arm: Remove no-longer-required RCU_NONIDLE wrapper

Commit 21111be8 "ARM: Fix negative idle stats for offline cpu" moved call
to cpu_die() to occur outside of rcu_idle_enter()/rcu_idle_exit() section.
As a result, the RCU_NONIDLE() wrapper to complete() call in
arch/arm/kernel/process.c:cpu_die() is no longer required (and is
technically incorrect to have). Removing RCU_NONIDLE() wrapper also removes
this warning seen during CPU offline:

[Note: Below message has been edited to fit 75-char per line limit.
Insignificant portions of warning message has been removed in each line.]

------------[ cut here ]------------
WARNING: at kernel/rcutree.c:456 rcu_idle_exit_common+0x4c/0xe0()
Modules linked in:
(unwind_backtrace+0x0/0x120) from (warn_slowpath_common+0x4c/0x64)
(warn_slowpath_common+0x4c/0x64) from (warn_slowpath_null+0x18/0x1c)
(warn_slowpath_null+0x18/0x1c) from (rcu_idle_exit_common+0x4c/0xe0)
(rcu_idle_exit_common+0x4c/0xe0) from (rcu_idle_exit+0xa8/0xc0)
(rcu_idle_exit+0xa8/0xc0) from (cpu_die+0x24/0x5c)
(cpu_die+0x24/0x5c) from (cpu_idle+0xdc/0xf0)
(cpu_idle+0xdc/0xf0) from (0x8160)
---[ end trace 61bf21937a496a37 ]---

Signed-off-by: Srivatsa Vaddagiri <vatsa@codeaurora.org>
Change-Id: I721e6b20651674e6f6f584cf8d814af00b688c91
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's 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>
hrtimer: Prevent hrtimer_enqueue_reprogram race

hrtimer_enqueue_reprogram contains a race which could result in
timer.base switch during unlock/lock sequence.

hrtimer_enqueue_reprogram is releasing the lock protecting the timer
base for calling raise_softirq_irqsoff() due to a lock ordering issue
versus rq->lock.

If during that time another CPU calls __hrtimer_start_range_ns() on
the same hrtimer, the timer base might switch, before the current CPU
can lock base->lock again and therefor the unlock_timer_base() call
will unlock the wrong lock.

[ tglx: Added comment and massaged changelog ]

Change-Id: I327d862c28f24b77a62861764393c4bf660a7318
Signed-off-by: Leonid Shatz <leonid.shatz@ravellosystems.com>
Signed-off-by: Izik Eidus <izik.eidus@ravellosystems.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1359981217-389-1-git-send-email-izik.eidus@ravellosystems.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Git-commit: b22affe0aef429d657bc6505aacb1c569340ddd2
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Taniya Das <tdas@codeaurora.org>
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: fix rq->lock recursion

Enabling SCHED_HRTICK currently results in rq->lock recursion and a hard
hang at bootup.  Essentially try_to_wakeup() grabs rq->lock and tries
arming a hrtimer via hrtimer_restart(), which deep down tries waking up
ksoftirqd, which leads to a recursive call to try_to_wakeup() and thus
attempt to take rq->lock recursively!!

This is fixed by having scheduler queue hrtimer via
__hrtimer_start_range_ns() which avoids waking up ksoftirqd.

Signed-off-by: Srivatsa Vaddagiri <vatsa@codeaurora.org>
Change-Id: I11a13be1d9db3a749614ccf3d4f5fb7bf6f18fa1
sched: fix reference to wrong cfs_rq

Commit 7db16c8c (sched: Fix SCHED_HRTICK bug leading to late preemption
of tasks) introduced a bug in sched_slice() calculation by using wrong
cfs_rq for tasks. rq->cfs was incorrectly used as task's cfs_rq, rather
than the correct one to which they belonged.

Fix the bug by using correct cfs_rq for tasks.

Signed-off-by: Srivatsa Vaddagiri <vatsa@codeaurora.org>
sched: provide per cpu-cgroup option to notify on migrations

On systems where CPUs may run asynchronously, task migrations
between CPUs running at grossly different speeds can cause
problems.

