sched: Add sysinterface for GENTLE_FAIR_SLEEPERS

Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
mm: remove compressed copy from zram in-memory

Swap subsystem does lazy swap slot free with expecting the page would be
swapped out again so we can avoid unnecessary write.

But the problem in in-memory swap(ex, zram) is that it consumes memory
space until vm_swap_full(ie, used half of all of swap device) condition
meet.  It could be bad if we use multiple swap device, small in-memory
swap and big storage swap or in-memory swap alone.

This patch makes swap subsystem free swap slot as soon as swap-read is
completed and make the swapcache page dirty so the page should be
written out the swap device to reclaim it.  It means we never lose it.

I tested this patch with kernel compile workload.

1. before

   compile time : 9882.42
   zram max wasted space by fragmentation: 13471881 byte
   memory space consumed by zram: 174227456 byte
   the number of slot free notify: 206684

2. after

   compile time : 9653.90
   zram max wasted space by fragmentation: 11805932 byte
   memory space consumed by zram: 154001408 byte
   the number of slot free notify: 426972

[akpm@linux-foundation.org: tweak comment text]
[artem.savkov@gmail.com: fix BUG due to non-swapcache pages in end_swap_bio_read()]
[akpm@linux-foundation.org: invert unlikely() test, augment comment, 80-col cleanup]
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Artem Savkov <artem.savkov@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Seth Jennings <sjenning@linux.vnet.ibm.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Konrad Rzeszutek Wilk <konrad@darnok.org>
Cc: Shaohua Li <shli@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
cpuidle: make a single register function for all

The usual scheme to initialize a cpuidle driver on a SMP is:

	cpuidle_register_driver(drv);
	for_each_possible_cpu(cpu) {
		device = &per_cpu(cpuidle_dev, cpu);
		cpuidle_register_device(device);
	}

This code is duplicated in each cpuidle driver.

On UP systems, it is done this way:

	cpuidle_register_driver(drv);
	device = &per_cpu(cpuidle_dev, cpu);
	cpuidle_register_device(device);

On UP, the macro 'for_each_cpu' does one iteration:

        for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask)

Hence, the initialization loop is the same for UP than SMP.

Beside, we saw different bugs / mis-initialization / return code unchecked in
the different drivers, the code is duplicated including bugs. After fixing all
these ones, it appears the initialization pattern is the same for everyone.

Please note, some drivers are doing dev->state_count = drv->state_count. This is
not necessary because it is done by the cpuidle_enable_device function in the
cpuidle framework. This is true, until you have the same states for all your
devices. Otherwise, the 'low level' API should be used instead with the specific
initialization for the driver.

Let's add a wrapper function doing this initialization with a cpumask parameter
for the coupled idle states and use it for all the drivers.

That will save a lot of LOC, consolidate the code, and the modifications in the
future could be done in a single place. Another benefit is the consolidation of
the cpuidle_device variable which is now in the cpuidle framework and no longer
spread accross the different arch specific drivers.

Change-Id: I8f75188d5770871620f758c2973b74384ac570d5
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Karthik Parsha <kparsha@codeaurora.org>
Signed-off-by: Mahesh Sivasubramanian <msivasub@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
sched: Fix select_idle_sibling() bouncing cow syndrome

If the previous CPU is cache affine and idle, select it.

The current implementation simply traverses the sd_llc domain,
taking the first idle CPU encountered, which walks buddy pairs
hand in hand over the package, inflicting excruciating pain.

1 tbench pair (worst case) in a 10 core + SMT package:

  pre   15.22 MB/sec 1 procs
  post 252.01 MB/sec 1 procs

Signed-off-by: Mike Galbraith <bitbucket@online.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1359371965.5783.127.camel@marge.simpson.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
kernel: disable audit logging messages

Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
nohz: Reduce overhead under high-freq idling patterns

One testbox of mine (Intel Nehalem, 16-way) uses MWAIT for its idle routine,
which apparently can break out of its idle loop rather frequently, with
high frequency.

