Some generic vtime APIs check if the vtime accounting
is enabled on the local CPU before doing their work.

Some of these are not needed because all their callers already
take care of that. Let's remove the checks on these.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Kevin Hilman <khilman@linaro.org>

Optimize guest entry/exit APIs with static keys. This minimize
the overhead for those who enable CONFIG_NO_HZ_FULL without
always using it. Having no range passed to nohz_full= should
result in the probes overhead to be minimized.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Kevin Hilman <khilman@linaro.org>

Update a stale comment from the old vtime era and document some
locking that might be non obvious.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Kevin Hilman <khilman@linaro.org>

preempt_schedule() and preempt_schedule_context() open
code their preemptability checks.

Use the standard API instead for consolidation.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Alex Shi <alex.shi@intel.com>
Cc: Paul Turner <pjt@google.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Vincent Guittot <vincent.guittot@linaro.org>

The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications.  For example, the fix in
commit 5e427ec2 ("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.

After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out.  Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.

This removes all the uses of the __cpuinit macros from C files in
the core kernel directories (kernel, init, lib, mm, and include)
that don't really have a specific maintainer.

[1] https://lkml.org/lkml/2013/5/20/589Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

David reported that the HRTICK sched feature was borken; which was enough
motivation for me to finally fix it ;-)

We should not allow hrtimer code to do softirq wakeups while holding scheduler
locks. The hrtimer code only needs this when we accidentally try to program an
expired time. We don't much care about those anyway since we have the regular
tick to fall back to.
Reported-by: NDavid Ahern <dsahern@gmail.com>
Tested-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20130628091853.GE29209@dyad.programming.kicks-ass.netSigned-off-by: NIngo Molnar <mingo@kernel.org>

When tsk->signal->cputimer->running is 1, signal->cputimer (i.e. per process
timer account) and tsk->sum_sched_runtime (i.e. per thread timer account)
increase at the same pace because update_curr() increases both accounting.

However, there is one exception. When thread exiting, __exit_signal() turns
over task's sum_shced_runtime to sig->sum_sched_runtime, but it doesn't stop
signal->cputimer accounting.

This inconsistency makes POSIX timer wake up too early. This patch fixes it.
Original-patch-by: NOlivier Langlois <olivier@trillion01.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Acked-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NOlivier Langlois <olivier@trillion01.com>
Signed-off-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>

Now that we are using runnable load avg in sched balance, we don't
need to keep it under CONFIG_FAIR_GROUP_SCHED.

Also align the code style to #ifdef instead of #if defined() and
reorder the tg output info.
Signed-off-by: NAlex Shi <alex.shi@intel.com>
Cc: pjt@google.com
Cc: kamalesh@linux.vnet.ibm.com
Cc: peterz@infradead.org
Link: http://lkml.kernel.org/r/1372417835-4698-1-git-send-email-alex.shi@intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

This patch alters format string's width, to align all statistics
at par with the longest struct sched_statistic member name under
/proc/<PID>/sched.
Signed-off-by: NKamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Cc: peterz@infradead.org
Link: http://lkml.kernel.org/r/20130627165005.GA15583@linux.vnet.ibm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Fix spelling of 'calling' in description of se flags in
enqueue_entity().
Signed-off-by: NKamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Cc: peterz@infradead.org
Link: http://lkml.kernel.org/r/20130627055418.GA18582@linux.vnet.ibm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

At present we print per-entity load-tracking statistics for
cfs_rq of cgroups/runqueues. Given that per task statistics
is maintained, it can be used to know the contribution made
by the task to its parenting cfs_rq level.

This patch adds per-task load-tracking statistics to /proc/<PID>/sched.
Signed-off-by: NKamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20130625080336.GA20175@linux.vnet.ibm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Based-on-patch-by: NFengguang Wu <fengguang.wu@intel.com>
Signed-off-by: NAlex Shi <alex.shi@intel.com>
Tested-by: NVincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1371694737-29336-14-git-send-email-alex.shi@intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Since no one use it.
Signed-off-by: NAlex Shi <alex.shi@intel.com>
Reviewed-by: NPaul Turner <pjt@google.com>
Tested-by: NVincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1371694737-29336-13-git-send-email-alex.shi@intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Similar to runnable_load_avg, blocked_load_avg variable, long type is
enough for removed_load in 64 bit or 32 bit machine.

