diff --git a/drivers/net/ethernet/google/gve/gve.h b/drivers/net/ethernet/google/gve/gve.h index d8bba0ba34e31ee66c9f8aeebd47085f7dc0c218..8aad4af2aa2b2df240571fbafdf3433851941a16 100644 --- a/drivers/net/ethernet/google/gve/gve.h +++ b/drivers/net/ethernet/google/gve/gve.h @@ -52,6 +52,7 @@ struct gve_rx_slot_page_info { struct page *page; void *page_address; u8 page_offset; /* flipped to second half? */ + u8 can_flip; }; /* A list of pages registered with the device during setup and used by a queue @@ -502,15 +503,6 @@ static inline enum dma_data_direction gve_qpl_dma_dir(struct gve_priv *priv, return DMA_FROM_DEVICE; } -/* Returns true if the max mtu allows page recycling */ -static inline bool gve_can_recycle_pages(struct net_device *dev) -{ - /* We can't recycle the pages if we can't fit a packet into half a - * page. - */ - return dev->max_mtu <= PAGE_SIZE / 2; -} - /* buffers */ int gve_alloc_page(struct gve_priv *priv, struct device *dev, struct page **page, dma_addr_t *dma, diff --git a/drivers/net/ethernet/google/gve/gve_rx.c b/drivers/net/ethernet/google/gve/gve_rx.c index 596772f5e29a9fb06322d1a84ae5b8c318ce147a..bf123fe524c44fcf33f00cf199994ebdb0bb2d90 100644 --- a/drivers/net/ethernet/google/gve/gve_rx.c +++ b/drivers/net/ethernet/google/gve/gve_rx.c @@ -279,8 +279,7 @@ static enum pkt_hash_types gve_rss_type(__be16 pkt_flags) return PKT_HASH_TYPE_L2; } -static struct sk_buff *gve_rx_copy(struct gve_rx_ring *rx, - struct net_device *dev, +static struct sk_buff *gve_rx_copy(struct net_device *dev, struct napi_struct *napi, struct gve_rx_slot_page_info *page_info, u16 len) @@ -298,10 +297,6 @@ static struct sk_buff *gve_rx_copy(struct gve_rx_ring *rx, skb->protocol = eth_type_trans(skb, dev); - u64_stats_update_begin(&rx->statss); - rx->rx_copied_pkt++; - u64_stats_update_end(&rx->statss); - return skb; } @@ -330,6 +325,79 @@ static void gve_rx_flip_buff(struct gve_rx_slot_page_info *page_info, __be64 *sl *(slot_addr) ^= offset; } +static bool gve_rx_can_flip_buffers(struct net_device *netdev) +{ + return PAGE_SIZE == 4096 + ? netdev->mtu + GVE_RX_PAD + ETH_HLEN <= PAGE_SIZE / 2 : false; +} + +static int gve_rx_can_recycle_buffer(struct page *page) +{ + int pagecount = page_count(page); + + /* This page is not being used by any SKBs - reuse */ + if (pagecount == 1) + return 1; + /* This page is still being used by an SKB - we can't reuse */ + else if (pagecount >= 2) + return 0; + WARN(pagecount < 1, "Pagecount should never be < 1"); + return -1; +} + +static struct sk_buff * +gve_rx_raw_addressing(struct device *dev, struct net_device *netdev, + struct gve_rx_slot_page_info *page_info, u16 len, + struct napi_struct *napi, + union gve_rx_data_slot *data_slot) +{ + struct sk_buff *skb; + + skb = gve_rx_add_frags(napi, page_info, len); + if (!skb) + return NULL; + + /* Optimistically stop the kernel from freeing the page by increasing + * the page bias. We will check the refcount in refill to determine if + * we need to alloc a new page. + */ + get_page(page_info->page); + + 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, + u16 len, struct napi_struct *napi, + union gve_rx_data_slot *data_slot) +{ + struct sk_buff *skb; + + /* if raw_addressing mode is not enabled gvnic can only receive into + * registered segments. If the buffer can't be recycled, our only + * choice is to copy the data out of it so that we can return it to the + * device. + */ + if (page_info->can_flip) { + skb = gve_rx_add_frags(napi, page_info, len); + /* No point in recycling if we didn't get the skb */ + if (skb) { + /* Make sure that the page isn't freed. */ + get_page(page_info->page); + gve_rx_flip_buff(page_info, &data_slot->qpl_offset); + } + } else { + skb = gve_rx_copy(netdev, napi, page_info, len); + if (skb) { + u64_stats_update_begin(&rx->statss); + rx->rx_copied_pkt++; + u64_stats_update_end(&rx->statss); + } + } + return skb; +} + static bool gve_rx(struct gve_rx_ring *rx, struct gve_rx_desc *rx_desc, netdev_features_t feat, u32 idx) { @@ -340,7 +408,6 @@ static bool gve_rx(struct gve_rx_ring *rx, struct gve_rx_desc *rx_desc, union gve_rx_data_slot *data_slot; struct sk_buff *skb = NULL; dma_addr_t page_bus; - int pagecount; u16 len; /* drop this packet */ @@ -361,60 +428,37 @@ static bool gve_rx(struct gve_rx_ring *rx, struct gve_rx_desc *rx_desc, dma_sync_single_for_cpu(&priv->pdev->dev, page_bus, PAGE_SIZE, DMA_FROM_DEVICE); - if (PAGE_SIZE == 4096) { - if (len <= priv->rx_copybreak) { - /* Just copy small packets */ - skb = gve_rx_copy(rx, dev, napi, page_info, len); - u64_stats_update_begin(&rx->statss); - rx->rx_copybreak_pkt++; - u64_stats_update_end(&rx->statss); - goto have_skb; - } - if (rx->data.raw_addressing) { - skb = gve_rx_add_frags(napi, page_info, len); - goto have_skb; - } - if (unlikely(!gve_can_recycle_pages(dev))) { - skb = gve_rx_copy(rx, dev, napi, page_info, len); - goto have_skb; - } - pagecount = page_count(page_info->page); - if (pagecount == 1) { - /* No part of this page is used by any SKBs; we attach - * the page fragment to a new SKB and pass it up the - * stack. - */ - skb = gve_rx_add_frags(napi, page_info, len); - if (!skb) { - u64_stats_update_begin(&rx->statss); - rx->rx_skb_alloc_fail++; - u64_stats_update_end(&rx->statss); + if (len <= priv->rx_copybreak) { + /* Just copy small packets */ + skb = gve_rx_copy(dev, napi, page_info, len); + u64_stats_update_begin(&rx->statss); + rx->rx_copied_pkt++; + rx->rx_copybreak_pkt++; + u64_stats_update_end(&rx->statss); + } else { + u8 can_flip = gve_rx_can_flip_buffers(dev); + int recycle = 0; + + if (can_flip) { + recycle = gve_rx_can_recycle_buffer(page_info->page); + if (recycle < 0) { + if (!rx->data.raw_addressing) + gve_schedule_reset(priv); return false; } - /* Make sure the kernel stack can't release the page */ - get_page(page_info->page); - /* "flip" to other packet buffer on this page */ - gve_rx_flip_buff(page_info, &rx->data.data_ring[idx].qpl_offset); - } else if (pagecount >= 2) { - /* We have previously passed the other half of this - * page up the stack, but it has not yet been freed. - */ - skb = gve_rx_copy(rx, dev, napi, page_info, len); + } + + page_info->can_flip = can_flip && recycle; + if (rx->data.raw_addressing) { + skb = gve_rx_raw_addressing(&priv->pdev->dev, dev, + page_info, len, napi, + data_slot); } else { - WARN(pagecount < 1, "Pagecount should never be < 1"); - return false; + skb = gve_rx_qpl(&priv->pdev->dev, dev, rx, + page_info, len, napi, data_slot); } - } else { - if (rx->data.raw_addressing) - skb = gve_rx_add_frags(napi, page_info, len); - else - skb = gve_rx_copy(rx, dev, napi, page_info, len); } -have_skb: - /* We didn't manage to allocate an skb but we haven't had any - * reset worthy failures. - */ if (!skb) { u64_stats_update_begin(&rx->statss); rx->rx_skb_alloc_fail++; @@ -467,19 +511,44 @@ static bool gve_rx_refill_buffers(struct gve_priv *priv, struct gve_rx_ring *rx) while (fill_cnt - rx->cnt < refill_target) { struct gve_rx_slot_page_info *page_info; - struct device *dev = &priv->pdev->dev; - union gve_rx_data_slot *data_slot; u32 idx = fill_cnt & rx->mask; page_info = &rx->data.page_info[idx]; - data_slot = &rx->data.data_ring[idx]; - gve_rx_free_buffer(dev, page_info, data_slot); - page_info->page = NULL; - if (gve_rx_alloc_buffer(priv, dev, page_info, data_slot)) { - u64_stats_update_begin(&rx->statss); - rx->rx_buf_alloc_fail++; - u64_stats_update_end(&rx->statss); - break; + if (page_info->can_flip) { + /* The other half of the page is free because it was + * free when we processed the descriptor. Flip to it. + */ + union gve_rx_data_slot *data_slot = + &rx->data.data_ring[idx]; + + gve_rx_flip_buff(page_info, &data_slot->addr); + page_info->can_flip = 0; + } else { + /* It is possible that the networking stack has already + * finished processing all outstanding packets in the buffer + * and it can be reused. + * Flipping is unnecessary here - if the networking stack still + * owns half the page it is impossible to tell which half. Either + * the whole page is free or it needs to be replaced. + */ + int recycle = gve_rx_can_recycle_buffer(page_info->page); + + if (recycle < 0) { + if (!rx->data.raw_addressing) + gve_schedule_reset(priv); + return false; + } + if (!recycle) { + /* We can't reuse the buffer - alloc a new one*/ + union gve_rx_data_slot *data_slot = + &rx->data.data_ring[idx]; + struct device *dev = &priv->pdev->dev; + + gve_rx_free_buffer(dev, page_info, data_slot); + page_info->page = NULL; + if (gve_rx_alloc_buffer(priv, dev, page_info, data_slot)) + break; + } } fill_cnt++; }