ARM: 7011/1: Add ARM cpu topology definition

The affinity between ARM processors is defined in the MPIDR register.
We can identify which processors are in the same cluster,
and which ones have performance interdependency. We can define the
cpu topology of ARM platform, that is then used by sched_mc and sched_smt.

The default state of sched_mc and sched_smt config is disable.
When enabled, the behavior of the scheduler can be modified with
sched_mc_power_savings and sched_smt_power_savings sysfs interfaces.

Changes since v4 :
*  Remove unnecessary parentheses and blank lines

Changes since v3 :
* Update the format of printk message
* Remove blank line

Changes since v2 :
* Update the commit message and some comments

Changes since v1 :
* Update the commit message
* Add read_cpuid_mpidr in arch/arm/include/asm/cputype.h
* Modify header of arch/arm/kernel/topology.c
* Modify tests and manipulation of MPIDR's bitfields
* Modify the place and dependancy of the config
* Modify Noop functions

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Conflicts:

	arch/arm/include/asm/topology.h
	arch/arm/kernel/smp.c
	arch/arm/kernel/topology.c
cpupower: update the cpu_power according to cpu load
msm: cpuidle: Don't disable irqs again

cpu_idle() disables irqs before calling down into the cpuidle
driver via cpuidle_idle_call(). Disabling irqs again in
msm_cpuidle_enter() is wasteful and unnecessary. It also inhibits
our ability to determine the largest irq latency when the cpu
idles for extended periods of time because the irqsoff trace is
reenabled when the irqs are disabled in msm_cpuidle_enter().

Note that we still reenable irqs before returning, as is required
by the ARM idle loop.

Change-Id: I925478d8fef88ab490959622bc68303f59cc6e79
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
ARM: add cpufreq transiton notifier to adjust loops_per_jiffy for smp

If CONFIG_SMP, cpufreq skips loops_per_jiffy update, because different
arch has different per-cpu loops_per_jiffy definition.

Signed-off-by: Richard Zhao <richard.zhao@linaro.org>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
ARM: smp: Fix cpu_up() racing with sys_reboot

Nothing stops a process from hotplugging in a CPU concurrently
with a sys_reboot() call. In such a situation we could have
ipi_cpu_stop() mark a cpu as 'offline' and _cpu_up() ignore the
fact that the CPU is not really offline and call the
CPU_UP_PREPARE notifier. When this happens stop_machine code will
complain that the cpu thread already exists and BUG_ON().

CPU0                      CPU1

sys_reboot()
 kernel_restart()
  machine_restart()
   machine_shutdown()
    smp_send_stop()
    ...                   ipi_cpu_stop()
                           set_cpu_online(1, false)
                            local_irq_disable()
                             while(1)
    <PREEMPT>
cpu_up()
 _cpu_up()
   if (!cpu_online(1))
    __cpu_notify(CPU_UP_PREPARE...)

cpu_stop_cpu_callback()
  BUG_ON(stopper->thread)

This is easily reproducible by hotplugging in and out in a tight
loop while also rebooting.

Since the CPU is not really offline and hasn't gone through the
proper steps to be marked as such, let's mark the CPU as inactive.
This is just as easily testable as online and avoids any possibility
of _cpu_up() trying to bring the CPU back online when it never was
offline to begin with.

Change-Id: Ia1daea407220578d4212ef6c65c4be837ca370fd
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
ARM: SoC: add per-platform SMP operations

This adds a 'struct smp_operations' to abstract the CPU initialization
and hot plugging functions on SMP systems, which otherwise conflict
in a multiplatform kernel. This also helps shmobile and potentially
others that have more than one method to do these.

To allow the kernel to continue building, the platform hooks are
defined as weak symbols which are overrided by the platform code.
Once all platforms are converted, the "weak" attribute will be
removed and the function made static.

Unlike the original version from Marc, this new version from Arnd
does not use a generalized abstraction for per-soc data structures
but only tries to solve the problem for the SMP operations. This
way, we can collapse the previous four data structures into a
single struct, which is less systematic but also easier to follow
as a causal reader.

