Right now, guest current governors have the following ratings:
* ladder -> 10
* teo -> 19
* menu -> 20
* haltpoll -> 21
* ladder + nohz=off -> 25
haltpoll governor got introduced and it is now the default governor given
its highest rating -- with ladder+nohz being the exception -- regardless of
idle driver in the guest. An example of an undesirable case is x86 KVM
guests with MWAIT which have intel_idle registered first, and consequently
will have haltpoll be used as governor which would get limited to a poll
state and state 1 and the other states wouldn't get used.
To keep the previous defaults we decrease rating of governor to 9 (below
current lowest rating) and thus rely on @governor switch on
cpuidle_register_driver() to tie in haltpoll idle driver and governor
together.
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The recently introduced haltpoll driver is largely only useful with
haltpoll governor. To allow drivers to associate with a particular idle
behaviour, add a @governor property to 'struct cpuidle_driver' and thus
allow a cpuidle driver to switch to a *preferred* governor on idle driver
registration. We save the previous governor, and when an idle driver is
unregistered we switch back to that.
The @governor can be overridden by cpuidle.governor= boot param or
alternatively be ignored if the governor doesn't exist.
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
When cpus != maxcpus cpuidle-haltpoll will fail to register all vcpus
past the online ones and thus fail to register the idle driver.
This is because cpuidle_add_sysfs() will return with -ENODEV as a
consequence from get_cpu_device() return no device for a non-existing
CPU.
Instead switch to cpuidle_register_driver() and manually register each
of the present cpus through cpuhp_setup_state() callbacks and future
ones that get onlined or offlined. This mimmics similar logic that
intel_idle does.
Fixes: fa86ee90eb ("add cpuidle-haltpoll driver")
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Notice that setting measured_us to UINT_MAX in teo_update() earlier
doesn't change the behavior of the following code, so do that and
eliminate a redundant check used for setting measured_us to UINT_MAX.
This change is not expected to alter functionality.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The TEO goveror prevents the scheduler tick from being stopped (unless
stopped already) if there is a PM QoS latency constraint for the given
CPU and the target residency of the deepest idle state matching that
constraint is below the tick boundary.
However, that is problematic if CPUs with PM QoS latency constraints
are idle for long times, because it effectively causes the tick to
run on them all the time which is wasteful. [It is also confusing
and questionable if they are full dynticks CPUs.]
To address that issue, modify the TEO governor to carry out the
entire search for the most suitable idle state (from the target
residency perspective) even if a latency constraint is present,
to allow it to determine the expected idle duration in all cases.
Also, when using the last several measured idle duration values
to refine the idle state selection, make it compare those values
with the current expected idle duration value (instead of
comparing them with the target residency of the idle state
selected so far) which should prevent the tick from being
retained when it makes sense to stop it sometimes (especially
in the presence of PM QoS latency constraints).
Fixes: b26bf6ab71 ("cpuidle: New timer events oriented governor for tickless systems")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
After commit 554c8aa8ec ("sched: idle: Select idle state before
stopping the tick") the menu governor prevents the scheduler tick from
being stopped (unless stopped already) if there is a PM QoS latency
constraint for the given CPU and the target residency of the deepest
idle state matching that constraint is below the tick boundary.
However, that is problematic if CPUs with PM QoS latency constraints
are idle for long times, because it effectively causes the tick to
run on them all the time which is wasteful. [It is also confusing
and questionable if they are full dynticks CPUs.]
To address that issue, make the menu governor allow the tick to be
stopped only if the idle duration predicted by it is beyond the tick
boundary, except when the shallowest idle state is selected upfront
and it is not a "polling" one.
Fixes: 554c8aa8ec ("sched: idle: Select idle state before stopping the tick")
Link: https://lore.kernel.org/lkml/79b247b3-e056-610e-9a07-e685dfdaa6c9@gmail.com/
Reported-by: Thomas Lindroth <thomas.lindroth@gmail.com>
Tested-by: Thomas Lindroth <thomas.lindroth@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
When performing guest side polling, it is not necessary to
also perform host side polling.
