TSQ: Raise default static TSQ limit
    
A new dynamic TSQ limit was introduced in c/s 605ad7f18 based on the
size of actual packets and the amount of data being transmitted.
Raise the default static limit to allow that new limit to actually
come into effect.
 
This fixes a regression where NICs with large transmit completion
times (such as xennet) had a 30% hit unless the user manually tweaked
the value in /proc.
    
Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 1db253e..8ad7cdf 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -50,8 +50,8 @@ int sysctl_tcp_retrans_collapse __read_mostly = 1;
  */
 int sysctl_tcp_workaround_signed_windows __read_mostly = 0;
 
-/* Default TSQ limit of two TSO segments */
-int sysctl_tcp_limit_output_bytes __read_mostly = 131072;
+/* Static TSQ limit.  A more dynamic limit is calculated in tcp_write_xmit. */
+int sysctl_tcp_limit_output_bytes __read_mostly = 1048576;
 
 /* This limits the percentage of the congestion window which we
  * will allow a single TSO frame to consume.  Building TSO frames