priv, rx->data.qpl->id);
> rx->data.qpl = NULL;
> +
> + for (i = 0; i < rx->qpl_copy_pool_mask + 1; i++) {
> + page_ref_sub(rx->qpl_copy_pool[i].page,
> + rx->qpl_copy_pool[i].pagecnt_bias - 1);
> + put_page(rx->qpl_copy_pool[i].page);
> + }
> }
> kvfree(rx->data.page_info);
> rx->data.page_info = NULL;
> @@ -63,6 +69,10 @@ static void gve_rx_free_ring(struct gve_priv *priv, int idx)
> dma_free_coherent(dev, bytes, rx->data.data_ring,
> rx->data.data_bus);
> rx->data.data_ring = NULL;
> +
> + kvfree(rx->qpl_copy_pool);
> + rx->qpl_copy_pool = NULL;
> +
> netif_dbg(priv, drv, priv->dev, "freed rx ring %d\n", idx);
> }
>
> @@ -101,6 +111,7 @@ static int gve_prefill_rx_pages(struct gve_rx_ring *rx)
> u32 slots;
> int err;
> int i;
> + int j;
>
> /* Allocate one page per Rx queue slot. Each page is split into two
> * packet buffers, when possible we "page flip" between the two.
> @@ -135,7 +146,31 @@ static int gve_prefill_rx_pages(struct gve_rx_ring *rx)
> goto alloc_err;
> }
>
> + if (!rx->data.raw_addressing) {
> + for (j = 0; j < rx->qpl_copy_pool_mask + 1; j++) {
> + struct page *page = alloc_page(GFP_KERNEL);
> +
> + if (!page)
This introduces a known issue fixed in
64c426dfbbd2710e4bcac42aaced21fe10f05fde.
> + goto alloc_err_qpl;
> +
> + rx->qpl_copy_pool[j].page = page;
> + rx->qpl_copy_pool[j].page_offset = 0;
> + rx->qpl_copy_pool[j].page_address = page_address(page);
> +
> + /* The page already has 1 ref. */
> + page_ref_add(page, INT_MAX - 1);
> + rx->qpl_copy_pool[j].pagecnt_bias = INT_MAX;
> + }
> + }
> +
> return slots;
> +
> +alloc_err_qpl:
> + while (j--) {
> + page_ref_sub(rx->qpl_copy_pool[j].page,
> + rx->qpl_copy_pool[j].pagecnt_bias - 1);
> + put_page(rx->qpl_copy_pool[j].page);
> + }
> alloc_err:
> while (i--)
> gve_rx_free_buffer(&priv->pdev->dev,
> @@ -146,12 +181,11 @@ static int gve_prefill_rx_pages(struct gve_rx_ring *rx)
>
> static void gve_rx_ctx_clear(struct gve_rx_ctx *ctx)
> {
> - ctx->curr_frag_cnt = 0;
> - ctx->total_expected_size = 0;
> - ctx->expected_frag_cnt = 0;
> ctx->skb_head = NULL;
> ctx->skb_tail = NULL;
> - ctx->reuse_frags = false;
> + ctx->total_size = 0;
> + ctx->frag_cnt = 0;
> + ctx->drop_pkt = false;
> }
>
> static int gve_rx_alloc_ring(struct gve_priv *priv, int idx)
> @@ -181,10 +215,22 @@ static int gve_rx_alloc_ring(struct gve_priv *priv, int idx)
> GFP_KERNEL);
> if (!rx->data.data_ring)
> return -ENOMEM;
> +
> + rx->qpl_copy_pool_mask = min_t(u32, U32_MAX, slots * 2) - 1;
> + rx->qpl_copy_pool_head = 0;
> + rx->qpl_copy_pool = kvcalloc(rx->qpl_copy_pool_mask + 1,
> + sizeof(rx->qpl_copy_pool[0]),
> + GFP_KERNEL);
> +
> + if (!rx->qpl_copy_pool) {
> + err = -ENOMEM;
> + goto abort_with_slots;
> + }
> +
> filled_pages = gve_prefill_rx_pages(rx);
> if (filled_pages < 0) {
> err = -ENOMEM;
> - goto abort_with_slots;
> + goto abort_with_copy_pool;
> }
> rx->fill_cnt = filled_pages;
> /* Ensure data ring slots (packet buffers) are visible. */
> @@ -236,6 +282,9 @@ static int gve_rx_alloc_ring(struct gve_priv *priv, int idx)
> rx->q_resources = NULL;
> abort_filled:
> gve_rx_unfill_pages(priv, rx);
