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: Francisco Franco <franciscofranco.1990@gmail.com>
sched: reinitialize rq->next_balance when a CPU is hot-added

Reinitialize rq->next_balance when a CPU is hot-added.  Otherwise,
scheduler domain rebalancing may be skipped if rq->next_balance was
set to a future time when the CPU was last active, and the
newly-re-added CPU is in idle_balance().  As a result, the
newly-re-added CPU will remain idle with no tasks scheduled until the
softlockup watchdog runs - potentially 4 seconds later.  This can
waste energy and reduce performance.

This behavior can be observed in some SoC kernels, which use CPU
hotplug to dynamically remove and add CPUs in response to load.  In
one case that triggered this behavior,

0. the system started with all cores enabled, running multi-threaded
   CPU-bound code;

1. the system entered some single-threaded code;

2. a CPU went idle and was hot-removed;

3. the system started executing a multi-threaded CPU-bound task;

4. the CPU from event 2 was re-added, to respond to the load.

The time interval between events 2 and 4 was approximately 300
milliseconds.

Of course, ideally CPU hotplug would not be used in this manner,
but this patch does appear to fix a real bug.

Nvidia folks: this patch is submitted as at least a partial fix for
bug 1243368 ("[sched] Load-balancing not happening correctly after
cores brought online")

Change-Id: Iabac21e110402bb581b7db40c42babc951d378d0
Signed-off-by: Paul Walmsley <pwalmsley@nvidia.com>
Cc: Peter Boonstoppel <pboonstoppel@nvidia.com>
Reviewed-on: http://git-master/r/208927
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Peter Zu <pzu@nvidia.com>
Reviewed-by: Peter Boonstoppel <pboonstoppel@nvidia.com>
GVS: Gerrit_Virtual_Submit
Tested-by: Peter Zu <pzu@nvidia.com>
Reviewed-by: Yu-Huan Hsu <yhsu@nvidia.com>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
freezer: shorten freezer sleep time using exponential backoff
 freezer: convert freezable helpers to freezer_do_not_count()

Freezing tasks will wake up almost every userspace task from
where it is blocking and force it to run until it hits a
call to try_to_sleep(), generally on the exit path from the syscall
it is blocking in.  On resume each task will run again, usually
restarting the syscall and running until it hits the same
blocking call as it was originally blocked in.

Convert the existing wait_event_freezable* wrappers to use
freezer_do_not_count().  Combined with a previous patch,
these tasks will not run during suspend or resume unless they wake
up for another reason, in which case they will run until they hit
the try_to_freeze() in freezer_count(), and then continue processing
the wakeup after tasks are thawed.

This results in a small change in behavior, previously a race
between freezing and a normal wakeup would be won by the wakeup,
now the task will freeze and then handle the wakeup after thawing.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: flar2 <asegaert@gmail.com>
freezer: add new freezable helpers using freezer_do_not_count

Conflicts:
	include/linux/freezer.h
 binder: use freezable blocking calls

Date	Wed, 1 May 2013 18:35:02 -0700

Avoid waking up every thread sleeping in a binder call during
suspend and resume by calling a freezable blocking call.  Previous
patches modified the freezer to avoid sending wakeups to threads
that are blocked in freezable blocking calls.

This call was selected to be converted to a freezable call because
it doesn't hold any locks or release any resources when interrupted
that might be needed by another freezing task or a kernel driver
during suspend, and is a common site where idle userspace tasks are
blocked.

Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: flar2 <asegaert@gmail.com>
 epoll: use freezable blocking call

Date	Wed, 1 May 2013 18:35:03 -0700

Avoid waking up every thread sleeping in an epoll_wait call during
suspend and resume by calling a freezable blocking call.  Previous
patches modified the freezer to avoid sending wakeups to threads
that are blocked in freezable blocking calls.

This call was selected to be converted to a freezable call because
it doesn't hold any locks or release any resources when interrupted
that might be needed by another freezing task or a kernel driver
during suspend, and is a common site where idle userspace tasks are
blocked.

Signed-off-by: Colin Cross <ccross@android.com>
 select: use freezable blocking call

Date	Wed, 1 May 2013 18:35:04 -0700

Avoid waking up every thread sleeping in a select call during
suspend and resume by calling a freezable blocking call.  Previous
patches modified the freezer to avoid sending wakeups to threads
that are blocked in freezable blocking calls.

This call was selected to be converted to a freezable call because
it doesn't hold any locks or release any resources when interrupted
that might be needed by another freezing task or a kernel driver
during suspend, and is a common site where idle userspace tasks are
blocked.

Signed-off-by: Colin Cross <ccross@android.com>
 futex: use freezable blocking call

Date	Wed, 1 May 2013 18:35:05 -0700

Avoid waking up every thread sleeping in a futex_wait call during
suspend and resume by calling a freezable blocking call.  Previous
patches modified the freezer to avoid sending wakeups to threads
that are blocked in freezable blocking calls.

