Commit Graph

118 Commits

Author SHA1 Message Date
T.Zhou 176cedc4ed sched/dl: Fix comment in pick_next_task_dl()
Fix cut & paste oversight:

  s/pull_rt_task/pull_dl_task

Signed-off-by: T.Zhou <t1zhou@163.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: juri.lelli@gmail.com
Link: http://lkml.kernel.org/r/20161123004832.GA2983@geo
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-23 10:23:21 +01:00
Daniel Bristot de Oliveira 9846d50df3 sched/deadline: Fix typo in a comment
In the comment:

        /*
         * The task might have changed its scheduling policy to something
         * different than SCHED_DEADLINE (through switched_fromd_dl()).
         */

s/fromd/from/

Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luca Abeni <luca.abeni@unitn.it>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/5408b3b3f9ee197a7b7f10fb834341100a4f2c88.1478599881.git.bristot@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-11 08:28:52 +01:00
Linus Torvalds af79ad2b1f Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler changes from Ingo Molnar:
 "The main changes are:

   - irqtime accounting cleanups and enhancements. (Frederic Weisbecker)

   - schedstat debugging enhancements, make it more broadly runtime
     available. (Josh Poimboeuf)

   - More work on asymmetric topology/capacity scheduling. (Morten
     Rasmussen)

   - sched/wait fixes and cleanups. (Oleg Nesterov)

   - PELT (per entity load tracking) improvements. (Peter Zijlstra)

   - Rewrite and enhance select_idle_siblings(). (Peter Zijlstra)

   - sched/numa enhancements/fixes (Rik van Riel)

   - sched/cputime scalability improvements (Stanislaw Gruszka)

   - Load calculation arithmetics fixes. (Dietmar Eggemann)

   - sched/deadline enhancements (Tommaso Cucinotta)

   - Fix utilization accounting when switching to the SCHED_NORMAL
     policy. (Vincent Guittot)

   - ... plus misc cleanups and enhancements"

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (64 commits)
  sched/irqtime: Consolidate irqtime flushing code
  sched/irqtime: Consolidate accounting synchronization with u64_stats API
  u64_stats: Introduce IRQs disabled helpers
  sched/irqtime: Remove needless IRQs disablement on kcpustat update
  sched/irqtime: No need for preempt-safe accessors
  sched/fair: Fix min_vruntime tracking
  sched/debug: Add SCHED_WARN_ON()
  sched/core: Fix set_user_nice()
  sched/fair: Introduce set_curr_task() helper
  sched/core, ia64: Rename set_curr_task()
  sched/core: Fix incorrect utilization accounting when switching to fair class
  sched/core: Optimize SCHED_SMT
  sched/core: Rewrite and improve select_idle_siblings()
  sched/core: Replace sd_busy/nr_busy_cpus with sched_domain_shared
  sched/core: Introduce 'struct sched_domain_shared'
  sched/core: Restructure destroy_sched_domain()
  sched/core: Remove unused @cpu argument from destroy_sched_domain*()
  sched/wait: Introduce init_wait_entry()
  sched/wait: Avoid abort_exclusive_wait() in __wait_on_bit_lock()
  sched/wait: Avoid abort_exclusive_wait() in ___wait_event()
  ...
2016-10-03 13:39:00 -07:00
Wanpeng Li 61c7aca695 sched/deadline: Fix the intention to re-evalute tick dependency for offline CPU
The dl task will be replenished after dl task timer fire and start a
new period. It will be enqueued and to re-evaluate its dependency on
the tick in order to restart it. However, if the CPU is hot-unplugged,
irq_work_queue will splash since the target CPU is offline.

As a result we get:

    WARNING: CPU: 2 PID: 0 at kernel/irq_work.c:69 irq_work_queue_on+0xad/0xe0
    Call Trace:
     dump_stack+0x99/0xd0
     __warn+0xd1/0xf0
     warn_slowpath_null+0x1d/0x20
     irq_work_queue_on+0xad/0xe0
     tick_nohz_full_kick_cpu+0x44/0x50
     tick_nohz_dep_set_cpu+0x74/0xb0
     enqueue_task_dl+0x226/0x480
     activate_task+0x5c/0xa0
     dl_task_timer+0x19b/0x2c0
     ? push_dl_task.part.31+0x190/0x190

This can be triggered by hot-unplugging the full dynticks CPU which dl
task is running on.

We enqueue the dl task on the offline CPU, because we need to do
replenish for start_dl_timer(). So, as Juri pointed out, we would
need to do is calling replenish_dl_entity() directly, instead of
enqueue_task_dl(). pi_se shouldn't be a problem as the task shouldn't
be boosted if it was throttled.

This patch fixes it by avoiding the whole enqueue+dequeue+enqueue story, by
first migrating (set_task_cpu()) and then doing 1 enqueue.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luca Abeni <luca.abeni@unitn.it>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1472639264-3932-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-09-05 13:29:45 +02:00
Tommaso Cucinotta d8206bb3ff sched/deadline: Split cpudl_set() into cpudl_set() and cpudl_clear()
These 2 exercise independent code paths and need different arguments.

After this change, you call:

  cpudl_clear(cp, cpu);
  cpudl_set(cp, cpu, dl);

instead of:

  cpudl_set(cp, cpu, 0 /* dl */, 0 /* is_valid */);
  cpudl_set(cp, cpu, dl, 1 /* is_valid */);

Signed-off-by: Tommaso Cucinotta <tommaso.cucinotta@sssup.it>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Luca Abeni <luca.abeni@unitn.it>
Reviewed-by: Juri Lelli <juri.lelli@arm.com>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-dl@retis.sssup.it
Link: http://lkml.kernel.org/r/1471184828-12644-4-git-send-email-tommaso.cucinotta@sssup.it
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-09-05 13:29:43 +02:00
Rafael J. Wysocki 12bde33dbb cpufreq / sched: Pass runqueue pointer to cpufreq_update_util()
All of the callers of cpufreq_update_util() pass rq_clock(rq) to it
as the time argument and some of them check whether or not cpu_of(rq)
is equal to smp_processor_id() before calling it, so rework it to
take a runqueue pointer as the argument and move the rq_clock(rq)
evaluation into it.