> +abort_with_copy_pool:
> + kvfree(rx->qpl_copy_pool);
> + rx->qpl_copy_pool = NULL;
> abort_with_slots:
> bytes = sizeof(*rx->data.data_ring) * slots;
> dma_free_coherent(hdev, bytes, rx->data.data_ring, rx->data.data_bus);
> @@ -292,30 +341,47 @@ static enum pkt_hash_types gve_rss_type(__be16 pkt_flags)
> return PKT_HASH_TYPE_L2;
> }
>
> -static u16 gve_rx_ctx_padding(struct gve_rx_ctx *ctx)
> -{
> - return (ctx->curr_frag_cnt == 0) ? GVE_RX_PAD : 0;
> -}
> -
> static struct sk_buff *gve_rx_add_frags(struct napi_struct *napi,
> struct gve_rx_slot_page_info *page_info,
> u16 packet_buffer_size, u16 len,
> struct gve_rx_ctx *ctx)
> {
> - u32 offset = page_info->page_offset + gve_rx_ctx_padding(ctx);
> - struct sk_buff *skb;
> + u32 offset = page_info->page_offset + page_info->pad;
> + struct sk_buff *skb = ctx->skb_tail;
> + int num_frags = 0;
>
> - if (!ctx->skb_head)
> - ctx->skb_head = napi_get_frags(napi);
> + if (!skb) {
> + skb = napi_get_frags(napi);
> + if (unlikely(!skb))
> + return NULL;
>
> - if (unlikely(!ctx->skb_head))
> - return NULL;
> + ctx->skb_head = skb;
> + ctx->skb_tail = skb;
> + } else {
> + num_frags = skb_shinfo(ctx->skb_tail)->nr_frags;
> + if (num_frags == MAX_SKB_FRAGS) {
> + skb = napi_alloc_skb(napi, 0);
> + if (!skb)
> + return NULL;
> +
> + // We will never chain more than two SKBs: 2 * 16 * 2k > 64k
> + // which is why we do not need to chain by using skb->next
> + skb_shinfo(ctx->skb_tail)->frag_list = skb;
>
> - skb = ctx->skb_head;
> - skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page_info->page,
> + ctx->skb_tail = skb;
> + num_frags = 0;
> + }
> + }
> +
> + if (skb != ctx->skb_head) {
> + ctx->skb_head->len += len;
> + ctx->skb_head->data_len += len;
> + ctx->skb_head->truesize += packet_buffer_size;
> + }
> + skb_add_rx_frag(skb, num_frags, page_info->page,
> offset, len, packet_buffer_size);
>
> - return skb;
> + return ctx->skb_head;
> }
>
> static void gve_rx_flip_buff(struct gve_rx_slot_page_info *page_info, __be64 *slot_addr)
> @@ -363,6 +429,92 @@ gve_rx_raw_addressing(struct device *dev, struct net_device *netdev,
> return skb;
> }
>
> +static struct sk_buff *gve_rx_copy_to_pool(struct gve_rx_ring *rx,
> + struct gve_rx_slot_page_info *page_info,
> + u16 len, struct napi_struct *napi)
> +{
> + u32 pool_idx = rx->qpl_copy_pool_head & rx->qpl_copy_pool_mask;
> + void *src = page_info->page_address + page_info->page_offset;
> + struct gve_rx_slot_page_info *copy_page_info;
> + struct gve_rx_ctx *ctx = &rx->ctx;
> + bool alloc_page = false;
> + struct sk_buff *skb;
> + void *dst;
> +
> + copy_page_info = &rx->qpl_copy_pool[pool_idx];
> + if (!copy_page_info->can_flip) {
> + int recycle = gve_rx_can_recycle_buffer(copy_page_info);
> +
> + if (unlikely(recycle < 0)) {
> + gve_schedule_reset(rx->gve);
> + return NULL;
> + }
> + alloc_page = !recycle;
> + }
> +
> + if (alloc_page) {
> + struct gve_rx_slot_page_info alloc_page_info;
> + struct page *page;
> +
> + /* The least recently used page turned out to be
> + * still in use by the kernel. Ignoring it and moving
> + * on alleviates head-of-line blocking.