In that case NO_HZ_FULL=y kernels show high ksoftirqd overhead and constant
context switching, because tick_nohz_stop_sched_tick() will, if
delta_jiffies == 0, mis-identify this as a timer event - activating the
TIMER_SOFTIRQ, which wakes up ksoftirqd.

Fix this by treating delta_jiffies == 0 the same way we treat other short
wakeups, delta_jiffies == 1.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
tick: Dynamically set broadcast irq affinity

When a cpu goes to a deep idle state where its local timer is
shutdown, it notifies the time frame work to use the broadcast timer
instead.  Unfortunately, the broadcast device could wake up any CPU,
including an idle one which is not concerned by the wake up at all. So
in the worst case an idle CPU will wake up to send an IPI to the CPU
whose timer expired.

Provide an opt-in feature CLOCK_EVT_FEAT_DYNIRQ which tells the core
that is should set the interrupt affinity of the broadcast interrupt
to the cpu which has the earliest expiry time. This avoids unnecessary
spurious wakeups and IPIs.

[ tglx: Adopted to cpumask rework, silenced an uninitialized warning,
  massaged changelog ]

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: viresh.kumar@linaro.org
Cc: jacob.jun.pan@linux.intel.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: santosh.shilimkar@ti.com
Cc: linaro-kernel@lists.linaro.org
Cc: patches@linaro.org
Cc: rickard.andersson@stericsson.com
Cc: vincent.guittot@linaro.org
Cc: linus.walleij@stericsson.com
Cc: john.stultz@linaro.org
Link: http://lkml.kernel.org/r/1362219013-18173-3-git-send-email-daniel.lezcano@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Karthik Parsha <kparsha@codeaurora.org>
Signed-off-by: Mahesh Sivasubramanian <msivasub@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
kthread: Implement park/unpark facility

To avoid the full teardown/setup of per cpu kthreads in the case of
cpu hot(un)plug, provide a facility which allows to put the kthread
into a park position and unpark it when the cpu comes online again.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20120716103948.236618824@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
stop_machine: Store task reference in a separate per cpu variable

To allow the stopper thread being managed by the smpboot thread
infrastructure separate out the task storage from the stopper data
structure.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Arjan van de Veen <arjan@infradead.org>
Cc: Paul Turner <pjt@google.com>
Cc: Richard Weinberger <rw@linutronix.de>
Cc: Magnus Damm <magnus.damm@gmail.com>
Link: http://lkml.kernel.org/r/20130131120741.626690384@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
drivers: gpu: Use SIMPLE governor as default

Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
staging: Add Snappy compression library

Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
staging: lmk: Fine tune OOM for screen on/off

* Increase no. of parmeters handled by minfree
* Add interface to set different OOM values for screen on/off
* Add parameter to turn on/off auto set of different OOM values

Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
fix warning transport.c
kernel: Fix leak in signal

Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
kernel: Allow exfat module load without hassle

Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
zram: simplify and optimize zram_to_dev()

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
zram: avoid invalid memory access in zram_exit()

Memory for zram->disk object may have already been freed after returning
from destroy_device(zram), then it's unsafe for zram_reset_device(zram)
to access zram->disk again.

Fix it by holding an extra reference to zram->disk before calling
destroy_device(zram).

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
zram: use zram->lock to protect zram_free_page() in swap free notify path

Date	Mon, 3 Jun 2013 23:42:15 +0800

zram_free_page() is protected by down_write(&zram->lock) when called by
zram_bvec_write(), but there's no such protection when called by
zram_slot_free_notify(), which may cause wrong states to zram object.

So enhance zram_slot_free_notify() to acquire writer lock on zram->lock
before calling zram_free_page().

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
zram: destroy all devices on error recovery path in zram_init()

On error recovery path of zram_init(), it leaks the zram device object
causing the failure.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
zram: avoid access beyond the zram device

Function valid_io_request() should verify the entire request doesn't
exceed the zram device, otherwise it will cause invalid memory access.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>