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tcp: cache line align MAX_TCP_HEADER

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[ 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>
This commit is contained in:
Eric Dumazet 2020-04-17 07:10:23 -07:00 committed by Greg Kroah-Hartman
parent 25765e8afb
commit ec63c6bde7
1 changed files with 1 additions and 1 deletions
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2
include/net/tcp.h
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@ -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)