> + */
> + rx->qpl_copy_pool_head++;
> +
> + page = alloc_page(GFP_ATOMIC);
> + if (!page)
> + return NULL;
> +
> + alloc_page_info.page = page;
> + alloc_page_info.page_offset = 0;
> + alloc_page_info.page_address = page_address(page);
> + alloc_page_info.pad = page_info->pad;
> +
> + memcpy(alloc_page_info.page_address, src, page_info->pad + len);
> + skb = gve_rx_add_frags(napi, &alloc_page_info,
> + rx->packet_buffer_size,
> + len, ctx);
> +
> + u64_stats_update_begin(&rx->statss);
> + rx->rx_frag_copy_cnt++;
> + rx->rx_frag_alloc_cnt++;
> + u64_stats_update_end(&rx->statss);
> +
> + return skb;
> + }
> +
> + dst = copy_page_info->page_address + copy_page_info->page_offset;
> + memcpy(dst, src, page_info->pad + len);
> + copy_page_info->pad = page_info->pad;
> +
> + skb = gve_rx_add_frags(napi, copy_page_info,
> + rx->packet_buffer_size, len, ctx);
> + if (unlikely(!skb))
> + return NULL;
> +
> + gve_dec_pagecnt_bias(copy_page_info);
> + copy_page_info->page_offset += rx->packet_buffer_size;
> + copy_page_info->page_offset &= (PAGE_SIZE - 1);
> +
> + if (copy_page_info->can_flip) {
> + /* We have used both halves of this copy page, it
> + * is time for it to go to the back of the queue.
> + */
> + copy_page_info->can_flip = false;
> + rx->qpl_copy_pool_head++;
> + prefetch(rx->qpl_copy_pool[rx->qpl_copy_pool_head & rx->qpl_copy_pool_mask].page);
> + } else {
> + copy_page_info->can_flip = true;
> + }
> +
> + u64_stats_update_begin(&rx->statss);
> + rx->rx_frag_copy_cnt++;
> + u64_stats_update_end(&rx->statss);
> +
> + return skb;
> +}
> +
> static struct sk_buff *
> gve_rx_qpl(struct device *dev, struct net_device *netdev,
> struct gve_rx_ring *rx, struct gve_rx_slot_page_info *page_info,
> @@ -377,7 +529,7 @@ gve_rx_qpl(struct device *dev, struct net_device *netdev,
> * choice is to copy the data out of it so that we can return it to the
> * device.
> */
> - if (ctx->reuse_frags) {
> + if (page_info->can_flip) {
> skb = gve_rx_add_frags(napi, page_info, rx->packet_buffer_size, len, ctx);
> /* No point in recycling if we didn't get the skb */
> if (skb) {
> @@ -386,116 +538,23 @@ gve_rx_qpl(struct device *dev, struct net_device *netdev,
> gve_rx_flip_buff(page_info, &data_slot->qpl_offset);
> }
> } else {
> - const u16 padding = gve_rx_ctx_padding(ctx);
> -
> - skb = gve_rx_copy(netdev, napi, page_info, len, padding, ctx);
> - if (skb) {
> - u64_stats_update_begin(&rx->statss);
> - rx->rx_frag_copy_cnt++;
> - u64_stats_update_end(&rx->statss);
> - }
> + skb = gve_rx_copy_to_pool(rx, page_info, len, napi);
> }
> return skb;
> }
>
> -#define GVE_PKTCONT_BIT_IS_SET(x) (GVE_RXF_PKT_CONT & (x))
> -static u16 gve_rx_get_fragment_size(struct gve_rx_ctx *ctx, struct gve_rx_desc *desc)
> -{
> - return be16_to_cpu(desc->len) - gve_rx_ctx_padding(ctx);
> -}
> -
> -static bool gve_rx_ctx_init(struct gve_rx_ctx *ctx, struct gve_rx_ring *rx)
> -{
> - bool qpl_mode = !rx->data.raw_addressing, packet_size_error = false;
> - bool buffer_error = false, desc_error = false, seqno_error = false;
> - struct gve_rx_slot_page_info *page_info;
> - struct gve_priv *priv = rx->gve;
> - u32 idx = rx->cnt & rx->mask;
> - bool reuse_frags, can_flip;
> - struct gve_rx_desc *desc;
> - u16 packet_size = 0;
> - u16 n_frags = 0;
> - int recycle;
> -
> - /** In QPL mode, we only flip buffers when all buffers containing the packet
> - * can be flipped. RDA can_flip decisions will be made later, per frag.