Then we avoid the expensive atomic64 operations on 32 bit machine.
Signed-off-by: NAlex Shi <alex.shi@intel.com>
Reviewed-by: NPaul Turner <pjt@google.com>
Tested-by: NVincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1371694737-29336-12-git-send-email-alex.shi@intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Since tg->load_avg is smaller than tg->load_weight, we don't need a
atomic64_t variable for load_avg in 32 bit machine.
The same reason for cfs_rq->tg_load_contrib.

The atomic_long_t/unsigned long variable type are more efficient and
convenience for them.
Signed-off-by: NAlex Shi <alex.shi@intel.com>
Tested-by: NVincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1371694737-29336-11-git-send-email-alex.shi@intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Since the 'u64 runnable_load_avg, blocked_load_avg' in cfs_rq struct are
smaller than 'unsigned long' cfs_rq->load.weight. We don't need u64
vaiables to describe them. unsigned long is more efficient and convenience.
Signed-off-by: NAlex Shi <alex.shi@intel.com>
Reviewed-by: NPaul Turner <pjt@google.com>
Tested-by: NVincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1371694737-29336-10-git-send-email-alex.shi@intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Aside from using runnable load average in background, move_tasks is
also the key function in load balance. We need consider the runnable
load average in it in order to make it an apple to apple load
comparison.

Morten had caught a div u64 bug on ARM, thanks!

Thanks-to: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: NAlex Shi <alex.shi@intel.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1371694737-29336-8-git-send-email-alex.shi@intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

They are the base values in load balance, update them with rq runnable
load average, then the load balance will consider runnable load avg
naturally.

We also try to include the blocked_load_avg as cpu load in balancing,
but that cause kbuild performance drop 6% on every Intel machine, and
aim7/oltp drop on some of 4 CPU sockets machines.
Or only add blocked_load_avg into get_rq_runable_load, hackbench still
drop a little on NHM EX.
Signed-off-by: NAlex Shi <alex.shi@intel.com>
Reviewed-by: NGu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1371694737-29336-7-git-send-email-alex.shi@intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

To get the latest runnable info, we need do this cpuload update after
task_tick.
Signed-off-by: NAlex Shi <alex.shi@intel.com>
Reviewed-by: NPaul Turner <pjt@google.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1371694737-29336-6-git-send-email-alex.shi@intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

The woken migrated task will __synchronize_entity_decay(se); in
migrate_task_rq_fair, then it needs to set
`se->avg.last_runnable_update -= (-se->avg.decay_count) << 20' before
update_entity_load_avg, in order to avoid sleep time is updated twice
for se.avg.load_avg_contrib in both __syncchronize and
update_entity_load_avg.

However if the sleeping task is woken up from the same cpu, it miss
the last_runnable_update before update_entity_load_avg(se, 0, 1), then
the sleep time was used twice in both functions.  So we need to remove
the double sleep time accounting.

Paul also contributed some code comments in this commit.
Signed-off-by: NAlex Shi <alex.shi@intel.com>
Reviewed-by: NPaul Turner <pjt@google.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1371694737-29336-5-git-send-email-alex.shi@intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

We need to initialize the se.avg.{decay_count, load_avg_contrib} for a
new forked task. Otherwise random values of above variables cause a
mess when a new task is enqueued:

    enqueue_task_fair
        enqueue_entity
            enqueue_entity_load_avg

and make fork balancing imbalance due to incorrect load_avg_contrib.

Further more, Morten Rasmussen notice some tasks were not launched at
once after created. So Paul and Peter suggest giving a start value for
new task runnable avg time same as sched_slice().

PeterZ said:

> So the 'problem' is that our running avg is a 'floating' average; ie. it
> decays with time. Now we have to guess about the future of our newly
> spawned task -- something that is nigh impossible seeing these CPU
> vendors keep refusing to implement the crystal ball instruction.
>
> So there's two asymptotic cases we want to deal well with; 1) the case
> where the newly spawned program will be 'nearly' idle for its lifetime;
> and 2) the case where its cpu-bound.
>
> Since we have to guess, we'll go for worst case and assume its
> cpu-bound; now we don't want to make the avg so heavy adjusting to the
> near-idle case takes forever. We want to be able to quickly adjust and
> lower our running avg.
>
> Now we also don't want to make our avg too light, such that it gets
> decremented just for the new task not having had a chance to run yet --
> even if when it would run, it would be more cpu-bound than not.
>
> So what we do is we make the initial avg of the same duration as that we
> guess it takes to run each task on the system at least once -- aka
> sched_slice().
>
> Of course we can defeat this with wakeup/fork bombs, but in the 'normal'
> case it should be good enough.

