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[TCP] Avoid two divides in tcp_output.c

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Because 'free_space' variable in __tcp_select_window() is signed,
expression (free_space / 2) forces compiler to emit an integer divide.

This can be changed to a plain right shift, less expensive.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2007-12-20 21:48:32 -08:00 • committed by David S. Miller
parent 68277accb3
commit b92edbe0b8
1 changed files with 2 additions and 2 deletions
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4
net/ipv4/tcp_output.c
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@ -1627,7 +1627,7 @@ u32 __tcp_select_window(struct sock *sk)
if (mss > full_space) if (mss > full_space)
mss = full_space; mss = full_space;
if (free_space < full_space/2) { if (free_space < (full_space >> 1)) {
icsk->icsk_ack.quick = 0; icsk->icsk_ack.quick = 0;
if (tcp_memory_pressure) if (tcp_memory_pressure)
@ -1666,7 +1666,7 @@ u32 __tcp_select_window(struct sock *sk)
if (window <= free_space - mss || window > free_space) if (window <= free_space - mss || window > free_space)
window = (free_space/mss)*mss; window = (free_space/mss)*mss;
else if (mss == full_space && else if (mss == full_space &&
free_space > window + full_space/2) free_space > window + (full_space >> 1))
window = free_space; window = free_space;
} }