This change provides a mechanism to notify a subsystem
in the kernel if a task in a particular cgroup migrates to a
different CPU. Other subsystems (such as cpufreq) may then
register for this notifier to take appropriate action when
such a task is migrated.

The cgroup attribute to set for this behavior is
"notify_on_migrate" .

Change-Id: Ie1868249e53ef901b89c837fdc33b0ad0c0a4590
Signed-off-by: Steve Muckle <smuckle@codeaurora.org>
sched: remove migration notification from RT class

Commit 88a7e37d265 (sched: provide per cpu-cgroup option to
notify on migrations) added a notifier call when a task is moved
to a different CPU. Unfortunately the two call sites in the RT
sched class where this occurs happens with a runqueue lock held.
This can result in a deadlock if the notifier call attempts to do
something like wake up a task.

Fortunately the benefit of 88a7e37d265 comes mainly from notifying
on migration of non-RT tasks, so we can simply ignore the movements
of RT tasks.

CRs-Fixed: 491370
Change-Id: I8849d826bf1eeaf85a6f6ad872acb475247c5926
Signed-off-by: Steve Muckle <smuckle@codeaurora.org>
sched: re-calculate a cpu's next_balance point upon sched domain changes

Commit 55ddeb0f (sched: Reset rq->next_interval before going idle) reset
a cpu's rq->next_balance when pulled_task = 0, which will be true when
the cpu failed to pull any task, causing it go idle. However that patch
relied on next_balance being calculated as a result of traversing cpu's
sched domain hierarchy.

A cpu that is the only online cpu will however not be attached to any
sched domain hierarchy. When such a cpu calls into idle_balance(), we
will end up initializing next_balance to be 1sec away! Such a CPU will
defer load balance check for another 1sec, even though we may bring up
more cpus in the meantime requiring it to check for load imbalance more
frequently. This could then lead to increased scheduling latency for
some tasks.

This patch results in a cpu's next_balance being re-calculated when its
attaching to a new sched domain hierarchy.  This should let cpus call
load balance checks at the right time we expect them to!

Change-Id: I855cff8da5ca28d278596c3bb0163b839d4704bc
Signed-off-by: Srivatsa Vaddagiri <vatsa@codeaurora.org>
sched: Make sure to not re-read variables after validation

We could re-read rq->rt_avg after we validated it was smaller than
total, invalidating the check and resulting in an unintended negative.

Change-Id: I8543974aad539107768e9e513ca3a8c4cb79b2ff
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: David Rientjes <rientjes@google.com>
Link: http://lkml.kernel.org/r/1337688268.9698.29.camel@twins
Signed-off-by: Ingo Molnar <mingo@kernel.org>
CRs-Fixed: 497236
Git-commit: b654f7de41b0e3903ee2b51d3b8db77fe52ce728
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Srivatsa Vaddagiri <vatsa@codeaurora.org>
workqueue: don't use WQ_HIGHPRI for unbound workqueues

Unbound wqs aren't concurrency-managed and try to execute work items
as soon as possible.  This is currently achieved by implicitly setting
%WQ_HIGHPRI on all unbound workqueues; however, WQ_HIGHPRI
implementation is about to be restructured and this usage won't be
valid anymore.

Add an explicit chain-wakeup path for unbound workqueues in
process_one_work() instead of piggy backing on %WQ_HIGHPRI.

Change-Id: Iecd17a9935ee28f856d8b726bb4c296762922bed
Signed-off-by: Tejun Heo <tj@kernel.org>
Git-commit: 974271c485a4d8bb801decc616748f90aafb07ec
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>

workqueue: factor out worker_pool from global_cwq

Move worklist and all worker management fields from global_cwq into
the new struct worker_pool.  worker_pool points back to the containing
gcwq.  worker and cpu_workqueue_struct are updated to point to
worker_pool instead of gcwq too.

This change is mechanical and doesn't introduce any functional
difference other than rearranging of fields and an added level of
indirection in some places.  This is to prepare for multiple pools per
gcwq.

v2: Comment typo fixes as suggested by Namhyung.