Additionally, provide a wrapper checking cpu_of(rq) against
smp_processor_id() for the cpufreq_update_util() callers that
need it.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2016-08-16 22:16:03 +02:00
Rafael J. Wysocki 58919e83c8 cpufreq / sched: Pass flags to cpufreq_update_util()
It is useful to know the reason why cpufreq_update_util() has just
been called and that can be passed as flags to cpufreq_update_util()
and to the ->func() callback in struct update_util_data.  However,
doing that in addition to passing the util and max arguments they
already take would be clumsy, so avoid it.

Instead, use the observation that the schedutil governor is part
of the scheduler proper, so it can access scheduler data directly.
This allows the util and max arguments of cpufreq_update_util()
and the ->func() callback in struct update_util_data to be replaced
with a flags one, but schedutil has to be modified to follow.

Thus make the schedutil governor obtain the CFS utilization
information from the scheduler and use the "RT" and "DL" flags
instead of the special utilization value of ULONG_MAX to track
updates from the RT and DL sched classes.  Make it non-modular
too to avoid having to export scheduler variables to modules at
large.

Next, update all of the other users of cpufreq_update_util()
and the ->func() callback in struct update_util_data accordingly.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2016-08-16 22:14:55 +02:00
Juri Lelli 98b0a85780 sched/deadline: Remove useless parameter from setup_new_dl_entity()
setup_new_dl_entity() takes two parameters, but it only actually uses
one of them, under a different name, to setup a new dl_entity, after:

  2f9f3fdc928 "sched/deadline: Remove dl_new from struct sched_dl_entity"

as we currently do:

  setup_new_dl_entity(&p->dl, &p->dl)

However, before Luca's change we were doing:

  setup_new_dl_entity(dl_se, pi_se)

in update_dl_entity() for a dl_se->new entity: we were using pi_se's
parameters (the potential PI donor) for setting up a new entity.

This change removes the useless second parameter of setup_new_dl_entity().

While we are at it we also optimize things further calling setup_new_dl_
entity() only for already queued tasks, since (as pointed out by Xunlei)
we already do the very same update at tasks wakeup time anyway. By doing
so, we don't need to worry about a potential PI donor anymore, as
rt_mutex_setprio() takes care of that already for us.

Signed-off-by: Juri Lelli <juri.lelli@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luca Abeni <luca.abeni@unitn.it>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Xunlei Pang <xpang@redhat.com>
Link: http://lkml.kernel.org/r/1470409675-20935-1-git-send-email-juri.lelli@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 14:03:32 +02:00
Wanpeng Li c0c8c9fa21 sched/deadline: Fix lock pinning warning during CPU hotplug
The following warning can be triggered by hot-unplugging the CPU
on which an active SCHED_DEADLINE task is running on:

  WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:3531 lock_release+0x690/0x6a0
  releasing a pinned lock
  Call Trace:
   dump_stack+0x99/0xd0
   __warn+0xd1/0xf0
   ? dl_task_timer+0x1a1/0x2b0
   warn_slowpath_fmt+0x4f/0x60
   ? sched_clock+0x13/0x20
   lock_release+0x690/0x6a0
   ? enqueue_pushable_dl_task+0x9b/0xa0
   ? enqueue_task_dl+0x1ca/0x480
   _raw_spin_unlock+0x1f/0x40
   dl_task_timer+0x1a1/0x2b0
   ? push_dl_task.part.31+0x190/0x190
  WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:3649 lock_unpin_lock+0x181/0x1a0
  unpinning an unpinned lock
  Call Trace:
   dump_stack+0x99/0xd0
   __warn+0xd1/0xf0
   warn_slowpath_fmt+0x4f/0x60
   lock_unpin_lock+0x181/0x1a0
   dl_task_timer+0x127/0x2b0
   ? push_dl_task.part.31+0x190/0x190

As per the comment before this code, its safe to drop the RQ lock
here, and since we (potentially) change rq, unpin and repin to avoid
the splat.

Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
[ Rewrote changelog. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luca Abeni <luca.abeni@unitn.it>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1470274940-17976-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 14:02:55 +02:00
Thomas Gleixner 50605ffbda sched/core: Provide a tsk_nr_cpus_allowed() helper
tsk_nr_cpus_allowed() is an accessor for task->nr_cpus_allowed which allows
us to change the representation of ->nr_cpus_allowed if required.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/1462969411-17735-2-git-send-email-bigeasy@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-12 09:55:36 +02:00
Thomas Gleixner ade42e092b sched/core: Use tsk_cpus_allowed() instead of accessing ->cpus_allowed
Use the future-safe accessor for struct task_struct's.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/1462969411-17735-1-git-send-email-bigeasy@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-12 09:55:35 +02:00
Ingo Molnar eb60b3e5e8 Merge branch 'sched/urgent' into sched/core to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-12 09:18:13 +02:00
Xunlei Pang 13b5ab02ae sched/rt, sched/dl: Don't push if task's scheduling class was changed
We got this warning:

    WARNING: CPU: 1 PID: 2468 at kernel/sched/core.c:1161 set_task_cpu+0x1af/0x1c0
    [...]
    Call Trace:

    dump_stack+0x63/0x87
    __warn+0xd1/0xf0
    warn_slowpath_null+0x1d/0x20
    set_task_cpu+0x1af/0x1c0
    push_dl_task.part.34+0xea/0x180
    push_dl_tasks+0x17/0x30
    __balance_callback+0x45/0x5c
    __sched_setscheduler+0x906/0xb90
    SyS_sched_setattr+0x150/0x190
    do_syscall_64+0x62/0x110
    entry_SYSCALL64_slow_path+0x25/0x25

This corresponds to:

    WARN_ON_ONCE(p->state == TASK_RUNNING &&
             p->sched_class == &fair_sched_class &&
             (p->on_rq && !task_on_rq_migrating(p)))

It happens because in find_lock_later_rq(), the task whose scheduling
class was changed to fair class is still pushed away as if it were
a deadline task ...

So, check in find_lock_later_rq() after double_lock_balance(), if the
scheduling class of the deadline task was changed, break and retry.

Apply the same logic to RT tasks.