> - */
> - can_flip = qpl_mode;
> - reuse_frags = can_flip;
> - do {
> - u16 frag_size;
> -
> - n_frags++;
> - desc = &rx->desc.desc_ring[idx];
> - desc_error = unlikely(desc->flags_seq & GVE_RXF_ERR) || desc_error;
> - if (GVE_SEQNO(desc->flags_seq) != rx->desc.seqno) {
> - seqno_error = true;
> - netdev_warn(priv->dev,
> - "RX seqno error: want=%d, got=%d, dropping packet and scheduling reset.",
> - rx->desc.seqno, GVE_SEQNO(desc->flags_seq));
> - }
> - frag_size = be16_to_cpu(desc->len);
> - packet_size += frag_size;
> - if (frag_size > rx->packet_buffer_size) {
> - packet_size_error = true;
> - netdev_warn(priv->dev,
> - "RX fragment error: packet_buffer_size=%d, frag_size=%d, dropping packet.",
> - rx->packet_buffer_size, be16_to_cpu(desc->len));
> - }
> - page_info = &rx->data.page_info[idx];
> - if (can_flip) {
> - recycle = gve_rx_can_recycle_buffer(page_info);
> - reuse_frags = reuse_frags && recycle > 0;
> - buffer_error = buffer_error || unlikely(recycle < 0);
> - }
> - idx = (idx + 1) & rx->mask;
> - rx->desc.seqno = gve_next_seqno(rx->desc.seqno);
> - } while (GVE_PKTCONT_BIT_IS_SET(desc->flags_seq));
> -
> - prefetch(rx->desc.desc_ring + idx);
> -
> - ctx->curr_frag_cnt = 0;
> - ctx->total_expected_size = packet_size - GVE_RX_PAD;
> - ctx->expected_frag_cnt = n_frags;
> - ctx->skb_head = NULL;
> - ctx->reuse_frags = reuse_frags;
> -
> - if (ctx->expected_frag_cnt > 1) {
> - u64_stats_update_begin(&rx->statss);
> - rx->rx_cont_packet_cnt++;
> - u64_stats_update_end(&rx->statss);
> - }
> - if (ctx->total_expected_size > priv->rx_copybreak && !ctx->reuse_frags && qpl_mode) {
> - u64_stats_update_begin(&rx->statss);
> - rx->rx_copied_pkt++;
> - u64_stats_update_end(&rx->statss);
> - }
> -
> - if (unlikely(buffer_error || seqno_error || packet_size_error)) {
> - gve_schedule_reset(priv);
> - return false;
> - }
> -
> - if (unlikely(desc_error)) {
> - u64_stats_update_begin(&rx->statss);
> - rx->rx_desc_err_dropped_pkt++;
> - u64_stats_update_end(&rx->statss);
> - return false;
> - }
> - return true;
> -}
> -
> static struct sk_buff *gve_rx_skb(struct gve_priv *priv, struct gve_rx_ring *rx,
> struct gve_rx_slot_page_info *page_info, struct napi_struct *napi,
> - u16 len, union gve_rx_data_slot *data_slot)
> + u16 len, union gve_rx_data_slot *data_slot,
> + bool is_only_frag)
> {
> struct net_device *netdev = priv->dev;
> struct gve_rx_ctx *ctx = &rx->ctx;
> struct sk_buff *skb = NULL;
>
> - if (len <= priv->rx_copybreak && ctx->expected_frag_cnt == 1) {
> + if (len <= priv->rx_copybreak && is_only_frag) {
> /* Just copy small packets */
> - skb = gve_rx_copy(netdev, napi, page_info, len, GVE_RX_PAD, ctx);
> + skb = gve_rx_copy(netdev, napi, page_info, len, GVE_RX_PAD);
> if (skb) {
> u64_stats_update_begin(&rx->statss);
> rx->rx_copied_pkt++;
> @@ -504,29 +563,25 @@ static struct sk_buff *gve_rx_skb(struct gve_priv *priv, struct gve_rx_ring *rx,
> u64_stats_update_end(&rx->statss);
> }
> } else {
> - if (rx->data.raw_addressing) {
> - int recycle = gve_rx_can_recycle_buffer(page_info);
> + int recycle = gve_rx_can_recycle_buffer(page_info);
>
> - if (unlikely(recycle < 0)) {
> - gve_schedule_reset(priv);
> - return NULL;
> - }
> - page_info->can_flip = recycle;
