sched: change cpu_avg_load_per_task using h_nr_running

Date	Sun, 18 Aug 2013 16:25:16 +0800

Since cpu_avg_load_per_task is used only by cfs scheduler, its meaning
should present the average cfs type task load in the current run queue.
Thus we change it to h_nr_running for well presenting its meaning.

Signed-off-by: Lei Wen <leiwen@marvell.com>
Signed-off-by: Paul Reioux <reioux@gmail.com>
sched: change pick_next_task_fair to h_nr_running

Date	Sun, 18 Aug 2013 16:25:18 +0800

Since pick_next_task_fair only want to ensure there is some task in the
run queue to be picked up, it should use the h_nr_running instead of
nr_running, since nr_running cannot present all tasks if group existed.

Signed-off-by: Lei Wen <leiwen@marvell.com>
Signed-off-by: Paul Reioux <reioux@gmail.com>
sched: change update_sg_lb_stats to h_nr_running

Date    Sun, 18 Aug 2013 16:25:19 +0800

Since update_sg_lb_stats is used to calculate sched_group load
difference of cfs type task, it should use h_nr_running instead of
nr_running of rq.
Signed-off-by: Lei Wen <leiwen@marvell.com>
bacported to Linux 3.4 by faux123

Signed-off-by: Paul Reioux <reioux@gmail.com>
sched: change find_busiest_queue to h_nr_running

Date    Sun, 18 Aug 2013 16:25:20 +0800

Since find_busiest_queue try to avoid do load balance for runqueue
which has only one cfs task and its load is above the imbalance
value calculated, we should use h_nr_running of cfs instead of
nr_running of rq.

Signed-off-by: Lei Wen <leiwen@marvell.com>
Signed-off-by: Paul Reioux <reioux@gmail.com>
sched: change active_load_balance_cpu_stop to use h_nr_running

Date	Sun, 18 Aug 2013 16:25:21 +0800

We should only avoid do the active load balance when there is no
cfs type task. If just use rq->nr_running, it is possible for the
source cpu has multiple rt task, while zero cfs task, so that it
would confuse the active load balance function that try to move,
but find no task it could move.

Signed-off-by: Lei Wen <leiwen@marvell.com>
Signed-off-by: Paul Reioux <reioux@gmail.com>
sched: document the difference between nr_running and h_nr_running

Date    Sun, 18 Aug 2013 16:25:22 +0800

Signed-off-by: Lei Wen <leiwen@marvell.com>

Signed-off-by: Paul Reioux <reioux@gmail.com>
msm: move printk out of spin lock low_water_lock

cpu3 stuck in printk more time in spin lock low_water_lock cause cpu0
get spin lock fail and system crashed.

CRs-Fixed: 521570
Change-Id: I75356a4b4171ae2888ce6cce792f569b5ca8cdcf
Signed-off-by: Tingting Yang <tingting@codeaurora.org>
sched: Implement smarter wake-affine logic

The wake-affine scheduler feature is currently always trying to pull
the wakee close to the waker. In theory this should be beneficial if
the waker's CPU caches hot data for the wakee, and it's also beneficial
in the extreme ping-pong high context switch rate case.

Testing shows it can benefit hackbench up to 15%.

However, the feature is somewhat blind, from which some workloads
such as pgbench suffer. It's also time-consuming algorithmically.

Testing shows it can damage pgbench up to 50% - far more than the
benefit it brings in the best case.

So wake-affine should be smarter and it should realize when to
stop its thankless effort at trying to find a suitable CPU to wake on.

This patch introduces 'wakee_flips', which will be increased each
time the task flips (switches) its wakee target.

So a high 'wakee_flips' value means the task has more than one
wakee, and the bigger the number, the higher the wakeup frequency.

Now when making the decision on whether to pull or not, pay attention to
the wakee with a high 'wakee_flips', pulling such a task may benefit
the wakee. Also imply that the waker will face cruel competition later,
it could be very cruel or very fast depends on the story behind
'wakee_flips', waker therefore suffers.

Furthermore, if waker also has a high 'wakee_flips', that implies that
multiple tasks rely on it, then waker's higher latency will damage all
of them, so pulling wakee seems to be a bad deal.

Thus, when 'waker->wakee_flips / wakee->wakee_flips' becomes
higher and higher, the cost of pulling seems to be worse and worse.