So disable host side polling, via the new MSR interface,
when loading cpuidle-haltpoll driver.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The cpuidle_haltpoll governor, in conjunction with the haltpoll cpuidle
driver, allows guest vcpus to poll for a specified amount of time before
halting.
This provides the following benefits to host side polling:
1) The POLL flag is set while polling is performed, which allows
a remote vCPU to avoid sending an IPI (and the associated
cost of handling the IPI) when performing a wakeup.
2) The VM-exit cost can be avoided.
The downside of guest side polling is that polling is performed
even with other runnable tasks in the host.
Results comparing halt_poll_ns and server/client application
where a small packet is ping-ponged:
host --> 31.33
halt_poll_ns=300000 / no guest busy spin --> 33.40 (93.8%)
halt_poll_ns=0 / guest_halt_poll_ns=300000 --> 32.73 (95.7%)
For the SAP HANA benchmarks (where idle_spin is a parameter
of the previous version of the patch, results should be the
same):
hpns == halt_poll_ns
idle_spin=0/ idle_spin=800/ idle_spin=0/
hpns=200000 hpns=0 hpns=800000
DeleteC06T03 (100 thread) 1.76 1.71 (-3%) 1.78 (+1%)
InsertC16T02 (100 thread) 2.14 2.07 (-3%) 2.18 (+1.8%)
DeleteC00T01 (1 thread) 1.34 1.28 (-4.5%) 1.29 (-3.7%)
UpdateC00T03 (1 thread) 4.72 4.18 (-12%) 4.53 (-5%)
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Since this field is shared by all governors, move it to
cpuidle device structure.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Add a poll_limit_ns variable to cpuidle_device structure.
Calculate and configure it in the new cpuidle_poll_time
function, in case its zero.
Individual governors are allowed to override this value.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Add a cpuidle driver that calls the architecture default_idle routine.
To be used in conjunction with the haltpoll governor.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* pm-cpufreq:
cpufreq: Make cpufreq_generic_init() return void
cpufreq: imx-cpufreq-dt: Add i.MX8MN support
cpufreq: Add QoS requests for userspace constraints
cpufreq: intel_pstate: Reuse refresh_frequency_limits()
cpufreq: Register notifiers with the PM QoS framework
PM / QoS: Add support for MIN/MAX frequency constraints
PM / QOS: Pass request type to dev_pm_qos_read_value()
PM / QOS: Rename __dev_pm_qos_read_value() and dev_pm_qos_raw_read_value()
PM / QOS: Pass request type to dev_pm_qos_{add|remove}_notifier()
dev_pm_qos_read_value() will soon need to support more constraint types
(min/max frequency) and will have another argument to it, i.e. type of
the constraint. While that is fine for the existing users of
dev_pm_qos_read_value(), but not that optimal for the callers of
__dev_pm_qos_read_value() and dev_pm_qos_raw_read_value() as all the
callers of these two routines are only looking for resume latency
constraint.
Lets make these two routines care only about the resume latency
constraint and rename them to __dev_pm_qos_resume_latency() and
dev_pm_qos_raw_resume_latency().