Signed-off-by: Xunlei Pang <xlpang@redhat.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Juri Lelli <juri.lelli@arm.com>
Link: http://lkml.kernel.org/r/1462767091-1215-1-git-send-email-xlpang@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-10 10:02:46 +02:00
Peter Zijlstra e7904a28f5 locking/lockdep, sched/core: Implement a better lock pinning scheme
The problem with the existing lock pinning is that each pin is of
value 1; this mean you can simply unpin if you know its pinned,
without having any extra information.

This scheme generates a random (16 bit) cookie for each pin and
requires this same cookie to unpin. This means you have to keep the
cookie in context.

No objsize difference for !LOCKDEP kernels.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-05 09:23:59 +02:00
Peter Zijlstra eb58075149 sched/core: Introduce 'struct rq_flags'
In order to be able to pass around more than just the IRQ flags in the
future, add a rq_flags structure.

No difference in code generation for the x86_64-defconfig build I
tested.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-05 09:23:59 +02:00
Wanpeng Li 594dd290cf sched/cpufreq: Optimize cpufreq update kicker to avoid update multiple times
Sometimes delta_exec is 0 due to update_curr() is called multiple times,
this is captured by:

	u64 delta_exec = rq_clock_task(rq) - curr->se.exec_start;

This patch optimizes the cpufreq update kicker by bailing out when nothing
changed, it will benefit the upcoming schedutil, since otherwise it will
(over)react to the special util/max combination.

Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1461316044-9520-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-28 10:39:54 +02:00
Linus Torvalds 277edbabf6 Power management and ACPI material for v4.6-rc1, part 1
- Redesign of cpufreq governors and the intel_pstate driver to
    make them use callbacks invoked by the scheduler to trigger CPU
    frequency evaluation instead of using per-CPU deferrable timers
    for that purpose (Rafael Wysocki).
 
  - Reorganization and cleanup of cpufreq governor code to make it
    more straightforward and fix some concurrency problems in it
    (Rafael Wysocki, Viresh Kumar).
 
  - Cleanup and improvements of locking in the cpufreq core (Viresh
    Kumar).
 
  - Assorted cleanups in the cpufreq core (Rafael Wysocki, Viresh
    Kumar, Eric Biggers).
 
  - intel_pstate driver updates including fixes, optimizations and a
    modification to make it enable enable hardware-coordinated P-state
    selection (HWP) by default if supported by the processor (Philippe
    Longepe, Srinivas Pandruvada, Rafael Wysocki, Viresh Kumar, Felipe
    Franciosi).
 
  - Operating Performance Points (OPP) framework updates to improve
    its handling of voltage regulators and device clocks and updates
    of the cpufreq-dt driver on top of that (Viresh Kumar, Jon Hunter).
 
  - Updates of the powernv cpufreq driver to fix initialization
    and cleanup problems in it and correct its worker thread handling
    with respect to CPU offline, new powernv_throttle tracepoint
    (Shilpasri Bhat).
 
  - ACPI cpufreq driver optimization and cleanup (Rafael Wysocki).
 
  - ACPICA updates including one fix for a regression introduced
    by previos changes in the ACPICA code (Bob Moore, Lv Zheng,
    David Box, Colin Ian King).
 
  - Support for installing ACPI tables from initrd (Lv Zheng).
 
  - Optimizations of the ACPI CPPC code (Prashanth Prakash, Ashwin
    Chaugule).
 
  - Support for _HID(ACPI0010) devices (ACPI processor containers)
    and ACPI processor driver cleanups (Sudeep Holla).
 
  - Support for ACPI-based enumeration of the AMBA bus (Graeme Gregory,
    Aleksey Makarov).
 
  - Modification of the ACPI PCI IRQ management code to make it treat
    255 in the Interrupt Line register as "not connected" on x86 (as
    per the specification) and avoid attempts to use that value as
    a valid interrupt vector (Chen Fan).
 
  - ACPI APEI fixes related to resource leaks (Josh Hunt).
 
  - Removal of modularity from a few ACPI drivers (BGRT, GHES,
    intel_pmic_crc) that cannot be built as modules in practice (Paul
    Gortmaker).
 
  - PNP framework update to make it treat ACPI_RESOURCE_TYPE_SERIAL_BUS
    as a valid resource type (Harb Abdulhamid).
 
  - New device ID (future AMD I2C controller) in the ACPI driver for
    AMD SoCs (APD) and in the designware I2C driver (Xiangliang Yu).
 
  - Assorted ACPI cleanups (Colin Ian King, Kaiyen Chang, Oleg Drokin).
 
  - cpuidle menu governor optimization to avoid a square root
    computation in it (Rasmus Villemoes).
 
  - Fix for potential use-after-free in the generic device properties
    framework (Heikki Krogerus).
 
  - Updates of the generic power domains (genpd) framework including
    support for multiple power states of a domain, fixes and debugfs
    output improvements (Axel Haslam, Jon Hunter, Laurent Pinchart,
    Geert Uytterhoeven).
 
  - Intel RAPL power capping driver updates to reduce IPI overhead in
    it (Jacob Pan).
 
  - System suspend/hibernation code cleanups (Eric Biggers, Saurabh
    Sengar).
 
  - Year 2038 fix for the process freezer (Abhilash Jindal).
 
  - turbostat utility updates including new features (decoding of more
    registers and CPUID fields, sub-second intervals support, GFX MHz
    and RC6 printout, --out command line option), fixes (syscall jitter
    detection and workaround, reductioin of the number of syscalls made,
    fixes related to Xeon x200 processors, compiler warning fixes) and
    cleanups (Len Brown, Hubert Chrzaniuk, Chen Yu).
 
 /
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Merge tag 'pm+acpi-4.6-rc1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management and ACPI updates from Rafael Wysocki:
 "This time the majority of changes go into cpufreq and they are
  significant.

  First off, the way CPU frequency updates are triggered is different
  now.  Instead of having to set up and manage a deferrable timer for
  each CPU in the system to evaluate and possibly change its frequency
  periodically, cpufreq governors set up callbacks to be invoked by the
  scheduler on a regular basis (basically on utilization updates).  The
  "old" governors, "ondemand" and "conservative", still do all of their
  work in process context (although that is triggered by the scheduler
  now), but intel_pstate does it all in the callback invoked by the
  scheduler with no need for any additional asynchronous processing.

