smp: Add generic smpboot facility

Start a new file, which will hold SMP and CPU hotplug related generic
infrastructure.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Howells <dhowells@redhat.com>
Cc: James E.J. Bottomley <jejb@parisc-linux.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/20120420124557.035417523@linutronix.de

Change-Id: Ia1ad435435aa12c47ac0d381ae031ebf6edcff1f
smp: Provide generic idle thread allocation

All SMP architectures have magic to fork the idle task and to store it
for reusage when cpu hotplug is enabled. Provide a generic
infrastructure for it.

Create/reinit the idle thread for the cpu which is brought up in the
generic code and hand the thread pointer to the architecture code via
__cpu_up().

Note, that fork_idle() is called via a workqueue, because this
guarantees that the idle thread does not get a reference to a user
space VM. This can happen when the boot process did not bring up all
possible cpus and a later cpu_up() is initiated via the sysfs
interface. In that case fork_idle() would be called in the context of
the user space task and take a reference on the user space VM.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Howells <dhowells@redhat.com>
Cc: James E.J. Bottomley <jejb@parisc-linux.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: x86@kernel.org
Acked-by: Venkatesh Pallipadi <venki@google.com>
Link: http://lkml.kernel.org/r/20120420124557.102478630@linutronix.de

Change-Id: Ie2d32789f3a69ee15f38ba704aaa84d6be85bcd4
Signed-off-by: Willi Ye <williye97@gmail.com>

Conflicts:
	kernel/sched/core.c
smp, idle: Allocate idle thread for each possible cpu during boot

percpu areas are already allocated during boot for each possible cpu.
percpu idle threads can be considered as an extension of the percpu areas,
and allocate them for each possible cpu during boot.

This will eliminate the need for workqueue based idle thread allocation.
In future we can move the idle thread area into the percpu area too.

[ tglx: Moved the loop into smpboot.c and added an error check when
  the init code failed to allocate an idle thread for a cpu which
  should be onlined ]

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: venki@google.com
Link: http://lkml.kernel.org/r/1334966930.28674.245.camel@sbsiddha-desk.sc.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Change-Id: I36828165fc08b7c0a8a0fe6a2aa24d358e623dd2
Signed-off-by: Willi Ye <williye97@gmail.com>

Conflicts:
	arch/arm/Kconfig

Conflicts:
	arch/arm/Kconfig
smpboot, idle: Optimize calls to smp_processor_id() in idle_threads_init()

While trying to initialize idle threads for all cpus, idle_threads_init()
calls smp_processor_id() in a loop, which is unnecessary. The intent
is to initialize idle threads for all non-boot cpus. So just use a variable
to note the boot cpu and use it in the loop.

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: suresh.b.siddha@intel.com
Cc: venki@google.com
Cc: nikunj@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/20120524151055.2549.64309.stgit@srivatsabhat.in.ibm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Change-Id: Ib65df4c31e93e1622c26f2c2a4946ffd28c1839d
smpboot, idle: Fix comment mismatch over idle_threads_init()

The comment over idle_threads_init() really talks about the functionality
of idle_init(). Move that comment to idle_init(), and add a suitable
comment over idle_threads_init().

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: suresh.b.siddha@intel.com
Cc: venki@google.com
Cc: nikunj@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/20120524151100.2549.66501.stgit@srivatsabhat.in.ibm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Change-Id: Ib0cd6d6e19e0c64868a42a77101b080a5f3b04f8
arm: if there's no handler we need to restore sigmask, syscall or no syscall

CRs-fixed: 592079
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Git-commit: 7dfae72027cd8345247e675a3b27439df95fe06e
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-stable.git
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>
arm: new way of handling ERESTART_RESTARTBLOCK

new "syscall start" flag; handled in syscall_trace() by switching
syscall number to that of syscall_restart(2).  Restarts of that
kind (ERESTART_RESTARTBLOCK) are handled by setting that bit;
syscall number is not modified until the actual call.

CRs-fixed: 592079
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Git-commit: 6b5c8045ecc7e726cdaa2a9d9c8e5008050e1252
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-stable.git
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>
Signed-off-by: Willi Ye <williye97@gmail.com>

Conflicts:
	arch/arm/include/asm/thread_info.h
	arch/arm/kernel/ptrace.c
staging: Add angle bracket before and after the URL

Add missing angle bracket before and after the URL.

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
cpufreq: enable sibling cpu policy sharing

disable Qualcomm's cpu policy restore (conflicts with sibling sharing)

Signed-off-by: Paul Reioux <reioux@gmail.com>
ARM: 7492/1: add strstr declaration for decompressors

With the generic unaligned.h, more kernel headers get pulled in including
dynamic_debug.h which needs strstr. As it is not really used, we only need
a declaration here.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Tested-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
mutex: Make more scalable by doing less atomic operations

Date	Mon, 15 Apr 2013 10:37:57 -0400

In the __mutex_lock_common() function, an initial entry into
the lock slow path will cause two atomic_xchg instructions to be
issued. Together with the atomic decrement in the fast path, a total
of three atomic read-modify-write instructions will be issued in
rapid succession. This can cause a lot of cache bouncing when many
tasks are trying to acquire the mutex at the same time.