Suggested-by: Rafael J. Wysocki <rjw@rjwysocki.net>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Based on 2 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 4122 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Based on 1 normalized pattern(s):
this file is released under the gplv2
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 68 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Armijn Hemel <armijn@tjaldur.nl>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531190114.292346262@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Based on 1 normalized pattern(s):
this code is licenced under the gpl version 2 as described in the
copying file that acompanies the linux kernel
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 1 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190528171439.466585205@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms and conditions of the gnu general public license
version 2 as published by the free software foundation this program
is distributed in the hope it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details you should have received a copy of the gnu general
public license along with this program if not see http www gnu org
licenses
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 228 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190528171438.107155473@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Based on 3 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version [author] [kishon] [vijay] [abraham]
[i] [kishon]@[ti] [com] this program is distributed in the hope that
it will be useful but without any warranty without even the implied
warranty of merchantability or fitness for a particular purpose see
the gnu general public license for more details
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version [author] [graeme] [gregory]
[gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i]
[kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema]
[hk] [hemahk]@[ti] [com] this program is distributed in the hope
that it will be useful but without any warranty without even the
implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-or-later
has been chosen to replace the boilerplate/reference in 1105 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-or-later
has been chosen to replace the boilerplate/reference in 3029 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add SPDX license identifiers to all Make/Kconfig files which:
- Have no license information of any form
These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:
GPL-2.0-only
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To be able to predict the sleep duration for a CPU entering idle, it
is essential to know the expiration time of the next timer. Both the
teo and the menu cpuidle governors already use this information for
CPU idle state selection.
Moving forward, a similar prediction needs to be made for a group of
idle CPUs rather than for a single one and the following changes
implement a new genpd governor for that purpose.
In order to support that feature, add a new function called
tick_nohz_get_next_hrtimer() that will return the next hrtimer
expiration time of a given CPU to be invoked after deciding
whether or not to stop the scheduler tick on that CPU.
Make the cpuidle core call tick_nohz_get_next_hrtimer() right
before invoking the ->enter() callback provided by the cpuidle
driver for the given state and store its return value in the
per-CPU struct cpuidle_device, so as to make it available to code
outside of cpuidle.
Note that at the point when cpuidle calls tick_nohz_get_next_hrtimer(),
the governor's ->select() callback has already returned and indicated
whether or not the tick should be stopped, so in fact the value
returned by tick_nohz_get_next_hrtimer() always is the next hrtimer
expiration time for the given CPU, possibly including the tick (if
it hasn't been stopped).
Co-developed-by: Lina Iyer <lina.iyer@linaro.org>
Co-developed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
[ rjw: Subject & changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Since commit 45f1ff59e2 ("cpuidle: Return nohz hint from
cpuidle_select()") Exynos CPUidle driver stopped entering C1 (AFTR) mode
on Exynos4412-based Trats2 board.
Further analysis revealed that the CPUidle framework changed the way
it handles predicted timer ticks and reported target residency for the
given idle states. As a result, the C1 (AFTR) state was not chosen
anymore on completely idle device. The main issue was to high target
residency value. The similar C1 (AFTR) state for 'coupled' CPUidle
version used 10 times lower value for the target residency, despite
the fact that it is the same state from the hardware perspective.
The 100000us value for standard C1 (AFTR) mode is there from the begining
of the support for this idle state, added by the commit 67173ca492
("ARM: EXYNOS: Add support AFTR mode on EXYNOS4210"). That commit doesn't
give any reason for it, instead it looks like it was blindly copied from
the WFI/IDLE state of the same driver that time. That time, that value
was probably not really used by the framework for any critical decision,
so it didn't matter that much.
Now it turned out to be an issue, so unify the target residency with the
'coupled' version, as it seems to better match the real use case values
and restores the operation of the Exynos CPUidle driver on the idle
device.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
After commit 61cb5758d3 ("cpuidle: Add cpuidle.governor= command
line parameter") new cpuidle governors are not added to the list
of available governors, so governor selection via sysfs doesn't
work as expected (even though it is rarely used anyway).
Fix that by making cpuidle_register_governor() add new governors to
cpuidle_governors again.
Fixes: 61cb5758d3 ("cpuidle: Add cpuidle.governor= command line parameter")
Reported-by: Kees Cook <keescook@chromium.org>
Cc: 5.0+ <stable@vger.kernel.org> # 5.0+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The variance computation in get_typical_interval() may overflow if
the square of the value of diff exceeds the maximum for the int64_t
data type value which basically is the case when it is of the order
of UINT_MAX.
However, data points so far in the future don't matter for idle
state selection anyway, so change the initial threshold value in
get_typical_interval() to INT_MAX which will cause more "outlying"
data points to be discarded without affecting the selection result.
