From 76620aafd66f0004829764940c5466144969cffc Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Thu, 16 Apr 2009 02:02:07 -0700 Subject: [PATCH] gro: New frags interface to avoid copying shinfo It turns out that copying a 16-byte area at ~800k times a second can be really expensive :) This patch redesigns the frags GRO interface to avoid copying that area twice. The two disciples of the frags interface have been converted. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller --- drivers/net/cxgb3/adapter.h | 2 +- drivers/net/cxgb3/sge.c | 53 +++++++++++++++++------------ drivers/net/sfc/rx.c | 26 ++++++++++----- include/linux/if_vlan.h | 6 ++-- include/linux/netdevice.h | 22 ++++++------ net/8021q/vlan_core.c | 4 +-- net/core/dev.c | 81 ++++++++++++++++++++------------------------- 7 files changed, 101 insertions(+), 93 deletions(-) diff --git a/drivers/net/cxgb3/adapter.h b/drivers/net/cxgb3/adapter.h index 714df2b..322434a 100644 --- a/drivers/net/cxgb3/adapter.h +++ b/drivers/net/cxgb3/adapter.h @@ -195,7 +195,7 @@ struct sge_qset { /* an SGE queue set */ struct sge_rspq rspq; struct sge_fl fl[SGE_RXQ_PER_SET]; struct sge_txq txq[SGE_TXQ_PER_SET]; - struct napi_gro_fraginfo lro_frag_tbl; + int nomem; int lro_enabled; void *lro_va; struct net_device *netdev; diff --git a/drivers/net/cxgb3/sge.c b/drivers/net/cxgb3/sge.c index 26d3587..73d569e 100644 --- a/drivers/net/cxgb3/sge.c +++ b/drivers/net/cxgb3/sge.c @@ -654,7 +654,8 @@ static void t3_reset_qset(struct sge_qset *q) q->txq_stopped = 0; q->tx_reclaim_timer.function = NULL; /* for t3_stop_sge_timers() */ q->rx_reclaim_timer.function = NULL; - q->lro_frag_tbl.nr_frags = q->lro_frag_tbl.len = 0; + q->nomem = 0; + napi_free_frags(&q->napi); } @@ -2074,20 +2075,19 @@ static void lro_add_page(struct adapter *adap, struct sge_qset *qs, struct sge_fl *fl, int len, int complete) { struct rx_sw_desc *sd = &fl->sdesc[fl->cidx]; + struct sk_buff *skb = NULL; struct cpl_rx_pkt *cpl; - struct skb_frag_struct *rx_frag = qs->lro_frag_tbl.frags; - int nr_frags = qs->lro_frag_tbl.nr_frags; - int frag_len = qs->lro_frag_tbl.len; + struct skb_frag_struct *rx_frag; + int nr_frags; int offset = 0; - if (!nr_frags) { - offset = 2 + sizeof(struct cpl_rx_pkt); - qs->lro_va = cpl = sd->pg_chunk.va + 2; + if (!qs->nomem) { + skb = napi_get_frags(&qs->napi); + qs->nomem = !skb; } fl->credits--; - len -= offset; pci_dma_sync_single_for_cpu(adap->pdev, pci_unmap_addr(sd, dma_addr), fl->buf_size - SGE_PG_RSVD, @@ -2100,21 +2100,38 @@ static void lro_add_page(struct adapter *adap, struct sge_qset *qs, fl->alloc_size, PCI_DMA_FROMDEVICE); + if (!skb) { + put_page(sd->pg_chunk.page); + if (complete) + qs->nomem = 0; + return; + } + + rx_frag = skb_shinfo(skb)->frags; + nr_frags = skb_shinfo(skb)->nr_frags; + + if (!nr_frags) { + offset = 2 + sizeof(struct cpl_rx_pkt); + qs->lro_va = sd->pg_chunk.va + 2; + } + len -= offset; + prefetch(qs->lro_va); rx_frag += nr_frags; rx_frag->page = sd->pg_chunk.page; rx_frag->page_offset = sd->pg_chunk.offset + offset; rx_frag->size = len; - frag_len += len; - qs->lro_frag_tbl.nr_frags++; - qs->lro_frag_tbl.len = frag_len; + skb->len += len; + skb->data_len += len; + skb->truesize += len; + skb_shinfo(skb)->nr_frags++; if (!complete) return; - qs->lro_frag_tbl.ip_summed = CHECKSUM_UNNECESSARY; + skb->ip_summed = CHECKSUM_UNNECESSARY; cpl = qs->lro_va; if (unlikely(cpl->vlan_valid)) { @@ -2123,15 +2140,11 @@ static void lro_add_page(struct adapter *adap, struct sge_qset *qs, struct vlan_group *grp = pi->vlan_grp; if (likely(grp != NULL)) { - vlan_gro_frags(&qs->napi, grp, ntohs(cpl->vlan), - &qs->lro_frag_tbl); - goto