Commit graph

2,695 commits

Author SHA1 Message Date
Chris Redpath
06dc94f19d ANDROID: sched: Honor sync flag for energy-aware wakeups
Since we don't do energy-aware wakeups when we are overutilized, always
honoring sync wakeups in this state does not prevent wake-wide mechanics
overruling the flag as normal.

Having the check for (cpu_rq(cpu)->nr_running == 1) in the test condition
means that we only bypass the energy model for sync wakeups where the
cpu is about to become idle. This matches the use of this flag in Binder
which is the main place where sync wakeups come from in Android.

This patch is based upon previous work to build EAS for android products.
It replaces
commit 79e3a4a27e ("ANDROID: sched: Unconditionally honor sync flag
 for energy-aware wakeups")
in what's considered to be 'EAS'.

sync-hint code taken from wahoo
https://android.googlesource.com/kernel/msm/+/4a5e890ec60d
written by Juri Lelli <juri.lelli@arm.com>

Change-Id: I4b3d79141fc8e53dc51cd63ac11096c2e3cb10f5
Signed-off-by: Chris Redpath <chris.redpath@arm.com>
(cherry-picked from commit f1ec666a62de)
[ Moved the feature to find_energy_efficient_cpu() and removed the
  sysctl knob ]
Signed-off-by: Quentin Perret <quentin.perret@arm.com>
[ Add 'cpu_rq(cpu)->nr_running == 1' to the condition and remove the
  word 'Unconditionally' from the patch name ]
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
2019-10-22 09:04:43 +00:00
Greg Kroah-Hartman
630839ac24 Linux 5.4-rc3
-----BEGIN PGP SIGNATURE-----
 
 iQFSBAABCAA8FiEEq68RxlopcLEwq+PEeb4+QwBBGIYFAl2jtUYeHHRvcnZhbGRz
 QGxpbnV4LWZvdW5kYXRpb24ub3JnAAoJEHm+PkMAQRiGL28H/Akb3JEXNKHCv3MI
 89dzKlLgf/W/e0qJirb9/YdcUL462NUFoC0Bg0qLgLFYdhT94Zp5J68C4oZPJfxA
 /LrTDsHWrbUtTvhxJqMueVT3JTpkF36ZTvTGwLTHzTqexM/o3kuDWjWTTxZlMGbX
 Uais/ywmmCVCmaX8IJ3GJFGCJse+T1W73VOSo7bm6C+Ruy6Euwasa9kc40uHiPpD
 6Xew9j9AJ0xIV96sLzDFOYAXYFQBZnAbFLA+Ho53TiuG78J6MP4Pm9+1VhMyF1uH
 mgeA5GAfKpqq/QXf32iMU7s7HTdoF5r1UaQJtu+p6BFTGhd7LrDrh4gA/9Wyv7+t
 9stS20U=
 =ima3
 -----END PGP SIGNATURE-----

Merge 5.4-rc3 into android-mainline

Linux 5.4-rc3

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Ia87ba662738dd58ddb917e32c1fbd812861e7a46
2019-10-17 05:28:13 -07:00
Linus Torvalds
328fefadd9 Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
 "Two fixes: a guest-cputime accounting fix, and a cgroup bandwidth
  quota precision fix"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/vtime: Fix guest/system mis-accounting on task switch
  sched/fair: Scale bandwidth quota and period without losing quota/period ratio precision
2019-10-12 15:29:54 -07:00
Frederic Weisbecker
68e7a4d66b sched/vtime: Fix guest/system mis-accounting on task switch
vtime_account_system() assumes that the target task to account cputime
to is always the current task. This is most often true indeed except on
task switch where we call:

	vtime_common_task_switch(prev)
		vtime_account_system(prev)

Here prev is the scheduling-out task where we account the cputime to. It
doesn't match current that is already the scheduling-in task at this
stage of the context switch.

So we end up checking the wrong task flags to determine if we are
accounting guest or system time to the previous task.

As a result the wrong task is used to check if the target is running in
guest mode. We may then spuriously account or leak either system or
guest time on task switch.

