Commit Graph

22312 Commits

Author SHA1 Message Date
Morten Rasmussen cfa1033431 sched/fair: Correct unit of load_above_capacity
In calculate_imbalance() load_above_capacity currently has the unit
[capacity] while it is used as being [load/capacity]. Not only is it
wrong it also makes it unlikely that load_above_capacity is ever used
as the subsequent code picks the smaller of load_above_capacity and
the avg_load

This patch ensures that load_above_capacity has the right unit
[load/capacity].

Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
[ Changed changelog to note it was in capacity unit; +rebase. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Dietmar Eggemann <dietmar.eggemann@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: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/1461958364-675-4-git-send-email-dietmar.eggemann@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-12 09:55:33 +02:00
Peter Zijlstra 1be0eb2a97 sched/fair: Clean up scale confusion
Wanpeng noted that the scale_load_down() in calculate_imbalance() was
weird. I agree, it should be SCHED_CAPACITY_SCALE, since we're going
to compare against busiest->group_capacity, which is in [capacity]
units.

Reported-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yuyang Du <yuyang.du@intel.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-12 09:55:33 +02:00
Wanpeng Li 444969223c sched/nohz: Fix affine unpinned timers mess
The following commit:

  9642d18eee ("nohz: Affine unpinned timers to housekeepers")'

intended to affine unpinned timers to housekeepers:

  unpinned timers(full dynaticks, idle)   =>   nearest busy housekeepers(otherwise, fallback to any housekeepers)
  unpinned timers(full dynaticks, busy)   =>   nearest busy housekeepers(otherwise, fallback to any housekeepers)
  unpinned timers(houserkeepers, idle)    =>   nearest busy housekeepers(otherwise, fallback to itself)

However, the !idle_cpu(i) && is_housekeeping_cpu(cpu) check modified the
intention to:

  unpinned timers(full dynaticks, idle)   =>   any housekeepers(no mattter cpu topology)
  unpinned timers(full dynaticks, busy)   =>   any housekeepers(no mattter cpu topology)
  unpinned timers(housekeepers, idle)     =>   any busy cpus(otherwise, fallback to any housekeepers)

This patch fixes it by checking if there are busy housekeepers nearby,
otherwise falls to any housekeepers/itself. After the patch:

  unpinned timers(full dynaticks, idle)   =>   nearest busy housekeepers(otherwise, fallback to any housekeepers)
  unpinned timers(full dynaticks, busy)   =>   nearest busy housekeepers(otherwise, fallback to any housekeepers)
  unpinned timers(housekeepers, idle)     =>   nearest busy housekeepers(otherwise, fallback to itself)

Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
[ Fixed the changelog. ]
Cc: Frederic Weisbecker <fweisbec@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>
Cc: linux-kernel@vger.kernel.org
Fixes: 'commit 9642d18eee ("nohz: Affine unpinned timers to housekeepers")'
Link: http://lkml.kernel.org/r/1462344334-8303-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-12 09:55:32 +02:00
Peter Zijlstra 2f950354e6 sched/fair: Fix fairness issue on migration
Pavan reported that in the presence of very light tasks (or cgroups)
the placement of migrated tasks can cause severe fairness issues.

The problem is that enqueue_entity() places the task before it updates
time, thereby it can place the task far in the past (remember that
light tasks will shoot virtual time forward at a high speed, so in
relation to the pre-existing light task, we can land far in the past).

This is done because update_curr() needs the current task, and we
might be placing the current task.

The obvious solution is to differentiate between the current and any
other task; placing the current before we update time, and placing any
other task after, such that !curr tasks end up at the current moment
in time, and not in the past.