  Of course, this eliminates the overhead related to the management of
  all those timers, but also it allows the cpufreq governor code to be
  simplified quite a bit.  On top of that, the common code and data
  structures used by the "ondemand" and "conservative" governors are
  cleaned up and made more straightforward and some long-standing and
  quite annoying problems are addressed.  In particular, the handling of
  governor sysfs attributes is modified and the related locking becomes
  more fine grained which allows some concurrency problems to be avoided
  (particularly deadlocks with the core cpufreq code).

  In principle, the new mechanism for triggering frequency updates
  allows utilization information to be passed from the scheduler to
  cpufreq.  Although the current code doesn't make use of it, in the
  works is a new cpufreq governor that will make decisions based on the
  scheduler's utilization data.  That should allow the scheduler and
  cpufreq to work more closely together in the long run.

  In addition to the core and governor changes, cpufreq drivers are
  updated too.  Fixes and optimizations go into intel_pstate, the
  cpufreq-dt driver is updated on top of some modification in the
  Operating Performance Points (OPP) framework and there are fixes and
  other updates in the powernv cpufreq driver.

  Apart from the cpufreq updates there is some new ACPICA material,
  including a fix for a problem introduced by previous ACPICA updates,
  and some less significant changes in the ACPI code, like CPPC code
  optimizations, ACPI processor driver cleanups and support for loading
  ACPI tables from initrd.

  Also updated are the generic power domains framework, the Intel RAPL
  power capping driver and the turbostat utility and we have a bunch of
  traditional assorted fixes and cleanups.

  Specifics:

   - Redesign of cpufreq governors and the intel_pstate driver to make
     them use callbacks invoked by the scheduler to trigger CPU
     frequency evaluation instead of using per-CPU deferrable timers for
     that purpose (Rafael Wysocki).

   - Reorganization and cleanup of cpufreq governor code to make it more
     straightforward and fix some concurrency problems in it (Rafael
     Wysocki, Viresh Kumar).

   - Cleanup and improvements of locking in the cpufreq core (Viresh
     Kumar).

   - Assorted cleanups in the cpufreq core (Rafael Wysocki, Viresh
     Kumar, Eric Biggers).

   - intel_pstate driver updates including fixes, optimizations and a
     modification to make it enable enable hardware-coordinated P-state
     selection (HWP) by default if supported by the processor (Philippe
     Longepe, Srinivas Pandruvada, Rafael Wysocki, Viresh Kumar, Felipe
     Franciosi).

   - Operating Performance Points (OPP) framework updates to improve its
     handling of voltage regulators and device clocks and updates of the
     cpufreq-dt driver on top of that (Viresh Kumar, Jon Hunter).

   - Updates of the powernv cpufreq driver to fix initialization and
     cleanup problems in it and correct its worker thread handling with
     respect to CPU offline, new powernv_throttle tracepoint (Shilpasri
     Bhat).

   - ACPI cpufreq driver optimization and cleanup (Rafael Wysocki).

   - ACPICA updates including one fix for a regression introduced by
     previos changes in the ACPICA code (Bob Moore, Lv Zheng, David Box,
     Colin Ian King).

   - Support for installing ACPI tables from initrd (Lv Zheng).

   - Optimizations of the ACPI CPPC code (Prashanth Prakash, Ashwin
     Chaugule).

   - Support for _HID(ACPI0010) devices (ACPI processor containers) and
     ACPI processor driver cleanups (Sudeep Holla).

   - Support for ACPI-based enumeration of the AMBA bus (Graeme Gregory,
     Aleksey Makarov).

   - Modification of the ACPI PCI IRQ management code to make it treat
     255 in the Interrupt Line register as "not connected" on x86 (as
     per the specification) and avoid attempts to use that value as a
     valid interrupt vector (Chen Fan).

   - ACPI APEI fixes related to resource leaks (Josh Hunt).

   - Removal of modularity from a few ACPI drivers (BGRT, GHES,
     intel_pmic_crc) that cannot be built as modules in practice (Paul
     Gortmaker).

   - PNP framework update to make it treat ACPI_RESOURCE_TYPE_SERIAL_BUS
     as a valid resource type (Harb Abdulhamid).

   - New device ID (future AMD I2C controller) in the ACPI driver for
     AMD SoCs (APD) and in the designware I2C driver (Xiangliang Yu).

   - Assorted ACPI cleanups (Colin Ian King, Kaiyen Chang, Oleg Drokin).

   - cpuidle menu governor optimization to avoid a square root
     computation in it (Rasmus Villemoes).

   - Fix for potential use-after-free in the generic device properties
     framework (Heikki Krogerus).

   - Updates of the generic power domains (genpd) framework including
     support for multiple power states of a domain, fixes and debugfs
     output improvements (Axel Haslam, Jon Hunter, Laurent Pinchart,
     Geert Uytterhoeven).

   - Intel RAPL power capping driver updates to reduce IPI overhead in
     it (Jacob Pan).

   - System suspend/hibernation code cleanups (Eric Biggers, Saurabh
     Sengar).

   - Year 2038 fix for the process freezer (Abhilash Jindal).

