linux-toradex.git/drivers/cpuidle/cpuidle.c, branch v4.19-rc4

cpuidle: Return nohz hint from cpuidle_select()

2018-04-06T07:29:34+00:00

Add a new pointer argument to cpuidle_select() and to the ->select
cpuidle governor callback to allow a boolean value indicating
whether or not the tick should be stopped before entering the
selected state to be returned from there.

Make the ladder governor ignore that pointer (to preserve its
current behavior) and make the menu governor return 'false" through
it if:
 (1) the idle exit latency is constrained at 0, or
 (2) the selected state is a polling one, or
 (3) the expected idle period duration is within the tick period
     range.

In addition to that, the correction factor computations in the menu
governor need to take the possibility that the tick may not be
stopped into account to avoid artificially small correction factor
values.  To that end, add a mechanism to record tick wakeups, as
suggested by Peter Zijlstra, and use it to modify the menu_update()
behavior when tick wakeup occurs.  Namely, if the CPU is woken up by
the tick and the return value of tick_nohz_get_sleep_length() is not
within the tick boundary, the predicted idle duration is likely too
short, so make menu_update() try to compensate for that by updating
the governor statistics as though the CPU was idle for a long time.

Since the value returned through the new argument pointer of
cpuidle_select() is not used by its caller yet, this change by
itself is not expected to alter the functionality of the code.

Signed-off-by: Rafael J. Wysocki 
Acked-by: Peter Zijlstra (Intel)

PM: cpuidle/suspend: Add s2idle usage and time state attributes

2018-03-29T11:06:08+00:00

Add a new attribute group called "s2idle" under the sysfs directory
of each cpuidle state that supports the ->enter_s2idle callback
and put two new attributes, "usage" and "time", into that group to
represent the number of times the given state was requested for
suspend-to-idle and the total time spent in suspend-to-idle after
requesting that state, respectively.

That will allow diagnostic information related to suspend-to-idle
to be collected without enabling advanced debug features and
analyzing dmesg output.

Signed-off-by: Rafael J. Wysocki

cpuidle: Avoid assignment in if () argument

2017-11-08T22:15:30+00:00

Clean up cpuidle_enable_device() to avoid doing an assignment
in an expression evaluated as an argument of if (), which also
makes the code in question more readable.

Signed-off-by: Gaurav Jindal 
[ rjw: Subject & changelog ]
Signed-off-by: Rafael J. Wysocki

cpuidle: Clean up cpuidle_enable_device() error handling a bit

2017-11-08T22:09:52+00:00

Do not fetch per CPU drv if cpuidle_curr_governor is NULL
to avoid useless per CPU processing.

Signed-off-by: Gaurav Jindal 
[ rjw: Subject & changelog ]
Signed-off-by: Rafael J. Wysocki

cpuidle: fix broadcast control when broadcast can not be entered

2017-09-28T00:18:07+00:00

When failing to enter broadcast timer mode for an idle state that
requires it, a new state is selected that does not require broadcast,
but the broadcast variable remains set. This causes
tick_broadcast_exit to be called despite not having entered broadcast
mode.

This causes the WARN_ON_ONCE(!irqs_disabled()) to trigger in some
cases. It does not appear to cause problems for code today, but seems
to violate the interface so should be fixed.

Signed-off-by: Nicholas Piggin 
Reviewed-by: Thomas Gleixner 
Signed-off-by: Rafael J. Wysocki

PM / s2idle: Rename ->enter_freeze to ->enter_s2idle

2017-08-10T23:29:56+00:00

Rename the ->enter_freeze cpuidle driver callback to ->enter_s2idle
to make it clear that it is used for entering suspend-to-idle and
rename the related functions, variables and so on accordingly.

Signed-off-by: Rafael J. Wysocki

cpuidle: Fix idle time tracking

2017-05-15T08:15:20+00:00

Ville reported that on his Core2, which has TSC stop in idle, we would
always report very short idle durations. He tracked this down to
commit:

  e93e59ce5b85 ("cpuidle: Replace ktime_get() with local_clock()")

which replaces ktime_get() with local_clock().

Add a sched_clock_idle_wakeup_event() call, which will re-sync the
clock with ktime_get_ns() when TSC is unstable and no-op otherwise.

Reported-by: Ville Syrjälä 
Tested-by: Ville Syrjälä 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Daniel Lezcano 
Cc: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Rafael J . Wysocki 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Fixes: e93e59ce5b85 ("cpuidle: Replace ktime_get() with local_clock()")
Signed-off-by: Ingo Molnar

cpuidle: check dev before usage in cpuidle_use_deepest_state()

2017-05-01T21:17:20+00:00

In case of there is no cpuidle devices registered, dev will be null, and
panic will be triggered like below;
In this patch, add checking of dev before usage, like that done in
cpuidle_idle_call.

Panic without fix:
[  184.961328] BUG: unable to handle kernel NULL pointer dereference at
  (null)
[  184.961328] IP: cpuidle_use_deepest_state+0x30/0x60
...
[  184.961328]  play_idle+0x8d/0x210
[  184.961328]  ? __schedule+0x359/0x8e0
[  184.961328]  ? _raw_spin_unlock_irqrestore+0x28/0x50
[  184.961328]  ? kthread_queue_delayed_work+0x41/0x80
[  184.961328]  clamp_idle_injection_func+0x64/0x1e0

Fixes: bb8313b603eb8 (cpuidle: Allow enforcing deepest idle state selection)
Signed-off-by: Li, Fei 
Tested-by: Shi, Feng 
Reviewed-by: Andy Shevchenko 
Cc: 4.10+  # 4.10+
Signed-off-by: Rafael J. Wysocki

sched/headers: Prepare for new header dependencies before moving code to

2017-03-02T07:42:27+00:00

We are going to split  out of , which
will have to be picked up from other headers and .c files.

Create a trivial placeholder  file that just
maps to  to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

cpuidle: Add a kerneldoc comment to cpuidle_use_deepest_state()

2016-12-06T01:25:03+00:00

Since cpuidle_use_deepest_state() is not static, add a proper
kerneldoc comment to it to document its purpose.

Signed-off-by: Rafael J. Wysocki