cpufreq: fix utilization statistics for sync cpus
If the cpus are using related_cpus policy, then the
current implementaion will overwrite the the calculated
load for every iteration in the for loop. Hence, mpdecision
will read incorrect value, if the cores are using related
cpus policy. With this change mpdecision will read the
sum of the loads of all cpu, if related cpu policy is
used.

Change-Id: I242c8fe39fd75dc3e48750a5b78a5d218b536ddd
Signed-off-by: Narayanan Gopalakrishnan <nargop@codeaurora.org>
Signed-off-by: Shruthi Krishna <skrish@codeaurora.org>
cpufreq: notify avg load for short sampling_rate
If the sampling rate is less than 50ms reporting
the actual load may lead to poor decision making
at user space. So, for sampling rates less than 50ms
report the average of load across two samples.

Change-Id: I0d1cf00801732bee8e4380158d7e892758226594
Signed-off-by: Narayanan Gopalakrishnan <nargop@codeaurora.org>
cpufreq: Resolve CPUFREQ_NOTIFY issue
When the cpufreq_stat receives the frequency policy notification,
it checks if the frequency table and stats table are present for the cpu.
If both are present, it returns with -EBUSY error to the notification.
Due to this, none of the other registered modules receive this
notification.

If the stat table and sysfs nodes are already created, return 0 instead
of returning EBUSY error.

Change-Id: I1fd4a46e6a65edfc6253c4271288f10912ae2ad7
Signed-off-by: Archana Sathyakumar <asathyak@codeaurora.org>
sched/nohz: Correctly initialize "next_balance" in "nohz" idle balancer
The "next_balance" field of "nohz" idle balancer must be initialized
to jiffies. Since jiffies is initialized to negative 300 seconds the
"nohz" idle balancer does not run for the first 300s (5mins) after
bootup. If no new processes are spawed or no idle cycles happen, the
load on the cpus will remain unbalanced for that duration.

Signed-off-by: Diwakar Tundlam <dtundlam@nvidia.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1DD7BFEDD3147247B1355BEFEFE4665237994F30EF@HQMAIL04.nvidia.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>

[xqi@codeaurora.org merge into different file location in 3.0]
Change-Id: I42c41210babb0881150d28d11c2d3fce24fe3a9f
Signed-off-by: Xin Qi <xqi@codeaurora.org>
sched/nohz: Fix logic in nohz_kick_needed
Update the logic so that as long as rq->nr_running is greater than 1,
nohz_kick will be needed, regardless of whether the current CPU has
successfully competed for the first or second cpu spot

Previous logic has the corner case that if current CPU has r_running more than
1, and two other CPUs alreay hold first and econd cpu spot, but they do not
meeting kicking criterial (first cpu has nr_running 1, and second cpu does not
have any load), then nohz_kick will not be set correctly.

Change-Id: I30790f22df0a2e90899daa44c67757284dcca25d
Signed-off-by: Xin Qi <xqi@codeaurora.org>

Conflicts:
kernel/sched_fair.c
sched/nohz: Fix logic in run_rebalance_domains
If triggered by nohz_balancer_kick, idle_at_tick is not updated
accordingly.  Update myself at this moment right before it is used

Change-Id: I20dd4314159e70f955ffe482160c8867c65c261e
Signed-off-by: Xin Qi <xqi@codeaurora.org>
sched/nohz: Fix logic in trigger_load_balance
Whether we need to kick nohz does not depend on current rq->next_balance,
meaning it does not depend on the check of previous if condition.

Change-Id: I566011d6341fa7a9a700c834f77e129043eaba11
Signed-off-by: Xin Qi <xqi@codeaurora.org>
sched: Fix select_fallback_rq() vs cpu_active/cpu_online
Commit 5fbd036b55 ("sched: Cleanup cpu_active madness"), which was
supposed to finally sort the cpu_active mess, instead uncovered more.

Since CPU_STARTING is ran before setting the cpu online, there is a
(small) window where the cpu has active,!online.

If during this time there is a wakeup of a task that used to reside on
that cpu select_task_rq() will use select_fallback_rq() to compute an
alternative cpu to run on since we find !online.

select_fallback_rq() however will compute the new cpu against
cpu_active, this means that it can return the same cpu it started out
with, the !online one, since that cpu is in fact marked active.

This results in us trying to scheduling a task on an offline cpu and
triggering a WARN in the IPI code.

The solution proposed by Chuansheng Liu of setting cpu_active in
set_cpu_online() is buggy, firstly not all archs actually use
set_cpu_online(), secondly, not all archs call set_cpu_online() with
IRQs disabled, this means we would introduce either the same race or
the race from fd8a7de ("x86: cpu-hotplug: Prevent softirq wakeup on
wrong CPU") -- albeit much narrower.

[ By setting online first and active later we have a window of
  online,!active, fresh and bound kthreads have task_cpu() of 0 and
  since cpu0 is not in tsk_cpus_allowed() we end up in
  select_fallback_rq() which excludes !active, resulting in a reset
  of ->cpus_allowed and the thread running all over the place. ]

The solution is to re-work select_fallback_rq() to require active
_and_ online. This makes the active,!online case work as expected,
OTOH archs running CPU_STARTING after setting online are now
vulnerable to the issue from fd8a7de -- these are alpha and
blackfin.

Reported-by: Chuansheng Liu <chuansheng.liu@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: linux-alpha@vger.kernel.org
Link: http://lkml.kernel.org/n/tip-hubqk1i10o4dpvlm06gq7v6j@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Conflicts:

kernel/sched/core.c

Change-Id: Ib22f61c28494bcccc40f9f7fa3812c72e5528203
bdi: use deferable timer for sync_supers task
sync_supers task currently wakes up periodically for superblock
writeback. This hurts power on battery driven devices. This patch
turns this housekeeping timer into a deferable timer so that it
does not fire when system is really idle.

