Revert "writeback: fix occasional slow sync(1)"

This reverts commit 4c65eb0ba2f118c409936dc2c5b916bef044f695.
Revert "Add fsync option"

This reverts commit 5abe3cc4d45dcae172d7473e35af6aedeb74a737.
fs/dyn_sync_cntrl: dynamic sync control

The dynamic sync control interface uses new power_suspend interface

While screen is on, file sync is disabled
when screen is off, a file sync is called to flush all outstanding writes
and restore file sync operation as normal.

updated for 8974 kernels

Signed-off-by: Paul Reioux <reioux@gmail.com>
Signed-off-by: Chester Kener <Cl3Kener@gmail.com>
Signed-off-by: Chet Kener <Cl3Kener@gmail.com>

Conflicts:
	fs/Kconfig

Signed-off-by: Chet Kener <Cl3Kener@gmail.com>

Conflicts:
	fs/Kconfig

Signed-off-by: Chet Kener <Cl3Kener@gmail.com>

Conflicts:
	fs/Kconfig

Conflicts:
	fs/Kconfig
	fs/Makefile
	fs/sync.c
Update defconfig
ksm: Provide support to use deferred timers for scanner thread

KSM thread to scan pages is getting schedule on definite timeout.
That wakes up CPU from idle state and hence may affect the power
consumption. Provide an optional support to use deferred timer
which suites low-power use-cases.

To enable deferred timers,
$ echo 1 > /sys/kernel/mm/ksm/deferred_timer

Change-Id: I07fe199f97fe1f72f9a9e1b0b757a3ac533719e8
Signed-off-by: Chintan Pandya <cpandya@codeaurora.org>
ksm: enable deferred_timer by default to prevent the CPU to be wakened for ksm activities.

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
cpufreq: cpu-boost: we can hit a small performance loss by not queuing input works less than 150ms apart when our default input work duration is only 40ms, so use that 40ms as a magic value instead of the 150ms minimum interval.

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
arch: arm: lib: optimize memcpy for cortex-A15

The LDRD/STRD instruction is faster than LDM/STM on Cortex-A15.
Also optimized preload cache size for Cortex-A15.

Added USE_LDRDSTRD_OVER_LDMSTM to turn on LDRD/STRD optimization.
Added ARM_PLD_SIZE, default 32. Should set to 64 for Cortex-A15.

Bug 1185248

Change-Id: I4fa8c25bcd9b7823a11018817a4d17e3357ae681
Signed-off-by: Chandler Zhang <chazhang@nvidia.com>
Reviewed-on: http://git-master/r/211599
GVS: Gerrit_Virtual_Submit
Reviewed-by: Krishna Reddy <vdumpa@nvidia.com>
Update defconfig
mm: optimize Kernel Samepage Merging(KSM)

Conflicts:
	mm/ksm.c
mm: Adjust dirty writeback for IO boost

Conflicts:
	mm/page-writeback.c
CHROMIUM: mm: Fix calculation of dirtyable memory

The system uses global_dirtyable_memory() to calculate
number of dirtyable pages/pages that can be allocated
to the page cache.  A bug causes an underflow thus making
the page count look like a big unsigned number.  This in turn
confuses the dirty writeback throttling to aggressively write
back pages as they become dirty (usually 1 page at a time).

Fix is to ensure there is no underflow while doing the math.

Signed-off-by: Sonny Rao <sonnyrao@chromium.org>
Signed-off-by: Puneet Kumar <puneetster@chromium.org>

BUG=chrome-os-partner:16011
TEST=Manual; boot kernel, powerwash, login with testaccount and
make sure no jank occurs on sync of applications

Change-Id: I614e7c3156e014f0f28a4ef9bdd8cb8a2cd07b2a
Reviewed-on: https://gerrit.chromium.org/gerrit/37612
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Olof Johansson <olofj@chromium.org>
Commit-Ready: Puneet Kumar <puneetster@chromium.org>
Reviewed-by: Puneet Kumar <puneetster@chromium.org>
Tested-by: Puneet Kumar <puneetster@chromium.org>
net: loopback: set default mtu to 64K

loopback current mtu of 16436 bytes allows no more than 3 MSS TCP
segments per frame, or 48 Kbytes. Changing mtu to 64K allows TCP
stack to build large frames and significantly reduces stack overhead.

Performance boost on bulk TCP transferts can be up to 30 %, partly
because we now have one ACK message for two 64KB segments, and a lower
probability of hitting /proc/sys/net/ipv4/tcp_reordering default limit.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>

Conflicts:
	drivers/net/loopback.c
vfs: fix bad hashing of dentries

Josef Bacik found a performance regression between 3.2 and 3.10 and
narrowed it down to commit bfcfaa77bdf0 ("vfs: use 'unsigned long'
accesses for dcache name comparison and hashing"). He reports:

 "The test case is essentially

      for (i = 0; i < 1000000; i++)
              mkdir("a$i");

  On xfs on a fio card this goes at about 20k dir/sec with 3.2, and 12k
  dir/sec with 3.10.  This is because we spend waaaaay more time in
  __d_lookup on 3.10 than in 3.2.

  The new hashing function for strings is suboptimal for <
  sizeof(unsigned long) string names (and hell even > sizeof(unsigned
  long) string names that I've tested).  I broke out the old hashing
  function and the new one into a userspace helper to get real numbers
  and this is what I'm getting:

      Old hash table had 1000000 entries, 0 dupes, 0 max dupes
      New hash table had 12628 entries, 987372 dupes, 900 max dupes
      We had 11400 buckets with a p50 of 30 dupes, p90 of 240 dupes, p99 of 567 dupes for the new hash

  My test does the hash, and then does the d_hash into a integer pointer
  array the same size as the dentry hash table on my system, and then
  just increments the value at the address we got to see how many
  entries we overlap with.

