As Ingo suggested, make "perf kmem" show help information.
"perf kmem stat [--caller] [--alloc] .." will show memory
statistics.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Acked-by: NPekka Enberg <penberg@cs.helsinki.fi>
LKML-Reference: <4B20A195.8030106@cn.fujitsu.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>