   - turbostat utility updates including new features (decoding of more
     registers and CPUID fields, sub-second intervals support, GFX MHz
     and RC6 printout, --out command line option), fixes (syscall jitter
     detection and workaround, reductioin of the number of syscalls
     made, fixes related to Xeon x200 processors, compiler warning
     fixes) and cleanups (Len Brown, Hubert Chrzaniuk, Chen Yu)"

* tag 'pm+acpi-4.6-rc1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (182 commits)
  tools/power turbostat: bugfix: TDP MSRs print bits fixing
  tools/power turbostat: correct output for MSR_NHM_SNB_PKG_CST_CFG_CTL dump
  tools/power turbostat: call __cpuid() instead of __get_cpuid()
  tools/power turbostat: indicate SMX and SGX support
  tools/power turbostat: detect and work around syscall jitter
  tools/power turbostat: show GFX%rc6
  tools/power turbostat: show GFXMHz
  tools/power turbostat: show IRQs per CPU
  tools/power turbostat: make fewer systems calls
  tools/power turbostat: fix compiler warnings
  tools/power turbostat: add --out option for saving output in a file
  tools/power turbostat: re-name "%Busy" field to "Busy%"
  tools/power turbostat: Intel Xeon x200: fix turbo-ratio decoding
  tools/power turbostat: Intel Xeon x200: fix erroneous bclk value
  tools/power turbostat: allow sub-sec intervals
  ACPI / APEI: ERST: Fixed leaked resources in erst_init
  ACPI / APEI: Fix leaked resources
  intel_pstate: Do not skip samples partially
  intel_pstate: Remove freq calculation from intel_pstate_calc_busy()
  intel_pstate: Move intel_pstate_calc_busy() into get_target_pstate_use_performance()
  ...
2016-03-16 14:10:53 -07:00
Rafael J. Wysocki 4ed3900427 Merge branch 'pm-cpufreq'
* pm-cpufreq: (94 commits)
  intel_pstate: Do not skip samples partially
  intel_pstate: Remove freq calculation from intel_pstate_calc_busy()
  intel_pstate: Move intel_pstate_calc_busy() into get_target_pstate_use_performance()
  intel_pstate: Optimize calculation for max/min_perf_adj
  intel_pstate: Remove extra conversions in pid calculation
  cpufreq: Move scheduler-related code to the sched directory
  Revert "cpufreq: postfix policy directory with the first CPU in related_cpus"
  cpufreq: Reduce cpufreq_update_util() overhead a bit
  cpufreq: Select IRQ_WORK if CPU_FREQ_GOV_COMMON is set
  cpufreq: Remove 'policy->governor_enabled'
  cpufreq: Rename __cpufreq_governor() to cpufreq_governor()
  cpufreq: Relocate handle_update() to kill its declaration
  cpufreq: governor: Drop unnecessary checks from show() and store()
  cpufreq: governor: Fix race in dbs_update_util_handler()
  cpufreq: governor: Make gov_set_update_util() static
  cpufreq: governor: Narrow down the dbs_data_mutex coverage
  cpufreq: governor: Make dbs_data_mutex static
  cpufreq: governor: Relocate definitions of tuners structures
  cpufreq: governor: Move per-CPU data to the common code
  cpufreq: governor: Make governor private data per-policy
  ...
2016-03-14 14:22:03 +01:00
Rafael J. Wysocki 34e2c555f3 cpufreq: Add mechanism for registering utilization update callbacks
Introduce a mechanism by which parts of the cpufreq subsystem
("setpolicy" drivers or the core) can register callbacks to be
executed from cpufreq_update_util() which is invoked by the
scheduler's update_load_avg() on CPU utilization changes.

This allows the "setpolicy" drivers to dispense with their timers
and do all of the computations they need and frequency/voltage
adjustments in the update_load_avg() code path, among other things.

The update_load_avg() changes were suggested by Peter Zijlstra.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Ingo Molnar <mingo@kernel.org>
2016-03-09 14:39:19 +01:00
Luca Abeni 72f9f3fdc9 sched/deadline: Remove dl_new from struct sched_dl_entity
The dl_new field of struct sched_dl_entity is currently used to
identify new deadline tasks, so that their deadline and runtime
can be properly initialised.

However, these tasks can be easily identified by checking if
their deadline is smaller than the current time when they switch
to SCHED_DEADLINE. So, dl_new can be removed by introducing this
check in switched_to_dl(); this allows to simplify the
SCHED_DEADLINE code.

Signed-off-by: Luca Abeni <luca.abeni@unitn.it>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1457350024-7825-2-git-send-email-luca.abeni@unitn.it
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-03-08 12:24:55 +01:00
Peter Zijlstra 801ccdbf01 sched/deadline: Remove superfluous call to switched_to_dl()
if (A || B) {

	} else if (A && !B) {

	}

If A we'll take the first branch, if !A we will not satisfy the second.
Therefore the second branch will never be taken.

Reported-by: luca abeni <luca.abeni@unitn.it>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160225140149.GK6357@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-02-29 09:53:11 +01:00
Peter Zijlstra 48be3a67da sched/deadline: Always calculate end of period on sched_yield()
Steven noticed that occasionally a sched_yield() call would not result
in a wait for the next period edge as expected.

It turns out that when we call update_curr_dl() and end up with
delta_exec <= 0, we will bail early and fail to throttle.

Further inspection of the yield code revealed that yield_task_dl()
clearing dl.runtime is wrong too, it will not account the last bit of
runtime which could result in dl.runtime < 0, which in turn means that
replenish would gift us with too much runtime.

Fix both issues by not relying on the dl.runtime value for yield.

Reported-by: Steven Rostedt <rostedt@goodmis.org>
Tested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160223122822.GP6357@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-02-29 09:41:51 +01:00
Steven Rostedt c219b7ddb6 sched/deadline: Fix trivial typo in printk() message
It's "too much" not "to much".

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Juri Lelli <juri.lelli@arm.com>
Cc: Jiri Kosina <trivial@kernel.org>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160210120422.4ca77e68@gandalf.local.home
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-02-17 10:02:00 +01:00
Wanpeng Li 7d92de3a82 sched/deadline: Fix the earliest_dl.next logic
earliest_dl.next should cache deadline of the earliest ready task that
is also enqueued in the pushable rbtree, as pull algorithm uses this
information to find candidates for migration: if the earliest_dl.next
deadline of source rq is earlier than the earliest_dl.curr deadline of
destination rq, the task from the source rq can be pulled.

However, current implementation only guarantees that earliest_dl.next is
the deadline of the next ready task instead of the next pushable task;
which will result in potentially holding both rqs' lock and find nothing
to migrate because of affinity constraints. In addition, current logic
doesn't update the next candidate for pushing in pick_next_task_dl(),
even if the running task is never eligible.

This patch fixes both problems by updating earliest_dl.next when
pushable dl task is enqueued/dequeued, similar to what we already do for
RT.

