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ip_tunnel: Create percpu gro_cell 

In the ipip tunnel, the skb->queue_mapping is lost in ipip_rcv().
All skb will be queued to the same cell->napi_skbs.  The
gro_cell_poll is pinned to one core under load.  In production traffic,
we also see severe rx_dropped in the tunl iface and it is probably due to
this limit: skb_queue_len(&cell->napi_skbs) > netdev_max_backlog.

This patch is trying to alloc_percpu(struct gro_cell) and schedule
gro_cell_poll to process the skb in the same core.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Martin KaFai Lau 2015-01-16 10:11:00 -08:00 committed by David S. Miller
parent f2bbca513c
commit 88340160f3
1 changed files with 12 additions and 17 deletions
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29
include/net/gro_cells.h
View File

@ -8,25 +8,23 @@
struct gro_cell {
struct sk_buff_head napi_skbs;
struct napi_struct napi;
} ____cacheline_aligned_in_smp;
};
struct gro_cells {
unsigned int gro_cells_mask;
struct gro_cell *cells;
struct gro_cell __percpu *cells;
};
static inline void gro_cells_receive(struct gro_cells *gcells, struct sk_buff *skb)
{
struct gro_cell *cell = gcells->cells;
struct gro_cell *cell;
struct net_device *dev = skb->dev;
if (!cell || skb_cloned(skb) || !(dev->features & NETIF_F_GRO)) {
if (!gcells->cells || skb_cloned(skb) || !(dev->features & NETIF_F_GRO)) {
netif_rx(skb);
return;
}
if (skb_rx_queue_recorded(skb))
cell += skb_get_rx_queue(skb) & gcells->gro_cells_mask;
cell = this_cpu_ptr(gcells->cells);
if (skb_queue_len(&cell->napi_skbs) > netdev_max_backlog) {
atomic_long_inc(&dev->rx_dropped);
@ -72,15 +70,12 @@ static inline int gro_cells_init(struct gro_cells *gcells, struct net_device *de
{
int i;
gcells->gro_cells_mask = roundup_pow_of_two(netif_get_num_default_rss_queues()) - 1;
gcells->cells = kcalloc(gcells->gro_cells_mask + 1,
sizeof(struct gro_cell),
GFP_KERNEL);
gcells->cells = alloc_percpu(struct gro_cell);
if (!gcells->cells)
return -ENOMEM;
for (i = 0; i <= gcells->gro_cells_mask; i++) {
struct gro_cell *cell = gcells->cells + i;
for_each_possible_cpu(i) {
struct gro_cell *cell = per_cpu_ptr(gcells->cells, i);
skb_queue_head_init(&cell->napi_skbs);
netif_napi_add(dev, &cell->napi, gro_cell_poll, 64);
@ -91,16 +86,16 @@ static inline int gro_cells_init(struct gro_cells *gcells, struct net_device *de
static inline void gro_cells_destroy(struct gro_cells *gcells)
{
struct gro_cell *cell = gcells->cells;
int i;
if (!cell)
if (!gcells->cells)
return;
for (i = 0; i <= gcells->gro_cells_mask; i++,cell++) {
for_each_possible_cpu(i) {
struct gro_cell *cell = per_cpu_ptr(gcells->cells, i);
netif_napi_del(&cell->napi);
skb_queue_purge(&cell->napi_skbs);
}
kfree(gcells->cells);
free_percpu(gcells->cells);
gcells->cells = NULL;
}