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Currently, the DT of the idle states will be parsed first whether it's
compatible or not. This could cause a warning message that comes from if
the CPU doesn't support identical idle states. E.g. Tegra186 can run
with 2 Cortex-A57 and 2 Denver cores with different idle states on
different types of these cores.
So fix it by checking the match node earlier, then it can make sure it
only goes through the idle states that the CPU supported.
Signed-off-by: Joseph Lo <josephl@nvidia.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The default time is declared in units of microsecnds,
but is used as nanoseconds, resulting in significant
accounting errors for idle state 0 time when all idle
states deeper than 0 are disabled.
Under these unusual conditions, we don't really care
about the poll time limit anyhow.
Fixes: 800fb34a99 ("cpuidle: poll_state: Disregard disable idle states")
Signed-off-by: Doug Smythies <dsmythies@telus.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The venerable menu governor does some things that are quite
questionable in my view.
First, it includes timer wakeups in the pattern detection data and
mixes them up with wakeups from other sources which in some cases
causes it to expect what essentially would be a timer wakeup in a
time frame in which no timer wakeups are possible (because it knows
the time until the next timer event and that is later than the
expected wakeup time).
Second, it uses the extra exit latency limit based on the predicted
idle duration and depending on the number of tasks waiting on I/O,
even though those tasks may run on a different CPU when they are
woken up. Moreover, the time ranges used by it for the sleep length
correction factors depend on whether or not there are tasks waiting
on I/O, which again doesn't imply anything in particular, and they
are not correlated to the list of available idle states in any way
whatever.
Also, the pattern detection code in menu may end up considering
values that are too large to matter at all, in which cases running
it is a waste of time.
A major rework of the menu governor would be required to address
these issues and the performance of at least some workloads (tuned
specifically to the current behavior of the menu governor) is likely
to suffer from that. It is thus better to introduce an entirely new
governor without them and let everybody use the governor that works
better with their actual workloads.
The new governor introduced here, the timer events oriented (TEO)
governor, uses the same basic strategy as menu: it always tries to
find the deepest idle state that can be used in the given conditions.
However, it applies a different approach to that problem.
First, it doesn't use "correction factors" for the time till the
closest timer, but instead it tries to correlate the measured idle
duration values with the available idle states and use that
information to pick up the idle state that is most likely to "match"
the upcoming CPU idle interval.
Second, it doesn't take the number of "I/O waiters" into account at
all and the pattern detection code in it avoids taking timer wakeups
into account. It also only uses idle duration values less than the
current time till the closest timer (with the tick excluded) for that
purpose.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Notable changes:
- Mitigations for Spectre v2 on some Freescale (NXP) CPUs.
- A large series adding support for pass-through of Nvidia V100 GPUs to guests
on Power9.
- Another large series to enable hardware assistance for TLB table walk on
MPC8xx CPUs.
- Some preparatory changes to our DMA code, to make way for further cleanups
from Christoph.
- Several fixes for our Transactional Memory handling discovered by fuzzing the
signal return path.
- Support for generating our system call table(s) from a text file like other
architectures.
- A fix to our page fault handler so that instead of generating a WARN_ON_ONCE,
user accesses of kernel addresses instead print a ratelimited and
appropriately scary warning.
- A cosmetic change to make our unhandled page fault messages more similar to
other arches and also more compact and informative.
- Freescale updates from Scott:
"Highlights include elimination of legacy clock bindings use from dts
files, an 83xx watchdog handler, fixes to old dts interrupt errors, and
some minor cleanup."
And many clean-ups, reworks and minor fixes etc.