Fix this assumption and also turn vtime_guest_enter/exit() to use the
task passed in parameter as well to avoid future similar issues.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpengli@tencent.com>
Fixes: 2a42eb9594 ("sched/cputime: Accumulate vtime on top of nsec clocksource")
Link: https://lkml.kernel.org/r/20190925214242.21873-1-frederic@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-10-09 12:38:03 +02:00
Xuewei Zhang
4929a4e6fa sched/fair: Scale bandwidth quota and period without losing quota/period ratio precision
The quota/period ratio is used to ensure a child task group won't get
more bandwidth than the parent task group, and is calculated as:

  normalized_cfs_quota() = [(quota_us << 20) / period_us]

If the quota/period ratio was changed during this scaling due to
precision loss, it will cause inconsistency between parent and child
task groups.

See below example:

A userspace container manager (kubelet) does three operations:

 1) Create a parent cgroup, set quota to 1,000us and period to 10,000us.
 2) Create a few children cgroups.
 3) Set quota to 1,000us and period to 10,000us on a child cgroup.

These operations are expected to succeed. However, if the scaling of
147/128 happens before step 3, quota and period of the parent cgroup
will be changed:

  new_quota: 1148437ns,   1148us
 new_period: 11484375ns, 11484us

And when step 3 comes in, the ratio of the child cgroup will be
104857, which will be larger than the parent cgroup ratio (104821),
and will fail.

Scaling them by a factor of 2 will fix the problem.

Tested-by: Phil Auld <pauld@redhat.com>
Signed-off-by: Xuewei Zhang <xueweiz@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Phil Auld <pauld@redhat.com>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Ben Segall <bsegall@google.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Fixes: 2e8e192263 ("sched/fair: Limit sched_cfs_period_timer() loop to avoid hard lockup")
Link: https://lkml.kernel.org/r/20191004001243.140897-1-xueweiz@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-10-09 12:38:02 +02:00
Greg Kroah-Hartman
8e9e0abf99 Linux 5.4-rc2
-----BEGIN PGP SIGNATURE-----
 
 iQFSBAABCAA8FiEEq68RxlopcLEwq+PEeb4+QwBBGIYFAl2aXEoeHHRvcnZhbGRz
 QGxpbnV4LWZvdW5kYXRpb24ub3JnAAoJEHm+PkMAQRiGZKUH/1S+unzPxmXwraBl
 ORnOSMCaoepaCS2kc4nFim3hpnwzuFLn8NHPSARPPBO7Jy9Shtku0om66rF6R4DD
 zoe/QSLvtUqiVU6xuPR8ymjeizN+qj+9RT8tDftCs2QCBqZ/jr/kKiiA32aipnrz
 IBC+I6eKFN0WqBep5NwAkIAok+JiUBMIEuEXjkF2q0Vw9fnmmNRMm6rPDk1dHgQi
 K6mr8N3Vbsdadn/XBt4DRje2c593cfOnryPUwyIIBGw5W6EECX6k9CeD+CNNxLYb
 mPNC34wQsqvbAOsP6Y+2lBLZw+0AG5uLytDrwNNO1JKSEYMSG6wH4t7C6w0IlTQt
 OkYK3S0=
 =0ny6
 -----END PGP SIGNATURE-----

Merge 5.4-rc2 into android-mainline

Linux 5.4-rc2

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Idfe13500feef5c1095d06c419fa121f751daa459
2019-10-07 07:09:37 +02:00
Linus Torvalds
e524d16e7e copy-struct-from-user-v5.4-rc2
-----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCXZZIgQAKCRCRxhvAZXjc
 orNOAP98B2nmoxvq8d5Z6PhoyTBC5NIUuJ5h2YMwcX/hAaj5uQEA58NTKtPmOPDR
 2ffUFFerGZ2+brlHgACa0ZKdH27TjAA=
 =QryD
 -----END PGP SIGNATURE-----

Merge tag 'copy-struct-from-user-v5.4-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux

Pull copy_struct_from_user() helper from Christian Brauner:
 "This contains the copy_struct_from_user() helper which got split out
  from the openat2() patchset. It is a generic interface designed to
  copy a struct from userspace.