This call was selected to be converted to a freezable call because
it doesn't hold any locks or release any resources when interrupted
that might be needed by another freezing task or a kernel driver
during suspend, and is a common site where idle userspace tasks are
blocked.

Signed-off-by: Colin Cross <ccross@android.com>
 nanosleep: use freezable blocking call

Date	Wed, 1 May 2013 18:35:06 -0700

Avoid waking up every thread sleeping in a nanosleep call during
suspend and resume by calling a freezable blocking call.  Previous
patches modified the freezer to avoid sending wakeups to threads
that are blocked in freezable blocking calls.

This call was selected to be converted to a freezable call because
it doesn't hold any locks or release any resources when interrupted
that might be needed by another freezing task or a kernel driver
during suspend, and is a common site where idle userspace tasks are
blocked.

Signed-off-by: Colin Cross <ccross@android.com>
 sigtimedwait: use freezable blocking call

Date	Wed, 1 May 2013 18:35:07 -0700

Avoid waking up every thread sleeping in a sigtimedwait call during
suspend and resume by calling a freezable blocking call.  Previous
patches modified the freezer to avoid sending wakeups to threads
that are blocked in freezable blocking calls.

This call was selected to be converted to a freezable call because
it doesn't hold any locks or release any resources when interrupted
that might be needed by another freezing task or a kernel driver
during suspend, and is a common site where idle userspace tasks are
blocked.

Signed-off-by: Colin Cross <ccross@android.com>
 af_unix: use freezable blocking calls in read

Date	Wed, 1 May 2013 18:35:08 -0700

Avoid waking up every thread sleeping in read call on an AF_UNIX
socket during suspend and resume by calling a freezable blocking
call.  Previous patches modified the freezer to avoid sending
wakeups to threads that are blocked in freezable blocking calls.

This call was selected to be converted to a freezable call because
it doesn't hold any locks or release any resources when interrupted
that might be needed by another freezing task or a kernel driver
during suspend, and is a common site where idle userspace tasks are
blocked.

Signed-off-by: Colin Cross <ccross@android.com>
freezer: add some missing functions

Conflicts:
	include/linux/freezer.h
arm: Makefile for optimized AES and SHA1 routines
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.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
arm: vfpmodule: Fix warning procfs vfp_bounce reporting failed

Creation of procfs cpu/vfp_bounce fails because we're initialized too early. Fix
this by creating it on rootfs_initcall as before the NEON patches.

<6>[    0.130770] VFP support v0.3: implementor 51 architecture 64 part 6f varia
nt 2 rev 0
<4>[    0.130795] ------------[ cut here ]------------
<4>[    0.130813] WARNING: at fs/proc/generic.c:323 __xlate_proc_name+0xac/0xcc(
)
<4>[    0.130822] name 'cpu/vfp_bounce'
<4>[    0.130855] [<c010e26c>] (unwind_backtrace+0x0/0x144) from [<c0a20f58>] (d
ump_stack+0x20/0x24)
<4>[    0.130879] [<c0a20f58>] (dump_stack+0x20/0x24) from [<c019b670>] (warn_sl
owpath_common+0x58/0x70)
<4>[    0.130899] [<c019b670>] (warn_slowpath_common+0x58/0x70) from [<c019b704>
] (warn_slowpath_fmt+0x40/0x48)
<4>[    0.130919] [<c019b704>] (warn_slowpath_fmt+0x40/0x48) from [<c02c2ad8>] (
__xlate_proc_name+0xac/0xcc)
<4>[    0.130938] [<c02c2ad8>] (__xlate_proc_name+0xac/0xcc) from [<c02c2b50>] (
__proc_create+0x58/0x100)
<4>[    0.130956] [<c02c2b50>] (__proc_create+0x58/0x100) from [<c02c2ed0>] (pro
c_create_data+0x5c/0xc0)
<4>[    0.130979] [<c02c2ed0>] (proc_create_data+0x5c/0xc0) from [<c0f03484>] (v
fp_init+0x19c/0x200)
<4>[    0.131000] [<c0f03484>] (vfp_init+0x19c/0x200) from [<c0f00c98>] (do_one_
initcall+0x98/0x168)
<4>[    0.131020] [<c0f00c98>] (do_one_initcall+0x98/0x168) from [<c0f00e60>] (k
ernel_init+0xf8/0x1b4)
<4>[    0.131043] [<c0f00e60>] (kernel_init+0xf8/0x1b4) from [<c01081a0>] (kerne
l_thread_exit+0x0/0x8)
<4>[    0.131076] ---[ end trace ea6d9a9b5e947151 ]---
<3>[    0.131086] Failed to create procfs node for VFP bounce reporting

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

Conflicts:
	arch/arm/vfp/vfpmodule.c

Conflicts:
	arch/arm/configs/lunar_m8_defconfig
	arch/arm/vfp/vfpmodule.c