sched: /proc/sched_stat fails on very very large machines

sched: /proc/sched_stat fails on very very large machines

On systems with 4096 cores doing a cat /proc/sched_stat fails.  We are
trying to push all the data into a single kmalloc buffer.  The issue is on
these very large machines all the data will not fit in 4mb.

A better solution is to not use the single_open() mechanism but to provide
our own seq_operations.

The output should be identical to previous version and thus not need the
version number.

Signed-off-by: Nathan Zimmer <nzimmer@sgi.com>
Reported-by: Dave Jones <davej@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>