> - if (page_info->can_flip) {
> - u64_stats_update_begin(&rx->statss);
> - rx->rx_frag_flip_cnt++;
> - u64_stats_update_end(&rx->statss);
> - }
> + if (unlikely(recycle < 0)) {
> + gve_schedule_reset(priv);
> + return NULL;
> + }
> + page_info->can_flip = recycle;
> + if (page_info->can_flip) {
> + u64_stats_update_begin(&rx->statss);
> + rx->rx_frag_flip_cnt++;
> + u64_stats_update_end(&rx->statss);
> + }
> +
> + if (rx->data.raw_addressing) {
> skb = gve_rx_raw_addressing(&priv->pdev->dev, netdev,
> page_info, len, napi,
> data_slot,
> rx->packet_buffer_size, ctx);
> } else {
> - if (ctx->reuse_frags) {
> - u64_stats_update_begin(&rx->statss);
> - rx->rx_frag_flip_cnt++;
> - u64_stats_update_end(&rx->statss);
> - }
> skb = gve_rx_qpl(&priv->pdev->dev, netdev, rx,
> page_info, len, napi, data_slot);
> }
> @@ -534,101 +589,113 @@ static struct sk_buff *gve_rx_skb(struct gve_priv *priv, struct gve_rx_ring *rx,
> return skb;
> }
>
> -static bool gve_rx(struct gve_rx_ring *rx, netdev_features_t feat,
> - u64 *packet_size_bytes, u32 *work_done)
> +#define GVE_PKTCONT_BIT_IS_SET(x) (GVE_RXF_PKT_CONT & (x))
> +static void gve_rx(struct gve_rx_ring *rx, netdev_features_t feat,
> + struct gve_rx_desc *desc, u32 idx,
> + struct gve_rx_cnts *cnts)
> {
> + bool is_last_frag = !GVE_PKTCONT_BIT_IS_SET(desc->flags_seq);
> struct gve_rx_slot_page_info *page_info;
> + u16 frag_size = be16_to_cpu(desc->len);
> struct gve_rx_ctx *ctx = &rx->ctx;
> union gve_rx_data_slot *data_slot;
> struct gve_priv *priv = rx->gve;
> - struct gve_rx_desc *first_desc;
> struct sk_buff *skb = NULL;
> - struct gve_rx_desc *desc;
> - struct napi_struct *napi;
> dma_addr_t page_bus;
> - u32 work_cnt = 0;
> void *va;
> - u32 idx;
> - u16 len;
>
> - idx = rx->cnt & rx->mask;
> - first_desc = &rx->desc.desc_ring[idx];
> - desc = first_desc;
> - napi = &priv->ntfy_blocks[rx->ntfy_id].napi;
> + struct napi_struct *napi = &priv->ntfy_blocks[rx->ntfy_id].napi;
> + bool is_first_frag = ctx->frag_cnt == 0;
>
> - if (unlikely(!gve_rx_ctx_init(ctx, rx)))
> - goto skb_alloc_fail;
> + bool is_only_frag = is_first_frag && is_last_frag;
>
> - while (ctx->curr_frag_cnt < ctx->expected_frag_cnt) {
> - /* Prefetch two packet buffers ahead, we will need it soon. */
> - page_info = &rx->data.page_info[(idx + 2) & rx->mask];
> - va = page_info->page_address + page_info->page_offset;
> + if (unlikely(ctx->drop_pkt))
> + goto finish_frag;
>
> - prefetch(page_info->page); /* Kernel page struct. */
> - prefetch(va); /* Packet header. */
> - prefetch(va + 64); /* Next cacheline too. */
> + if (desc->flags_seq & GVE_RXF_ERR) {
> + ctx->drop_pkt = true;
> + cnts->desc_err_pkt_cnt++;
> + napi_free_frags(napi);
> + goto finish_frag;
> + }
>
> - len = gve_rx_get_fragment_size(ctx, desc);
> + if (unlikely(frag_size > rx->packet_buffer_size)) {
> + netdev_warn(priv->dev, "Unexpected frag size %d, can't exceed %d, scheduling reset",
> + frag_size, rx->packet_buffer_size);
> + ctx->drop_pkt = true;
> + napi_free_frags(napi);
> + gve_schedule_reset(rx->gve);
> + goto finish_frag;
> + }
>
> - page_info = &rx->data.page_info[idx];
> - data_slot = &rx->data.data_ring[idx];
> - page_bus = rx->data.raw_addressing ?