This commit re-introduces the previously reverted commit:

  3a47d5124a ("sched/fair: Fix fairness issue on migration")

... which is now safe to do, after we've also fixed another
underlying bug first, in:

  sched/fair: Prepare to fix fairness problems on migration

and cleaned up other details in the migration code:

  sched/core: Kill sched_class::task_waking

Reported-by: Pavan Kondeti <pkondeti@codeaurora.org>
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: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-12 09:55:32 +02:00
Peter Zijlstra 59efa0bac9 sched/core: Kill sched_class::task_waking to clean up the migration logic
With sched_class::task_waking being called only when we do
set_task_cpu(), we can make sched_class::migrate_task_rq() do the work
and eliminate sched_class::task_waking entirely.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Hunter <ahh@google.com>
Cc: Ben Segall <bsegall@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Paul Turner <pjt@google.com>
Cc: Pavan Kondeti <pkondeti@codeaurora.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: byungchul.park@lge.com
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-12 09:55:31 +02:00
Peter Zijlstra b5179ac70d sched/fair: Prepare to fix fairness problems on migration
Mike reported that our recent attempt to fix migration problems:

  3a47d5124a ("sched/fair: Fix fairness issue on migration")

broke interactivity and the signal starve test. We reverted that
commit and now let's try it again more carefully, with some other
underlying problems fixed first.

One problem is that I assumed ENQUEUE_WAKING was only set when we do a
cross-cpu wakeup (migration), which isn't true. This means we now
destroy the vruntime history of tasks and wakeup-preemption suffers.

Cure this by making my assumption true, only call
sched_class::task_waking() when we do a cross-cpu wakeup. This avoids
the indirect call in the case we do a local wakeup.

Reported-by: Mike Galbraith <mgalbraith@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Hunter <ahh@google.com>
Cc: Ben Segall <bsegall@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Paul Turner <pjt@google.com>
Cc: Pavan Kondeti <pkondeti@codeaurora.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: byungchul.park@lge.com
Cc: linux-kernel@vger.kernel.org
Fixes: 3a47d5124a ("sched/fair: Fix fairness issue on migration")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-12 09:55:31 +02:00
Peter Zijlstra c58d25f371 sched/fair: Move record_wakee()
Since I want to make ->task_woken() conditional on the task getting
migrated, we cannot use it to call record_wakee().

Move it to select_task_rq_fair(), which gets called in almost all the
same conditions. The only exception is if the woken task (@p) is
CPU-bound (as per the nr_cpus_allowed test in select_task_rq()).

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Hunter <ahh@google.com>
Cc: Ben Segall <bsegall@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Paul Turner <pjt@google.com>
Cc: Pavan Kondeti <pkondeti@codeaurora.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: byungchul.park@lge.com
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-12 09:55:30 +02:00
Ingo Molnar 4eb8676517 Merge branch 'smp/hotplug' into sched/core, to resolve conflicts
Conflicts:
	kernel/sched/core.c

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-12 09:51:36 +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
Ingo Molnar 53d3bc773e Revert "sched/fair: Fix fairness issue on migration"
Mike reported that this recent commit:

  3a47d5124a ("sched/fair: Fix fairness issue on migration")

... broke interactivity and the signal starvation test.

We have a proper fix series in the works but ran out of time for
v4.6, so revert the commit.

Reported-by: Mike Galbraith <efault@gmx.de>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-11 08:25:53 +02:00
Linus Torvalds ac2440654d Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
 "A UP kernel cpufreq fix and a rt/dl scheduler corner case fix"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/rt, sched/dl: Don't push if task's scheduling class was changed
  sched/fair: Fix !CONFIG_SMP kernel cpufreq governor breakage
2016-05-10 11:32:01 -07:00
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
Andy Lutomirski 0161028b7c perf/core: Change the default paranoia level to 2
Allowing unprivileged kernel profiling lets any user dump follow kernel
control flow and dump kernel registers.  This most likely allows trivial
kASLR bypassing, and it may allow other mischief as well.  (Off the top
of my head, the PERF_SAMPLE_REGS_INTR output during /dev/urandom reads
could be quite interesting.)

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-09 17:57:12 -07:00
Davidlohr Bueso 58fe9c4621 sched/core: Fix comment typo in wake_q_add()
... the comment clearly refers to wake_up_q(), and not
wake_up_list().

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dave@stgolabs.net
Link: http://lkml.kernel.org/r/1462766290-28664-1-git-send-email-dave@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-09 08:39:52 +02:00
Muhammad Falak R Wani 8c5e95548d sched/core: Remove unused variable
Remove unused variable 'ret', and directly return 0.