CRs-Fixed: 353700
Signed-off-by: Yong Wang <yong.y.wang@intel.com>
Signed-off-by: Xia Wu <xia.wu@intel.com>
Signed-off-by: Krishna Vanka <kvanka@codeaurora.org>
(cherry picked from commit f398f30)

Change-Id: I6ec6310d66c0d014adf0f41e75cd4c48c233f83d
Signed-off-by: Sridhar Gujje <sgujje@codeaurora.org>

Change-Id: Ib22f61c28494bcccc40f9f7fa3812c72e5528203
The BCM4330 has problems with the WME video (AC_VI) queue in IBSS mode. If we
put packets into this AC, the symptoms are excessive RTS/CTS, most packets get
lost and the device get is stuck and no more packets can be sent, even on other
queues.

Since the AC queue selection happens in the firmware based on the DSCP priority
and we do not know a way to configure this in the driver the workaround is to
simply downgrade all packets which would go into AC_VI (priority 4 and 5, TOS
0x80 and 0xa0) to AC_BE (priority 3 "Excellent Effort"). It is not pretty but
makes the device usable.

Change-Id: I8911c0eef7f189fc55547f02279e7012bc267d47
Signed-off-by: Bruno Randolf <br1@einfach.org>

Change-Id: Ib22f61c28494bcccc40f9f7fa3812c72e5528203
opp4xxx.data.c: disable 180, 230 Mhz Cpu freq.
Paranoid Android style bootlogo
cpufreq: stats: Do not stop notification call chain
The notification call chain is stopped if error returned. Since
no further steps is needed to handle such error, let is just print
a debug message here so the other registered cpufreq notifier can
be called correctly.

Signed-off-by: Lianwei Wang <a22439@motorola.com>
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
ARM: Fix deadlock scenario with smp_send_stop()
If one process calls sys_reboot and that process then stops other
CPUs while those CPUs are within a spin_lock() region we can
potentially encounter a deadlock scenario like below.

CPU 0                   CPU 1
-----                   -----
                        spin_lock(my_lock)
smp_send_stop()
 send_IPI               handle_IPI()
                         disable_preemption/irqs
                          while(1);
 <PREEMPT>
spin_lock(my_lock) <--- Waits forever

We should nt attempt to run any other tasks after we send a stop
IPI to a CPU so disable preemption so that this task runs to
completion.

Change-Id: I528af0b4448433bd9d6ca12d6a0e2c422a55d4be
CRs-Fixed: 396169
Reported-by: Sundarajan Srinivasan <sundaraj@codeaurora.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
cpufreq: interactive: reduce chance of zero time delta on load eval
Reschedule load sampling timer after timestamp of sample start taken,
hold spinlock across entire sequence to avoid preemption.  Avoid the
WARN for zero time delta in the load sampling timer function.

Change-Id: Idc10a756f09141decb6df92669521a1ebf0dbc10
Signed-off-by: Todd Poynor <toddpoynor@google.com>
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
cpufreq: interactive: handle errors from cpufreq_frequency_table_target
Add checks for error return from cpufreq_frequency_table_target, and be
less noisy on the existing call with an error check.  CPU hotplug and
system shutdown may cause this call to return -EINVAL.

Bug: 8613560
Change-Id: Id78d8829920462c0db1c7e14e717d91740d6cb44
Signed-off-by: Todd Poynor <toddpoynor@google.com>
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
Revert "hrtimer: Prevent enqueue of hrtimer on dead CPU"
This reverts commit 22c9c7e.
Revert "hrtimer: Consider preemption when migrating hrtimer cpu_bases"
This reverts commit 736da2e.
sched: Fix SCHED_HRTICK bug leading to late preemption of tasks
SCHED_HRTICK feature is useful to preempt SCHED_FAIR tasks on-the-dot
(just when they would have exceeded their ideal_runtime). It makes use
of a a per-cpu hrtimer resource and hence alarming that hrtimer should
be based on total SCHED_FAIR tasks a cpu has across its various cfs_rqs,
rather than being based on number of tasks in a particular cfs_rq (as
implemented currently). As a result, with current code, its possible for
a running task (which is the sole task in its cfs_rq) to be preempted
much after its ideal_runtime has elapsed, resulting in increased latency
for tasks in other cfs_rq on same cpu.

Fix this by alarming sched hrtimer based on total number of SCHED_FAIR
tasks a CPU has across its various cfs_rqs.

Change-Id: I1f23680a64872f8ce0f451ac4bcae28e8967918f
Signed-off-by: Srivatsa Vaddagiri <vatsa@codeaurora.org>
sched: Reset rq->next_interval before going idle
next_balance, the point in jiffy time scale when a cpu will next load
balance, could have been calculated when the cpu was busy. A busy cpu
will apply its sched domain busy_factor (usually > 1) in computing
next_balance for that sched domain, which causes the (busy) cpu to load
balance less frequently in its sched domains. However when the same cpu
is going idle, its next_balance needs to be reset without consideration
of busy_factor. Failure to do so would not trigger nohz idle balancer on
that cpu for unnecessarily long time (introducing additional scheduling
latencies for tasks). Fix bug in scheduler which aims to reset
next_balance before a cpu goes idle (as per existing comment) but is
clearly not doing so.

Change-Id: I7e027a51686528c4092d770c7d33c874d38f5df4
Signed-off-by: Srivatsa Vaddagiri <vatsa@codeaurora.org>