From: Eric Dumazet edumazet@google.com
[ Upstream commit 9bacd256f1354883d3c1402655153367982bba49 ]
TCP stack is dumb in how it cooks its output packets.
Depending on MAX_HEADER value, we might chose a bad ending point for the headers.
If we align the end of TCP headers to cache line boundary, we make sure to always use the smallest number of cache lines, which always help.
Signed-off-by: Eric Dumazet edumazet@google.com Cc: Soheil Hassas Yeganeh soheil@google.com Acked-by: Soheil Hassas Yeganeh soheil@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/net/tcp.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -52,7 +52,7 @@ extern struct inet_hashinfo tcp_hashinfo extern struct percpu_counter tcp_orphan_count; void tcp_time_wait(struct sock *sk, int state, int timeo);
-#define MAX_TCP_HEADER (128 + MAX_HEADER) +#define MAX_TCP_HEADER L1_CACHE_ALIGN(128 + MAX_HEADER) #define MAX_TCP_OPTION_SPACE 40 #define TCP_MIN_SND_MSS 48 #define TCP_MIN_GSO_SIZE (TCP_MIN_SND_MSS - MAX_TCP_OPTION_SPACE)