diff options
Diffstat (limited to 'include/linux/skbuff.h')
| -rw-r--r-- | include/linux/skbuff.h | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 122d08396e56..ac74ee085d74 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -1414,12 +1414,14 @@ static inline int skb_network_offset(const struct sk_buff *skb) * * Various parts of the networking layer expect at least 32 bytes of * headroom, you should not reduce this. - * With RPS, we raised NET_SKB_PAD to 64 so that get_rps_cpus() fetches span - * a 64 bytes aligned block to fit modern (>= 64 bytes) cache line sizes + * + * Using max(32, L1_CACHE_BYTES) makes sense (especially with RPS) + * to reduce average number of cache lines per packet. + * get_rps_cpus() for example only access one 64 bytes aligned block : * NET_IP_ALIGN(2) + ethernet_header(14) + IP_header(20/40) + ports(8) */ #ifndef NET_SKB_PAD -#define NET_SKB_PAD 64 +#define NET_SKB_PAD max(32, L1_CACHE_BYTES) #endif extern int ___pskb_trim(struct sk_buff *skb, unsigned int len); |
