net: combat buffer bloat

Set tx_queue_len to 50 (FreeBSD default) from 1000 to reduce latencies.  Set
tcp_ecn to 1 to force enable Explicit Congestion Notification.  These two
changes should make a positive impact network performance.  Possible drop in
throughput with 1 gbit and faster networks.

net: restore tcp_ecn default

Forcing ECN breaks some Cisco routers with SPI firewall enabled.

Signed-off-by: Luka Karinja <lk@varjanta.com>
zen-tune: Implement zen-tune v3
ext4: optimize test_root()

The test_root() function could potentially loop forever due to
overflow issues.  So rewrite test_root() to avoid this issue; as a
bonus, it is 38% faster when benchmarked via a test loop:

int main(int argc, char **argv)
{
	int  i;

	for (i = 0; i < 1 << 24; i++) {
		if (test_root(i, 7))
			printf("%d\n", i);
	}
}

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
ext4: remove useless marking of superblock dirty

Commit a0375156 properly notes that superblock doesn't need to be marked
as dirty when only number of free inodes / blocks / number of directories
changes since that is recomputed on each mount anyway. However that comment
leaves some unnecessary markings as dirty in place. Remove these.

Artem: tested using xfstests for both journalled and non-journalled ext4.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Tested-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
ARM: msm: disable MSM_SMD_LOGGING
disable OPROFILE
Not cool to force that debugging.