Change-Id: Iefae84798c2af580f425b92ed79117935d99f21f
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Git-commit: bd7bdd43dcb81bb08240b9401b36a104f77dc135
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>

workqueue: use @pool instead of @gcwq or @cpu where applicable

Modify all functions which deal with per-pool properties to pass
around @pool instead of @gcwq or @cpu.

The changes in this patch are mechanical and don't caues any
functional difference.  This is to prepare for multiple pools per
gcwq.

Change-Id: I4be6727e1cce6f9aa2a0057b96bdc725c84f1ea8
Signed-off-by: Tejun Heo <tj@kernel.org>
Git-commit: 63d95a9150ee3bbd4117fcd609dee40313b454d9
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>

workqueue: separate out worker_pool flags

GCWQ_MANAGE_WORKERS, GCWQ_MANAGING_WORKERS and GCWQ_HIGHPRI_PENDING
are per-pool properties.  Add worker_pool->flags and make the above
three flags per-pool flags.

The changes in this patch are mechanical and don't caues any
functional difference.  This is to prepare for multiple pools per
gcwq.

Change-Id: I1824fd1c509d8ac6b0619536621a22b15b316256
Signed-off-by: Tejun Heo <tj@kernel.org>
Git-commit: 11ebea50dbc1ade5994b2c838a096078d4c02399
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>

workqueue: introduce NR_WORKER_POOLS and for_each_worker_pool()

Introduce NR_WORKER_POOLS and for_each_worker_pool() and convert code
paths which need to manipulate all pools in a gcwq to use them.
NR_WORKER_POOLS is currently one and for_each_worker_pool() iterates
over only @gcwq->pool.

Note that nr_running is per-pool property and converted to an array
with NR_WORKER_POOLS elements and renamed to pool_nr_running.  Note
that get_pool_nr_running() currently assumes 0 index.  The next patch
will make use of non-zero index.

The changes in this patch are mechanical and don't caues any
functional difference.  This is to prepare for multiple pools per
gcwq.

v2: nr_running indexing bug in get_pool_nr_running() fixed.

v3: Pointer to array is stupid.  Don't use it in get_pool_nr_running()
    as suggested by Linus.

Change-Id: I46e9488601d764d25e4a6c707de129ab68f7064c
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Git-commit: 4ce62e9e30cacc26885cab133ad1de358dd79f21
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>

workqueue: reimplement WQ_HIGHPRI using a separate worker_pool

WQ_HIGHPRI was implemented by queueing highpri work items at the head
of the global worklist.  Other than queueing at the head, they weren't
handled differently; unfortunately, this could lead to execution
latency of a few seconds on heavily loaded systems.

Now that workqueue code has been updated to deal with multiple
worker_pools per global_cwq, this patch reimplements WQ_HIGHPRI using
a separate worker_pool.  NR_WORKER_POOLS is bumped to two and
gcwq->pools[0] is used for normal pri work items and ->pools[1] for
highpri.  Highpri workers get -20 nice level and has 'H' suffix in
their names.  Note that this change increases the number of kworkers
per cpu.

POOL_HIGHPRI_PENDING, pool_determine_ins_pos() and highpri chain
wakeup code in process_one_work() are no longer used and removed.

This allows proper prioritization of highpri work items and removes
high execution latency of highpri work items.

v2: nr_running indexing bug in get_pool_nr_running() fixed.

v3: Refreshed for the get_pool_nr_running() update in the previous
    patch.

Change-Id: Id843c0a425f51f84083786fbf413d999d35771b7
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Josh Hunt <joshhunt00@gmail.com>
LKML-Reference: <CAKA=qzaHqwZ8eqpLNFjxnO2fX-tgAOjmpvxgBFjv6dJeQaOW1w@mail.gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Git-commit: 3270476a6c0ce322354df8679652f060d66526dc
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>
msm: mdp: Adjust bandwidth parameters

720p video on 1080p panel have upscaling, mdp clk should not be
increased for this case. Also slightly increase mdp ib to make
sure there is no bw access bottleneck.