  The helper will be especially useful for structs versioned by size of
  which we have quite a few. This allows for backwards compatibility,
  i.e. an extended struct can be passed to an older kernel, or a legacy
  struct can be passed to a newer kernel. For the first case (extended
  struct, older kernel) the new fields in an extended struct can be set
  to zero and the struct safely passed to an older kernel.

  The most obvious benefit is that this helper lets us get rid of
  duplicate code present in at least sched_setattr(), perf_event_open(),
  and clone3(). More importantly it will also help to ensure that users
  implementing versioning-by-size end up with the same core semantics.

  This point is especially crucial since we have at least one case where
  versioning-by-size is used but with slighly different semantics:
  sched_setattr(), perf_event_open(), and clone3() all do do similar
  checks to copy_struct_from_user() while rt_sigprocmask(2) always
  rejects differently-sized struct arguments.

  With this pull request we also switch over sched_setattr(),
  perf_event_open(), and clone3() to use the new helper"

* tag 'copy-struct-from-user-v5.4-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
  usercopy: Add parentheses around assignment in test_copy_struct_from_user
  perf_event_open: switch to copy_struct_from_user()
  sched_setattr: switch to copy_struct_from_user()
  clone3: switch to copy_struct_from_user()
  lib: introduce copy_struct_from_user() helper
2019-10-04 10:36:31 -07:00
Todd Kjos
8ecfc2ebdf Merge branch 'eas-dev' into android-mainline
Update to latest version of EAS

Change-Id: I760cf5c0b7b869abf0564da2e4e944ee0654c88c
2019-10-02 15:30:40 -07:00
Greg Kroah-Hartman
935f8bc6f7 UPSTREAM: fix "sched/membarrier: Fix p->mm->membarrier_state racy load"
Upstream patch fix from this thread:
https://lore.kernel.org/lkml/20191001071921.GJ4519@hirez.programming.kicks-ass.net/

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Change-Id: Ia54bf5a29eba3c6d36e7a0b32442af7ff09a3998
2019-10-02 19:13:20 +02:00
Greg Kroah-Hartman
cb33d78781 Linux 5.4-rc1
-----BEGIN PGP SIGNATURE-----
 
 iQFSBAABCAA8FiEEq68RxlopcLEwq+PEeb4+QwBBGIYFAl2SPPkeHHRvcnZhbGRz
 QGxpbnV4LWZvdW5kYXRpb24ub3JnAAoJEHm+PkMAQRiG3dcH/2iCaNvD0Ify+Ke/
 d0Ncf7KhBejfW1pjGjfpfbAQkdaY/gSLsWPJmQ2HT00SmnTJ4y3zvr/HmEE8mIBA
 fMzY4TFHMRNNEOrCugoNxzjU5ycgIMq5doontDdHeS7Pfa8mgDLLwH/dzoORA0+b
 T1ZZT3yDsQ92/jW97LEhTv7UcKqgBdVT5PauU/pe6LHpqmzn8XwdiKaNTM1uY8vw
 U9rIrYnfxCuLfxyK7xUp6bRUlqluZrY4U+pqEnGOVlFYX1xMjjPIE9sDHJ/z5WvY
 JSH4/aOqVxRII2oU0+uITsO658tS912iUsa8++F6Z5R1gZSqQD1FqrvW7Z0S58Ay
 vjXIX3Q=
 =epsM
 -----END PGP SIGNATURE-----

Merge 5.4-rc1 into android-mainline

Linux 5.4-rc1

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I15eec52df70f829acf81ff614a1c2a5fb443a4e0
2019-10-02 19:10:07 +02:00
Greg Kroah-Hartman
94139142d9 Merge 5.4-rc1-prelrease into android-mainline
To make the 5.4-rc1 merge easier, merge at a prerelease point in time
before the final release happens.