> - be64_to_cpu(data_slot->addr) - page_info->page_offset :
> - rx->data.qpl->page_buses[idx];
> - dma_sync_single_for_cpu(&priv->pdev->dev, page_bus, PAGE_SIZE, DMA_FROM_DEVICE);
> -
> - skb = gve_rx_skb(priv, rx, page_info, napi, len, data_slot);
> - if (!skb) {
> - u64_stats_update_begin(&rx->statss);
> - rx->rx_skb_alloc_fail++;
> - u64_stats_update_end(&rx->statss);
> - goto skb_alloc_fail;
> + /* Prefetch two packet buffers ahead, we will need it soon. */
> + page_info = &rx->data.page_info[(idx + 2) & rx->mask];
> + va = page_info->page_address + page_info->page_offset;
> + prefetch(page_info->page); /* Kernel page struct. */
> + prefetch(va); /* Packet header. */
> + prefetch(va + 64); /* Next cacheline too. */
> +
> + page_info = &rx->data.page_info[idx];
> + data_slot = &rx->data.data_ring[idx];
> + page_bus = (rx->data.raw_addressing) ?
> + be64_to_cpu(data_slot->addr) - page_info->page_offset :
> + rx->data.qpl->page_buses[idx];
> + dma_sync_single_for_cpu(&priv->pdev->dev, page_bus,
> + PAGE_SIZE, DMA_FROM_DEVICE);
> + page_info->pad = is_first_frag ? GVE_RX_PAD : 0;
> + frag_size -= page_info->pad;
> +
> + skb = gve_rx_skb(priv, rx, page_info, napi, frag_size,
> + data_slot, is_only_frag);
> + if (!skb) {
> + u64_stats_update_begin(&rx->statss);
> + rx->rx_skb_alloc_fail++;
> + u64_stats_update_end(&rx->statss);
> +
> + napi_free_frags(napi);
> + ctx->drop_pkt = true;
> + goto finish_frag;
> + }
> + ctx->total_size += frag_size;
> +
> + if (is_first_frag) {
> + if (likely(feat & NETIF_F_RXCSUM)) {
> + /* NIC passes up the partial sum */
> + if (desc->csum)
> + skb->ip_summed = CHECKSUM_COMPLETE;
> + else
> + skb->ip_summed = CHECKSUM_NONE;
> + skb->csum = csum_unfold(desc->csum);
> }
>
> - ctx->curr_frag_cnt++;
> - rx->cnt++;
> - idx = rx->cnt & rx->mask;
> - work_cnt++;
> - desc = &rx->desc.desc_ring[idx];
> + /* parse flags & pass relevant info up */
> + if (likely(feat & NETIF_F_RXHASH) &&
> + gve_needs_rss(desc->flags_seq))
> + skb_set_hash(skb, be32_to_cpu(desc->rss_hash),
> + gve_rss_type(desc->flags_seq));
> }
>
> - if (likely(feat & NETIF_F_RXCSUM)) {
> - /* NIC passes up the partial sum */
> - if (first_desc->csum)
> - skb->ip_summed = CHECKSUM_COMPLETE;
> + if (is_last_frag) {
> + skb_record_rx_queue(skb, rx->q_num);
> + if (skb_is_nonlinear(skb))
> + napi_gro_frags(napi);
> else
> - skb->ip_summed = CHECKSUM_NONE;
> - skb->csum = csum_unfold(first_desc->csum);
> + napi_gro_receive(napi, skb);
> + goto finish_ok_pkt;
> }
>
> - /* parse flags & pass relevant info up */
> - if (likely(feat & NETIF_F_RXHASH) &&
> - gve_needs_rss(first_desc->flags_seq))
> - skb_set_hash(skb, be32_to_cpu(first_desc->rss_hash),