Signed-off-by: Muhammad Falak R Wani <falakreyaz@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/1462441879-10092-1-git-send-email-falakreyaz@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-09 08:39:52 +02:00
Rafael J. Wysocki 536bd00cdb sched/fair: Fix !CONFIG_SMP kernel cpufreq governor breakage
The following commit:

  34e2c555f3 ("cpufreq: Add mechanism for registering utilization update callbacks")

overlooked the fact that update_load_avg(), where CFS invokes cpufreq
utilization update callbacks, becomes an empty stub on UP kernels.

In consequence, if !CONFIG_SMP, cpufreq governors are never invoked
from CFS and they do not have a chance to evaluate CPU performace
levels and update them often enough.

Needless to say, things don't work as expected then.

Fix the problem by making the !CONFIG_SMP stub of update_load_avg()
invoke cpufreq update callbacks too.

Reported-by: Steve Muckle <steve.muckle@linaro.org>
Tested-by: Steve Muckle <steve.muckle@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Steve Muckle <steve.muckle@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux PM list <linux-pm@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Fixes: 34e2c555f3 (cpufreq: Add mechanism for registering utilization update callbacks)
Link: http://lkml.kernel.org/r/6282396.VVEdgVYxO3@vostro.rjw.lan
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-07 07:45:34 +02:00
Linus Torvalds 17d25a337b Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fix from Ingo Molnar:
 "This contains a single fix that fixes a nohz tick stopping bug when
  mixed-poliocy SCHED_FIFO and SCHED_RR tasks are present on a runqueue"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  nohz/full, sched/rt: Fix missed tick-reenabling bug in sched_can_stop_tick()
2016-05-06 11:53:27 -07:00
Thomas Gleixner e5ef27d0f5 sched: Make hrtick_notifier an explicit call
No need for an extra notifier. We don't need to handle all these states. It's
sufficient to kill the timer when the cpu dies.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160310120025.770528462@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-05-06 14:58:26 +02:00
Thomas Gleixner 20a5c8cc74 sched/fair: Make ilb_notifier an explicit call
No need for an extra notifier.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160310120025.693720241@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-05-06 14:58:26 +02:00
Thomas Gleixner aaddd7d1c7 sched/hotplug: Make activate() the last hotplug step
The scheduler can handle per cpu threads before the cpu is set to active and
it does not allow user space threads on the cpu before active is
set. Attaching to the scheduling domains is also not required before user
space threads can be handled.

Move the activation to the end of the hotplug state space. That also means
that deactivation is the first action when a cpu is shut down.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160310120025.597477199@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-05-06 14:58:25 +02:00
Thomas Gleixner f2785ddb53 sched/hotplug: Move migration CPU_DYING to sched_cpu_dying()
Remove the hotplug notifier and make it an explicit state.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160310120025.502222097@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-05-06 14:58:25 +02:00
Thomas Gleixner 7d97669933 sched/migration: Move CPU_ONLINE into scheduler state
The alleged requirement that the migration notifier has a lower priority than
perf is completely undocumented and there is no indication at all that this is
true. perf does not even handle the CPU_ONLINE notification and perf really
has nothing to do with migration.

Move the CPU_ONLINE code into the sched_activate_cpu() state callback.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160310120025.421743581@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-05-06 14:58:25 +02:00
Thomas Gleixner e9cd8fa4fc sched/migration: Move calc_load_migrate() into CPU_DYING
It really does not matter when we fold the load for the outgoing cpu. It's
almost dead anyway, so there is no harm if we fail to fold the few
microseconds which are required for going fully away.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160310120025.328739226@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-05-06 14:58:25 +02:00
Thomas Gleixner 94baf7a5d8 sched/migration: Move prepare transition to SCHED_STARTING state
We can piggy pack that on the SCHED_STARTING state. It's not required before
the cpu actually comes online. Name the function proper as it has nothing to
do with migration.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160310120025.248226511@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-05-06 14:58:24 +02:00
Peter Zijlstra b2454caa89 sched/hotplug: Move sync_rcu to be with set_cpu_active(false)
The sync_rcu stuff is specificically for clearing bits in the active
mask, such that everybody will observe the bit cleared and will not
consider the cleared CPU for load-balancing etc.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160310120025.169219710@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-05-06 14:58:24 +02:00
Thomas Gleixner 40190a78f8 sched/hotplug: Convert cpu_[in]active notifiers to state machine
Now that we reduced everything into single notifiers, it's simple to move them
into the hotplug state machine space.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: rt@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-05-06 14:58:24 +02:00
Thomas Gleixner c6d2c7475c sched: Move sched_domains_numa_masks_clear() to DOWN_PREPARE
This is the last operation on the cpu before vanishing. No point in calling
that on CPU_DEAD.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: rt@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-05-06 14:58:23 +02:00
Thomas Gleixner 135fb3e197 sched: Consolidate the notifier maze
We can maintain the ordering of the scheduler cpu hotplug functionality nicely
in one notifer. Get rid of the maze.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: rt@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-05-06 14:58:23 +02:00
Thomas Gleixner e26fbffd32 sched: Allow hotplug notifiers to be setup early
Prevent the SMP scheduler related notifiers to be executed before the smp
scheduler is initialized and install them early.