  As you can see the old hash function ended up with all 1 million
  entries in their own bucket, whereas the new one they are only
  distributed among ~12.5k buckets, which is why we're using so much
  more CPU in __d_lookup".

The reason for this hash regression is two-fold:

 - On 64-bit architectures the down-mixing of the original 64-bit
   word-at-a-time hash into the final 32-bit hash value is very
   simplistic and suboptimal, and just adds the two 32-bit parts
   together.

   In particular, because there is no bit shuffling and the mixing
   boundary is also a byte boundary, similar character patterns in the
   low and high word easily end up just canceling each other out.

 - the old byte-at-a-time hash mixed each byte into the final hash as it
   hashed the path component name, resulting in the low bits of the hash
   generally being a good source of hash data.  That is not true for the
   word-at-a-time case, and the hash data is distributed among all the
   bits.

The fix is the same in both cases: do a better job of mixing the bits up
and using as much of the hash data as possible.  We already have the
"hash_32|64()" functions to do that.

Reported-by: Josef Bacik <jbacik@fb.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Chris Mason <clm@fb.com>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
selinux: fix inode security list corruption

sb_finish_set_opts() can race with inode_free_security()
when initializing inode security structures for inodes
created prior to initial policy load or by the filesystem
during ->mount().   This appears to have always been
a possible race, but commit 3dc91d4 ("SELinux:  Fix possible
NULL pointer dereference in selinux_inode_permission()")
made it more evident by immediately reusing the unioned
list/rcu element  of the inode security structure for call_rcu()
upon an inode_free_security().  But the underlying issue
was already present before that commit as a possible use-after-free
of isec.

Shivnandan Kumar reported the list corruption and proposed
a patch to split the list and rcu elements out of the union
as separate fields of the inode_security_struct so that setting
the rcu element would not affect the list element.  However,
this would merely hide the issue and not truly fix the code.

This patch instead moves up the deletion of the list entry
prior to dropping the sbsec->isec_lock initially.  Then,
if the inode is dropped subsequently, there will be no further
references to the isec.

Reported-by: Shivnandan Kumar <shivnandan.k@samsung.com>
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Cc: stable@vger.kernel.org
Signed-off-by: Paul Moore <pmoore@redhat.com>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
mm: increase dirty rations
lets try these values picked from Nexus 5

Conflicts:
	mm/page-writeback.c
ARM: introduce Kernel Mode NEON

ARM: move VFP init to an earlier boot stage

In order to use the NEON unit in the kernel, we should
initialize it a bit earlier in the boot process so NEON users
that like to do a quick benchmark at load time (like the
xor_blocks or RAID-6 code) find the NEON/VFP unit already
enabled.

Replaced late_initcall() with core_initcall().

Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
Acked-by: Nicolas Pitre <nico at linaro.org>

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

Conflicts:
	arch/arm/vfp/vfpmodule.c

ARM: be strict about FP exceptions in kernel mode

The support code in vfp_support_entry does not care whether the
exception that caused it to be invoked occurred in kernel mode or
in user mode. However, neither condition that could trigger this
exception (lazy restore and VFP bounce to support code) is
currently allowable in kernel mode.

In either case, print a message describing the condition before
letting the undefined instruction handler run its course and trigger
an oops.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
Acked-by: Nicolas Pitre <nico at linaro.org>
Signed-off-by: Paul Reioux <reioux@gmail.com>

Conflicts:
	arch/arm/vfp/vfpmodule.c

ARM: add support for kernel mode NEON

In order to safely support the use of NEON instructions in
kernel mode, some precautions need to be taken:
- the userland context that may be present in the registers (even
  if the NEON/VFP is currently disabled) must be stored under the
  correct task (which may not be 'current' in the UP case),
- to avoid having to keep track of additional vfpstates for the
  kernel side, disallow the use of NEON in interrupt context
  and run with preemption disabled,
- after use, re-enable preemption and re-enable the lazy restore
  machinery by disabling the NEON/VFP unit.

This patch adds the functions kernel_neon_begin() and
kernel_neon_end() which take care of the above. It also adds
the Kconfig symbol KERNEL_MODE_NEON to enable it.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Paul Reioux <reioux@gmail.com>

Conflicts:
	arch/arm/vfp/vfpmodule.c

ARM: crypto: add NEON accelerated XOR implementation

Add a source file xor-neon.c (which is really just the reference
C implementation passed through the GCC vectorizer) and hook it
up to the XOR framework.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Nicolas Pitre <nico@linaro.org>

ARM: 7835/2: fix modular build of xor_blocks() with NEON enabled

Commit 0195659 introduced a NEON accelerated version of the xor_blocks()
function, but it needs the changes in this patch to allow it to be built
as a module rather than statically into the kernel.

This patch creates a separate module xor-neon.ko which exports the NEON
inner xor_blocks() functions depended upon by the regular xor.ko if it
is built with CONFIG_KERNEL_MODE_NEON=y

Reported-by: Josh Boyer <jwboyer@fedoraproject.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

ARM: only allow kernel mode neon with AEABI

This prevents the linker erroring with:

arm-linux-ld: error: arch/arm/lib/xor-neon.o uses VFP instructions, whereas arch/arm/lib/built-in.o does not
arm-linux-ld: failed to merge target specific data of file arch/arm/lib/xor-neon.o

This is due to the non-neon files being marked as containing FPA data/
instructions (even though they do not) being mixed with files which
contain VFP, which is an incompatible floating point format.

Change-Id: Ib86af25a348a07fac3ca3b688e02e885d4ce7ea0
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>