sched/dl: Use dl_bw_of() under rcu_read_lock_sched()

rq->rd is freed using call_rcu_sched(), so rcu_read_lock() to access it
is not enough. We should use either rcu_read_lock_sched() or preempt_disable().

Reported-by: Sasha Levin <sasha.levin@oracle.com>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Kirill Tkhai <ktkhai@parallels.com
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Fixes: 66339c31bc39 "sched: Use dl_bw_of() under RCU read lock"
Link: http://lkml.kernel.org/r/1412065417.20287.24.camel@tkhai
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched/fair: Delete resched_cpu() from idle_balance()

We already reschedule env.dst_cpu in attach_tasks()->check_preempt_curr()
if this is necessary.

Furthermore, a higher priority class task may be current on dest rq,
we shouldn't disturb it.

Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Cc: Juri Lelli <juri.lelli@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140930210441.5258.55054.stgit@localhost
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched, time: Fix build error with 64 bit cputime_t on 32 bit systems

On 32 bit systems cmpxchg cannot handle 64 bit values, so
some additional magic is required to allow a 32 bit system
with CONFIG_VIRT_CPU_ACCOUNTING_GEN=y enabled to build.

Make sure the correct cmpxchg function is used when doing
an atomic swap of a cputime_t.

Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rik van Riel <riel@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: umgwanakikbuti@gmail.com
Cc: fweisbec@gmail.com
Cc: srao@redhat.com
Cc: lwoodman@redhat.com
Cc: atheurer@redhat.com
Cc: oleg@redhat.com
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linux390@de.ibm.com
Cc: linux-arch@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Link: http://lkml.kernel.org/r/20140930155947.070cdb1f@annuminas.surriel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched: Improve sysbench performance by fixing spurious active migration

Since commit caeb178c60f4 ("sched/fair: Make update_sd_pick_busiest() ...")
sd_pick_busiest returns a group that can be neither imbalanced nor overloaded
but is only more loaded than others. This change has been introduced to ensure
a better load balance in system that are not overloaded but as a side effect,
it can also generate useless active migration between groups.

Let take the example of 3 tasks on a quad cores system. We will always have an
idle core so the load balance will find a busiest group (core) whenever an ILB
is triggered and it will force an active migration (once above
nr_balance_failed threshold) so the idle core becomes busy but another core
will become idle. With the next ILB, the freshly idle core will try to pull the
task of a busy CPU.
The number of spurious active migration is not so huge in quad core system
because the ILB is not triggered so much. But it becomes significant as soon as
you have more than one sched_domain level like on a dual cluster of quad cores
where the ILB is triggered every tick when you have more than 1 busy_cpu

We need to ensure that the migration generate a real improveùent and will not
only move the avg_load imbalance on another CPU.

Before caeb178c60f4f93f1b45c0bc056b5cf6d217b67f, the filtering of such use
case was ensured by the following test in f_b_g:

  if ((local->idle_cpus < busiest->idle_cpus) &&
    busiest->sum_nr_running  <= busiest->group_weight)

This patch modified the condition to take into account situation where busiest
group is not overloaded: If the diff between the number of idle cpus in 2
groups is less than or equal to 1 and the busiest group is not overloaded,
moving a task will not improve the load balance but just move it.

A test with sysbench on a dual clusters of quad cores gives the following
results:

  command: sysbench --test=cpu --num-threads=5 --max-time=5 run

The HZ is 200 which means that 1000 ticks has fired during the test.

With Mainline, perf gives the following figures:

 Samples: 727  of event 'sched:sched_migrate_task'
 Event count (approx.): 727
  Overhead  Command          Shared Object  Symbol
  ........  ...............  .............  ..............
    12.52%  migration/1      [unknown]      [.] 00000000
    12.52%  migration/5      [unknown]      [.] 00000000
    12.52%  migration/7      [unknown]      [.] 00000000
    12.10%  migration/6      [unknown]      [.] 00000000
    11.83%  migration/0      [unknown]      [.] 00000000
    11.83%  migration/3      [unknown]      [.] 00000000
    11.14%  migration/4      [unknown]      [.] 00000000
    10.87%  migration/2      [unknown]      [.] 00000000
     2.75%  sysbench         [unknown]      [.] 00000000
     0.83%  swapper          [unknown]      [.] 00000000
     0.55%  ktps65090charge  [unknown]      [.] 00000000
     0.41%  mmcqd/1          [unknown]      [.] 00000000
     0.14%  perf             [unknown]      [.] 00000000

With this patch, perf gives the following figures

 Samples: 20  of event 'sched:sched_migrate_task'
 Event count (approx.): 20
  Overhead  Command          Shared Object  Symbol
  ........  ...............  .............  ..............
    80.00%  sysbench         [unknown]      [.] 00000000
    10.00%  swapper          [unknown]      [.] 00000000
     5.00%  ktps65090charge  [unknown]      [.] 00000000
     5.00%  migration/1      [unknown]      [.] 00000000

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1412170735-5356-1-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched/x86: Fix up typo in topology detection

Commit:

  cebf15eb09a2 ("x86, sched: Add new topology for multi-NUMA-node CPUs")

some code to try to detect the situation where we have a NUMA node
inside of the "DIE" sched domain.

It detected this by looking for cpus which match_die() but do not match
NUMA nodes via topology_same_node().

I wrote it up as:

if (match_die(c, o) == !topology_same_node(c, o))

which actually seemed to work some of the time, albiet
accidentally.

It should have been doing an &&, not an ==.

This code essentially chopped off the "DIE" domain on one of
Andrew Morton's systems.  He reported that this patch fixed his
issue.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Dave Hansen <dave@sr71.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Lan Tianyu <tianyu.lan@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Link: http://lkml.kernel.org/r/20140930214546.FD481CFF@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86, sched: Add new topology for multi-NUMA-node CPUs

I'm getting the spew below when booting with Haswell (Xeon
E5-2699 v3) CPUs and the "Cluster-on-Die" (CoD) feature enabled
in the BIOS.  It seems similar to the issue that some folks from
AMD ran in to on their systems and addressed in this commit:

  161270fc1f9d ("x86/smp: Fix topology checks on AMD MCM CPUs")

Both these Intel and AMD systems break an assumption which is
being enforced by topology_sane(): a socket may not contain more
than one NUMA node.

AMD special-cased their system by looking for a cpuid flag.  The
Intel mode is dependent on BIOS options and I do not know of a
way which it is enumerated other than the tables being parsed
during the CPU bringup process.  In other words, we have to trust
the ACPI tables <shudder>.

This detects the situation where a NUMA node occurs at a place in
the middle of the "CPU" sched domains.  It replaces the default
topology with one that relies on the NUMA information from the
firmware (SRAT table) for all levels of sched domains above the
hyperthreads.

This also fixes a sysfs bug.  We used to freak out when we saw
the "mc" group cross a node boundary, so we stopped building the
MC group.  MC gets exported as the 'core_siblings_list' in
/sys/devices/system/cpu/cpu*/topology/ and this caused CPUs with
the same 'physical_package_id' to not be listed together in
'core_siblings_list'.  This violates a statement from
Documentation/ABI/testing/sysfs-devices-system-cpu:

core_siblings: internal kernel map of cpu#'s hardware threads
within the same physical_package_id.

core_siblings_list: human-readable list of the logical CPU
numbers within the same physical_package_id as cpu#.

The sysfs effects here cause an issue with the hwloc tool where
it gets confused and thinks there are more sockets than are
physically present.

Before this patch, there are two packages:

# cd /sys/devices/system/cpu/
# cat cpu*/topology/physical_package_id | sort | uniq -c
     18 0
     18 1

But 4 _sets_ of core siblings:

# cat cpu*/topology/core_siblings_list | sort | uniq -c
      9 0-8
      9 18-26
      9 27-35
      9 9-17

After this set, there are only 2 sets of core siblings, which
is what we expect for a 2-socket system.