Thanks to:
Alexandre Belloni, Alexey Kardashevskiy, Andrew Donnellan, Aneesh Kumar K.V,
Arnd Bergmann, Benjamin Herrenschmidt, Breno Leitao, Christian Lamparter,
Christophe Leroy, Christoph Hellwig, Daniel Axtens, Darren Stevens, David
Gibson, Diana Craciun, Dmitry V. Levin, Firoz Khan, Geert Uytterhoeven, Greg
Kurz, Gustavo Romero, Hari Bathini, Joel Stanley, Kees Cook, Madhavan
Srinivasan, Mahesh Salgaonkar, Markus Elfring, Mathieu Malaterre, Michal
Suchánek, Naveen N. Rao, Nick Desaulniers, Oliver O'Halloran, Paul Mackerras,
Ram Pai, Ravi Bangoria, Rob Herring, Russell Currey, Sabyasachi Gupta, Sam
Bobroff, Satheesh Rajendran, Scott Wood, Segher Boessenkool, Stephen Rothwell,
Tang Yuantian, Thiago Jung Bauermann, Yangtao Li, Yuantian Tang, Yue Haibing.
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Merge tag 'powerpc-4.21-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
"Notable changes:
- Mitigations for Spectre v2 on some Freescale (NXP) CPUs.
- A large series adding support for pass-through of Nvidia V100 GPUs
to guests on Power9.
- Another large series to enable hardware assistance for TLB table
walk on MPC8xx CPUs.
- Some preparatory changes to our DMA code, to make way for further
cleanups from Christoph.
- Several fixes for our Transactional Memory handling discovered by
fuzzing the signal return path.
- Support for generating our system call table(s) from a text file
like other architectures.
- A fix to our page fault handler so that instead of generating a
WARN_ON_ONCE, user accesses of kernel addresses instead print a
ratelimited and appropriately scary warning.
- A cosmetic change to make our unhandled page fault messages more
similar to other arches and also more compact and informative.
- Freescale updates from Scott:
"Highlights include elimination of legacy clock bindings use from
dts files, an 83xx watchdog handler, fixes to old dts interrupt
errors, and some minor cleanup."
And many clean-ups, reworks and minor fixes etc.
Thanks to: Alexandre Belloni, Alexey Kardashevskiy, Andrew Donnellan,
Aneesh Kumar K.V, Arnd Bergmann, Benjamin Herrenschmidt, Breno Leitao,
Christian Lamparter, Christophe Leroy, Christoph Hellwig, Daniel
Axtens, Darren Stevens, David Gibson, Diana Craciun, Dmitry V. Levin,
Firoz Khan, Geert Uytterhoeven, Greg Kurz, Gustavo Romero, Hari
Bathini, Joel Stanley, Kees Cook, Madhavan Srinivasan, Mahesh
Salgaonkar, Markus Elfring, Mathieu Malaterre, Michal Suchánek, Naveen
N. Rao, Nick Desaulniers, Oliver O'Halloran, Paul Mackerras, Ram Pai,
Ravi Bangoria, Rob Herring, Russell Currey, Sabyasachi Gupta, Sam
Bobroff, Satheesh Rajendran, Scott Wood, Segher Boessenkool, Stephen
Rothwell, Tang Yuantian, Thiago Jung Bauermann, Yangtao Li, Yuantian
Tang, Yue Haibing"
* tag 'powerpc-4.21-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (201 commits)
Revert "powerpc/fsl_pci: simplify fsl_pci_dma_set_mask"
powerpc/zImage: Also check for stdout-path
powerpc: Fix HMIs on big-endian with CONFIG_RELOCATABLE=y
macintosh: Use of_node_name_{eq, prefix} for node name comparisons
ide: Use of_node_name_eq for node name comparisons
powerpc: Use of_node_name_eq for node name comparisons
powerpc/pseries/pmem: Convert to %pOFn instead of device_node.name
powerpc/mm: Remove very old comment in hash-4k.h
powerpc/pseries: Fix node leak in update_lmb_associativity_index()
powerpc/configs/85xx: Enable CONFIG_DEBUG_KERNEL
powerpc/dts/fsl: Fix dtc-flagged interrupt errors
clk: qoriq: add more compatibles strings
powerpc/fsl: Use new clockgen binding
powerpc/83xx: handle machine check caused by watchdog timer
powerpc/fsl-rio: fix spelling mistake "reserverd" -> "reserved"
powerpc/fsl_pci: simplify fsl_pci_dma_set_mask
arch/powerpc/fsl_rmu: Use dma_zalloc_coherent
vfio_pci: Add NVIDIA GV100GL [Tesla V100 SXM2] subdriver
vfio_pci: Allow regions to add own capabilities
vfio_pci: Allow mapping extra regions
...