This is a preparatory change for further consolidation of the hotplug notifier
maze.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: rt@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-05-06 14:58:23 +02:00
Thomas Gleixner 9cf7243d5d sched: Make set_cpu_rq_start_time() a built in hotplug state
Start distangling the maze of hotplug notifiers in the scheduler.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: rt@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-05-06 14:58:23 +02:00
Peter Zijlstra (Intel) e9d867a67f sched: Allow per-cpu kernel threads to run on online && !active
In order to enable symmetric hotplug, we must mirror the online &&
!active state of cpu-down on the cpu-up side.

However, to retain sanity, limit this state to per-cpu kthreads.

Aside from the change to set_cpus_allowed_ptr(), which allow moving
the per-cpu kthreads on, the other critical piece is the cpu selection
for pinned tasks in select_task_rq(). This avoids dropping into
select_fallback_rq().

select_fallback_rq() cannot be allowed to select !active cpus because
its used to migrate user tasks away. And we do not want to move user
tasks onto cpus that are in transition.

Requested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Jan H. Schönherr <jschoenh@amazon.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160301152303.GV6356@twins.programming.kicks-ass.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-05-06 14:58:22 +02:00
Dietmar Eggemann 885e542ce8 sched/fair: Fix comment in calculate_imbalance()
The comment in calculate_imbalance() was introduced in commit:

 2dd73a4f09 ("[PATCH] sched: implement smpnice")

which described the logic as it was then, but a later commit:

  b18855500f ("sched/balancing: Fix 'local->avg_load > sds->avg_load' case in calculate_imbalance()")

.. complicated this logic some more so that the comment does not match anymore.

Update the comment to match the code.

Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1461958364-675-3-git-send-email-dietmar.eggemann@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-05 09:41:10 +02:00
Dietmar Eggemann 0a9b23ce46 sched/fair: Remove stale power aware scheduling comments
Commit 8e7fbcbc22 ("sched: Remove stale power aware scheduling remnants
and dysfunctional knobs") deleted the power aware scheduling support.

This patch gets rid of the remaining power aware scheduling related
comments in the code as well.

Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1461958364-675-2-git-send-email-dietmar.eggemann@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-05 09:41:09 +02:00
Matt Fleming b52fad2db5 sched/fair: Update rq clock before updating nohz CPU load
If we're accessing rq_clock() (e.g. in sched_avg_update()) we should
update the rq clock before calling cpu_load_update(), otherwise any
time calculations will be stale.

All other paths currently call update_rq_clock().

Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1462304814-11715-1-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-05 09:41:09 +02:00
Wanpeng Li db6ea2fb09 sched/debug: Print out idle balance values even on !CONFIG_SCHEDSTATS kernels
The max_idle_balance_cost and avg_idle values which are tracked and ar used to
capture short idle incidents, are not associated with schedstats, however the
information of these two values isn't printed out on !CONFIG_SCHEDSTATS kernels.

Fix this by moving the value printout out of the CONFIG_SCHEDSTATS section.

Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.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/1462250305-4523-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-05 09:41:09 +02:00
Yuyang Du 7b20b916e9 sched/fair: Optimize sum computation with a lookup table
__compute_runnable_contrib() uses a loop to compute sum, whereas a
table lookup can do it faster in a constant amount of time.