Tested-by: Luca Abeni <luca.abeni@unitn.it>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1449135730-27202-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-01-06 11:05:56 +01:00
Peter Zijlstra 0aaafaabfc sched/core: Add missing lockdep_unpin() annotations
Luca and Wanpeng reported two missing annotations that led to
false lockdep complaints. Add the missing annotations.

Reported-by: Luca Abeni <luca.abeni@unitn.it>
Reported-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: cbce1a6867 ("sched,lockdep: Employ lock pinning")
Link: http://lkml.kernel.org/r/20151023095008.GY17308@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-10-23 12:02:10 +02:00
Luca Abeni 5aa5050787 sched/deadline: Fix migration of SCHED_DEADLINE tasks
Commit:

  9d51426242 ("sched/deadline: Reduce rq lock contention by eliminating locking of non-feasible target")

broke select_task_rq_dl() and find_lock_later_rq(), because it introduced
a comparison between the local task's deadline and dl.earliest_dl.curr of
the remote queue.

However, if the remote runqueue does not contain any SCHED_DEADLINE
task its earliest_dl.curr is 0 (always smaller than the deadline of
the local task) and the remote runqueue is not selected for pushing.

As a result, if an application creates multiple SCHED_DEADLINE
threads, they will never be pushed to runqueues that do not already
contain SCHED_DEADLINE tasks.

This patch fixes the issue by checking if dl.dl_nr_running == 0.

Signed-off-by: Luca Abeni <luca.abeni@unitn.it>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@linux.intel.com>
Fixes: 9d51426242 ("sched/deadline: Reduce rq lock contention by eliminating locking of non-feasible target")
Link: http://lkml.kernel.org/r/1444982781-15608-1-git-send-email-luca.abeni@unitn.it
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-10-20 10:13:36 +02:00
Andrea Parri ff277d4250 sched/deadline: Fix comment in enqueue_task_dl()
The "dl_boosted" flag is set by comparing *absolute* deadlines
(c.f., rt_mutex_setprio()).

Signed-off-by: Andrea Parri <parri.andrea@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1438782979-9057-2-git-send-email-parri.andrea@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-08-12 12:06:10 +02:00
Andrea Parri 4ffa08ed4c sched/deadline: Fix comment in push_dl_tasks()
The comment is "misleading"; fix it by adapting a comment from
push_rt_tasks().

Signed-off-by: Andrea Parri <parri.andrea@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1438782979-9057-1-git-send-email-parri.andrea@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-08-12 12:06:10 +02:00
Peter Zijlstra 6c37067e27 sched: Change the sched_class::set_cpus_allowed() calling context
Change the calling context of sched_class::set_cpus_allowed() such
that we can assume the task is inactive.

This allows us to easily make changes that affect accounting done by
enqueue/dequeue. This does in fact completely remove
set_cpus_allowed_rt() and greatly reduces set_cpus_allowed_dl().

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dedekind1@gmail.com
Cc: juri.lelli@arm.com
Cc: mgorman@suse.de
Cc: riel@redhat.com
Cc: rostedt@goodmis.org
Link: http://lkml.kernel.org/r/20150515154833.667516139@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-08-12 12:06:10 +02:00
Peter Zijlstra c5b2803840 sched: Make sched_class::set_cpus_allowed() unconditional
Give every class a set_cpus_allowed() method, this enables some small
optimization in the RT,DL implementation by avoiding a double
cpumask_weight() call.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dedekind1@gmail.com
Cc: juri.lelli@arm.com
Cc: mgorman@suse.de
Cc: riel@redhat.com
Cc: rostedt@goodmis.org
Link: http://lkml.kernel.org/r/20150515154833.614517487@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-08-12 12:06:09 +02:00
Xunlei Pang 3fe33bcdd3 sched/deadline: Remove a redundant condition from task_woken_dl()
'p' has been already queued at this point, so "!task_running(rq, p)"
and "p->nr_cpus_allowed > 1" imply that "has_pushable_dl_tasks(rq)"
is true, so it can be removed.

Signed-off-by: Xunlei Pang <pang.xunlei@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1435995563-3723-2-git-send-email-xlpang@126.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-08-03 12:21:20 +02:00
Linus Torvalds 98ec21a018 Merge branch 'sched-hrtimers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Thomas Gleixner:
 "This series of scheduler updates depends on sched/core and timers/core
  branches, which are already in your tree:

   - Scheduler balancing overhaul to plug a hard to trigger race which
     causes an oops in the balancer (Peter Zijlstra)

   - Lockdep updates which are related to the balancing updates (Peter
     Zijlstra)"

* 'sched-hrtimers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched,lockdep: Employ lock pinning
  lockdep: Implement lock pinning
  lockdep: Simplify lock_release()
  sched: Streamline the task migration locking a little
  sched: Move code around
  sched,dl: Fix sched class hopping CBS hole
  sched, dl: Convert switched_{from, to}_dl() / prio_changed_dl() to balance callbacks
  sched,dl: Remove return value from pull_dl_task()
  sched, rt: Convert switched_{from, to}_rt() / prio_changed_rt() to balance callbacks
  sched,rt: Remove return value from pull_rt_task()
  sched: Allow balance callbacks for check_class_changed()
  sched: Use replace normalize_task() with __sched_setscheduler()
  sched: Replace post_schedule with a balance callback list
2015-06-24 15:09:40 -07:00
Linus Torvalds 43224b96af Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer updates from Thomas Gleixner:
 "A rather largish update for everything time and timer related:

   - Cache footprint optimizations for both hrtimers and timer wheel

   - Lower the NOHZ impact on systems which have NOHZ or timer migration
     disabled at runtime.

