gve: Reduce alloc and copy costs in the GQ rx path
authorShailend Chand <shailend@google.com>
Sat, 29 Oct 2022 16:53:22 +0000 (09:53 -0700)
committerDavid S. Miller <davem@davemloft.net>
Wed, 2 Nov 2022 11:52:51 +0000 (11:52 +0000)
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@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/net/ethernet/google/gve/gve.h
drivers/net/ethernet/google/gve/gve_ethtool.c
drivers/net/ethernet/google/gve/gve_rx.c
drivers/net/ethernet/google/gve/gve_rx_dqo.c
drivers/net/ethernet/google/gve/gve_utils.c
drivers/net/ethernet/google/gve/gve_utils.h

index 1607354..5655da9 100644 (file)
@@ -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 */
index 50b3849..ce574d0 100644 (file)
@@ -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 +
index 021bbf3..e2f4494 100644 (file)
@@ -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)
+                               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 @@ alloc_err:
 
 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 @@ abort_with_q_resources:
        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)
index 2e6461b..630f42a 100644 (file)
@@ -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;
index d57508b..6ba46ad 100644 (file)
@@ -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;
 }
index 6d98e69..7959594 100644 (file)
@@ -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);