out; + vlan_gro_frags(&qs->napi, grp, ntohs(cpl->vlan)); + return; } } - napi_gro_frags(&qs->napi, &qs->lro_frag_tbl); - -out: - qs->lro_frag_tbl.nr_frags = qs->lro_frag_tbl.len = 0; + napi_gro_frags(&qs->napi); } /** @@ -2300,8 +2313,6 @@ no_mem: if (fl->use_pages) { void *addr = fl->sdesc[fl->cidx].pg_chunk.va; - prefetch(&qs->lro_frag_tbl); - prefetch(addr); #if L1_CACHE_BYTES < 128 prefetch(addr + L1_CACHE_BYTES); diff --git a/drivers/net/sfc/rx.c b/drivers/net/sfc/rx.c index 66d7fe3..01f9432 100644 --- a/drivers/net/sfc/rx.c +++ b/drivers/net/sfc/rx.c @@ -450,17 +450,27 @@ static void efx_rx_packet_lro(struct efx_channel *channel, /* Pass the skb/page into the LRO engine */ if (rx_buf->page) { - struct napi_gro_fraginfo info; + struct sk_buff *skb = napi_get_frags(napi); - info.frags[0].page = rx_buf->page; - info.frags[0].page_offset = efx_rx_buf_offset(rx_buf); - info.frags[0].size = rx_buf->len; - info.nr_frags = 1; - info.ip_summed = CHECKSUM_UNNECESSARY; - info.len = rx_buf->len; + if (!skb) { + put_page(rx_buf->page); + goto out; + } + + skb_shinfo(skb)->frags[0].page = rx_buf->page; + skb_shinfo(skb)->frags[0].page_offset = + efx_rx_buf_offset(rx_buf); + skb_shinfo(skb)->frags[0].size = rx_buf->len; + skb_shinfo(skb)->nr_frags = 1; + + skb->len = rx_buf->len; + skb->data_len = rx_buf->len; + skb->truesize += rx_buf->len; + skb->ip_summed = CHECKSUM_UNNECESSARY; - napi_gro_frags(napi, &info); + napi_gro_frags(napi); +out: EFX_BUG_ON_PARANOID(rx_buf->skb); rx_buf->page = NULL; } else { diff --git a/include/linux/if_vlan.h b/include/linux/if_vlan.h index e1ff5b1..7ff9af1 100644 --- a/include/linux/if_vlan.h +++ b/include/linux/if_vlan.h @@ -118,8 +118,7 @@ extern int vlan_hwaccel_do_receive(struct sk_buff *skb); extern int vlan_gro_receive(struct napi_struct *napi, struct vlan_group *grp, unsigned int vlan_tci, struct sk_buff *skb); extern int vlan_gro_frags(struct napi_struct *napi, struct vlan_group *grp, - unsigned int vlan_tci, - struct napi_gro_fraginfo *info); + unsigned int vlan_tci); #else static inline struct net_device *vlan_dev_real_dev(const struct net_device *dev) @@ -154,8 +153,7 @@ static inline int vlan_gro_receive(struct napi_struct *napi, } static inline int vlan_gro_frags(struct napi_struct *napi, - struct vlan_group *grp, unsigned int vlan_tci, - struct napi_gro_fraginfo *info) + struct vlan_group *grp, unsigned int vlan_tci) { return NET_RX_DROP; } diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 2e7783f..54db3eb 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1047,14 +1047,6 @@ struct packet_type { struct list_head list; }; -struct napi_gro_fraginfo { - skb_frag_t frags[MAX_SKB_FRAGS]; - unsigned int nr_frags; - unsigned int ip_summed; - unsigned int len; - __wsum csum; -}; - #include #include @@ -1442,12 +1434,18 @@ extern int napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb); extern void napi_reuse_skb(struct napi_struct *napi, struct sk_buff *skb); -extern struct sk_buff * napi_fraginfo_skb(struct napi_struct *napi, - struct napi_gro_fraginfo *info); +extern struct sk_buff * napi_get_frags(struct napi_struct *napi); extern int napi_frags_finish(struct napi_struct *napi, struct sk_buff *skb, int ret); -extern int napi_gro_frags(struct napi_struct *napi, - struct napi_gro_fraginfo *info); +extern struct sk_buff * napi_frags_skb(struct napi_struct *napi); +extern int napi_gro_frags(struct napi_struct *napi); + +static inline void napi_free_frags(struct napi_struct *napi) +{ + kfree_skb(napi->skb); + napi->skb = NULL; +} + extern void netif_nit_deliver(struct sk_buff *skb); extern int