Change-Id: I9d022d4e789f8f87f26a237fa2e9e410be070976
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
[rameezmustafa@codeaurora.org: backport to kernel 3.4]
Signed-off-by: Syed Rameez Mustafa <rameezmustafa@codeaurora.org>

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
smp: fix derp.

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
cpufreq / ondemand: update frequency when limits are relaxed

Reevaluate CPU load and update frequency immediately whenever limits
are changed. Currently ondemand doesn't do that when limits are
relaxed, wasting power on systems with relatively low sampling rate.

Signed-off-by: Michal Pecio <mpecio@nvidia.com>
Reviewed-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
cpufreq / core: Fix typo in comment describing show_bios_limit()

show_bios_limit is mistakenly written as show_scaling_driver in a comment
describing purpose of show_bios_limit() routine.

Fix it.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
cpufreq / core: Fix printing of governor and driver name

Arrays for governer and driver name are of size CPUFREQ_NAME_LEN or 16.
i.e. 15 bytes for name and 1 for trailing '\0'.

When cpufreq driver print these names (for sysfs), it includes '\n' or ' ' in
the fmt string and still passes length as CPUFREQ_NAME_LEN. If the driver or
governor names are using all 15 fields allocated to them, then the trailing '\n'
or ' ' will never be printed. And so commands like:

root@linaro-developer# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver

will print something like:

cpufreq_foodrvroot@linaro-developer#

Fix this by increasing print length by one character.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
rwsem-spinlock: Implement writer lock-stealing for better scalability

We (Linux Kernel Performance project) found a regression
introduced by commit:

  5a505085f043 mm/rmap: Convert the struct anon_vma::mutex to an rwsem

which converted all anon_vma::mutex locks rwsem write locks.

The semantics are the same, but the behavioral difference is
quite huge in some cases. After investigating it we found the
root cause: mutexes support lock stealing while rwsems don't.

Here is the link for the detailed regression report:

  https://lkml.org/lkml/2013/1/29/84

Ingo suggested adding write lock stealing to rwsems:

    "I think we should allow lock-steal between rwsem writers - that
     will not hurt fairness as most rwsem fairness concerns relate to
     reader vs. writer fairness"

And here is the rwsem-spinlock version.

With this patch, we got a double performance increase in one
test box with following aim7 workfile:

    FILESIZE: 1M
    POOLSIZE: 10M
    10 fork_test

 /usr/bin/time output w/o patch                       /usr/bin/time_output with patch
 -- Percent of CPU this job got: 369%                 Percent of CPU this job got: 537%
 Voluntary context switches: 640595016                Voluntary context switches: 157915561

We got a 45% increase in CPU usage and saved about 3/4 voluntary context switches.

Reported-by: LKP project <lkp@linux.intel.com>
Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Cc: Alex Shi <alex.shi@intel.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Anton Blanchard <anton@samba.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: paul.gortmaker@windriver.com
Link: http://lkml.kernel.org/r/1359716356-23865-1-git-send-email-yuanhan.liu@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
rwsem: Implement writer lock-stealing for better scalability

Commit 5a505085f043 ("mm/rmap: Convert the struct anon_vma::mutex
to an rwsem") changed struct anon_vma::mutex to an rwsem, which
caused aim7 fork_test performance to drop by 50%.

Yuanhan Liu did the following excellent analysis:

    https://lkml.org/lkml/2013/1/29/84

and found that the regression is caused by strict, serialized,
FIFO sequential write-ownership of rwsems. Ingo suggested
implementing opportunistic lock-stealing for the front writer
task in the waitqueue.

Yuanhan Liu implemented lock-stealing for spinlock-rwsems,
which indeed recovered much of the regression - confirming
the analysis that the main factor in the regression was the
FIFO writer-fairness of rwsems.

In this patch we allow lock-stealing to happen when the first
waiter is also writer. With that change in place the
aim7 fork_test performance is fully recovered on my
Intel NHM EP, NHM EX, SNB EP 2S and 4S test-machines.