Add two new metrics for CPU idle states, "above" and "below", to count
the number of times the given state had been asked for (or entered
from the kernel's perspective), but the observed idle duration turned
out to be too short or too long for it (respectively).
These metrics help to estimate the quality of the CPU idle governor
in use.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
of_find_node_by_path() acquires a reference to the node
returned by it and that reference needs to be dropped by its caller.
bl_idle_init() doesn't do that, so fix it.
Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Add cpuidle.governor= command line parameter to allow the default
cpuidle governor to be replaced.
That is useful, for example, if someone running a tickful kernel
wants to use the menu governor on it.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
When computing the limit of time to spend in the loop in poll_idle(),
use the target residency of the first enabled idle state deeper than
state 0 instead of always using the target residency of state 1.
This helps when state 1 is disabled for diagnostics, for instance.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
When booting a pseries kernel with PREEMPT enabled, it dumps the
following warning:
BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1
caller is pseries_processor_idle_init+0x5c/0x22c
CPU: 13 PID: 1 Comm: swapper/0 Not tainted 4.20.0-rc3-00090-g12201a0128bc-dirty #828
Call Trace:
[c000000429437ab0] [c0000000009c8878] dump_stack+0xec/0x164 (unreliable)
[c000000429437b00] [c0000000005f2f24] check_preemption_disabled+0x154/0x160
[c000000429437b90] [c000000000cab8e8] pseries_processor_idle_init+0x5c/0x22c
[c000000429437c10] [c000000000010ed4] do_one_initcall+0x64/0x300
[c000000429437ce0] [c000000000c54500] kernel_init_freeable+0x3f0/0x500
[c000000429437db0] [c0000000000112dc] kernel_init+0x2c/0x160
[c000000429437e20] [c00000000000c1d0] ret_from_kernel_thread+0x5c/0x6c
This happens because the code calls get_lppaca() which calls
get_paca() and it checks if preemption is disabled through
check_preemption_disabled().
Preemption should be disabled because the per CPU variable may make no
sense if there is a preemption (and a CPU switch) after it reads the
per CPU data and when it is used.
In this device driver specifically, it is not a problem, because this
code just needs to have access to one lppaca struct, and it does not
matter if it is the current per CPU lppaca struct or not (i.e. when
there is a preemption and a CPU migration).
That said, the most appropriate fix seems to be related to avoiding
the debug_smp_processor_id() call at get_paca(), instead of calling
preempt_disable() before get_paca().
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The only reason that remains, to why the ARM cpuidle driver calls
cpuidle_register_driver(), is to avoid printing an error message in case
another driver already have been registered for the CPU. This seems a bit
silly, but more importantly, if that is a common scenario, perhaps we
should change cpuidle_register() accordingly instead.
In either case, let's consolidate the code, by converting to use
cpuidle_register|unregister(), which also avoids the unnecessary allocation
of the struct cpuidle_device.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
There's no point to register the cpuidle driver for the current CPU, when
the initialization of the arch specific back-end data fails by returning
-ENXIO.
Instead, let's re-order the sequence to its original flow, by first trying
to initialize the back-end part and then act accordingly on the returned
error code. Additionally, let's print the error message, no matter of what
error code that was returned.
Fixes: a0d46a3dfd (ARM: cpuidle: Register per cpuidle device)
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: 4.19+ <stable@vger.kernel.org> # v4.19+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
- Fix build regression in the intel_pstate driver that doesn't
build without CONFIG_ACPI after recent changes (Dominik Brodowski).