# cat cpu*/topology/physical_package_id | sort | uniq -c
     18 0
     18 1
# cat cpu*/topology/core_siblings_list | sort | uniq -c
     18 0-17
     18 18-35

Example spew:
...
NMI watchdog: enabled on all CPUs, permanently consumes one hw-PMU counter.
 #2  #3  #4  #5  #6  #7  #8
.... node  #1, CPUs:    #9
------------[ cut here ]------------
WARNING: CPU: 9 PID: 0 at /home/ak/hle/linux-hle-2.6/arch/x86/kernel/smpboot.c:306 topology_sane.isra.2+0x74/0x90()
sched: CPU #9's mc-sibling CPU #0 is not on the same node! [node: 1 != 0]. Ignoring dependency.
Modules linked in:
CPU: 9 PID: 0 Comm: swapper/9 Not tainted 3.17.0-rc1-00293-g8e01c4d-dirty #631
Hardware name: Intel Corporation S2600WTT/S2600WTT, BIOS GRNDSDP1.86B.0036.R05.1407140519 07/14/2014
0000000000000009 ffff88046ddabe00 ffffffff8172e485 ffff88046ddabe48
ffff88046ddabe38 ffffffff8109691d 000000000000b001 0000000000000009
ffff88086fc12580 000000000000b020 0000000000000009 ffff88046ddabe98
Call Trace:
[<ffffffff8172e485>] dump_stack+0x45/0x56
[<ffffffff8109691d>] warn_slowpath_common+0x7d/0xa0
[<ffffffff8109698c>] warn_slowpath_fmt+0x4c/0x50
[<ffffffff81074f94>] topology_sane.isra.2+0x74/0x90
[<ffffffff8107530e>] set_cpu_sibling_map+0x31e/0x4f0
[<ffffffff8107568d>] start_secondary+0x1ad/0x240
---[ end trace 3fe5f587a9fcde61 ]---
#10 #11 #12 #13 #14 #15 #16 #17
.... node  #2, CPUs:   #18 #19 #20 #21 #22 #23 #24 #25 #26
.... node  #3, CPUs:   #27 #28 #29 #30 #31 #32 #33 #34 #35

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
[ Added LLC domain and s/match_mc/match_die/ ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: brice.goglin@gmail.com
Cc: "H. Peter Anvin" <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/20140918193334.C065EBCE@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched/rt: Use resched_curr() in task_tick_rt()

Some time ago PREEMPT_NEED_RESCHED was implemented,
so reschedule technics is a little more difficult now.

Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140922183642.11015.66039.stgit@localhost
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched: Use rq->rd in sched_setaffinity() under RCU read lock

Probability of use-after-free isn't zero in this place.

Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org> # v3.14+
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140922183636.11015.83611.stgit@localhost
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched: cleanup: Rename 'out_unlock' to 'out_free_new_mask'

Nothing is locked there, so label's name only confuses a reader.

Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140922183630.11015.59500.stgit@localhost
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched: Use dl_bw_of() under RCU read lock

dl_bw_of() dereferences rq->rd which has to have RCU read lock held.
Probability of use-after-free isn't zero here.

Also add lockdep assert into dl_bw_cpus().

Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org> # v3.14+
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140922183624.11015.71558.stgit@localhost
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched/fair: Remove duplicate code from can_migrate_task()

Combine two branches which do the same.

Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140922183612.11015.64200.stgit@localhost
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched, mips, ia64: Remove __ARCH_WANT_UNLOCKED_CTXSW

Kirill found that there's a subtle race in the
__ARCH_WANT_UNLOCKED_CTXSW code, and instead of fixing it, remove the
entire exception because neither arch that uses it seems to actually
still require it.

Boot tested on mips64el (qemu) only.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kirill Tkhai <tkhai@yandex.ru>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Qais Yousef <qais.yousef@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: oleg@redhat.com
Cc: linux@roeck-us.net
Cc: linux-ia64@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Link: http://lkml.kernel.org/r/20140923150641.GH3312@worktop.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched: print_rq(): Don't use tasklist_lock

read_lock_irqsave(tasklist_lock) in print_rq() looks strange. We do
not need to disable irqs, and they are already disabled by the caller.

And afaics this lock buys nothing, we can rely on rcu_read_lock().
In this case it makes sense to also move rcu_read_lock/unlock from
the caller to print_rq().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140921193341.GA28628@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched: normalize_rt_tasks(): Don't use _irqsave for tasklist_lock, use task_rq_lock()

1. read_lock(tasklist_lock) does not need to disable irqs.

2. ->mm != NULL is a common mistake, use PF_KTHREAD.

3. The second ->mm check can be simply removed.

4. task_rq_lock() looks better than raw_spin_lock(&p->pi_lock) +
   __task_rq_lock().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140921193338.GA28621@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched: Fix the task-group check in tg_has_rt_tasks()

tg_has_rt_tasks() wants to find an RT task in this task_group, but
task_rq(p)->rt.tg wrongly checks the root rt_rq.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Link: http://lkml.kernel.org/r/20140921193336.GA28618@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched/fair: Leverage the idle state info when choosing the "idlest" cpu

The code in find_idlest_cpu() looks for the CPU with the smallest load.
However, if multiple CPUs are idle, the first idle CPU is selected
irrespective of the depth of its idle state.

Among the idle CPUs we should pick the one with with the shallowest idle
state, or the latest to have gone idle if all idle CPUs are in the same
state.  The later applies even when cpuidle is configured out.

This patch doesn't cover the following issues:

- The idle exit latency of a CPU might be larger than the time needed
  to migrate the waking task to an already running CPU with sufficient
  capacity, and therefore performance would benefit from task packing
  in such case (in most cases task packing is about power saving).

- Some idle states have a non negligible and non abortable entry latency
  which needs to run to completion before the exit latency can start.
  A concurrent patch series is making this info available to the cpuidle
  core.  Once available, the entry latency with the idle timestamp could
  determine when the exit latency may be effective.

Those issues will be handled in due course.  In the mean time, what
is implemented here should improve things already compared to the current
state of affairs.

Based on an initial patch from Daniel Lezcano.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-pm@vger.kernel.org
Cc: linaro-kernel@lists.linaro.org
Link: http://lkml.kernel.org/n/tip-@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched: Let the scheduler see CPU idle states

When the cpu enters idle, it stores the cpuidle state pointer in its
struct rq instance which in turn could be used to make a better decision
when balancing tasks.

As soon as the cpu exits its idle state, the struct rq reference is
cleared.

There are a couple of situations where the idle state pointer could be changed
while it is being consulted:

1. For x86/acpi with dynamic c-states, when a laptop switches from battery
   to AC that could result on removing the deeper idle state. The acpi driver
   triggers:
'acpi_processor_cst_has_changed'
'cpuidle_pause_and_lock'
'cpuidle_uninstall_idle_handler'
'kick_all_cpus_sync'.

All cpus will exit their idle state and the pointed object will be set to
NULL.

2. The cpuidle driver is unloaded. Logically that could happen but not
in practice because the drivers are always compiled in and 95% of them are
not coded to unregister themselves.  In any case, the unloading code must
call 'cpuidle_unregister_device', that calls 'cpuidle_pause_and_lock'
leading to 'kick_all_cpus_sync' as mentioned above.

A race can happen if we use the pointer and then one of these two scenarios
occurs at the same moment.

In order to be safe, the idle state pointer stored in the rq must be
used inside a rcu_read_lock section where we are protected with the
'rcu_barrier' in the 'cpuidle_uninstall_idle_handler' function. The
idle_get_state() and idle_put_state() accessors should be used to that
effect.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: linux-pm@vger.kernel.org
Cc: linaro-kernel@lists.linaro.org
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched/deadline: Fix inter- exclusive cpusets migrations

Users can perform clustered scheduling using the cpuset facility.
After an exclusive cpuset is created, task migrations happen only
between CPUs belonging to the same cpuset. Inter- cpuset migrations
can only happen when the user requires so, moving a task between
different cpusets. This behaviour is broken in SCHED_DEADLINE, as
currently spurious inter- cpuset migration may happen without user
intervention.

This patch fix the problem (and shuffles the code a bit to improve
clarity).

Signed-off-by: Juri Lelli <juri.lelli@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: raistlin@linux.it
Cc: michael@amarulasolutions.com
Cc: fchecconi@gmail.com
Cc: daniel.wagner@bmw-carit.de
Cc: vincent@legout.info
Cc: luca.abeni@unitn.it
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1411118561-26323-4-git-send-email-juri.lelli@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched/deadline: Clear dl_entity params when setscheduling to different class

When a task is using SCHED_DEADLINE and the user setschedules it to a
different class its sched_dl_entity static parameters are not cleaned
up. This causes a bug if the user sets it back to SCHED_DEADLINE with
the same parameters again.  The problem resides in the check we
perform at the very beginning of dl_overflow():

if (new_bw == p->dl.dl_bw)
return 0;

This condition is met in the case depicted above, so the function
returns and dl_b->total_bw is not updated (the p->dl.dl_bw is not
added to it). After this, admission control is broken.

This patch fixes the thing, properly clearing static parameters for a
task that ceases to use SCHED_DEADLINE.

Reported-by: Daniele Alessandrelli <daniele.alessandrelli@gmail.com>
Reported-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Reported-by: Vincent Legout <vincent@legout.info>
Tested-by: Luca Abeni <luca.abeni@unitn.it>
Tested-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Tested-by: Vincent Legout <vincent@legout.info>
Signed-off-by: Juri Lelli <juri.lelli@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Fabio Checconi <fchecconi@gmail.com>
Cc: Dario Faggioli <raistlin@linux.it>
Cc: Michael Trimarchi <michael@amarulasolutions.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1411118561-26323-2-git-send-email-juri.lelli@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched/numa: Kill the wrong/dead TASK_DEAD check in task_numa_fault()

current->state == TASK_DEAD means that the task is doing its
last schedule(), page fault is obviously impossible at this
stage.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140921194743.GA30114@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched: Clean up some typos and grammatical errors in code/comments

Signed-off-by: Zhihui Zhang <zzhsuny@gmail.com>
Cc: peterz@infradead.org
Link: http://lkml.kernel.org/r/1411262676-19928-1-git-send-email-zzhsuny@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched: Test the CPU's capacity in wake_affine()

Currently the task always wakes affine on this_cpu if the latter is idle.
Before waking up the task on this_cpu, we check that this_cpu capacity is not
significantly reduced because of RT tasks or irq activity.