The program to generate the constants is located at:

  Documentation/scheduler/sched-avg.txt

Signed-off-by: Yuyang Du <yuyang.du@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Morten Rasmussen <morten.rasmussen@arm.com>
Acked-by: Vincent Guittot <vincent.guittot@linaro.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: bsegall@google.com
Cc: dietmar.eggemann@arm.com
Cc: juri.lelli@arm.com
Cc: pjt@google.com
Link: http://lkml.kernel.org/r/1462226078-31904-2-git-send-email-yuyang.du@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-05 09:41:08 +02:00
Yuyang Du 172895e6b5 sched/fair: Rename SCHED_LOAD_SHIFT to NICE_0_LOAD_SHIFT and remove SCHED_LOAD_SCALE
After cleaning up the sched metrics, there are two definitions that are
ambiguous and confusing: SCHED_LOAD_SHIFT and SCHED_LOAD_SHIFT.

Resolve this:

 - Rename SCHED_LOAD_SHIFT to NICE_0_LOAD_SHIFT, which better reflects what
   it is.

 - Replace SCHED_LOAD_SCALE use with SCHED_CAPACITY_SCALE and remove SCHED_LOAD_SCALE.

Suggested-by: Ben Segall <bsegall@google.com>
Signed-off-by: Yuyang Du <yuyang.du@intel.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>
Cc: dietmar.eggemann@arm.com
Cc: lizefan@huawei.com
Cc: morten.rasmussen@arm.com
Cc: pjt@google.com
Cc: umgwanakikbuti@gmail.com
Cc: vincent.guittot@linaro.org
Link: http://lkml.kernel.org/r/1459829551-21625-3-git-send-email-yuyang.du@intel.com
[ Rewrote the changelog and fixed the build on 32-bit kernels. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-05 09:35:21 +02:00
Yuyang Du 6ecdd74962 sched/fair: Generalize the load/util averages resolution definition
Integer metric needs fixed point arithmetic. In sched/fair, a few
metrics, e.g., weight, load, load_avg, util_avg, freq, and capacity,
may have different fixed point ranges, which makes their update and
usage error-prone.

In order to avoid the errors relating to the fixed point range, we
definie a basic fixed point range, and then formalize all metrics to
base on the basic range.

The basic range is 1024 or (1 << 10). Further, one can recursively
apply the basic range to have larger range.

Pointed out by Ben Segall, weight (visible to user, e.g., NICE-0 has
1024) and load (e.g., NICE_0_LOAD) have independent ranges, but they
must be well calibrated.

Signed-off-by: Yuyang Du <yuyang.du@intel.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>
Cc: bsegall@google.com
Cc: dietmar.eggemann@arm.com
Cc: lizefan@huawei.com
Cc: morten.rasmussen@arm.com
Cc: pjt@google.com
Cc: umgwanakikbuti@gmail.com
Cc: vincent.guittot@linaro.org
Link: http://lkml.kernel.org/r/1459829551-21625-2-git-send-email-yuyang.du@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-05 09:24:00 +02:00
Peter Zijlstra 2159197d66 sched/core: Enable increased load resolution on 64-bit kernels
Mike ran into the low load resolution limitation on his big machine.

So reenable these bits; nobody could ever reproduce/analyze the
reported power usage claim and Google has been running with this for
years as well.

Reported-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Tested-by: Mike Galbraith <umgwanakikbuti@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>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-05 09:24:00 +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
Peter Zijlstra 3e71a462dd sched/core: Move task_rq_lock() out of line
Its a rather large function, inline doesn't seems to make much sense:

 $ size defconfig-build/kernel/sched/core.o{.orig,}
    text    data     bss     dec     hex filename
   56533   21037    2320   79890   13812 defconfig-build/kernel/sched/core.o.orig
   55733   21037    2320   79090   134f2 defconfig-build/kernel/sched/core.o

The 'perf bench sched messaging' micro-benchmark shows a visible improvement
of 4-5%:

  $ for i in /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor ; do echo performance > $i ; done
  $ perf stat --null --repeat 25 -- perf bench sched messaging -g 40 -l 5000

  pre:
       4.582798193 seconds time elapsed          ( +-  1.41% )
       4.733374877 seconds time elapsed          ( +-  2.10% )
       4.560955136 seconds time elapsed          ( +-  1.43% )
       4.631062303 seconds time elapsed          ( +-  1.40% )

  post:
       4.364765213 seconds time elapsed          ( +-  0.91% )
       4.454442734 seconds time elapsed          ( +-  1.18% )
       4.448893817 seconds time elapsed          ( +-  1.41% )
       4.424346872 seconds time elapsed          ( +-  0.97% )

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: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-05 09:23:58 +02:00
Ingo Molnar 64b7aad579 Merge branch 'sched/urgent' into sched/core, to pick up fixes before applying new changes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-05 09:01:49 +02:00
Linus Torvalds 83858a701c Chunyu Hu noticed that if one writes into the trigger files within the
ftrace subsystem of events that it can cause an oops. This file is only
 writable by root, but still is a bug that needs to be fixed.
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1
 
 iQEcBAABAgAGBQJXKSHAAAoJEKKk/i67LK/8wgQH/jEWQOJhxexkjG8v/RW5iabi
 mGZQeJ/pYTWulW5OJItKGs38fgtSMkT5G4/UitB92l/8/JV4rFyrQrNp29Vfmzv6
 KDnColJ/DYRQoY7+lz7hG0Y2Dft23qaj7l1hBIxtSYJgDC8Omq1dwHCRzzjyJzep
 WPuA/f0W5QGRqupgP7zBd8o0hGO16faMFZQgBcSs263HFY9hssL/y4dfrdN/mi3e
 VjfytGxjwyY6XLH7JTcuhy+F29h0Bo0BT1C9YuXuBuOq1D9ijjQaObUtuGqvsmn0
 HrxLzllj/6w9bcUFxgAHp02yWN5TV8aWgHmvQYmdVWcupp3Vl+4OaO/w9X3MlCQ=
 =l3NN
 -----END PGP SIGNATURE-----

Merge tag 'trace-fixes-v4.6-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fix from Steven Rostedt:
 "Chunyu Hu noticed that if one writes into the trigger files within the
  ftrace subsystem of events that it can cause an oops.  This file is
  only writable by root, but still is a bug that needs to be fixed"

* tag 'trace-fixes-v4.6-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Don't display trigger file for events that can't be enabled
2016-05-03 18:02:38 -07:00
Chunyu Hu 854145e0a8 tracing: Don't display trigger file for events that can't be enabled
Currently register functions for events will be called
through the 'reg' field of event class directly without
any check when seting up triggers.

Triggers for events that don't support register through
debug fs (events under events/ftrace are for trace-cmd to
read event format, and most of them don't have a register
function except events/ftrace/functionx) can't be enabled
at all, and an oops will be hit when setting up trigger
for those events, so just not creating them is an easy way
to avoid the oops.

Link: http://lkml.kernel.org/r/1462275274-3911-1-git-send-email-chuhu@redhat.com

Cc: stable@vger.kernel.org # 3.14+
Fixes: 85f2b08268 ("tracing: Add basic event trigger framework")
Signed-off-by: Chunyu Hu <chuhu@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-05-03 12:59:30 -04:00
Linus Torvalds 9c5d1bc2b7 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Pull networking fixes from David Miller:

 1) MODULE_FIRMWARE firmware string not correct for iwlwifi 8000 chips,
    from Sara Sharon.

 2) Fix SKB size checks in batman-adv stack on receive, from Sven
    Eckelmann.

 3) Leak fix on mac80211 interface add error paths, from Johannes Berg.

 4) Cannot invoke napi_disable() with BH disabled in myri10ge driver,
    fix from Stanislaw Gruszka.

 5) Fix sign extension problem when computing feature masks in
    net_gso_ok(), from Marcelo Ricardo Leitner.

 6) lan78xx driver doesn't count packets and packet lengths in its
    statistics properly, fix from Woojung Huh.

 7) Fix the buffer allocation sizes in pegasus USB driver, from Petko
    Manolov.

 8) Fix refcount overflows in bpf, from Alexei Starovoitov.