This patch will reduce the number of atomic_xchg instructions used by
checking the counter value first before issuing the instruction. The
atomic_read() function is just a simple memory read. The atomic_xchg()
function, on the other hand, can be up to 2 order of magnitude or even
more in cost when compared with atomic_read(). By using atomic_read()
to check the value first before calling atomic_xchg(), we can avoid a
lot of unnecessary cache coherency traffic. The only downside with this
change is that a task on the slow path will have a tiny bit
less chance of getting the mutex when competing with another task
in the fast path.

The same is true for the atomic_cmpxchg() function in the
mutex-spin-on-owner loop. So an atomic_read() is also performed before
calling atomic_cmpxchg().

The mutex locking and unlocking code for the x86 architecture can allow
any negative number to be used in the mutex count to indicate that some
tasks are waiting for the mutex. I am not so sure if that is the case
for the other architectures. So the default is to avoid atomic_xchg()
if the count has already been set to -1. For x86, the check is modified
to include all negative numbers to cover a larger case.

The following table shows the jobs per minutes (JPM) scalability data
on an 8-node 80-core Westmere box with a 3.7.10 kernel. The numactl
command is used to restrict the running of the high_systime workloads
to 1/2/4/8 nodes with hyperthreading on and off.

+-----------------+-----------+------------+----------+
|  Configuration  | Mean JPM  |  Mean JPM  | % Change |
|		  | w/o patch | with patch |	      |
+-----------------+-----------------------------------+
|		  |      User Range 1100 - 2000	      |
+-----------------+-----------------------------------+
| 8 nodes, HT on  |    36980   |   148590  | +301.8%  |
| 8 nodes, HT off |    42799   |   145011  | +238.8%  |
| 4 nodes, HT on  |    61318   |   118445  |  +51.1%  |
| 4 nodes, HT off |   158481   |   158592  |   +0.1%  |
| 2 nodes, HT on  |   180602   |   173967  |   -3.7%  |
| 2 nodes, HT off |   198409   |   198073  |   -0.2%  |
| 1 node , HT on  |   149042   |   147671  |   -0.9%  |
| 1 node , HT off |   126036   |   126533  |   +0.4%  |
+-----------------+-----------------------------------+
|		  |       User Range 200 - 1000	      |
+-----------------+-----------------------------------+
| 8 nodes, HT on  |   41525    |   122349  | +194.6%  |
| 8 nodes, HT off |   49866    |   124032  | +148.7%  |
| 4 nodes, HT on  |   66409    |   106984  |  +61.1%  |
| 4 nodes, HT off |  119880    |   130508  |   +8.9%  |
| 2 nodes, HT on  |  138003    |   133948  |   -2.9%  |
| 2 nodes, HT off |  132792    |   131997  |   -0.6%  |
| 1 node , HT on  |  116593    |   115859  |   -0.6%  |
| 1 node , HT off |  104499    |   104597  |   +0.1%  |
+-----------------+------------+-----------+----------+
At low user range 10-100, the JPM differences were within +/-1%. So
they are not that interesting.

AIM7 benchmark run has a pretty large run-to-run variance due to random
nature of the subtests executed. So a difference of less than +-5%
may not be really significant.

This patch improves high_systime workload performance at 4 nodes
and up by maintaining transaction rates without significant drop-off
at high node count.  The patch has practically no impact on 1 and 2
nodes system.

The table below shows the percentage time (as reported by perf
record -a -s -g) spent on the __mutex_lock_slowpath() function by
the high_systime workload at 1500 users for 2/4/8-node configurations
with hyperthreading off.

+---------------+-----------------+------------------+---------+
| Configuration | %Time w/o patch | %Time with patch | %Change |
+---------------+-----------------+------------------+---------+
|    8 nodes    |      65.34%     |      0.69%       |  -99%   |
|    4 nodes    |       8.70%	  |      1.02%	     |  -88%   |
|    2 nodes    |       0.41%     |      0.32%       |  -22%   |
+---------------+-----------------+------------------+---------+
It is obvious that the dramatic performance improvement at 8
nodes was due to the drastic cut in the time spent within the
__mutex_lock_slowpath() function.

The table below show the improvements in other AIM7 workloads (at 8
nodes, hyperthreading off).

+--------------+---------------+----------------+-----------------+
|   Workload   | mean % change | mean % change  | mean % change   |
|              | 10-100 users  | 200-1000 users | 1100-2000 users |
+--------------+---------------+----------------+-----------------+
| alltests     |     +0.6%     |   +104.2%      |   +185.9%       |
| five_sec     |     +1.9%     |     +0.9%      |     +0.9%       |
| fserver      |     +1.4%     |     -7.7%      |     +5.1%       |
| new_fserver  |     -0.5%     |     +3.2%      |     +3.1%       |
| shared       |    +13.1%     |   +146.1%      |   +181.5%       |
| short        |     +7.4%     |     +5.0%      |     +4.2%       |
+--------------+---------------+----------------+-----------------+
Signed-off-by: Waiman Long <Waiman.Long@hp.com>
Reviewed-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
mutex: back out architecture specific check for negative mutex count

Date	Mon, 15 Apr 2013 10:37:59 -0400

If it is confirmed that all the supported architectures can allow a
negative mutex count without incorrect behavior, we can then back
out the architecture specific change and allow the mutex count to
go to any negative number. That should further reduce contention for
non-x86 architecture.