Use case where the number of irq and/or the time spent under irq is important
will take benefit of this because the task that is woken up by irq or softirq
will not use the same CPU than irq (and softirq) but a idle one.

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: preeti@linux.vnet.ibm.com
Cc: riel@redhat.com
Cc: Morten.Rasmussen@arm.com
Cc: efault@gmx.de
Cc: nicolas.pitre@linaro.org
Cc: daniel.lezcano@linaro.org
Cc: dietmar.eggemann@arm.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1409051215-16788-8-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

ARM: topology: Use the new cpu_capacity interface

Use the new arch_scale_cpu_capacity() scheduler facility in order to reflect
the original capacity of a CPU instead of arch_scale_freq_capacity() which is
more linked to a scaling of the capacity linked to the frequency.

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: preeti@linux.vnet.ibm.com
Cc: riel@redhat.com
Cc: Morten.Rasmussen@arm.com
Cc: efault@gmx.de
Cc: daniel.lezcano@linaro.org
Cc: dietmar.eggemann@arm.com
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Brown <broonie@linaro.org>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: devicetree@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1409051215-16788-6-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched: Allow all architectures to set 'capacity_orig'

'capacity_orig' is only changed for systems with an SMT sched_domain level in order
to reflect the lower capacity of CPUs. Heterogenous systems also have to reflect an
original capacity that is different from the default value.

Create a more generic function arch_scale_cpu_capacity that can be also used by
non SMT platforms to set capacity_orig.

The __weak implementation of arch_scale_cpu_capacity() is the previous SMT variant,
in order to keep backward compatibility with the use of capacity_orig.

arch_scale_smt_capacity() and default_scale_smt_capacity() have been removed as
they were not used elsewhere than in arch_scale_cpu_capacity().

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Reviewed-by: Preeti U. Murthy <preeti@linux.vnet.ibm.com>
[ Added default_scale_cpu_capacity() back. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: riel@redhat.com
Cc: Morten.Rasmussen@arm.com
Cc: efault@gmx.de
Cc: nicolas.pitre@linaro.org
Cc: daniel.lezcano@linaro.org
Cc: dietmar.eggemann@arm.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1409051215-16788-5-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched: Fix avg_load computation

The computation of avg_load and avg_load_per_task should only take into
account the number of CFS tasks. The non-CFS tasks are already taken into
account by decreasing the CPU's capacity and they will be tracked in the
CPU's utilization (group_utilization) of the next patches.

Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: riel@redhat.com
Cc: Morten.Rasmussen@arm.com
Cc: efault@gmx.de
Cc: nicolas.pitre@linaro.org
Cc: daniel.lezcano@linaro.org
Cc: dietmar.eggemann@arm.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1409051215-16788-4-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched: Remove a wake_affine() condition

In wake_affine() I have tried to understand the meaning of the condition:

 (this_load <= load &&
  this_load + target_load(prev_cpu, idx) <= tl_per_task)

but I failed to find a use case that can take advantage of it and I haven't
found clear description in the previous commit's log.

Futhermore, the comment of the condition refers to the task_hot function that
was used before being replaced by the current condition:

/*
 * This domain has SD_WAKE_AFFINE and
 * p is cache cold in this domain, and
 * there is no bad imbalance.
 */

If we look more deeply the below condition:

 this_load + target_load(prev_cpu, idx) <= tl_per_task

When sync is clear, we have:

 tl_per_task = runnable_load_avg / nr_running
 this_load = max(runnable_load_avg, cpuload[idx])
 target_load =  max(runnable_load_avg', cpuload'[idx])

It implies that runnable_load_avg == 0 and nr_running <= 1 in order to match the
condition. This implies that runnable_load_avg == 0 too because of the
condition: this_load <= load.

but if this _load is null, 'balanced' is already set and the test is redundant.

If sync is set, it's not as straight forward as above (especially if cgroup
are involved) but the policy should be similar as we have removed a task that's
going to sleep in order to get a more accurate load and this_load values.

The current conclusion is that these additional condition don't give any benefit
so we can remove them.

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: preeti@linux.vnet.ibm.com
Cc: riel@redhat.com
Cc: Morten.Rasmussen@arm.com
Cc: efault@gmx.de
Cc: nicolas.pitre@linaro.org
Cc: daniel.lezcano@linaro.org
Cc: dietmar.eggemann@arm.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1409051215-16788-3-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched: Fix imbalance flag reset

The imbalance flag can stay set whereas there is no imbalance.

Let assume that we have 3 tasks that run on a dual cores /dual cluster system.
We will have some idle load balance which are triggered during tick.
Unfortunately, the tick is also used to queue background work so we can reach
the situation where short work has been queued on a CPU which already runs a
task. The load balance will detect this imbalance (2 tasks on 1 CPU and an idle
CPU) and will try to pull the waiting task on the idle CPU. The waiting task is
a worker thread that is pinned on a CPU so an imbalance due to pinned task is
detected and the imbalance flag is set.

Then, we will not be able to clear the flag because we have at most 1 task on
each CPU but the imbalance flag will trig to useless active load balance
between the idle CPU and the busy CPU.

We need to reset of the imbalance flag as soon as we have reached a balanced
state. If all tasks are pinned, we don't consider that as a balanced state and
let the imbalance flag set.

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: riel@redhat.com
Cc: Morten.Rasmussen@arm.com
Cc: efault@gmx.de
Cc: nicolas.pitre@linaro.org
Cc: daniel.lezcano@linaro.org
Cc: dietmar.eggemann@arm.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1409051215-16788-2-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched: Add default-disabled option to BUG() when stack end location is overwritten

Currently in the event of a stack overrun a call to schedule()
does not check for this type of corruption. This corruption is
often silent and can go unnoticed. However once the corrupted
region is examined at a later stage, the outcome is undefined
and often results in a sporadic page fault which cannot be
handled.

This patch checks for a stack overrun and takes appropriate
action since the damage is already done, there is no point
in continuing.

Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: aneesh.kumar@linux.vnet.ibm.com
Cc: dzickus@redhat.com
Cc: bmr@redhat.com
Cc: jcastillo@redhat.com
Cc: oleg@redhat.com
Cc: riel@redhat.com
Cc: prarit@redhat.com
Cc: jgh@redhat.com
Cc: minchan@kernel.org
Cc: mpe@ellerman.id.au
Cc: tglx@linutronix.de
Cc: rostedt@goodmis.org
Cc: hannes@cmpxchg.org
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Lubomir Rintel <lkundrak@v3.sk>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1410527779-8133-4-git-send-email-atomlin@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched: Add helper for task stack page overrun checking

This facility is used in a few places so let's introduce
a helper function to improve code readability.

Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: aneesh.kumar@linux.vnet.ibm.com
Cc: dzickus@redhat.com
Cc: bmr@redhat.com
Cc: jcastillo@redhat.com
Cc: oleg@redhat.com
Cc: riel@redhat.com
Cc: prarit@redhat.com
Cc: jgh@redhat.com
Cc: minchan@kernel.org
Cc: mpe@ellerman.id.au
Cc: tglx@linutronix.de
Cc: hannes@cmpxchg.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1410527779-8133-3-git-send-email-atomlin@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

init/main.c: Give init_task a canary

Tasks get their end of stack set to STACK_END_MAGIC with the
aim to catch stack overruns. Currently this feature does not
apply to init_task. This patch removes this restriction.

Note that a similar patch was posted by Prarit Bhargava
some time ago but was never merged:

  http://marc.info/?l=linux-kernel&m=127144305403241&w=2

Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: aneesh.kumar@linux.vnet.ibm.com
Cc: dzickus@redhat.com
Cc: bmr@redhat.com
Cc: jcastillo@redhat.com
Cc: jgh@redhat.com
Cc: minchan@kernel.org
Cc: tglx@linutronix.de
Cc: hannes@cmpxchg.org
Cc: Alex Thorlton <athorlton@sgi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Daeseok Youn <daeseok.youn@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Fabian Frederick <fabf@skynet.be>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Michael Opdenacker <michael.opdenacker@free-electrons.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1410527779-8133-2-git-send-email-atomlin@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched: Do not stop cpu in set_cpus_allowed_ptr() if task is not running

If a task is queued but not running on it rq, we can simply migrate
it without migration thread and switching of context.

Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1410519814.3569.7.camel@tkhai
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched/dl: Simplify pick_dl_task()

1) Nobody calls pick_dl_task() with negative cpu, it's old RT leftover.

2) If p->nr_cpus_allowed is 1, than the affinity has just been changed
  in set_cpus_allowed_ptr(); we'll pick it just earlier than migration
  thread.

Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1410529340.3569.27.camel@tkhai
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched/rt: Remove useless if from cleanup pick_next_task_rt()

_pick_next_task_rt() never returns NULL.

Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1410529321.3569.26.camel@tkhai
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched/core: Use put_prev_task() accessor where possible

Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1410529300.3569.25.camel@tkhai
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched/fair: cleanup: Remove useless assignment in select_task_rq_fair()

new_cpu is reassigned below, so we do not need this here.

Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1410529276.3569.24.camel@tkhai
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched, cleanup, treewide: Remove set_current_state(TASK_RUNNING) after schedule()

schedule(), io_schedule() and schedule_timeout() always return
with TASK_RUNNING state set, so one more setting is unnecessary.

(All places in patch are visible good, only exception is
 kiblnd_scheduler() from:

      drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c

 Its schedule() is one line above standard 3 lines of unified diff)

No places where set_current_state() is used for mb().

Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1410529254.3569.23.camel@tkhai
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Anil Belur <askb23@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dave Kleikamp <shaggy@kernel.org>
Cc: David Airlie <airlied@linux.ie>
Cc: David Howells <dhowells@redhat.com>
Cc: Dmitry Eremin <dmitry.eremin@intel.com>
Cc: Frank Blaschka <blaschka@linux.vnet.ibm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Isaac Huang <he.huang@intel.com>
Cc: James E.J. Bottomley <JBottomley@parallels.com>
Cc: James E.J. Bottomley <jejb@parisc-linux.org>
Cc: J. Bruce Fields <bfields@fieldses.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Laura Abbott <lauraa@codeaurora.org>
Cc: Liang Zhen <liang.zhen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Masaru Nomura <massa.nomura@gmail.com>
Cc: Michael Opdenacker <michael.opdenacker@free-electrons.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Oleg Drokin <green@linuxhacker.ru>
Cc: Peng Tao <bergwolf@gmail.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Robert Love <robert.w.love@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: Ursula Braun <ursula.braun@de.ibm.com>
Cc: Zi Shen Lim <zlim.lnx@gmail.com>
Cc: devel@driverdev.osuosl.org
Cc: dm-devel@redhat.com
Cc: dri-devel@lists.freedesktop.org
Cc: fcoe-devel@open-fcoe.org
Cc: jfs-discussion@lists.sourceforge.net
Cc: linux390@de.ibm.com
Cc: linux-afs@lists.infradead.org
Cc: linux-cris-kernel@axis.com
Cc: linux-kernel@vger.kernel.org
Cc: linux-nfs@vger.kernel.org
Cc: linux-parisc@vger.kernel.org
Cc: linux-raid@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: linux-scsi@vger.kernel.org
Cc: qla2xxx-upstream@qlogic.com
Cc: user-mode-linux-devel@lists.sourceforge.net
Cc: user-mode-linux-user@lists.sourceforge.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched, time: Fix lock inversion in thread_group_cputime()

The sig->stats_lock nests inside the tasklist_lock and the
sighand->siglock in __exit_signal and wait_task_zombie.

However, both of those locks can be taken from irq context,
which means we need to use the interrupt safe variant of
read_seqbegin_or_lock. This blocks interrupts when the "lock"
branch is taken (seq is odd), preventing the lock inversion.

On the first (lockless) pass through the loop, irqs are not
blocked.

Reported-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: prarit@redhat.com
Cc: oleg@redhat.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1410527535-9814-3-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

seqlock: Add irqsave variant of read_seqbegin_or_lock()

There are cases where read_seqbegin_or_lock() needs to block irqs,
because the seqlock in question nests inside a lock that is also
be taken from irq context.

Add read_seqbegin_or_lock_irqsave() and done_seqretry_irqrestore(), which
are almost identical to read_seqbegin_or_lock() and done_seqretry().

Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: prarit@redhat.com
Cc: oleg@redhat.com
Cc: sgruszka@redhat.com
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Trond Myklebust <trond.myklebust@primarydata.com>
Link: http://lkml.kernel.org/r/1410527535-9814-2-git-send-email-riel@redhat.com
[ Improved the readability of the code a bit. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

cpuidle: Use wake_up_all_idle_cpus() to wake up all idle cpus

Currently kick_all_cpus_sync() or smp_call_function() can not
break the polling idle cpu immediately.

Instead using wake_up_all_idle_cpus() which can wake up the polling idle
cpu quickly is much more helpful for power.

Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: linux-pm@vger.kernel.org
Cc: changcheng.liu@intel.com
Cc: xiaoming.wang@intel.com
Cc: souvik.k.chakravarty@intel.com
Cc: luto@amacapital.net
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: linux-pm@vger.kernel.org
Link: http://lkml.kernel.org/r/1409815075-4180-3-git-send-email-chuansheng.liu@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

smp: Add new wake_up_all_idle_cpus() function

Currently kick_all_cpus_sync() can break non-polling idle cpus
thru IPI interrupts.

But sometimes we need to break the polling idle cpus immediately
to reselect the suitable c-state, also for non-idle cpus, we need
to do nothing if we try to wake up them.

Here adding one new function wake_up_all_idle_cpus() to let all cpus
out of idle based on function wake_up_if_idle().

Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: daniel.lezcano@linaro.org
Cc: rjw@rjwysocki.net
Cc: linux-pm@vger.kernel.org
Cc: changcheng.liu@intel.com
Cc: xiaoming.wang@intel.com
Cc: souvik.k.chakravarty@intel.com
Cc: luto@amacapital.net
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@fb.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Roman Gushchin <klamm@yandex-team.ru>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1409815075-4180-2-git-send-email-chuansheng.liu@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched: Add new API wake_up_if_idle() to wake up the idle cpu

Implementing one new API wake_up_if_idle(), which is used to
wake up the idle CPU.

Suggested-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: daniel.lezcano@linaro.org
Cc: rjw@rjwysocki.net
Cc: linux-pm@vger.kernel.org
Cc: changcheng.liu@intel.com
Cc: xiaoming.wang@intel.com
Cc: souvik.k.chakravarty@intel.com
Cc: chuansheng.liu@intel.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1409815075-4180-1-git-send-email-chuansheng.liu@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched/numa: Use select_idle_sibling() to select a destination for task_numa_move()

The code in task_numa_compare() will only examine at most one idle CPU per node,
because they all have the same score. However, some idle CPUs are better
candidates than others, due to busy or idle SMT siblings, etc...

The scheduler has logic to find the best CPU within an LLC to place a
task. The NUMA code should probably use it.

This seems to reduce the standard deviation for single instance SPECjbb2005
with a low warehouse count on my 4 node test system.

Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: mgorman@suse.de
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140904163530.189d410a@cuia.bos.redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Documentation/scheduler/sched-deadline.txt: Add minimal main() appendix

Add an appendix providing a simple self-contained code snippet
showing how SCHED_DEADLINE reservations can be created by
application developers.

Signed-off-by: Juri Lelli <juri.lelli@arm.com>
Reviewed-by: Henrik Austad <henrik@austad.us>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Dario Faggioli <raistlin@linux.it>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1410256636-26171-6-git-send-email-juri.lelli@arm.com
[ Fixed some whitespace inconsistencies. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Documentation/scheduler/sched-deadline.txt: Add tests suite appendix

Add an appendix briefly describing tools that can be used to
test SCHED_DEADLINE (and the scheduler in general). Links to
where source code of the tools is hosted are also provided.

Signed-off-by: Juri Lelli <juri.lelli@arm.com>
Reviewed-by: Henrik Austad <henrik@austad.us>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Dario Faggioli <raistlin@linux.it>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1410256636-26171-5-git-send-email-juri.lelli@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Documentation/scheduler/sched-deadline.txt: Improve and clarify AC bits

Admission control is of key importance for SCHED_DEADLINE, since
it guarantees system schedulability (or tells us something about
the degree of guarantees we can provide to the user).

This patch improves and clarifies bits and pieces regarding AC,
both for UP and SMP systems.

Signed-off-by: Luca Abeni <luca.abeni@unitn.it>
Signed-off-by: Juri Lelli <juri.lelli@arm.com>
Reviewed-by: Henrik Austad <henrik@austad.us>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Dario Faggioli <raistlin@linux.it>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1410256636-26171-4-git-send-email-juri.lelli@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Documentation/scheduler/sched-deadline.txt: Rewrite section 4 intro

Section 4 intro was still describing the old interface. Rewrite
it.

Signed-off-by: Juri Lelli <juri.lelli@arm.com>
Signed-off-by: Luca Abeni <luca.abeni@unitn.it>
Reviewed-by: Henrik Austad <henrik@austad.us>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Dario Faggioli <raistlin@linux.it>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1410256636-26171-3-git-send-email-juri.lelli@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Documentation/scheduler/sched-deadline.txt: Fix terminology and improve clarity

Several small changes regarding SCHED_DEADLINE documentation
that fix terminology and improve clarity and readability:

 - "current runtime" becomes "remaining runtime"

 - readablity of an equation is improved by introducing more spacing

 - clarify when admission control will certainly fail

 - new URL for CBS technical report

 - substitue "smallest" with "earliest"

Signed-off-by: Luca Abeni <luca.abeni@unitn.it>
Signed-off-by: Juri Lelli <juri.lelli@arm.com>
Reviewed-by: Henrik Austad <henrik@austad.us>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Dario Faggioli <raistlin@linux.it>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1410256636-26171-2-git-send-email-juri.lelli@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched: Reduce contention in update_cfs_rq_blocked_load()

When running workloads on 2+ socket systems, based on perf profiles, the
update_cfs_rq_blocked_load() function often shows up as taking up a
noticeable % of run time.