> - gve_rss_type(first_desc->flags_seq));
> -
> - *packet_size_bytes = skb->len + (skb->protocol ? ETH_HLEN : 0);
> - *work_done = work_cnt;
> - skb_record_rx_queue(skb, rx->q_num);
> - if (skb_is_nonlinear(skb))
> - napi_gro_frags(napi);
> - else
> - napi_gro_receive(napi, skb);
> -
> - gve_rx_ctx_clear(ctx);
> - return true;
> -
> -skb_alloc_fail:
> - if (napi->skb)
> - napi_free_frags(napi);
> - *packet_size_bytes = 0;
> - *work_done = ctx->expected_frag_cnt;
> - while (ctx->curr_frag_cnt < ctx->expected_frag_cnt) {
> - rx->cnt++;
> - ctx->curr_frag_cnt++;
> + goto finish_frag;
> +
> +finish_ok_pkt:
> + cnts->ok_pkt_bytes += ctx->total_size;
> + cnts->ok_pkt_cnt++;
> +finish_frag:
> + ctx->frag_cnt++;
> + if (is_last_frag) {
> + cnts->total_pkt_cnt++;
> + cnts->cont_pkt_cnt += (ctx->frag_cnt > 1);
> + gve_rx_ctx_clear(ctx);
> }
> - gve_rx_ctx_clear(ctx);
> - return false;
> }
>
> bool gve_rx_work_pending(struct gve_rx_ring *rx)
> @@ -704,36 +771,39 @@ static bool gve_rx_refill_buffers(struct gve_priv *priv, struct gve_rx_ring *rx)
> static int gve_clean_rx_done(struct gve_rx_ring *rx, int budget,
> netdev_features_t feat)
> {
> - u32 work_done = 0, total_packet_cnt = 0, ok_packet_cnt = 0;
> + struct gve_rx_ctx *ctx = &rx->ctx;
> struct gve_priv *priv = rx->gve;
> + struct gve_rx_cnts cnts = {0};
> + struct gve_rx_desc *next_desc;
> u32 idx = rx->cnt & rx->mask;
> - struct gve_rx_desc *desc;
> - u64 bytes = 0;
> + u32 work_done = 0;
> +
> + struct gve_rx_desc *desc = &rx->desc.desc_ring[idx];
>
> - desc = &rx->desc.desc_ring[idx];
> + // Exceed budget only if (and till) the inflight packet is consumed.
> while ((GVE_SEQNO(desc->flags_seq) == rx->desc.seqno) &&
> - work_done < budget) {
> - u64 packet_size_bytes = 0;
> - u32 work_cnt = 0;
> - bool dropped;
> -
> - netif_info(priv, rx_status, priv->dev,
> - "[%d] idx=%d desc=%p desc->flags_seq=0x%x\n",
> - rx->q_num, idx, desc, desc->flags_seq);
> - netif_info(priv, rx_status, priv->dev,
> - "[%d] seqno=%d rx->desc.seqno=%d\n",
> - rx->q_num, GVE_SEQNO(desc->flags_seq),
> - rx->desc.seqno);
> -
> - dropped = !gve_rx(rx, feat, &packet_size_bytes, &work_cnt);
> - if (!dropped) {
> - bytes += packet_size_bytes;
> - ok_packet_cnt++;
> - }
> - total_packet_cnt++;
> + (work_done < budget || ctx->frag_cnt)) {
> + next_desc = &rx->desc.desc_ring[(idx + 1) & rx->mask];
> + prefetch(next_desc);
> +
> + gve_rx(rx, feat, desc, idx, &cnts);
> +
> + rx->cnt++;
> idx = rx->cnt & rx->mask;
> desc = &rx->desc.desc_ring[idx];
> - work_done += work_cnt;
> + rx->desc.seqno = gve_next_seqno(rx->desc.seqno);
> + work_done++;
> + }
> +
> + // The device will only send whole packets.