dev_valid_name(const char *name); extern int dev_ioctl(struct net *net, unsigned int cmd, void __user *); diff --git a/net/8021q/vlan_core.c b/net/8021q/vlan_core.c index 654e45f..c1f51e4 100644 --- a/net/8021q/vlan_core.c +++ b/net/8021q/vlan_core.c @@ -114,9 +114,9 @@ int vlan_gro_receive(struct napi_struct *napi, struct vlan_group *grp, EXPORT_SYMBOL(vlan_gro_receive); int vlan_gro_frags(struct napi_struct *napi, struct vlan_group *grp, - unsigned int vlan_tci, struct napi_gro_fraginfo *info) + unsigned int vlan_tci) { - struct sk_buff *skb = napi_fraginfo_skb(napi, info); + struct sk_buff *skb = napi_frags_skb(napi); if (!skb) return NET_RX_DROP; diff --git a/net/core/dev.c b/net/core/dev.c index 91d792d..619fa14 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2519,16 +2519,10 @@ void napi_reuse_skb(struct napi_struct *napi, struct sk_buff *skb) } EXPORT_SYMBOL(napi_reuse_skb); -struct sk_buff *napi_fraginfo_skb(struct napi_struct *napi, - struct napi_gro_fraginfo *info) +struct sk_buff *napi_get_frags(struct napi_struct *napi) { struct net_device *dev = napi->dev; struct sk_buff *skb = napi->skb; - struct ethhdr *eth; - skb_frag_t *frag; - int i; - - napi->skb = NULL; if (!skb) { skb = netdev_alloc_skb(dev, GRO_MAX_HEAD + NET_IP_ALIGN); @@ -2536,47 +2530,14 @@ struct sk_buff *napi_fraginfo_skb(struct napi_struct *napi, goto out; skb_reserve(skb, NET_IP_ALIGN); - } - - BUG_ON(info->nr_frags > MAX_SKB_FRAGS); - frag = &info->frags[info->nr_frags - 1]; - for (i = skb_shinfo(skb)->nr_frags; i < info->nr_frags; i++) { - skb_fill_page_desc(skb, i, frag->page, frag->page_offset, - frag->size); - frag++; + napi->skb = skb; } - skb_shinfo(skb)->nr_frags = info->nr_frags; - - skb->data_len = info->len; - skb->len += info->len; - skb->truesize += info->len; - - skb_reset_mac_header(skb); - skb_gro_reset_offset(skb); - - eth = skb_gro_header(skb, sizeof(*eth)); - if (!eth) { - napi_reuse_skb(napi, skb); - skb = NULL; - goto out; - } - - skb_gro_pull(skb, sizeof(*eth)); - - /* - * This works because the only protocols we care about don't require - * special handling. We'll fix it up properly at the end. - */ - skb->protocol = eth->h_proto; - - skb->ip_summed = info->ip_summed; - skb->csum = info->csum; out: return skb; } -EXPORT_SYMBOL(napi_fraginfo_skb); +EXPORT_SYMBOL(napi_get_frags); int napi_frags_finish(struct napi_struct *napi, struct sk_buff *skb, int ret) { @@ -2606,9 +2567,39 @@ int napi_frags_finish(struct napi_struct *napi, struct sk_buff *skb, int ret) } EXPORT_SYMBOL(napi_frags_finish); -int napi_gro_frags(struct napi_struct *napi, struct napi_gro_fraginfo *info) +struct sk_buff *napi_frags_skb(struct napi_struct *napi) +{ + struct sk_buff *skb = napi->skb; + struct ethhdr *eth; + + napi->skb = NULL; + + skb_reset_mac_header(skb); + skb_gro_reset_offset(skb); + + eth = skb_gro_header(skb, sizeof(*eth)); + if (!eth) { + napi_reuse_skb(napi, skb); + skb = NULL; + goto out; + } + + skb_gro_pull(skb, sizeof(*eth)); + + /* + * This works because the only protocols we care about don't require + * special handling. We'll fix it up properly at the end. + */ + skb->protocol = eth->h_proto; + +out: + return skb; +} +EXPORT_SYMBOL(napi_frags_skb); + +int napi_gro_frags(struct napi_struct *napi) { - struct sk_buff *skb = napi_fraginfo_skb(napi, info); + struct sk_buff *skb = napi_frags_skb(napi); if (!skb) return NET_RX_DROP; @@ -2712,7 +2703,7 @@ void netif_napi_del(struct napi_struct *napi) struct sk_buff *skb, *next; list_del_init(&napi->dev_list); - kfree_skb(napi->skb); + napi_free_frags(napi); for (skb = napi->gro_list; skb; skb = next) { next = skb->next; -- 2.7.4