Much of the contention is in __update_cfs_rq_tg_load_contrib() when we
update the tg load contribution stats.  However, it turns out that in many
cases, they don't need to be updated and "tg_contrib" is 0.

This patch adds a check in __update_cfs_rq_tg_load_contrib() to skip updating
tg load contribution stats when nothing needs to be updated. This reduces the
cacheline contention that would be unnecessary.

Reviewed-by: Ben Segall <bsegall@google.com>
Reviewed-by: Waiman Long <Waiman.Long@hp.com>
Signed-off-by: Jason Low <jason.low2@hp.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Turner <pjt@google.com>
Cc: jason.low2@hp.com
Cc: Yuyang Du <yuyang.du@intel.com>
Cc: Aswin Chandramouleeswaran <aswin@hp.com>
Cc: Chegu Vinod <chegu_vinod@hp.com>
Cc: Scott J Norton <scott.norton@hp.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1409643684.19197.15.camel@j-VirtualBox
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched: Migrate waking tasks

Current code can fail to migrate a waking task (silently) when TTWU_QUEUE is
enabled.

When a task is waking, it is pending on the wake_list of the rq, but it is not
queued (task->on_rq == 0). In this case, set_cpus_allowed_ptr() and
__migrate_task() will not migrate it because its invisible to them.

This behavior is incorrect, because the task has been already woken, it will be
running on the wrong CPU without correct placement until the next wake-up or
update for cpus_allowed.

To fix this problem, we need to finish the wakeup (so they appear on
the runqueue) before we migrate them.

Reported-by: Sasha Levin <sasha.levin@oracle.com>
Reported-by: Jason J. Herne <jjherne@linux.vnet.ibm.com>
Tested-by: Jason J. Herne <jjherne@linux.vnet.ibm.com>
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/538ED7EB.5050303@cn.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched, time: Atomically increment stime & utime

The functions task_cputime_adjusted and thread_group_cputime_adjusted()
can be called locklessly, as well as concurrently on many different CPUs.

This can occasionally lead to the utime and stime reported by times(), and
other syscalls like it, going backward. The cause for this appears to be
multiple threads racing in cputime_adjust(), both with values for utime or
stime that is larger than the original, but each with a different value.

Sometimes the larger value gets saved first, only to be immediately
overwritten with a smaller value by another thread.

Using atomic exchange prevents that problem, and ensures time
progresses monotonically.

Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: umgwanakikbuti@gmail.com
Cc: fweisbec@gmail.com
Cc: akpm@linux-foundation.org
Cc: srao@redhat.com
Cc: lwoodman@redhat.com
Cc: atheurer@redhat.com
Cc: oleg@redhat.com
Link: http://lkml.kernel.org/r/1408133138-22048-4-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

time, signal: Protect resource use statistics with seqlock

Both times() and clock_gettime(CLOCK_PROCESS_CPUTIME_ID) have scalability
issues on large systems, due to both functions being serialized with a
lock.

The lock protects against reporting a wrong value, due to a thread in the
task group exiting, its statistics reporting up to the signal struct, and
that exited task's statistics being counted twice (or not at all).

Protecting that with a lock results in times() and clock_gettime() being
completely serialized on large systems.

This can be fixed by using a seqlock around the events that gather and
propagate statistics. As an additional benefit, the protection code can
be moved into thread_group_cputime(), slightly simplifying the calling
functions.

In the case of posix_cpu_clock_get_task() things can be simplified a
lot, because the calling function already ensures that the task sticks
around, and the rest is now taken care of in thread_group_cputime().

This way the statistics reporting code can run lockless.

Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alex Thorlton <athorlton@sgi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Daeseok Youn <daeseok.youn@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guillaume Morin <guillaume@morinfr.org>
Cc: Ionut Alexa <ionut.m.alexa@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Michal Schmidt <mschmidt@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Cc: umgwanakikbuti@gmail.com
Cc: fweisbec@gmail.com
Cc: srao@redhat.com
Cc: lwoodman@redhat.com
Cc: atheurer@redhat.com
Link: http://lkml.kernel.org/r/20140816134010.26a9b572@annuminas.surriel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

exit: Always reap resource stats in __exit_signal()

Oleg pointed out that wait_task_zombie adds a task's usage statistics
to the parent's signal struct, but the task's own signal struct should
also propagate the statistics at exit time.

This allows thread_group_cputime(reaped_zombie) to get the statistics
after __unhash_process() has made the task invisible to for_each_thread,
but before the thread has actually been rcu freed, making sure no
non-monotonic results are returned inside that window.

Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Guillaume Morin <guillaume@morinfr.org>
Cc: Ionut Alexa <ionut.m.alexa@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Michal Schmidt <mschmidt@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: umgwanakikbuti@gmail.com
Cc: fweisbec@gmail.com
Cc: srao@redhat.com
Cc: lwoodman@redhat.com
Cc: atheurer@redhat.com
Link: http://lkml.kernel.org/r/1408133138-22048-2-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge tag 'v3.17-rc4' into sched/core, to prevent conflicts with upcoming patches, and to refresh the tree

Linux 3.17-rc4

Linux 3.17-rc4

Documentation: new page link in SubmittingPatches

new link for - How to piss off a Linux kernel subsystem maintainer

Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation: NFS/RDMA: Document separate Kconfig symbols

The NFS/RDMA Kconfig symbol was split into separate options for client
and server in commit 2e8c12e1b765 ("xprtrdma: add separate Kconfig
options for NFSoRDMA client and server support").

Update the documentation to reflect this split.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: "J. Bruce Fields" <bfields@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation: misc-devices: Rename freefall.c from hpfall.c in lis2lv02d

hpfall.c was renamed to freefall.c in 3.16, but this file still refer to
hpfall.c instead of freefall.c

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation: i2c: rename variable "register" to "reg"

The example code provided with the i2c device interface documentation
won't compile since it uses the reserved word "register" to name a
variable.

The compiler fails with this error message:

 error: expected identifier or '(' before '=' token
   __u8 register = 0x20; /* Device register to access */
                 ^

Rename the variable "register" to simply "reg" in the example code.

Another couple of typos has been fixed as well.
[Change "! =" to "!=".]

Signed-off-by: Jose Alarcon Roldan <jose.alarcon.roldan@gmail.com>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation: seq_file: Document seq_open_private(), seq_release_private()

Despite the fact that these functions have been around for years, they
are little used (only 15 uses in 13 files at the preseht time) even
though many other files use work-arounds to achieve the same result.

By documenting them, hopefully they will become more widely used.

Signed-off-by: Rob Jones <rob.jones@codethink.co.uk>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge tag 'pm+acpi-3.17-rc4' of git://git./linux/kernel/git/rafael/linux-pm

Pull ACPI and power management fixes from Rafael Wysocki:
 "These are regression fixes (ACPI sysfs, ACPI video, suspend test),
  ACPI cpuidle deadlock fix, missing runtime validation of ACPI _DSD
  output, a fix and a new CPU ID for the RAPL driver, new blacklist
  entry for the ACPI EC driver and a couple of trivial cleanups
  (intel_pstate and generic PM domains).

  Specifics:

   - Fix for recently broken test_suspend= command line argument (Rafael
     Wysocki).

   - Fixes for regressions related to the ACPI video driver caused by
     switching the default to native backlight handling in 3.16 from
     Hans de Goede.

   - Fix for a sysfs attribute of ACPI device objects that returns stale
     values sometimes due to the fact that they are cached instead of
     executing the appropriate method (_SUN) every time (broken in
     3.14).  From Yasuaki Ishimatsu.

   - Fix for a deadlock between cpuidle_lock and cpu_hotplug.lock in the
     ACPI processor driver from Jiri Kosina.

   - Runtime output validation for the ACPI _DSD device configuration
     object missing from the support for it that has been introduced
     recently.  From Mika Westerberg.

   - Fix for an unuseful and misleading RAPL (Running Average Power
     Limit) domain detection message in the RAPL driver from Jacob Pan.

   - New Intel Haswell CPU ID for the RAPL driver from Jason Baron.

   - New Clevo W350etq blacklist entry for the ACPI EC driver from Lan
     Tianyu.

   - Cleanup for the intel_pstate driver and the core generic PM domains
     code from Gabriele Mazzotta and Geert Uytterhoeven"

* tag 'pm+acpi-3.17-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI / cpuidle: fix deadlock between cpuidle_lock and cpu_hotplug.lock
  ACPI / scan: not cache _SUN value in struct acpi_device_pnp
  cpufreq: intel_pstate: Remove unneeded variable
  powercap / RAPL: change domain detection message
  powercap / RAPL: add support for CPU model 0x3f
  PM / domains: Make generic_pm_domain.name const
  PM / sleep: Fix test_suspend= command line option
  ACPI / EC: Add msi quirk for Clevo W350etq
  ACPI / video: Disable native_backlight on HP ENVY 15 Notebook PC
  ACPI / video: Add a disable_native_backlight quirk
  ACPI / video: Fix use_native_backlight selection logic
  ACPICA: ACPI 5.1: Add support for runtime validation of _DSD package.

