add extra free kbytes tunable

Add a userspace visible knob to tell the VM to keep an extra amount
of memory free, by increasing the gap between each zone's min and
low watermarks.

This is useful for realtime applications that call system
calls and have a bound on the number of allocations that happen
in any short time period.  In this application, extra_free_kbytes
would be left at an amount equal to or larger than than the
maximum number of allocations that happen in any burst.

It may also be useful to reduce the memory use of virtual
machines (temporarily?), in a way that does not cause memory
fragmentation like ballooning does.

[ccross]
Revived for use on old kernels where no other solution exists.
The tunable will be removed on kernels that do better at avoiding
direct reclaim.

Prev-Change-Id: I765a42be8e964bfd3e2886d1ca85a29d60c3bb3e
Signed-off-by: Rik van Riel<riel@redhat.com>
Signed-off-by: Colin Cross <ccross@android.com>

Conflicts:

	mm/page_alloc.c

Change-Id: I23d3e46647605898fe34f9af27d722cb249f3353
msm: vidc: Initialize kernel space stack variables

This change initializes kernel space stack variables
that are passed between kernel space and user space
using ioctls.
Non initialization of these variables may lead to
leakage of memory values from the kernel stack to
user space.

Change-Id: Icb195470545ee48b55671ac09798610178e833e1
CRs-fixed: 556771,563420
Signed-off-by: Deepak Verma <dverma@codeaurora.org>

Conflicts:
	drivers/video/msm/vidc/common/enc/venc.c
vidc: Modify shift value for extended PAR width.

Currently extended pixel aspect ratio register shift
value for width is 15. Due to this the actual width
value returned by core is getting doubled while
sending to user space. Now correct values are returned
by modifying the shift value to 16.

CRs-fixed: 362985
Change-Id: I996bfc79b327492a791017fd5b33638f82240d76
Signed-off-by: Rajeshwar Kurapaty <rkurapat@codeaurora.org>
msm: vidc: Validate input data before processing

User controlled data needs to be validated before
processing, otherwise it may corrupt existing data
and other programming variables which may further
lead to crash in kernel space.
This change validates user specified buffer's data,
such as offset and data length, before performing
any operations in kernel.

Change-Id: Idb2a5c4c270cdbb55adfc0c22b9296b7dd359de9
CRs-fixed: 547695
Signed-off-by: Deepak Verma <dverma@codeaurora.org>
ARM: Use -mcpu=cortex-a15 when targeting MSM Krait CPUs

Enable compiler optimizations specific to the Cortex-A15
processor when targeting MSM Krait CPUs. This is necessary
take advantage of the UDIV/SDIV instructions supported by
these processors. To accomplish this, we need to remove the
-march=armv7-a ISA restriction from the compiler options
because 'cortex-a15' is a superset of 'armv7-a'.

Change-Id: I6215aecc11fb4f77c971de7b84f68649ef234357
Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org>