- One of the heuristics in the menu cpuidle governor is based on a
function returning 0 most of the time, so drop it and clean up
the scheduler code related to it (Daniel Lezcano).
- Prevent the arm_big_little cpufreq driver from being used on ARM64
which is not suitable for it and drop the arm_big_little_dt driver
that is not used any more (Sudeep Holla).
- Prevent the hung task watchdog from triggering during resume from
system-wide sleep states by disabling it before freezing tasks and
enabling it again after they have been thawed (Vitaly Kuznetsov).
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Merge tag 'pm-4.20-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull more power management updates from Rafael Wysocki:
"These remove a questionable heuristic from the menu cpuidle governor,
fix a recent build regression in the intel_pstate driver, clean up ARM
big-Little support in cpufreq and fix up hung task watchdog's
interaction with system-wide power management transitions.
Specifics:
- Fix build regression in the intel_pstate driver that doesn't build
without CONFIG_ACPI after recent changes (Dominik Brodowski).
- One of the heuristics in the menu cpuidle governor is based on a
function returning 0 most of the time, so drop it and clean up the
scheduler code related to it (Daniel Lezcano).
- Prevent the arm_big_little cpufreq driver from being used on ARM64
which is not suitable for it and drop the arm_big_little_dt driver
that is not used any more (Sudeep Holla).
- Prevent the hung task watchdog from triggering during resume from
system-wide sleep states by disabling it before freezing tasks and
enabling it again after they have been thawed (Vitaly Kuznetsov)"
* tag 'pm-4.20-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
kernel: hung_task.c: disable on suspend
cpufreq: remove unused arm_big_little_dt driver
cpufreq: drop ARM_BIG_LITTLE_CPUFREQ support for ARM64
cpufreq: intel_pstate: Fix compilation for !CONFIG_ACPI
cpuidle: menu: Remove get_loadavg() from the performance multiplier
sched: Factor out nr_iowait and nr_iowait_cpu
There are several definitions of those functions/macros in places that
mess with fixed-point load averages. Provide an official version.
[akpm@linux-foundation.org: fix missed conversion in block/blk-iolatency.c]
Link: http://lkml.kernel.org/r/20180828172258.3185-5-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Suren Baghdasaryan <surenb@google.com>
Tested-by: Daniel Drake <drake@endlessm.com>
Cc: Christopher Lameter <cl@linux.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <jweiner@fb.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Enderborg <peter.enderborg@sony.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vinayak Menon <vinmenon@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The function get_loadavg() returns almost always zero. To be more
precise, statistically speaking for a total of 1023379 times passing
in the function, the load is equal to zero 1020728 times, greater than
100, 610 times, the remaining is between 0 and 5.
In 2011, the get_loadavg() was removed from the Android tree because
of the above [1]. At this time, the load was:
unsigned long this_cpu_load(void)
{
struct rq *this = this_rq();
return this->cpu_load[0];
}
In 2014, the code was changed by commit 372ba8cb46 (cpuidle: menu: Lookup CPU
runqueues less) and the load is:
void get_iowait_load(unsigned long *nr_waiters, unsigned long *load)
{
struct rq *rq = this_rq();
*nr_waiters = atomic_read(&rq->nr_iowait);
*load = rq->load.weight;
}
with the same result.
Both measurements show using the load in this code path does no matter
anymore. Removing it.
[1] 4dedd9f124
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
If the minimum interval taken into account in the average computation
loop in get_typical_interval() is less than the expected idle
duration determined so far, the resultant average cannot be greater
than that value as well and the entire return result of the function
is going to be discarded anyway going forward.
In that case, it is a waste of time to carry out the remaining
computations in get_typical_interval(), so avoid that by returning
early if the minimum interval is not below the expected idle duration.
No intentional changes of behavior.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Since the correction factor cannot be greater than RESOLUTION * DECAY,
the result of the predicted_us computation in menu_select() cannot be
greater than data->next_timer_us, so it is not necessary to compare
the "typical interval" value coming from get_typical_interval() with
data->next_timer_us separately.