Merge branch 'for-linus' of git://git./linux/kernel/git/viro/vfs

Pull filesystem fixes from Al Viro:
 "Several bugfixes (all of them -stable fodder).

  Alexey's one deals with double mutex_lock() in UFS (apparently, nobody
  has tried to test "ufs: sb mutex merge + mutex_destroy" on something
  like file creation/removal on ufs).  Mine deal with two kinds of
  umount bugs, in umount propagation and in handling of automounted
  submounts, both resulting in bogus transient EBUSY from umount"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  ufs: fix deadlocks introduced by sb mutex merge
  fix EBUSY on umount() from MNT_SHRINKABLE
  get rid of propagate_umount() mistakenly treating slaves as busy.

Merge branch 'core-urgent-for-linus' of git://git./linux/kernel/git/tip/tip

Pull RCU fix from Ingo Molnar:
 "A boot hang fix for the offloaded callback RCU model (RCU_NOCB_CPU=y
  && (TREE_CPU=y || TREE_PREEMPT_RC)) in certain bootup scenarios"

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  rcu: Make nocb leader kthreads process pending callbacks after spawning

Merge branch 'timers-urgent-for-linus' of git://git./linux/kernel/git/tip/tip

Pull timer fixes from Thomas Gleixner:
 "Three fixlets from the timer departement:

   - Update the timekeeper before updating vsyscall and pvclock.  This
     fixes the kvm-clock regression reported by Chris and Paolo.

   - Use the proper irq work interface from NMI.  This fixes the
     regression reported by Catalin and Dave.

   - Clarify the compat_nanosleep error handling mechanism to avoid
     future confusion"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timekeeping: Update timekeeper before updating vsyscall and pvclock
  compat: nanosleep: Clarify error handling
  nohz: Restore NMI safe local irq work for local nohz kick

ufs: fix deadlocks introduced by sb mutex merge

Commit 0244756edc4b ("ufs: sb mutex merge + mutex_destroy") introduces
deadlocks in ufs_new_inode() and ufs_free_inode().
Most callers of that functions acqure the mutex by themselves and
ufs_{new,free}_inode() do that via lock_ufs(),
i.e we have an unavoidable double lock.

The patch proposes to resolve the issue by making sure that
ufs_{new,free}_inode() are not called with the mutex held.

Found by Linux Driver Verification project (linuxtesting.org).

Cc: stable@vger.kernel.org # 3.16
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

sched/deadline: Fix a precision problem in the microseconds range

An overrun could happen in function start_hrtick_dl()
when a task with SCHED_DEADLINE runs in the microseconds
range.

For example, if a task with SCHED_DEADLINE has the following parameters:

  Task  runtime  deadline  period
   P1   200us     500us    500us

The deadline and period from task P1 are less than 1ms.

In order to achieve microsecond precision, we need to enable HRTICK feature
by the next command:

  PC#echo "HRTICK" > /sys/kernel/debug/sched_features
  PC#trace-cmd record -e sched_switch &
  PC#./schedtool -E -t 200000:500000:500000 -e ./test

The binary test is in an endless while(1) loop here.
Some pieces of trace.dat are as follows:

  <idle>-0   157.603157: sched_switch: :R ==> 2481:4294967295: test
  test-2481  157.603203: sched_switch:  2481:R ==> 0:120: swapper/2
  <idle>-0   157.605657: sched_switch:  :R ==> 2481:4294967295: test
  test-2481  157.608183: sched_switch:  2481:R ==> 2483:120: trace-cmd
  trace-cmd-2483 157.609656: sched_switch:2483:R==>2481:4294967295: test

We can get the runtime of P1 from the information above:

  runtime = 157.608183 - 157.605657
  runtime = 0.002526(2.526ms)

The correct runtime should be less than or equal to 200us at some point.

The problem is caused by a conditional judgment "delta > 10000"
in function start_hrtick_dl().

Because no hrtimer start up to control the rest of runtime
when the reset of runtime is less than 10us.

So the process will continue to run until tick-period is coming.

Move the code with the limit of the least time slice
from hrtick_start_fair() to hrtick_start() because the
EDF schedule class also needs this function in start_hrtick_dl().

To fix this problem, we call hrtimer_start() unconditionally in
start_hrtick_dl(), and make sure the scheduling slice won't be smaller
than 10us in hrtimer_start().

Signed-off-by: Xiaofeng Yan <xiaofeng.yan@huawei.com>
Reviewed-by: Li Zefan <lizefan@huawei.com>
Acked-by: Juri Lelli <juri.lelli@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1409022941-5880-1-git-send-email-xiaofeng.yan@huawei.com
[ Massaged the changelog and the code. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge tag 'for-linus' of git://git./virt/kvm/kvm

Pull kvm fixes from Paolo Bonzini:
 "A smattering of bug fixes across most architectures"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  powerpc/kvm/cma: Fix panic introduces by signed shift operation
  KVM: s390/mm: Fix guest storage key corruption in ptep_set_access_flags
  KVM: s390/mm: Fix storage key corruption during swapping
  arm/arm64: KVM: Complete WFI/WFE instructions
  ARM/ARM64: KVM: Nuke Hyp-mode tlbs before enabling MMU
  KVM: s390/mm: try a cow on read only pages for key ops
  KVM: s390: Fix user triggerable bug in dead code

Merge tag 'fixes-for-linus' of git://git./linux/kernel/git/arm/arm-soc

Pull ARM SoC fixes from Kevin Hilman:
 "Another round of fixes from arm-soc land, which are mostly DT fixes
  for:

   - OMAP: handful of DT fixes devices on newly supported hardware
   - davinci: fix 2nd EDMA channel
   - ux500: extend previous pinctrl fix to another board
   - at91: clock registration fixes, compatibility string precision

  And one more fix for event cleanup in drivers/bus/arm-ccn"

* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  bus: arm-ccn: Move event cleanup routine
  ARM: at91/dt: rm9200: fix usb clock definition
  ARM: at91: rm9200: fix clock registration
  ARM: at91/dt: sam9g20: set at91sam9g20 pllb driver
  ARM: dts: dra7-evm: Add vtt regulator support
  ARM: dts: dra7-evm: Fix spi1 mux documentation
  ARM: dts: am43x-epos-evm: Disable QSPI to prevent conflict with GPMC-NAND
  ARM: OMAP2+: gpmc: Don't complain if wait pin is used without r/w monitoring
  ARM: dts: am43xx-epos-evm: Don't use read/write wait monitoring
  ARM: dts: am437x-gp-evm: Don't use read/write wait monitoring
  ARM: dts: am437x-gp-evm: Use BCH16 ECC scheme instead of BCH8
  ARM: dts: am43x-epos-evm: Use BCH16 ECC scheme instead of BCH8
  ARM: dts: am4372: fix USB regs size
  ARM: dts: am437x-gp: switch i2c0 to 100KHz
  ARM: dts: dra7-evm: Fix 8th NAND partition's name
  ARM: dts: dra7-evm: Fix i2c3 pinmux and frequency
  ARM: ux500: disable msp2 node on Snowball
  ARM: edma: Fix configuration parsing for SoCs with multiple eDMA3 CC
  ARM: dts: set 'ti,set-rate-parent' for dpll4_m5x2 clock

Merge tag 'xfs-for-linus-3.17-rc3' of git://git./linux/kernel/git/dgc/linux-xfs

Pull xfs fixes from Dave Chinner:
 "The fixes all address recently discovered data corruption issues.

  The original Direct IO issue was discovered by Chris Mason @ Facebook
  on a production workload which mixed buffered reads with direct reads
  and writes IO to the same file.  The fix for that exposed other issues
  with page invalidation (exposed by millions of fsx operations) failing
  due to dirty buffers beyond EOF.

  Finally, the collapse_range code could also cause problems due to
  racing writeback changing the extent map while it was being shifted
  around.  The commits for that problem are simple mitigation fixes that
  prevent the problem from occuring.  A more robust fix for 3.18 that
  addresses the underlying problem is currently being worked on by
  Brian.

