Add ROW I/O Scheduler by Qualcomm.
block: row: squash commits from codeaurora.

thanks to franciscofranco
block: Add support for reinsert a dispatched req

Add support for reinserting a dispatched request back to the
scheduler's internal data structures.
This capability is used by the device driver when it chooses to
interrupt the current request transmission and execute another (more
urgent) pending request. For example: interrupting long write in order
to handle pending read. The device driver re-inserts the
remaining write request back to the scheduler, to be rescheduled
for transmission later on.

Add API for verifying whether the current scheduler
supports reinserting requests mechanism. If reinsert mechanism isn't
supported by the scheduler, this code path will never be activated.
block: Add API for urgent request handling

This patch add support in block & elevator layers for handling
urgent requests. The decision if a request is urgent or not is taken
by the scheduler. Urgent request notification is passed to the
underlying
block device driver (eMMC for example). Block device driver may decide
to
interrupt the currently running low priority request to serve the new
urgent request. By doing so READ latency is greatly reduced in
read&write
collision scenarios.

Note that if the current scheduler doesn't implement the urgent request
mechanism, this code path is never activated.
block: fixes required to make the kernel compile with ROW.
cpu-tegra.c: cpu freq transition latency is huge, decrease to 30ms
Added optimized ARM RWSEM algorithm.
mm: writeback: every 500ms the writeback daemon kicks in and flushes

the dirty pages into disk. Thats not very pleasant for performance and
*maybe* battery. This patch disables the writeback function while the
screen is on, and enables it back when the screen is off to flush all
the dirty pages. In my real world usage testing I notice a slight bump
in smoothness and performance while using the device.
Thanks to franciscoFranco
Staging: android: binder: Fix memory leak on thread/process exit

If a thread or process exited while a reply, one-way transaction or
death notification was pending, the struct holding the pending work
was leaked.
block: row: hardcode tunables.

thanks to franciscofranco
defconfig IO: set ROW as default
PM / Hibernate: Freeze kernel threads after preallocating memory

There is a problem with the current ordering of hibernate code which
leads to deadlocks in some filesystems' memory shrinkers.  Namely,
some filesystems use freezable kernel threads that are inactive when
the hibernate memory preallocation is carried out.  Those same
filesystems use memory shrinkers that may be triggered by the
hibernate memory preallocation.  If those memory shrinkers wait for
the frozen kernel threads, the hibernate process deadlocks (this
happens with XFS, for one example).

Apparently, it is not technically viable to redesign the filesystems
in question to avoid the situation described above, so the only
possible solution of this issue is to defer the freezing of kernel
threads until the hibernate memory preallocation is done, which is
implemented by this change.

Unfortunately, this requires the memory preallocation to be done
before the "prepare" stage of device freeze, so after this change the
only way drivers can allocate additional memory for their freeze
routines in a clean way is to use PM notifiers.

Reported-by: Christoph <cr2005@u-club.de>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
freezer: fix current->state restoration race in refrigerator()

refrigerator() saves current->state before entering frozen state and
restores it before returning using __set_current_state(); however,
this is racy, for example, please consider the following sequence.

set_current_state(TASK_INTERRUPTIBLE);
try_to_freeze();
if (kthread_should_stop())
break;
schedule();

If kthread_stop() races with ->state restoration, the restoration can
restore ->state to TASK_INTERRUPTIBLE after kthread_stop() sets it to
TASK_RUNNING but kthread_should_stop() may still see zero
->should_stop because there's no memory barrier between restoring
TASK_INTERRUPTIBLE and kthread_should_stop() test.

This isn't restricted to kthread_should_stop().  current->state is
often used in memory barrier based synchronization and silently
restoring it w/o mb breaks them.

Use set_current_state() instead.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
Add Joe's RCU. Original patch from Joe Korty.
lib/string & lib/memcpy: use GNU implementation.

thanks to franciscofranco
arm: tegra: hotplug: modify down_delay

Modified the hot-plug governor down_delay to be 500ms instead of 2s

Bug 958978

Change-Id: I55b5a4994f8e4564879cfd206fc683ff6f32d9ac
Signed-off-by: Wen Yi <wyi@nvidia.com>
(cherry picked from commit dd47739)
Reviewed-on: http://git-master/r/111640
Reviewed-by: Sai Gurrappadi <sgurrappadi@nvidia.com>
Tested-by: Sai Gurrappadi <sgurrappadi@nvidia.com>
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Peter Boonstoppel <pboonstoppel@nvidia.com>
Reviewed-by: Yu-Huan Hsu <yhsu@nvidia.com>
i2c: tegra: Fix i2c unknown interrupt issue

writes to modules on APB bus may complete out-of-order. need
to guarantee that the write is completed by reading it back.

read I2C_INT_STATUS back right after writing the current int status
in the isr to make sure the clear operation of I2C_INT_STATUS is
done before the interrupt is re-enabled.
the same also done for DVC_STATUS.

bug 980763

Change-Id: I34f18804d530ccadf561fe1736552b6a4dd6e4ce
Signed-off-by: Ken Chang <kenc@nvidia.com>
Reviewed-on: http://git-master/r/101925
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>
Asynchronous I/O latency to a solid-state disk greatly increased

between the 2.6.32 and 3.0 kernels. By removing the plug from
do_io_submit(), we observed a 34% improvement in the I/O latency.

Unfortunately, at this level, we don't know if the request is to
a rotating disk or not.

Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Cc: linux-aio@kvack.org
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
sched: don't call task_group() many times in set_task_rq()

It improves perfomance, especially if autogroup enabled.

The size of set_task_rq() was 0x180 and now it is 0xa0.

Signed-off-by: Andrew Vagin <avagin@openvz.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
Makefile: Added ARM optimizations

thanks to Vorbeth