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: If613d657fd0abf9910c5bf3435a745f01b89765e
2019-10-02 17:58:47 +02:00
Peter Zijlstra
73956fc07d membarrier: Fix RCU locking bug caused by faulty merge
The following commit:

  227a4aadc7 ("sched/membarrier: Fix p->mm->membarrier_state racy load")

got fat fingered by me when merging it with other patches. It meant to move
the RCU section out of the for loop but ended up doing it partially, leaving
a superfluous rcu_read_lock() inside, causing havok.

Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-tip-commits@vger.kernel.org
Fixes: 227a4aadc7 ("sched/membarrier: Fix p->mm->membarrier_state racy load")
Link: https://lkml.kernel.org/r/20191001085033.GP4519@hirez.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-10-01 21:27:50 +02:00
Aleksa Sarai
dff3a85fec sched_setattr: switch to copy_struct_from_user()
Switch sched_setattr() syscall from it's own copying struct sched_attr
from userspace to the new dedicated copy_struct_from_user() helper.

The change is very straightforward, and helps unify the syscall
interface for struct-from-userspace syscalls. Ideally we could also
unify sched_getattr(2)-style syscalls as well, but unfortunately the
correct semantics for such syscalls are much less clear (see [1] for
more detail). In future we could come up with a more sane idea for how
the syscall interface should look.

[1]: commit 1251201c0d ("sched/core: Fix uclamp ABI bug, clean up and
     robustify sched_read_attr() ABI logic and code")

Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com>
[christian.brauner@ubuntu.com: improve commit message]
Link: https://lore.kernel.org/r/20191001011055.19283-4-cyphar@cyphar.com
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2019-10-01 15:45:17 +02:00
Quentin Perret
760b82c9b8 ANDROID: sched/fair: Bias EAS placement for latency
Add to find_energy_efficient_cpu() a latency sensitive case which mimics
what was done for prefer-idle in android-4.19 and before (see [1] for
reference).

This isn't strictly equivalent to the legacy algorithm but comes real
close, and isn't very invasive. Overall, the idea is to select the
biggest idle CPU we can find for latency-sensitive boosted tasks, and
the smallest CPU where the can fit for latency-sensitive non-boosted
tasks.

The main differences with the legacy behaviour are the following:

 1. the policy for 'prefer idle' when there isn't a single idle CPU in
    the system is simpler now. We just pick the CPU with the highest
    spare capacity;

 2. the cstate awareness is implemented by minimizing the exit latency
    rather than the idle state index. This is how it is done in the slow
    path (find_idlest_group_cpu()), it doesn't require us to keep hooks
    into CPUIdle, and should actually be better because what we want is
    a CPU that can wake up quickly;

 3. non-latency-sensitive tasks just use the standard mainline
    energy-aware wake-up path, which decides the placement using the
    Energy Model;

 4. the 'boosted' and 'latency_sensitive' attributes of a task come from
    util_clamp (which now replaces schedtune).

[1] https://android.googlesource.com/kernel/common.git/+/c27c56105dcaaae54ecc39ef33fbfac87a1486fc

Change-Id: Ia58516906e9cb5abe08385a8cd088097043d8703
Signed-off-by: Quentin Perret <quentin.perret@arm.com>
2019-10-01 10:36:34 +01:00
Quentin Perret
0e00b6f9dd ANDROID: sched: Introduce uclamp latency and boost wrapper
Introduce a simple helper to read the latency_sensitive flag from a
task. It is called uclamp_latency_sensitive() to match the API
proposed by Patrick.

While at it, introduce uclamp_boosted() which returns true only when a
task has a non-null min-clamp.

Change-Id: I5fc747da8b58625257a6604a3c88487b657fbe7a
Suggested-by: Patrick Bellasi <patrick.bellasi@arm.com>
Signed-off-by: Quentin Perret <quentin.perret@arm.com>
2019-10-01 10:36:34 +01:00
Quentin Perret
c28f9d3945 ANDROID: sched/core: Add a latency-sensitive flag to uclamp
Add a 'latency_sensitive' flag to uclamp in order to express the need
for some tasks to find a CPU where they can wake-up quickly. This is not
expected to be used without cgroup support, so add solely a cgroup
interface for it.