Paul also contributed most of the code comments in this commit.
Signed-off-by: NAlex Shi <alex.shi@intel.com>
Reviewed-by: NGu Zheng <guz.fnst@cn.fujitsu.com>
Reviewed-by: NPaul Turner <pjt@google.com>
[peterz; added explanation of sched_slice() usage]
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1371694737-29336-4-git-send-email-alex.shi@intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

The following 2 variables are only used under CONFIG_SMP, so its
better to move their definiation into CONFIG_SMP too.

        atomic64_t load_avg;
        atomic_t runnable_avg;
Signed-off-by: NAlex Shi <alex.shi@intel.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1371694737-29336-3-git-send-email-alex.shi@intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Remove CONFIG_FAIR_GROUP_SCHED that covers the runnable info, then
we can use runnable load variables.

Also remove 2 CONFIG_FAIR_GROUP_SCHED setting which is not in reverted
patch(introduced in 9ee474f5), but also need to revert.
Signed-off-by: NAlex Shi <alex.shi@intel.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/51CA76A3.3050207@intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Just use struct ctl_table.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1371063336.2069.22.camel@joe-AO722Signed-off-by: NIngo Molnar <mingo@kernel.org>

sd can't be NULL in init_sched_groups_power() and so checking it for NULL isn't
useful. In case it is required, then also we need to rearrange the code a bit as
we already accessed invalid pointer sd to get sg: sg = sd->groups.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/2bbe633cd74b431c05253a8ce61fdfd5066a531b.1370948150.git.viresh.kumar@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

In build_sched_groups() we don't need to call get_group() for cpus
which are already covered in previous iterations. Calling get_group()
would mark the group used and eventually leak it since we wouldn't
connect it and not find it again to free it.

This will happen only in cases where sg->cpumask contained more than
one cpu (For any topology level). This patch would free sg's memory
for all cpus leaving the group leader as the group isn't marked used
now.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/7a61e955abdcbb1dfa9fe493f11a5ec53a11ddd3.1370948150.git.viresh.kumar@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

In the beginning of build_sched_groups() we called sched_domain_span() and
cached its return value in span. Few statements later we are calling it again to
get the same pointer.

Lets use the cached value instead as it hasn't changed in between.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/834ecd507071ad88aff039352dbc7e063dd996a7.1370948150.git.viresh.kumar@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

For loop for traversing sched_domain_topology was used at multiple placed in
core.c. This patch removes code redundancy by creating for_each_sd_topology().
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/e0e04542f54e9464bd9da54f5ccfe62ec6c4c0bc.1370861520.git.viresh.kumar@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Memory for sd is allocated with kzalloc_node() which will initialize its fields
with zero. In build_sched_domain() we are setting sd->child to child even if
child is NULL, which isn't required.

Lets do it only if child isn't NULL.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/f4753a1730051341003ad2ad29a3229c7356678e.1370861520.git.viresh.kumar@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

alloc_state will be overwritten by __visit_domain_allocation_hell() and so we
don't actually need to initialize alloc_state.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/df57734a075cc5ad130e1ae498702e24f2529ab8.1370861520.git.viresh.kumar@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

We are saving first scheduling domain for a cpu in build_sched_domains() by
iterating over the nested sd->child list. We don't actually need to do it this
way.

tl will be equal to sched_domain_topology for the first iteration and so we can
set *per_cpu_ptr(d.sd, i) based on that.  So, save pointer to first SD while
running the iteration loop over tl's.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/fc473527cbc4dfa0b8eeef2a59db74684eb59a83.1370436120.git.viresh.kumar@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

build_sched_domain() never uses parameter struct s_data *d and so passing it is
useless.