The patch therefore helps the wake-affine feature to stop its pulling
work when:

	wakee->wakee_flips > factor &&
	waker->wakee_flips > (factor * wakee->wakee_flips)
The 'factor' here is the number of CPUs in the current CPU's NUMA node,
so a bigger node will lead to more pulling since the trial becomes more
severe.

After applying the patch, pgbench shows up to 40% improvements and no regressions.

Tested with 12 cpu x86 server and tip 3.10.0-rc7.

The percentages in the final column highlight the areas with the biggest wins,
all other areas improved as well:

	pgbench		    base	smart

	| db_size | clients |  tps  |	|  tps  |
	+---------+---------+-------+   +-------+
	| 22 MB   |       1 | 10598 |   | 10796 |
	| 22 MB   |       2 | 21257 |   | 21336 |
	| 22 MB   |       4 | 41386 |   | 41622 |
	| 22 MB   |       8 | 51253 |   | 57932 |
	| 22 MB   |      12 | 48570 |   | 54000 |
	| 22 MB   |      16 | 46748 |   | 55982 | +19.75%
	| 22 MB   |      24 | 44346 |   | 55847 | +25.93%
	| 22 MB   |      32 | 43460 |   | 54614 | +25.66%
	| 7484 MB |       1 |  8951 |   |  9193 |
	| 7484 MB |       2 | 19233 |   | 19240 |
	| 7484 MB |       4 | 37239 |   | 37302 |
	| 7484 MB |       8 | 46087 |   | 50018 |
	| 7484 MB |      12 | 42054 |   | 48763 |
	| 7484 MB |      16 | 40765 |   | 51633 | +26.66%
	| 7484 MB |      24 | 37651 |   | 52377 | +39.11%
	| 7484 MB |      32 | 37056 |   | 51108 | +37.92%
	| 15 GB   |       1 |  8845 |   |  9104 |
	| 15 GB   |       2 | 19094 |   | 19162 |
	| 15 GB   |       4 | 36979 |   | 36983 |
	| 15 GB   |       8 | 46087 |   | 49977 |
	| 15 GB   |      12 | 41901 |   | 48591 |
	| 15 GB   |      16 | 40147 |   | 50651 | +26.16%
	| 15 GB   |      24 | 37250 |   | 52365 | +40.58%
	| 15 GB   |      32 | 36470 |   | 50015 | +37.14%
Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/51D50057.9000809@linux.vnet.ibm.com
[ Improved the changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Signed-off-by: Paul Reioux <reioux@gmail.com>
sched: Micro-optimize the smart wake-affine logic

Smart wake-affine is using node-size as the factor currently, but the overhead
of the mask operation is high.

Thus, this patch introduce the 'sd_llc_size' percpu variable, which will record
the highest cache-share domain size, and make it to be the new factor, in order
to reduce the overhead and make it more reasonable.

Tested-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Tested-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Link: http://lkml.kernel.org/r/51D5008E.6030102@linux.vnet.ibm.com
[ Tidied up the changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Signed-off-by: Paul Reioux <reioux@gmail.com>
sched/rt: Remove redundant nr_cpus_allowed test

Date	Fri, 4 Oct 2013 14:24:53 -0500

From: Shawn Bohrer <sbohrer@rgmadvisors.com>

In 76854c7e8f3f4172fef091e78d88b3b751463ac6 "sched: Use
rt.nr_cpus_allowed to recover select_task_rq() cycles" an optimization
was added to select_task_rq_rt() that immediately returns when
p->nr_cpus_allowed == 1 at the beginning of the function.  This makes
the latter p->nr_cpus_allowed > 1 check redundant and can be removed.
Signed-off-by: Shawn Bohrer <sbohrer@rgmadvisors.com>

Signed-off-by: Paul Reioux <reioux@gmail.com>
SELinux: include definition of new capabilities

The kernel has added CAP_WAKE_ALARM and CAP_EPOLLWAKEUP.  We need to
define these in SELinux so they can be mediated by policy.

Change-Id: I8a3e0db15ec5f4eb05d455a57e8446a8c2b484c2
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
[sds: rename epollwakeup to block_suspend to match upstream merge]
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
jiffies conversions: Use compile time constants when possible

Date	Fri, 04 Jan 2013 13:15:43 -0800

Do the multiplications and divisions at compile time
instead of runtime when the converted value is a constant.

Make the calculation functions static __always_inline to jiffies.h.

Add #defines with __builtin_constant_p to test and use the
static inline or the runtime functions as appropriate.

Prefix the old exported symbols/functions with __

Signed-off-by: Paul Reioux <reioux@gmail.com>