As this flag represents a boolean attribute and not an amount of
resources to be shared, it is not clear what the delegation logic should
be. As such, it is kept simple: every new cgroup starts with
latency_sensitive set to false, regardless of the parent.

In essence, this is similar to SchedTune's prefer-idle flag which was
used in android-4.19 and prior.

Change-Id: I722d8ecabb428bb7b95a5b54bc70a87f182dde2a
Signed-off-by: Quentin Perret <quentin.perret@arm.com>
2019-10-01 10:36:34 +01:00
Chris Redpath
44ab1611a8 ANDROID: sched/fair: Also do misfit in overloaded groups
If we can classify the group as overloaded, that overrides
any classification as misfit but we may still have misfit
tasks present. Check the rq we're looking at to see if
this is the case.

Change-Id: Ida8eb66aa625e34de3fe2ee1b0dd8a78926273d8
Signed-off-by: Chris Redpath <chris.redpath@arm.com>
[Removed stray reference to rq_has_misfit]
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Quentin Perret <quentin.perret@arm.com>
2019-10-01 10:36:34 +01:00
Chris Redpath
a7455f8123 ANDROID: sched/fair: Don't balance misfits if it would overload local group
When load balancing in a system with misfit tasks present, if we always
pull a misfit task to the local group this can lead to pulling a running
task from a smaller capacity CPUs to a bigger CPU which is busy. In this
situation, the pulled task is likely not to get a chance to run before
an idle balance on another small CPU pulls it back. This penalises the
pulled task as it is stopped for a short amount of time and then likely
relocated to a different CPU (since the original CPU just did a NEWLY_IDLE
balance and reset the periodic interval).

If we only do this unconditionally for NEWLY_IDLE balance, we can be
sure that any tasks and load which are present on the local group are
related to short-running tasks which we are happy to displace for a
longer running task in a system with misfit tasks present.

However, other balance types should only pull a task if we think
that the local group is underutilized - checking the number of tasks
gives us a conservative estimate here since if they were short tasks
we would have been doing NEWLY_IDLE balances instead.

Change-Id: I710add1ab1139482620b6addc8370ad194791beb
Signed-off-by: Chris Redpath <chris.redpath@arm.com>
Signed-off-by: Quentin Perret <quentin.perret@arm.com>
2019-10-01 10:36:34 +01:00
Chris Redpath
f351885fc7 ANDROID: sched/fair: Attempt to improve throughput for asym cap systems
In some systems the capacity and group weights line up to defeat all the
small imbalance correction conditions in fix_small_imbalance, which can
cause bad task placement. Add a new condition if the existing code can't
see anything to fix:

If we have asymmetric capacity, and there are more tasks than CPUs in
the busiest group *and* there are less tasks than CPUs in the local group
then we try to pull something. There could be transient small tasks which
prevent this from working, but on the whole it is beneficial for those
systems with inconvenient capacity/cluster size relationships.

Change-Id: Icf81cde215c082a61f816534b7990ccb70aee409
Signed-off-by: Chris Redpath <chris.redpath@arm.com>
Signed-off-by: Quentin Perret <quentin.perret@arm.com>
2019-10-01 10:36:33 +01:00
Morten Rasmussen
65b8ddef4e ANDROID: sched: Prevent unnecessary active balance of single task in sched group
Scenarios with the busiest group having just one task and the local
being idle on topologies with sched groups with different numbers of
cpus manage to dodge all load-balance bailout conditions resulting the
nr_balance_failed counter to be incremented. This eventually causes a
pointless active migration of the task. This patch prevents this by not
incrementing the counter when the busiest group only has one task.
ASYM_PACKING migrations and migrations due to reduced capacity should
still take place as these are explicitly captured by
need_active_balance().

A better solution would be to not attempt the load-balance in the first
place, but that requires significant changes to the order of bailout
conditions and statistics gathering.