  Summary of fixes:
   - a direct IO read/buffered read data corruption
   - the associated fallout from the DIO data corruption fix
   - collapse range bugs that are potential data corruption issues"

* tag 'xfs-for-linus-3.17-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs:
  xfs: trim eofblocks before collapse range
  xfs: xfs_file_collapse_range is delalloc challenged
  xfs: don't log inode unless extent shift makes extent modifications
  xfs: use ranged writeback and invalidation for direct IO
  xfs: don't zero partial page cache pages during O_DIRECT writes
  xfs: don't zero partial page cache pages during O_DIRECT writes
  xfs: don't dirty buffers beyond EOF

Merge tag 'for-linus-20140905' of git://git.infradead.org/linux-mtd

Pull mtd fixes from Brian Norris:
 "Two trivial MTD updates for 3.17-rc4:

   - a tiny comment tweak, to kill a bunch of DocBook warnings added
     during the merge window

   - a small fixup to the OTP routines' error handling"

* tag 'for-linus-20140905' of git://git.infradead.org/linux-mtd:
  mtd: nand: fix DocBook warnings on nand_sdr_timings doc
  mtd: cfi_cmdset_0002: check return code for get_chip()

timekeeping: Update timekeeper before updating vsyscall and pvclock

The update_walltime() code works on the shadow timekeeper to make the
seqcount protected region as short as possible. But that update to the
shadow timekeeper does not update all timekeeper fields because it's
sufficient to do that once before it becomes life. One of these fields
is tkr.base_mono. That stays stale in the shadow timekeeper unless an
operation happens which copies the real timekeeper to the shadow.

The update function is called after the update calls to vsyscall and
pvclock. While not correct, it did not cause any problems because none
of the invoked update functions used base_mono.

commit cbcf2dd3b3d4 (x86: kvm: Make kvm_get_time_and_clockread()
nanoseconds based) changed that in the kvm pvclock update function, so
the stale mono_base value got used and caused kvm-clock to malfunction.

Put the update where it belongs and fix the issue.

Reported-by: Chris J Arges <chris.j.arges@canonical.com>
Reported-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1409050000570.3333@nanos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

compat: nanosleep: Clarify error handling

The error handling in compat_sys_nanosleep() is correct, but
completely non obvious. Document it and restrict it to the
-ERESTART_RESTARTBLOCK return value for clarity.

Reported-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Merge branch 'i2c/for-current' of git://git./linux/kernel/git/wsa/linux

Pull i2c bugfixes from Wolfram Sang:
 "I2C driver bugfixes for the 3.17 release.  Details can be found in the
  commit messages, yet I think this is typical driver stuff"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  Revert "i2c: rcar: remove spinlock"
  i2c: at91: add bound checking on SMBus block length bytes
  i2c: rk3x: fix bug that cause transfer fails in master receive mode
  i2c: at91: Fix a race condition during signal handling in at91_do_twi_xfer.
  i2c: mv64xxx: continue probe when clock-frequency is missing
  i2c: rcar: fix MNR interrupt handling

Merge tag 'at91-fixes' of git://github.com/at91linux/linux-at91 into fixes

Merge "at91: fixes for 3.17 #1" from Nicols Ferre:

First AT91 fixes batch for 3.17:
- compatibility string precision
- clock registration and USB DT fix for at91rm9200

* tag 'at91-fixes' of git://github.com/at91linux/linux-at91:
  ARM: at91/dt: rm9200: fix usb clock definition
  ARM: at91: rm9200: fix clock registration
  ARM: at91/dt: sam9g20: set at91sam9g20 pllb driver

Signed-off-by: Kevin Hilman <khilman@linaro.org>

bus: arm-ccn: Move event cleanup routine

The function cleaning up an initialized event
was called from the "event_del" handler, instead
of being used as the "destroy" callback. In case of
events group allocation this caused NULL pointer
dereference (as events are added and deleted
multiple times then). Fixed now.

Signed-off-by: Pawel Moll <mail@pawelmoll.com>
Signed-off-by: Kevin Hilman <khilman@linaro.org>

Merge branch 'for-linus' of git://git./linux/kernel/git/geert/linux-m68k

Pull m68k updates from Geert Uytterhoeven:
 "Wire up new syscalls getrandom and memfd_create"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k:
  m68k: Wire up memfd_create
  m68k: Wire up getrandom

ARM: at91/dt: rm9200: fix usb clock definition

The atmel,clk-divisors property is taking 4 divisors, if less are
provided, the clock registration will fail.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>

ARM: at91: rm9200: fix clock registration

Actually register clocks from device tree when using the common clock
framework.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
[nicolas.ferre@atmel.com: add at91 to function name]
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>

ARM: at91/dt: sam9g20: set at91sam9g20 pllb driver

The at91sam9g20 SOC uses its own pllb implementation which is different
from the one inherited from at91sam9260 SOC.

Signed-off-by: Gaël PORTAY <gael.portay@gmail.com>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>

mm: memcontrol: revert use of root_mem_cgroup res_counter

Dave Hansen reports a massive scalability regression in an uncontained
page fault benchmark with more than 30 concurrent threads, which he
bisected down to 05b843012335 ("mm: memcontrol: use root_mem_cgroup
res_counter") and pin-pointed on res_counter spinlock contention.

That change relied on the per-cpu charge caches to mostly swallow the
res_counter costs, but it's apparent that the caches don't scale yet.

Revert memcg back to bypassing res_counters on the root level in order
to restore performance for uncontained workloads.

Reported-by: Dave Hansen <dave@sr71.net>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Tested-by: Dave Hansen <dave.hansen@intel.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Export sync_filesystem() for modular ->remount_fs() use

This patch changes sync_filesystem() to be EXPORT_SYMBOL().

The reason this is needed is that starting with 3.15 kernel, due to
Theodore Ts'o's commit 02b9984d6408 ("fs: push sync_filesystem() down to
the file system's remount_fs()"), all file systems that have dirty data
to be written out need to call sync_filesystem() from their
->remount_fs() method when remounting read-only.

As this is now a generically required function rather than an internal
only function it should be EXPORT_SYMBOL() so that all file systems can
call it.

Signed-off-by: Anton Altaparmakov <aia21@cantab.net>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge tag 'regulator-v3.17-rc3' of git://git./linux/kernel/git/broonie/regulator

Pull regulator documentation fixes from Mark Brown:
 "All the fixes people have found for the regulator API have been
  documentation fixes, avoiding warnings while building the kerneldoc,
  fixing some errors in one of the DT bindings documents and fixing some
  typos in the header"

* tag 'regulator-v3.17-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator:
  regulator: fix kernel-doc warnings in header files
  regulator: Proofread documentation
  regulator: tps65090: Fix tps65090 typos in example

Merge tag 'omap-fixes-against-v3.17-rc3' of git://git./linux/kernel/git/tmlind/linux-omap into fixes

Merge "omap fixes against v3.17-rc3" from Tony Lindgren:

Few fixes for omaps mostly for various devices to get them working
properly on the new am437x and dra7 hardware for several devices
such as I2C, NAND, DDR3 and USB. There's also a clock fix for omap3.

And also included are two minor cosmetic fixes that are not
stictly fixes for the new hardware support added recently to
downgrade a GPMC warning into a debug statement, and fix the
confusing comments for dra7-evm spi1 mux.

Note that these are all .dts changes except for a GPMC change.

* tag 'omap-fixes-against-v3.17-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap: (255 commits)
  ARM: dts: dra7-evm: Add vtt regulator support
  ARM: dts: dra7-evm: Fix spi1 mux documentation
  ARM: dts: am43x-epos-evm: Disable QSPI to prevent conflict with GPMC-NAND
  ARM: OMAP2+: gpmc: Don't complain if wait pin is used without r/w monitoring
  ARM: dts: am43xx-epos-evm: Don't use read/write wait monitoring
  ARM: dts: am437x-gp-evm: Don't use read/write wait monitoring
  ARM: dts: am437x-gp-evm: Use BCH16 ECC scheme instead of BCH8
  ARM: dts: am43x-epos-evm: Use BCH16 ECC scheme instead of BCH8
  ARM: dts: am4372: fix USB regs size
  ARM: dts: am437x-gp: switch i2c0 to 100KHz
  ARM: dts: dra7-evm: Fix 8th NAND partition's name
  ARM: dts: dra7-evm: Fix i2c3 pinmux and frequency
  Linux 3.17-rc3
  ...

Signed-off-by: Kevin Hilman <khilman@linaro.org>

Merge tag 'gpio-v3.17-3' of git://git./linux/kernel/git/linusw/linux-gpio

Pull GPIO fixes from Linus Walleij:
 - some documentation sync
 - resource leak in the bt8xx driver
 - again fix the way varargs are used to handle the optional flags on
   the gpiod_* accessors.  Now hopefully nailed the entire problem.