If this is not the case, this patch should be dropped.

Signed-off-by: Waiman Long <Waiman.Long@hp.com>
cpufreq: Retain only online cpus in managed_policy->cpus

cpufreq's handling of cpu online event can incorrectly initialize
managed_policy->cpus to include offline cpus. This causes cpufreq
governors to include offline cpus in their idle time computation, which
causes frequency to shoot up beyond normal levels (on systems where 2 or
more cpus need to be synchronized wrt frequency change).

This frequency shootup was not seen prior to commit 21111be8 which
changed idle time accounting for offline cpus. Prior to commit 21111be8,
idle time statistics for offline cpus would include their offline time
as well. Post commit 21111be8, offline time is not included in a cpu's
idle time statistics.

As a result, ondemand (or other cpufreq) governors would see unchanged
idle time for offline cpus, causing them to interpret those (offline)
cpus as 100% busy, which is wrong.

This patch fixes the issue by modifying cpufreq's hotplug handling to
retain only online cpus in managed_policy->cpus field. cpufreq governors
would then skip such offline cpus from idle time calculations.

Change-Id: Id2eba8c0ec3367609369b2e42a4e1386ff2e7ab5
Signed-off-by: Srivatsa Vaddagiri <vatsa@codeaurora.org>
workqueue: don't use WQ_HIGHPRI for unbound workqueues

Unbound wqs aren't concurrency-managed and try to execute work items
as soon as possible.  This is currently achieved by implicitly setting
%WQ_HIGHPRI on all unbound workqueues; however, WQ_HIGHPRI
implementation is about to be restructured and this usage won't be
valid anymore.

Add an explicit chain-wakeup path for unbound workqueues in
process_one_work() instead of piggy backing on %WQ_HIGHPRI.

Change-Id: Iecd17a9935ee28f856d8b726bb4c296762922bed
Signed-off-by: Tejun Heo <tj@kernel.org>
Git-commit: 974271c485a4d8bb801decc616748f90aafb07ec
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>
(cherry picked from commit 5b92cea36d8328c17380d7997744284707134397)
random: prime last_data value per fips requirements

The value stored in last_data must be primed for FIPS 140-2 purposes. Upon
first use, either on system startup or after an RNDCLEARPOOL ioctl, we
need to take an initial random sample, store it internally in last_data,
then pass along the value after that to the requester, so that consistency
checks aren't being run against stale and possibly known data.

CC: Herbert Xu <herbert@gondor.apana.org.au>
CC: "David S. Miller" <davem@davemloft.net>
CC: Matt Mackall <mpm@selenic.com>
CC: linux-crypto@vger.kernel.org
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
ARM: fault: assume no context when IRQs are disabled during data abort.

Bail out early if IRQs are disabled in do_page_fault or else
  [14415.157266] BUG: sleeping function called from invalid context at arch/arm/mm/fault.c:301

Russell King's idea from
  http://comments.gmane.org/gmane.linux.ports.arm.omap/59256

Signed-off-by: JP Abgrall <jpa@google.com>
f_fs: ffs_func_free: cleanup requests allocated by autoconfig

functionfs was leaking request objects created by autoconfig.

Bug: 8659094

Change-Id: I641326cb5cb26e0a2ffa082cd2be2c21c66c38e5
Signed-off-by: Peter Korsgaard <peter.korsgaard@barco.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Benoit Goby <benoit@android.com>
slub: use __SetPageSlab function to set PG_slab flag

To set page-flag, using SetPageXXXX() and __SetPageXXXX() is more
understandable and maintainable. So change it.

Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
fbcon: clear the logo bitmap from the margin area

Explicitly clear_margins when clearing the logo, in case the font dimensions
are non-integral to the framebuffer dimensions.

Signed-off-by: Kamal Mostafa <kamal@whence.com>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mmc: core: Increase write data timeout value for bad SDHC cards

SD2.0 specification says the max. timeout for writes is 250msecs
for SDHC cards. But when the card is almost full and there are too few
free sectors, the garbage collectors inside SD card  may take more time
and hence delaying the write more than 250msecs. This typically happens
with cards that don't adhere to specification. Based on this the timeout
is increased to 300msecs but still for some cards this is not sufficient.

Few SanDisk class4 SD cards violate the spec. and may take more time than
expected when the card is full. So increase the data timeout to 800msecs,
otherwise we might see file system corruption due to loss of important FS
metadata in timeouts.

Change-Id: Ie8f0616dbbb2a15d7dbe95cd49eeb2308a5badd1
Signed-off-by: Sujith Reddy Thumma <sthumma@codeaurora.org>