It is sufficient to copmare predicted_us with the return value of
get_typical_interval() directly, so do that and drop the now
redundant expected_interval variable.
No intentional changes of behavior.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
After some recent menu governor changes, the promotion of the
"polling" state to a physical one is mostly controlled by the
latency limit (resulting from the "interactivity" factor) and
not by the time to the closest timer event, so it should be
sufficient to check the exit latency of that state for this
purpose (of course, its target residency still needs to be
within the next timer event range for energy-efficiency).
Also, the physical state the "polling" one is promoted to need not
be the next one in principle (in case the next state is disabled,
for example).
For these reasons, simplify the checks made to decide whether or
not to promote the "polling" state to a physical one and update
the target idle duration when it is promoted in case the residency
of the new state turns out to be above the tick boundary (in which
case there is no reason to stop the tick).
Tested-by: Doug Smythies <dsmythies@telus.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
If need_resched() returns "false", breaking out of the loop in
poll_idle() will cause a new idle state to be selected, so in fact
it usually doesn't make sense to spin in it longer than the target
residency of the second state. [Note that the "polling" state is
used only if there is at least one "real" state defined in addition
to it, so the second state is always there.] On the other hand,
breaking out of it early (say in case the next state is disabled)
shouldn't hurt as it is polling anyway.
For this reason, make the loop in poll_idle() break if the CPU has
been spinning longer than the target residency of the second state
(the "polling" state can only be state[0]).
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
It is better to always update data->bucket before returning from
menu_select() to avoid updating the correction factor for a stale
bucket, so combine the latency_req == 0 special check with the more
general check below.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
If the next timer event (not including the tick) is closer than the
target residency of the second state or the PM QoS latency constraint
is below its exit latency, state[0] will be used regardless of any
other factors, so skip the computations in menu_select() then and
return 0 straight away from it.
Still, do that after the bucket has been determined to avoid
updating the correction factor for a stale bucket.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
It is not necessary to update data->last_state_idx in menu_select()
as it only is used in menu_update() which only runs when
data->needs_update is set and that is set only when updating
data->last_state_idx in menu_reflect().
Accordingly, drop the update of data->last_state_idx from
menu_select() and get rid of the (now redundant) "out" label
from it.
No intentional behavior changes.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Rearrange the code in menu_select() so that the loop over idle states
always starts from 0 and get rid of the first_idx variable.
While at it, add two empty lines to separate conditional statements
from one another.
No intentional behavior changes.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Since menu_select() can only set first_idx to 1 if the exit latency
of the second state is not greater than the latency limit, it should
first determine that limit. Thus first_idx should be computed after
the "interactivity" factor has been taken into account.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewedy-by: Daniel Lezcano <daniel.lezcano@linaro.org>
If the CPU exits the "polling" state due to the time limit in the
loop in poll_idle(), this is not a real wakeup and it just means
that the "polling" state selection was not adequate. The governor
mispredicted short idle duration, but had a more suitable state been
selected, the CPU might have spent more time in it. In fact, there
is no reason to expect that there would have been a wakeup event
earlier than the next timer in that case.
Handling such cases as regular wakeups in menu_update() may cause the
menu governor to make suboptimal decisions going forward, but ignoring
them altogether would not be correct either, because every time
menu_select() is invoked, it makes a separate new attempt to predict
the idle duration taking distinct time to the closest timer event as
input and the outcomes of all those attempts should be recorded.
For this reason, make menu_update() always assume that if the
"polling" state was exited due to the time limit, the next proper
wakeup event for the CPU would be the next timer event (not
including the tick).
Fixes: a37b969a61 "cpuidle: poll_state: Add time limit to poll_idle()"
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
The predicted_us field in struct menu_device is only accessed in
menu_select(), so replace it with a local variable in that function.
With that, stop using expected_interval instead of predicted_us to
store the new predicted idle duration value if it is set to the
selected state's target residency which is quite confusing.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