 9) Unified dst cache handling introduced a preempt warning in
    ip_tunnel, fix by resetting rather then setting the cached route.
    From Paolo Abeni.

10) Listener hash collision test fix in soreuseport, from Craig Gallak

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (47 commits)
  gre: do not pull header in ICMP error processing
  net: Implement net_dbg_ratelimited() for CONFIG_DYNAMIC_DEBUG case
  tipc: only process unicast on intended node
  cxgb3: fix out of bounds read
  net/smscx5xx: use the device tree for mac address
  soreuseport: Fix TCP listener hash collision
  net: l2tp: fix reversed udp6 checksum flags
  ip_tunnel: fix preempt warning in ip tunnel creation/updating
  samples/bpf: fix trace_output example
  bpf: fix check_map_func_compatibility logic
  bpf: fix refcnt overflow
  drivers: net: cpsw: use of_phy_connect() in fixed-link case
  dt: cpsw: phy-handle, phy_id, and fixed-link are mutually exclusive
  drivers: net: cpsw: don't ignore phy-mode if phy-handle is used
  drivers: net: cpsw: fix segfault in case of bad phy-handle
  drivers: net: cpsw: fix parsing of phy-handle DT property in dual_emac config
  MAINTAINERS: net: Change maintainer for GRETH 10/100/1G Ethernet MAC device driver
  gre: reject GUE and FOU in collect metadata mode
  pegasus: fixes reported packet length
  pegasus: fixes URB buffer allocation size;
  ...
2016-05-02 09:40:42 -07:00
Linus Torvalds 1d003af2ef Merge branch 'akpm' (patches from Andrew)
Merge fixes from Andrew Morton:
 "20 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  Documentation/sysctl/vm.txt: update numa_zonelist_order description
  lib/stackdepot.c: allow the stack trace hash to be zero
  rapidio: fix potential NULL pointer dereference
  mm/memory-failure: fix race with compound page split/merge
  ocfs2/dlm: return zero if deref_done message is successfully handled
  Ananth has moved
  kcov: don't profile branches in kcov
  kcov: don't trace the code coverage code
  mm: wake kcompactd before kswapd's short sleep
  .mailmap: add Frank Rowand
  mm/hwpoison: fix wrong num_poisoned_pages accounting
  mm: call swap_slot_free_notify() with page lock held
  mm: vmscan: reclaim highmem zone if buffer_heads is over limit
  numa: fix /proc/<pid>/numa_maps for THP
  mm/huge_memory: replace VM_NO_THP VM_BUG_ON with actual VMA check
  mailmap: fix Krzysztof Kozlowski's misspelled name
  thp: keep huge zero page pinned until tlb flush
  mm: exclude HugeTLB pages from THP page_mapped() logic
  kexec: export OFFSET(page.compound_head) to find out compound tail page
  kexec: update VMCOREINFO for compound_order/dtor
2016-04-29 11:21:22 -07:00
Linus Torvalds 814dd9481d Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar:
 "x86 PMU driver fixes plus a core code race fix"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/intel: Fix incorrect lbr_sel_mask value
  perf/x86/intel/pt: Don't die on VMXON
  perf/core: Fix perf_event_open() vs. execve() race
  perf/x86/amd: Set the size of event map array to PERF_COUNT_HW_MAX
  perf/core: Make sysctl_perf_cpu_time_max_percent conform to documentation
  perf/x86/intel/rapl: Add missing Haswell model
  perf/x86/intel: Add model number for Skylake Server to perf
2016-04-28 20:19:04 -07:00
Linus Torvalds 2113caed87 Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fixes from Ingo Molnar:
 "Two lockdep fixes"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  lockdep: Fix lock_chain::base size
  locking/lockdep: Fix ->irq_context calculation
2016-04-28 19:59:17 -07:00
Andrey Ryabinin 36f05ae8bc kcov: don't profile branches in kcov
Profiling 'if' statements in __sanitizer_cov_trace_pc() leads to
unbound recursion and crash:

	__sanitizer_cov_trace_pc() ->
		ftrace_likely_update ->
			__sanitizer_cov_trace_pc() ...

Define DISABLE_BRANCH_PROFILING to disable this tracer.

Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-28 19:34:04 -07:00