   - Optimize run time overhead of hrtimer interrupt by making the clock
     offset updates smarter

   - hrtimer cleanups and removal of restrictions to tackle some
     problems in sched/perf

   - Some more leap second tweaks

   - Another round of changes addressing the 2038 problem

   - First step to change the internals of clock event devices by
     introducing the necessary infrastructure

   - Allow constant folding for usecs/msecs_to_jiffies()

   - The usual pile of clockevent/clocksource driver updates

  The hrtimer changes contain updates to sched, perf and x86 as they
  depend on them plus changes all over the tree to cleanup API changes
  and redundant code, which got copied all over the place.  The y2038
  changes touch s390 to remove the last non 2038 safe code related to
  boot/persistant clock"

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (114 commits)
  clocksource: Increase dependencies of timer-stm32 to limit build wreckage
  timer: Minimize nohz off overhead
  timer: Reduce timer migration overhead if disabled
  timer: Stats: Simplify the flags handling
  timer: Replace timer base by a cpu index
  timer: Use hlist for the timer wheel hash buckets
  timer: Remove FIFO "guarantee"
  timers: Sanitize catchup_timer_jiffies() usage
  hrtimer: Allow hrtimer::function() to free the timer
  seqcount: Introduce raw_write_seqcount_barrier()
  seqcount: Rename write_seqcount_barrier()
  hrtimer: Fix hrtimer_is_queued() hole
  hrtimer: Remove HRTIMER_STATE_MIGRATE
  selftest: Timers: Avoid signal deadlock in leap-a-day
  timekeeping: Copy the shadow-timekeeper over the real timekeeper last
  clockevents: Check state instead of mode in suspend/resume path
  selftests: timers: Add leap-second timer edge testing to leap-a-day.c
  ntp: Do leapsecond adjustment in adjtimex read path
  time: Prevent early expiry of hrtimers[CLOCK_REALTIME] at the leap second edge
  ntp: Introduce and use SECS_PER_DAY macro instead of 86400
  ...
2015-06-22 18:57:44 -07:00
Zhiqiang Zhang 6fab541019 sched/deadline: Remove needless parameter in dl_runtime_exceeded()
Sine commit 269ad8015a ("sched/deadline: Avoid double-accounting in
case of missed deadlines), parameter 'rq' is no longer used, so
remove it.

Signed-off-by: Zhiqiang Zhang <zhangzhiqiang.zhang@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <juri.lelli@gmail.com>
Cc: <luca.abeni@unitn.it>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1434338120-43773-1-git-send-email-zhangzhiqiang.zhang@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-06-19 10:06:48 +02:00
Wanpeng Li 9d51426242 sched/deadline: Reduce rq lock contention by eliminating locking of non-feasible target
This patch adds a check that prevents futile attempts to move DL tasks
to a CPU with active tasks of equal or earlier deadline. The same
behavior as commit 80e3d87b2c ("sched/rt: Reduce rq lock contention
by eliminating locking of non-feasible target") for rt class.

Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1431496867-4194-3-git-send-email-wanpeng.li@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-06-19 10:06:46 +02:00
Wanpeng Li a6c0e746fb sched/deadline: Make init_sched_dl_class() __init
It's a bootstrap function, make init_sched_dl_class() __init.

Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1431496867-4194-2-git-send-email-wanpeng.li@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-06-19 10:06:46 +02:00
Wanpeng Li 8b5e770ed7 sched/deadline: Optimize pull_dl_task()
pull_dl_task() uses pick_next_earliest_dl_task() to select a migration
candidate; this is sub-optimal since the next earliest task -- as per
the regular runqueue -- might not be migratable at all. This could
result in iterating the entire runqueue looking for a task.

Instead iterate the pushable queue -- this queue only contains tasks
that have at least 2 cpus set in their cpus_allowed mask.

Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
[ Improved the changelog. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1431496867-4194-1-git-send-email-wanpeng.li@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-06-19 10:06:45 +02:00
Peter Zijlstra cbce1a6867 sched,lockdep: Employ lock pinning
Employ the new lockdep lock pinning annotation to ensure no
'accidental' lock-breaks happen with rq->lock.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: ktkhai@parallels.com
Cc: rostedt@goodmis.org
Cc: juri.lelli@gmail.com
Cc: pang.xunlei@linaro.org
Cc: oleg@redhat.com
Cc: wanpeng.li@linux.intel.com
Cc: umgwanakikbuti@gmail.com
Link: http://lkml.kernel.org/r/20150611124744.003233193@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-06-19 00:25:27 +02:00
Peter Zijlstra a649f237db sched,dl: Fix sched class hopping CBS hole
We still have a few pending issues with the deadline code, one of which
is that switching between scheduling classes can 'leak' CBS state.

Close the hole by retaining the current CBS state when leaving
SCHED_DEADLINE and unconditionally programming the deadline timer.
The timer will then reset the CBS state if the task is still
!SCHED_DEADLINE by the time it hits.

If the task left SCHED_DEADLINE it will not call task_dead_dl() and
we'll not cancel the hrtimer, leaving us a pending timer in free
space. Avoid this by giving the timer a task reference, this avoids
littering the task exit path for this rather uncommon case.

In order to do this, I had to move dl_task_offline_migration() below
the replenishment, such that the task_rq()->lock fully covers that.
While doing this, I noticed that it (was) buggy in assuming a task is
enqueued and or we need to enqueue the task now. Fixing this means
select_task_rq_dl() might encounter an offline rq -- look into that.

As a result this kills cancel_dl_timer() which included a rq->lock
break.

Fixes: 40767b0dc7 ("sched/deadline: Fix deadline parameter modification handling")
Cc: Wanpeng Li <wanpeng.li@linux.intel.com>
Cc: Luca Abeni <luca.abeni@unitn.it>
Cc: Juri Lelli <juri.lelli@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: ktkhai@parallels.com
Cc: rostedt@goodmis.org
Cc: juri.lelli@gmail.com
Cc: pang.xunlei@linaro.org
Cc: oleg@redhat.com
Cc: wanpeng.li@linux.intel.com
Cc: Luca Abeni <luca.abeni@unitn.it>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: umgwanakikbuti@gmail.com
Link: http://lkml.kernel.org/r/20150611124743.574192138@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-06-19 00:25:26 +02:00
Peter Zijlstra 9916e21499 sched, dl: Convert switched_{from, to}_dl() / prio_changed_dl() to balance callbacks
Remove the direct {push,pull} balancing operations from
switched_{from,to}_dl() / prio_changed_dl() and use the balance
callback queue.

