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gro: New frags interface to avoid copying shinfo

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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 <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Herbert Xu 2009-04-16 02:02:07 -07:00 committed by David S. Miller
parent 861ab44059
commit 76620aafd6
7 changed files with 102 additions and 94 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/net/cxgb3/adapter.h
View File

@ -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;

53
drivers/net/cxgb3/sge.c
View File

@ -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);

26
drivers/net/sfc/rx.c
View File

@ -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;
}
napi_gro_frags(napi, &info);
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);
out:
EFX_BUG_ON_PARANOID(rx_buf->skb);
rx_buf->page = NULL;
} else {

6
include/linux/if_vlan.h
View File

@ -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;
}

22
include/linux/netdevice.h
View File

@ -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 <linux/interrupt.h>
#include <linux/notifier.h>
@ -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 *);

4
net/8021q/vlan_core.c
View File

@ -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;

83
net/core/dev.c
View File

@ -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);
napi->skb = skb;
}
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++;
}
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_fraginfo_skb(napi, info);
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_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;