Remove it.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/545e0b4536166a15b4475abcafe5ed0db4ad4a2c.1370436120.git.viresh.kumar@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

default_cfs_period(), do_sched_cfs_period_timer(), do_sched_cfs_slack_timer()
already defined previously, no need to declare again.
Signed-off-by: NMichael Wang <wangyun@linux.vnet.ibm.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/51AD8808.7020608@linux.vnet.ibm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Directly use rq to save some code.
Signed-off-by: NMichael Wang <wangyun@linux.vnet.ibm.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/51AD87EB.1070605@linux.vnet.ibm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

[ Peter, this is based off of some of my work, I ran it though a few
  tests and it passed. I also reviewed it, and added my SOB as I am
  somewhat a co-author to it. ]

Based on the patch by Steven Rostedt from previous year:

https://lkml.org/lkml/2012/4/18/517

1)Simplify pull_rt_task() logic: search in pushable tasks of dest runqueue.
The only pullable tasks are the tasks which are pushable in their local rq,
and no others.

2)Remove .leaf_rt_rq_list member of struct rt_rq and functions connected
with it: nobody uses it since now.
Signed-off-by: NKirill Tkhai <tkhai@yandex.ru>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/287571370557898@web7d.yandex.ruSigned-off-by: NIngo Molnar <mingo@kernel.org>

I have faced a sequence where the Idle Load Balance was sometime not
triggered for a while on my platform, in the following scenario:

 CPU 0 and CPU 1 are running tasks and CPU 2 is idle

 CPU 1 kicks the Idle Load Balance
 CPU 1 selects CPU 2 as the new Idle Load Balancer
 CPU 2 sets NOHZ_BALANCE_KICK for CPU 2
 CPU 2 sends a reschedule IPI to CPU 2

 While CPU 3 wakes up, CPU 0 or CPU 1 migrates a waking up task A on CPU 2

 CPU 2 finally wakes up, runs task A and discards the Idle Load Balance
       task A quickly goes back to sleep (before a tick occurs on CPU 2)
 CPU 2 goes back to idle with NOHZ_BALANCE_KICK set

Whenever CPU 2 will be selected as the ILB, no reschedule IPI will be sent
because NOHZ_BALANCE_KICK is already set and no Idle Load Balance will be
performed.

We must wait for the sched softirq to be raised on CPU 2 thanks to another
part the kernel to come back to clear NOHZ_BALANCE_KICK.

The proposed solution clears NOHZ_BALANCE_KICK in schedule_ipi if
we can't raise the sched_softirq for the Idle Load Balance.

Change since V1:

- move the clear of NOHZ_BALANCE_KICK in got_nohz_idle_kick if the ILB
  can't run on this CPU (as suggested by Peter)
Signed-off-by: NVincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1370419991-13870-1-git-send-email-vincent.guittot@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Commit 78becc27 ("sched: Use an accessor to read the rq clock")
introduces rq_clock(), which obsoletes the use of the "rq" variable
in expire_cfs_rq_runtime() and triggers this build warning:

  kernel/sched/fair.c: In function 'expire_cfs_rq_runtime':
  kernel/sched/fair.c:2159:13: warning: unused variable 'rq' [-Wunused-variable]
Signed-off-by: NKamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Acked-by: NFrederic Weisbecker <fweisbec@gmail.com>
Acked-by: NPaul Turner <pjt@google.com>
Cc: peterz@infradead.org
Link: http://lkml.kernel.org/r/1369904660-14169-1-git-send-email-kamalesh@linux.vnet.ibm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

While computing the cputime delta of dynticks CPUs,
we are mixing up clocks of differents natures:

* local_clock() which takes care of unstable clock
sources and fix these if needed.

* sched_clock() which is the weaker version of
local_clock(). It doesn't compute any fixup in case
of unstable source.

If the clock source is stable, those two clocks are the
same and we can safely compute the difference against
two random points.

Otherwise it results in random deltas as sched_clock()
can randomly drift away, back or forward, from local_clock().

As a consequence, some strange behaviour with unstable tsc
has been observed such as non progressing constant zero cputime.
(The 'top' command showing no load).

Fix this by only using local_clock(), or its irq safe/remote
equivalent, in vtime code.
Reported-by: NMike Galbraith <efault@gmx.de>
Suggested-by: NMike Galbraith <efault@gmx.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Simple cleanup.
Reported-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NStanislaw Gruszka <sgruszka@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/1367501673-6563-1-git-send-email-sgruszka@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Read the runqueue clock through an accessor. This
prepares for adding a debugging infrastructure to
detect missing or redundant calls to update_rq_clock()
between a scheduler's entry and exit point.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul Turner <pjt@google.com>
Cc: Mike Galbraith <efault@gmx.de>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1365724262-20142-6-git-send-email-fweisbec@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>