> + if (unlikely(ctx->frag_cnt)) {
> + struct napi_struct *napi = &priv->ntfy_blocks[rx->ntfy_id].napi;
> +
> + napi_free_frags(napi);
> + gve_rx_ctx_clear(&rx->ctx);
> + netdev_warn(priv->dev, "Unexpected seq number %d with incomplete packet, expected %d, scheduling reset",
> + GVE_SEQNO(desc->flags_seq), rx->desc.seqno);
> + gve_schedule_reset(rx->gve);
> }
>
> if (!work_done && rx->fill_cnt - rx->cnt > rx->db_threshold)
> @@ -741,8 +811,10 @@ static int gve_clean_rx_done(struct gve_rx_ring *rx, int budget,
>
> if (work_done) {
> u64_stats_update_begin(&rx->statss);
> - rx->rpackets += ok_packet_cnt;
> - rx->rbytes += bytes;
> + rx->rpackets += cnts.ok_pkt_cnt;
> + rx->rbytes += cnts.ok_pkt_bytes;
> + rx->rx_cont_packet_cnt += cnts.cont_pkt_cnt;
> + rx->rx_desc_err_dropped_pkt += cnts.desc_err_pkt_cnt;
> u64_stats_update_end(&rx->statss);
> }
>
> @@ -767,7 +839,7 @@ static int gve_clean_rx_done(struct gve_rx_ring *rx, int budget,
> }
>
> gve_rx_write_doorbell(priv, rx);
> - return total_packet_cnt;
> + return cnts.total_pkt_cnt;
> }
>
> int gve_rx_poll(struct gve_notify_block *block, int budget)
> diff --git a/drivers/net/ethernet/google/gve/gve_rx_dqo.c b/drivers/net/ethernet/google/gve/gve_rx_dqo.c
> index 2e6461b0ea8b..630f42a3037b 100644
> --- a/drivers/net/ethernet/google/gve/gve_rx_dqo.c
> +++ b/drivers/net/ethernet/google/gve/gve_rx_dqo.c
> @@ -568,7 +568,7 @@ static int gve_rx_dqo(struct napi_struct *napi, struct gve_rx_ring *rx,
>
> if (eop && buf_len <= priv->rx_copybreak) {
> rx->ctx.skb_head = gve_rx_copy(priv->dev, napi,
> - &buf_state->page_info, buf_len, 0, NULL);
> + &buf_state->page_info, buf_len, 0);
> if (unlikely(!rx->ctx.skb_head))
> goto error;
> rx->ctx.skb_tail = rx->ctx.skb_head;
> diff --git a/drivers/net/ethernet/google/gve/gve_utils.c b/drivers/net/ethernet/google/gve/gve_utils.c
> index d57508bc4307..6ba46adaaee3 100644
> --- a/drivers/net/ethernet/google/gve/gve_utils.c
> +++ b/drivers/net/ethernet/google/gve/gve_utils.c
> @@ -50,34 +50,18 @@ void gve_rx_add_to_block(struct gve_priv *priv, int queue_idx)
>
> struct sk_buff *gve_rx_copy(struct net_device *dev, struct napi_struct *napi,
> struct gve_rx_slot_page_info *page_info, u16 len,
> - u16 padding, struct gve_rx_ctx *ctx)
> + u16 padding)
> {
> void *va = page_info->page_address + padding + page_info->page_offset;
> - int skb_linear_offset = 0;
> - bool set_protocol = false;
> struct sk_buff *skb;
>
> - if (ctx) {
> - if (!ctx->skb_head)
> - ctx->skb_head = napi_alloc_skb(napi, ctx->total_expected_size);
> -
> - if (unlikely(!ctx->skb_head))
> - return NULL;
> - skb = ctx->skb_head;
> - skb_linear_offset = skb->len;
> - set_protocol = ctx->curr_frag_cnt == ctx->expected_frag_cnt - 1;
> - } else {
> - skb = napi_alloc_skb(napi, len);
> -
> - if (unlikely(!skb))
> - return NULL;
> - set_protocol = true;
> - }
> - __skb_put(skb, len);
> - skb_copy_to_linear_data_offset(skb, skb_linear_offset, va, len);
> + skb = napi_alloc_skb(napi, len);
> + if (unlikely(!skb))
> + return NULL;
>
> - if (set_protocol)
> - skb->protocol = eth_type_trans(skb, dev);
> + __skb_put(skb, len);
> + skb_copy_to_linear_data_offset(skb, 0, va, len);
> + skb->protocol = eth_type_trans(skb, dev);
>
> return skb;
> }
> diff --git a/drivers/net/ethernet/google/gve/gve_utils.h b/drivers/net/ethernet/google/gve/gve_utils.h
> index 6d98e69fd3b8..79595940b351 100644
> --- a/drivers/net/ethernet/google/gve/gve_utils.h
> +++ b/drivers/net/ethernet/google/gve/gve_utils.h
> @@ -19,7 +19,7 @@ void gve_rx_add_to_block(struct gve_priv *priv, int queue_idx);
>
> struct sk_buff *gve_rx_copy(struct net_device *dev, struct napi_struct *napi,
> struct gve_rx_slot_page_info *page_info, u16 len,
> - u16 pad, struct gve_rx_ctx *ctx);
> + u16 pad);
>
> /* Decrement pagecnt_bias. Set it back to INT_MAX if it reached zero. */
> void gve_dec_pagecnt_bias(struct gve_rx_slot_page_info *page_info);
> --
> 2.34.1
--
Andrei Gherzan
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