Change-Id: I2f1dcd8e8fcd1b2bd296a709d66e51b5ebe3603f
Signed-off-by: Huaibin Yang <huaibiny@codeaurora.org>
Signed-off-by: naseer <naseer@codeaurora.org>
msm: cpufreq: Configure WQ for higer priority

When the workqueue runs at a lower priority, it gets starved by higher
priority threads. Bump the WQ priority to high to ensure cpufreq work
queue gets a fair scheduling chance

Change-Id: I9e994da94a347dceb884e72ec3dd3da468a4471d
Signed-off-by: Mahesh Sivasubramanian <msivasub@codeaurora.org>
msm: cpufreq: Always update frequency limits when core is online

Remove condition in msm_cpufreq_init() so that when cpu is set to
online, it will call set_cpu_freq() and update the frequency limits.

CRs-Fixed: 462816
Change-Id: I40ac33c9cb4b42590a83f9d61b74f23379f5642e
Signed-off-by: Jennifer Liu <chihning@codeaurora.org>
msm: hotplug: Change the pen variable in one place

Other WFI based hotplug implementations set the pen variable to
-1 in C code and do the appropriate flushing operations in one
location. They also don't try to invalidate the cache on a
spurious wakeup and report how many spurious wakeups there were.
Let's do the same in our code so that we can remove our
dependence on the dmac_{inv,flush}_range() functions (which are
no longer upstream) and easily report spurious wakeups to the
kernel logs.

This does delay the time we set the pen back to its default
value, but that doesn't actually matter because generic ARM
hotplug code already waits for a completion before continuing.

Change-Id: Ic36fbf744fe8abeda20ad9859a207b5e37c5e63c
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
msm: Remove idle stats and cpuidle hooks

Calling RCU functions from within the RCU quiescent state is
illegal and probably a bug. The idlestats code uses an atomic
notifier called from msm_cpuidle_enter() and that atomic notifier
takes an rcu read lock. We could fix this with a raw notifier,
but this code is unused so let's just remove the code entirely.

Change-Id: I319f0eabb56a8721c19a3b2b4bc9a7f416c88384
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
msm: cpuidle: Don't disable irqs again

cpu_idle() disables irqs before calling down into the cpuidle
driver via cpuidle_idle_call(). Disabling irqs again in
msm_cpuidle_enter() is wasteful and unnecessary. It also inhibits
our ability to determine the largest irq latency when the cpu
idles for extended periods of time because the irqsoff trace is
reenabled when the irqs are disabled in msm_cpuidle_enter().

Note that we still reenable irqs before returning, as is required
by the ARM idle loop.

Change-Id: I925478d8fef88ab490959622bc68303f59cc6e79
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
(cherry picked from commit 27361508474098444013f96acb95f0e3f1ed55c4)

Signed-off-by: Sudhir Sharma <sudsha@codeaurora.org>
(cherry picked from commit 1c3d38b5c85412f89e2973896cfc5d1e793e1828)
msm: pm: send notification only for SPC and PC

Today the pm notification is sent for all the power
modes of each CPU. This is not necessary for shallow
power modes.

This change is to send the notification for only
standalone power collapse for each core and idle
power collapse of core0.

Change-Id: I9b3df3d72e43d645387c94b1b9c5da3bcf2f2e5f
Signed-off-by: Venkat Devarasetty <vdevaras@codeaurora.org>
msm: pm: Adjust for events with hard wakeups

Get the next event and setup a new timer to expire
earlier than the next event after accounting for the
latency of the low power state being entered. This
will ensure that the core is active to handle the event
when it arrives.

(cherry picked from commit dc318fd0c3d04f7af9720af50c0eb0c6ed2653e9)
Signed-off-by: Girish Mahadevan <girishm@codeaurora.org>

Change-Id: I6609a886df227c68ce78e270ef7d235e07725d44
Signed-off-by: Neha Pandey <nehap@codeaurora.org>
m7: Enable EVENT_TIMER

Change-Id: I9f667116fe9335fb721154509e966e7f93d456d8