Again, err on the side of too many reschedules; since too few is a
hard bug while too many is just annoying.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: ktkhai@parallels.com
Cc: rostedt@goodmis.org
Cc: juri.lelli@gmail.com
Cc: pang.xunlei@linaro.org
Cc: oleg@redhat.com
Cc: wanpeng.li@linux.intel.com
Cc: umgwanakikbuti@gmail.com
Link: http://lkml.kernel.org/r/20150611124742.968262663@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-06-19 00:25:26 +02:00
Peter Zijlstra 0ea60c2054 sched,dl: Remove return value from pull_dl_task()
In order to be able to use pull_dl_task() from a callback, we need to
do away with the return value.

Since the return value indicates if we should reschedule, do this
inside the function. Since not all callers currently do this, this can
increase the number of reschedules due rt balancing.

Too many reschedules is not a correctness issues, too few are.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: ktkhai@parallels.com
Cc: rostedt@goodmis.org
Cc: juri.lelli@gmail.com
Cc: pang.xunlei@linaro.org
Cc: oleg@redhat.com
Cc: wanpeng.li@linux.intel.com
Cc: umgwanakikbuti@gmail.com
Link: http://lkml.kernel.org/r/20150611124742.859398977@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-06-19 00:25:26 +02:00
Peter Zijlstra e3fca9e7cb sched: Replace post_schedule with a balance callback list
Generalize the post_schedule() stuff into a balance callback list.
This allows us to more easily use it outside of schedule() and cross
sched_class.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: ktkhai@parallels.com
Cc: rostedt@goodmis.org
Cc: juri.lelli@gmail.com
Cc: pang.xunlei@linaro.org
Cc: oleg@redhat.com
Cc: wanpeng.li@linux.intel.com
Cc: umgwanakikbuti@gmail.com
Link: http://lkml.kernel.org/r/20150611124742.424032725@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-06-19 00:25:26 +02:00
Thomas Gleixner 624bbdfac9 Merge branch 'timers/core' into sched/hrtimers
Merge sched/core and timers/core so we can apply the sched balancing
patch queue, which depends on both.
2015-06-19 00:17:47 +02:00
Jason Low 316c1608d1 sched, timer: Convert usages of ACCESS_ONCE() in the scheduler to READ_ONCE()/WRITE_ONCE()
ACCESS_ONCE doesn't work reliably on non-scalar types. This patch removes
the rest of the existing usages of ACCESS_ONCE() in the scheduler, and use
the new READ_ONCE() and WRITE_ONCE() APIs as appropriate.

Signed-off-by: Jason Low <jason.low2@hp.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Waiman Long <Waiman.Long@hp.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Aswin Chandramouleeswaran <aswin@hp.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: Scott J Norton <scott.norton@hp.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1430251224-5764-2-git-send-email-jason.low2@hp.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-05-08 12:11:32 +02:00
Thomas Gleixner cc9684d3c1 sched: deadline: Use hrtimer_start()
hrtimer_start() does not longer defer already expired timers to the
softirq. Get rid of the __hrtimer_start_range_ns() invocation.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20150414203502.627353666@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-04-22 17:06:51 +02:00
Wanpeng Li fa9c9d10e9 sched/deadline: Support DL task migration during CPU hotplug
I observed that DL tasks can't be migrated to other CPUs during CPU
hotplug, in addition, task may/may not be running again if CPU is
added back.

The root cause which I found is that DL tasks will be throtted and
removed from the DL rq after comsuming all their budget, which
leads to the situation that stop task can't pick them up from the
DL rq and migrate them to other CPUs during hotplug.

The method to reproduce:

  schedtool -E -t 50000:100000 -e ./test

Actually './test' is just a simple for loop. Then observe which CPU the
test task is on and offline it:

  echo 0 > /sys/devices/system/cpu/cpuN/online

This patch adds the DL task migration during CPU hotplug by finding a
most suitable later deadline rq after DL timer fires if current rq is
offline.

If it fails to find a suitable later deadline rq then it falls back to
any eligible online CPU in so that the deadline task will come back
to us, and the push/pull mechanism should then move it around properly.

Suggested-and-Acked-by: Juri Lelli <juri.lelli@arm.com>
Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1427411315-4298-1-git-send-email-wanpeng.li@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-02 17:42:57 +02:00
Juri Lelli 4cd57f9713 sched/deadline: Always enqueue on previous rq when dl_task_timer() fires
dl_task_timer() may fire on a different rq from where a task was removed
after throttling. Since the call path is:

  dl_task_timer() ->
    enqueue_task_dl() ->
      enqueue_dl_entity() ->
        replenish_dl_entity()

and replenish_dl_entity() uses dl_se's rq, we can't use current's rq
in dl_task_timer(), but we need to lock the task's previous one.

Tested-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Signed-off-by: Juri Lelli <juri.lelli@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Kirill Tkhai <ktkhai@parallels.com>
Cc: Juri Lelli <juri.lelli@gmail.com>
Fixes: 3960c8c0c7 ("sched: Make dl_task_time() use task_rq_lock()")
Link: http://lkml.kernel.org/r/1427792017-7356-1-git-send-email-juri.lelli@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-02 17:42:56 +02:00
Abel Vesa 07c54f7a7f sched/core: Remove unused argument from init_[rt|dl]_rq()
Obviously, 'rq' is not used in these two functions, therefore,
there is no reason for it to be passed as an argument.

Signed-off-by: Abel Vesa <abelvesa@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1425383427-26244-1-git-send-email-abelvesa@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-02 17:42:55 +02:00
Wanpeng Li bd4bde14b9 sched/deadline: Avoid a superfluous check
Since commit 40767b0dc7 ("sched/deadline: Fix deadline parameter
modification handling") we clear the thottled state when switching
from a dl task, therefore we should never find it set in switching to
a dl task.

Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
[ Improved the changelog. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Juri Lelli <juri.lelli@arm.com>
Link: http://lkml.kernel.org/r/1426590931-4639-1-git-send-email-wanpeng.li@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-27 09:36:12 +01:00
Wanpeng Li 44fb085bfa sched/deadline: Add rq->clock update skip for dl task yield
This patch adds rq->clock update skip for SCHED_DEADLINE task yield,
to tell update_rq_clock() that we've just updated the clock, so that
we don't do a microscopic update in schedule() and double the
fastpath cost.

Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1425961200-3809-1-git-send-email-wanpeng.li@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-10 05:46:50 +01:00