* tag 'gpio-v3.17-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio:
  gpio: move varargs hack outside #ifdef GPIOLIB
  gpio: bt8xx: fix release of managed resources
  Documentation: gpio: documentation for optional getters functions

Merge branch 'drm-fixes' of git://people.freedesktop.org/~airlied/linux

Pull drm fixes from Dave Airlie:
 - i915 fixes: a few display regressions
 - vmwgfx: possible loop forever fix
 - nouveau: one userspace interface fix

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
  drm/nouveau/core: don't leak oclass type bits to user
  drm/i915: Fix lock dropping in intel_tv_detect()
  drm/i915: handle G45/GM45 pulse detection connected state.
  drm/vmwgfx: Fix a potential infinite spin waiting for fifo idle
  drm/vmwgfx: Fix an incorrect OOM return value
  drm/i915: Remove bogus __init annotation from DMI callbacks
  drm/i915: don't warn if backlight unexpectedly enabled
  drm/i915: Move intel_ddi_set_vc_payload_alloc(false) to haswell_crtc_disable()
  drm/i915: fix plane/cursor handling when runtime suspended
  drm/i915: Ignore VBT backlight presence check on Acer C720 (4005U)

Merge branches 'pm-sleep', 'powercap', 'pm-domains' and 'pm-cpufreq'

* pm-sleep:
  PM / sleep: Fix test_suspend= command line option

* powercap:
  powercap / RAPL: change domain detection message
  powercap / RAPL: add support for CPU model 0x3f

* pm-domains:
  PM / domains: Make generic_pm_domain.name const

* pm-cpufreq:
  cpufreq: intel_pstate: Remove unneeded variable

Merge branches 'acpi-video' and 'acpi-ec'

* acpi-video:
  ACPI / video: Disable native_backlight on HP ENVY 15 Notebook PC
  ACPI / video: Add a disable_native_backlight quirk
  ACPI / video: Fix use_native_backlight selection logic

* acpi-ec:
  ACPI / EC: Add msi quirk for Clevo W350etq

Merge branches 'acpica', 'acpi-processor' and 'acpi-scan'

* acpica:
  ACPICA: ACPI 5.1: Add support for runtime validation of _DSD package.

* acpi-processor:
  ACPI / cpuidle: fix deadlock between cpuidle_lock and cpu_hotplug.lock

* acpi-scan:
  ACPI / scan: not cache _SUN value in struct acpi_device_pnp

sched/wait: Document timeout corner case

The timeout may elapse without 0 being returned, such as when waiting
on an unused queue. Document this possibility.

Signed-off-by: Scot Doyle <lkml14@scotdoyle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/alpine.LNX.2.11.1408241710070.6462@localhost.localdomain
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge remote-tracking branches 'regulator/fix/doc' and 'regulator/fix/tps65090' into regulator-linus

sched/fair: Replace rcu_assign_pointer() with RCU_INIT_POINTER()

The use of "rcu_assign_pointer()" is NULLing out the pointer.
According to RCU_INIT_POINTER()'s block comment:

  "1.   This use of RCU_INIT_POINTER() is NULLing out the pointer"

it is better to use it instead of rcu_assign_pointer() because it has a
smaller overhead.

The following Coccinelle semantic patch was used:
 @@
 @@

 - rcu_assign_pointer
 + RCU_INIT_POINTER
   (..., NULL)

Signed-off-by: Andreea-Cristina Bernat <bernat.ada@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: paulmck@linux.vnet.ibm.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140822145043.GA580@ada
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge branch 'linux-3.17' of git://anongit.freedesktop.org/git/nouveau/linux-2.6 into drm-fixes

single fix for nouveau.

* 'linux-3.17' of git://anongit.freedesktop.org/git/nouveau/linux-2.6:
  drm/nouveau/core: don't leak oclass type bits to user

drm/nouveau/core: don't leak oclass type bits to user

Fixes not being able to init fence subsystem when multiple boards are
present.

Reported-by: Ilia Mirkin <imirkin@alum.mit.edu>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

Merge git://git.kvack.org/~bcrl/aio-fixes

Pull aio bugfixes from Ben LaHaise:
 "Two small fixes"

* git://git.kvack.org/~bcrl/aio-fixes:
  aio: block exit_aio() until all context requests are completed
  aio: add missing smp_rmb() in read_events_ring

aio: block exit_aio() until all context requests are completed

It seems that exit_aio() also needs to wait for all iocbs to complete (like
io_destroy), but we missed the wait step in current implemention, so fix
it in the same way as we did in io_destroy.

Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
Cc: stable@vger.kernel.org

nohz: Restore NMI safe local irq work for local nohz kick

The local nohz kick is currently used by perf which needs it to be
NMI-safe. Recent commit though (7d1311b93e58ed55f3a31cc8f94c4b8fe988a2b9)
changed its implementation to fire the local kick using the remote kick
API. It was convenient to make the code more generic but the remote kick
isn't NMI-safe.

As a result:

WARNING: CPU: 3 PID: 18062 at kernel/irq_work.c:72 irq_work_queue_on+0x11e/0x140()
CPU: 3 PID: 18062 Comm: trinity-subchil Not tainted 3.16.0+ #34
0000000000000009 00000000903774d1 ffff880244e06c00 ffffffff9a7f1e37
0000000000000000 ffff880244e06c38 ffffffff9a0791dd ffff880244fce180
0000000000000003 ffff880244e06d58 ffff880244e06ef8 0000000000000000
Call Trace:
<NMI>  [<ffffffff9a7f1e37>] dump_stack+0x4e/0x7a
[<ffffffff9a0791dd>] warn_slowpath_common+0x7d/0xa0
[<ffffffff9a07930a>] warn_slowpath_null+0x1a/0x20
[<ffffffff9a17ca1e>] irq_work_queue_on+0x11e/0x140
[<ffffffff9a10a2c7>] tick_nohz_full_kick_cpu+0x57/0x90
[<ffffffff9a186cd5>] __perf_event_overflow+0x275/0x350
[<ffffffff9a184f80>] ? perf_event_task_disable+0xa0/0xa0
[<ffffffff9a01a4cf>] ? x86_perf_event_set_period+0xbf/0x150
[<ffffffff9a187934>] perf_event_overflow+0x14/0x20
[<ffffffff9a020386>] intel_pmu_handle_irq+0x206/0x410
[<ffffffff9a0b54d3>] ? arch_vtime_task_switch+0x63/0x130
[<ffffffff9a01937b>] perf_event_nmi_handler+0x2b/0x50
[<ffffffff9a007b72>] nmi_handle+0xd2/0x390
[<ffffffff9a007aa5>] ? nmi_handle+0x5/0x390
[<ffffffff9a0d131b>] ? lock_release+0xab/0x330
[<ffffffff9a008062>] default_do_nmi+0x72/0x1c0
[<ffffffff9a0c925f>] ? cpuacct_account_field+0xcf/0x200
[<ffffffff9a008268>] do_nmi+0xb8/0x100

Lets fix this by restoring the use of local irq work for the nohz local
kick.

Reported-by: Catalin Iacob <iacobcatalin@gmail.com>
Reported-and-tested-by: Dave Jones <davej@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

Merge tag 'davinci-fixes-for-v3.17-rc4' of git://git./linux/kernel/git/nsekhar/linux-davinci into fixes

This patch fixes setup of second EDMA channel controller
on DA850.

* tag 'davinci-fixes-for-v3.17-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/nsekhar/linux-davinci:
  ARM: edma: Fix configuration parsing for SoCs with multiple eDMA3 CC

ARM: dts: dra7-evm: Add vtt regulator support

DRA7 evm REV G and later boards uses a vtt regulator for DDR3
termination and this is controlled by gpio7_11. This gpio is
configured in boot loader. gpio7_11, which is only available only on
Pad A22, in previous boards, is connected only to an unused pad on
expansion connector EXP_P3 and is safe to be muxed as GPIO on all
DRA7-evm versions (without a need to spin off another dts file).

Since gpio7_11 is used to control VTT and should not be reset or kept
in idle state during boot up else VTT will be disconnected and DDR
gets corrupted. So, as part of this change, mark gpio7 as no-reset and
no-idle on init.

Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

ARM: dts: dra7-evm: Fix spi1 mux documentation

While auditing the various pin ctrl configurations using the following
command:
grep PIN_ arch/arm/boot/dts/dra7-evm.dts|(while read line;
do
v=`echo "$line" | sed -e "s/\s\s*/|/g" | cut -d '|' -f1 |
cut -d 'x' -f2|tr [a-z] [A-Z]`;
HEX=`echo "obase=16;ibase=16;4A003400+$v"| bc`;
echo "$HEX ===> $line";
done)
against DRA75x/74x NDA TRM revision S(SPRUHI2S August 2014),
documentation errors were found for spi1 pinctrl. Fix the same.

Fixes: 6e58b8f1daaf1af ("ARM: dts: DRA7: Add the dts files for dra7 SoC and dra7-evm board")
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

ARM: dts: am43x-epos-evm: Disable QSPI to prevent conflict with GPMC-NAND

Both QSPI and GPMC-NAND share the same Pin (A8) from the SoC for Chip Select
functionality. So both can't be enabled simultaneously.

Disable QSPI node to prevent the pin conflict as well as
be similar to 3.12 release.

CC: Sourav Poddar <sourav.poddar@ti.com>
Signed-off-by: Roger Quadros <rogerq@ti.com>
Reviewed-by: Pekon Gupta <pekon@pek-sem.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

ARM: OMAP2+: gpmc: Don't complain if wait pin is used without r/w monitoring

For NAND read & write wait pin monitoring must be kept disabled as the
wait pin is only used to indicate NAND device ready status and not to
extend each read/write cycle.

So don't print a warning if wait pin is specified while read/write
monitoring is not in the device tree.

Sanity check wait pin number irrespective if read/write monitoring is
set or not.

Signed-off-by: Roger Quadros <rogerq@ti.com>
Reviewed-by: Pekon Gupta <pekon@pek-sem.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>