sched: Rate-limit newidle

Rate limit newidle to migration_cost. It's a win for all
stages of sysbench oltp tests.

Signed-off-by: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
sched: Teach might_sleep() about preemptible RCU

In practice, it is harmless to voluntarily sleep in a
rcu_read_lock() section if we are running under preempt rcu, but
it is illegal if we build a kernel running non-preemptable rcu.

Currently, might_sleep() doesn't notice sleepable operations
under rcu_read_lock() sections if we are running under
preemptable rcu because preempt_count() is left untouched after
rcu_read_lock() in this case. But we want developers who test
their changes under such config to notice the "sleeping while
atomic" issues.

So we add rcu_read_lock_nesting to prempt_count() in
might_sleep() checks.

[ v2: Handle rcu-tiny ]
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <1260991265-8451-1-git-send-regression-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
sched: Reassign prev and switch_count when reacquire_kernel_lock() fail

Assume A->B schedule is processing, if B have acquired BKL before and it
need reschedule this time. Then on B's context, it will go to
need_resched_nonpreemptible for reschedule. But at this time, prev and
switch_count are related to A. It's wrong and will lead to incorrect
scheduler statistics.

Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <2674af741001102238w7b0ddcadref00d345e2181d11@mail.gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
ext4: Support for 64-bit quota format

Add support for new 64-bit quota format. It is enough to add proper
mount options handling. The rest is done by the generic code.

Signed-off-by: Jan Kara <jack@suse.cz>