Reported-by: lkp@linux.intel.com
Reported-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Signed-off-by: Alex Shi <alex.shi@intel.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Anton Blanchard <anton@samba.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: paul.gortmaker@windriver.com
Link: https://lkml.org/lkml/2013/1/29/84
Link: http://lkml.kernel.org/r/1360069915-31619-1-git-send-email-alex.shi@intel.com
[ Small stylistic fixes, updated changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
wake_up_process() should be never used to wakeup a TASK_STOPPED/TRACED task

wake_up_process() should never wakeup a TASK_STOPPED/TRACED task.
Change it to use TASK_NORMAL and add the WARN_ON().

TASK_ALL has no other users, probably can be killed.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
msm: kgsl: Set requested power state to NONE after resume

When GPU resumes from suspend requested state is not cleared to NONE.
Due to this idle reporting is not done and GPU stays at MAX freq. As
a fix if the current power state is already ACTIVE and request is
made for active power state then clear the requested state immediately.

CRs-fixed: 424682
Change-Id: I7f0d7fa819308f166cbbbf30b2c20aee73644cfb
Signed-off-by: Vinay Roy <vroy@codeaurora.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
msm: rq_stats: Fix missing initalization of cur_freq

Initialize cur_freq variable of each online cpu to the current
running cpu clock frequency. This avoids zeroing out the load
calculations until the first notification of the change in CPU
frequency comes in after CPUFREQ governors are intialized.

Also when a non boot cpu is up, update its cur_freq variable.

Change-Id: I950686deff02e2339eefae7d09392dda2174a545
CRs-fixed: 446017
Signed-off-by: Venkat Devarasetty <vdevaras@codeaurora.org>
block/partitions: optimize memory allocation in check_partition()

Currently, sizeof(struct parsed_partitions) may be 64KB in 32bit arch, so
it is easy to trigger page allocation failure by check_partition,
especially in hotplug block device situation(such as, USB mass storage,
MMC card, ...), and Felipe Balbi has observed the failure.

This patch does below optimizations on the allocation of struct
parsed_partitions to try to address the issue:

- make parsed_partitions.parts as pointer so that the pointed memory can
  fit in 32KB buffer, then approximate 32KB memory can be saved

- vmalloc the buffer pointed by parsed_partitions.parts because 32KB is
  still a bit big for kmalloc

- given that many devices have the partition count limit, so only
  allocate disk_max_parts() partitions instead of 256 partitions always

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Reported-by: Felipe Balbi <balbi@ti.com>
Cc: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
fs/direct-io.c: adjust suspicious bit operation

READ is 0, so the result of the bit-and operation is 0.  Rewrite with == as
done elsewhere in the same file.

This problem was found using Coccinelle (http://coccinelle.lip6.fr/).

Signed-off-by: Julia Lawall <julia@diku.dk>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
block: move down direct IO plugging

Move unplugging for direct I/O from around ->direct_IO() down to
do_blockdev_direct_IO(). This implicitly adds plugging for direct
writes.

CC: Li Shaohua <shli@fusionio.com>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
direct-io: don't read inode->i_blkbits multiple times

Since directio can work on a raw block device, and the block size of the
device can change under it, we need to do the same thing that
fs/buffer.c now does: read the block size a single time, using
ACCESS_ONCE().

Reading it multiple times can get different results, which will then
confuse the code because it actually encodes the i_blksize in
relationship to the underlying logical blocksize.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mmc: queue: amend buffer swap for non-blocking transfer

In case both 'req' and 'mq->mqrq_prev->req' are null, there is no request
to be processed. That means there is no need to switch buffer.
Switching buffer is required only after finishing 'issue_fn'.

Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
Reviewed-by: Per Forlin <per.forlin@stericsson.com>
Tested-by: Johan Rudholm <johan.rudholm@stericsson.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
Signed-off-by: Konstantin Dorfman <kdorfman@codeaurora.org>