From 8ec2cd48fe0d08f4c5370e925f083a68e4593ec8 Mon Sep 17 00:00:00 2001 From: willy tarreau Date: Thu, 16 Jan 2014 08:20:16 +0100 Subject: [PATCH] net: mvneta: convert to build_skb() Make use of build_skb() to allocate frags on the RX path. When frag size is lower than a page size, we can use netdev_alloc_frag(), and we fall back to kmalloc() for larger sizes. The frag size is stored into the mvneta_port struct. The alloc/free functions check the frag size to decide what alloc/ free method to use. MTU changes are safe because the MTU change function stops the device and clears the queues before applying the change. With this patch, I observed a reproducible 2% performance improvement on HTTP-based benchmarks, and 5% on small packet RX rate. Cc: Thomas Petazzoni Cc: Gregory CLEMENT Tested-by: Arnaud Ebalard Signed-off-by: Willy Tarreau Signed-off-by: David S. Miller --- drivers/net/ethernet/marvell/mvneta.c | 49 +++++++++++++++++++-------- 1 file changed, 35 insertions(+), 14 deletions(-) diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c index c7b37e07f870..726a8d292a08 100644 --- a/drivers/net/ethernet/marvell/mvneta.c +++ b/drivers/net/ethernet/marvell/mvneta.c @@ -268,6 +268,7 @@ struct mvneta_pcpu_stats { struct mvneta_port { int pkt_size; + unsigned int frag_size; void __iomem *base; struct mvneta_rx_queue *rxqs; struct mvneta_tx_queue *txqs; @@ -1332,28 +1333,43 @@ static int mvneta_txq_done(struct mvneta_port *pp, return tx_done; } +static void *mvneta_frag_alloc(const struct mvneta_port *pp) +{ + if (likely(pp->frag_size <= PAGE_SIZE)) + return netdev_alloc_frag(pp->frag_size); + else + return kmalloc(pp->frag_size, GFP_ATOMIC); +} + +static void mvneta_frag_free(const struct mvneta_port *pp, void *data) +{ + if (likely(pp->frag_size <= PAGE_SIZE)) + put_page(virt_to_head_page(data)); + else + kfree(data); +} + /* Refill processing */ static int mvneta_rx_refill(struct mvneta_port *pp, struct mvneta_rx_desc *rx_desc) { dma_addr_t phys_addr; - struct sk_buff *skb; + void *data; - skb = netdev_alloc_skb(pp->dev, pp->pkt_size); - if (!skb) + data = mvneta_frag_alloc(pp); + if (!data) return -ENOMEM; - phys_addr = dma_map_single(pp->dev->dev.parent, skb->head, + phys_addr = dma_map_single(pp->dev->dev.parent, data, MVNETA_RX_BUF_SIZE(pp->pkt_size), DMA_FROM_DEVICE); if (unlikely(dma_mapping_error(pp->dev->dev.parent, phys_addr))) { - dev_kfree_skb(skb); + mvneta_frag_free(pp, data); return -ENOMEM; } - mvneta_rx_desc_fill(rx_desc, phys_addr, (u32)skb); - + mvneta_rx_desc_fill(rx_desc, phys_addr, (u32)data); return 0; } @@ -1407,9 +1423,9 @@ static void mvneta_rxq_drop_pkts(struct mvneta_port *pp, rx_done = mvneta_rxq_busy_desc_num_get(pp, rxq); for (i = 0; i < rxq->size; i++) { struct mvneta_rx_desc *rx_desc = rxq->descs + i; - struct sk_buff *skb = (struct sk_buff *)rx_desc->buf_cookie; + void *data = (void *)rx_desc->buf_cookie; - dev_kfree_skb_any(skb); + mvneta_frag_free(pp, data); dma_unmap_single(pp->dev->dev.parent, rx_desc->buf_phys_addr, MVNETA_RX_BUF_SIZE(pp->pkt_size), DMA_FROM_DEVICE); } @@ -1440,20 +1456,21 @@ static int mvneta_rx(struct mvneta_port *pp, int rx_todo, while (rx_done < rx_todo) { struct mvneta_rx_desc *rx_desc = mvneta_rxq_next_desc_get(rxq); struct sk_buff *skb; + unsigned char *data; u32 rx_status; int rx_bytes, err; rx_done++; rx_filled++; rx_status = rx_desc->status; - skb = (struct sk_buff *)rx_desc->buf_cookie; + data = (unsigned char *)rx_desc->buf_cookie; if (!mvneta_rxq_desc_is_first_last(rx_status) || - (rx_status & MVNETA_RXD_ERR_SUMMARY)) { + (rx_status & MVNETA_RXD_ERR_SUMMARY) || + !(skb = build_skb(data, pp->frag_size > PAGE_SIZE ? 0 : pp->frag_size))) { dev->stats.rx_errors++; mvneta_rx_error(pp, rx_desc); - mvneta_rx_desc_fill(rx_desc, rx_desc->buf_phys_addr, - (u32)skb); + /* leave the descriptor untouched */ continue; } @@ -1466,7 +1483,7 @@ static int mvneta_rx(struct mvneta_port *pp, int rx_todo, rcvd_bytes += rx_bytes; /* Linux processing */ - skb_reserve(skb, MVNETA_MH_SIZE); + skb_reserve(skb, MVNETA_MH_SIZE + NET_SKB_PAD); skb_put(skb, rx_bytes); skb->protocol = eth_type_trans(skb, dev); @@ -2276,6 +2293,8 @@ static int mvneta_change_mtu(struct net_device *dev, int mtu) mvneta_cleanup_rxqs(pp); pp->pkt_size = MVNETA_RX_PKT_SIZE(pp->dev->mtu); + pp->frag_size = SKB_DATA_ALIGN(MVNETA_RX_BUF_SIZE(pp->pkt_size)) + + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); ret = mvneta_setup_rxqs(pp); if (ret) { @@ -2423,6 +2442,8 @@ static int mvneta_open(struct net_device *dev) mvneta_mac_addr_set(pp, dev->dev_addr, rxq_def); pp->pkt_size = MVNETA_RX_PKT_SIZE(pp->dev->mtu); + pp->frag_size = SKB_DATA_ALIGN(MVNETA_RX_BUF_SIZE(pp->pkt_size)) + + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); ret = mvneta_setup_rxqs(pp); if (ret) -- 2.20.1