Change-Id: I28f69c72febe0211decbe77b7bc3e48839d3d7b3
cc: Ingo Molnar <mingo@redhat.com>
cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Quentin Perret <quentin.perret@arm.com>
2019-10-01 10:36:33 +01:00
Dietmar Eggemann
24c4437797 ANDROID: sched: Update max cpu capacity in case of max frequency constraints
Wakeup balancing uses cpu capacity awareness and needs to know the
system-wide maximum cpu capacity.

Patch "sched: Store system-wide maximum cpu capacity in root domain"
finds the system-wide maximum cpu capacity during scheduler domain
hierarchy setup. This is sufficient as long as maximum frequency
invariance is not enabled.

If it is enabled, the system-wide maximum cpu capacity can change
between scheduler domain hierarchy setups due to frequency capping.

The cpu capacity is changed in update_cpu_capacity() which is called in
load balance on the lowest scheduler domain hierarchy level. To be able
to know if a change in cpu capacity for a certain cpu also has an effect
on the system-wide maximum cpu capacity it is normally necessary to
iterate over all cpus. This would be way too costly. That's why this
patch follows a different approach.

The unsigned long max_cpu_capacity value in struct root_domain is
replaced with a struct max_cpu_capacity, containing value (the
max_cpu_capacity) and cpu (the cpu index of the cpu providing the
maximum cpu_capacity).

Changes to the system-wide maximum cpu capacity and the cpu index are
made if:

 1 System-wide maximum cpu capacity < cpu capacity
 2 System-wide maximum cpu capacity > cpu capacity and cpu index == cpu

There are no changes to the system-wide maximum cpu capacity in all
other cases.

Atomic read and write access to the pair (max_cpu_capacity.val,
max_cpu_capacity.cpu) is enforced by max_cpu_capacity.lock.

The access to max_cpu_capacity.val in task_fits_max() is still performed
without taking the max_cpu_capacity.lock.

The code to set max cpu capacity in build_sched_domains() has been
removed because the whole functionality is now provided by
update_cpu_capacity() instead.

This approach can introduce errors temporarily, e.g. in case the cpu
currently providing the max cpu capacity has its cpu capacity lowered
due to frequency capping and calls update_cpu_capacity() before any cpu
which might provide the max cpu now.

Change-Id: I5063befab088fbf49e5d5e484ce0c6ee6165283a
Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>*
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
(- Fixed cherry-pick issues, and conflict with a0fe2cf086 "sched/fair:
   Tune down misfit NOHZ kicks" which makes use of max_cpu_capacity
 - Squashed "sched/fair: remove printk while schedule is in progress"
   fix from Caesar Wang <wxt@rock-chips.com>)
Signed-off-by: Quentin Perret <quentin.perret@arm.com>
2019-10-01 10:36:33 +01:00
Dietmar Eggemann
27ad2abc03 ANDROID: sched/fair: add arch scaling function for max frequency capping
To be able to scale the cpu capacity by this factor introduce a call to
the new arch scaling function arch_scale_max_freq_capacity() in
update_cpu_capacity() and provide a default implementation which returns
SCHED_CAPACITY_SCALE.

Another subsystem (e.g. cpufreq) or architectural or platform specific
code can overwrite this default implementation, exactly as for frequency
and cpu invariance. It has to be enabled by the arch by defining
arch_scale_max_freq_capacity to the actual implementation.

Change-Id: I770a8b1f4f7340e9e314f71c64a765bf880f4b4d
Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
( Fixed conflict with scaling against the PELT-based scale_rt_capacity )
Signed-off-by: Quentin Perret <quentin.perret@arm.com>
2019-10-01 10:36:33 +01:00
Chris Redpath
79e3a4a27e ANDROID: sched: Unconditionally honor sync flag for energy-aware wakeups
Since we don't do energy-aware wakeups when we are overutilized, always
honoring sync wakeups in this state does not prevent wake-wide mechanics
overruling the flag as normal.

This patch is based upon previous work to build EAS for android products.

sync-hint code taken from commit 4a5e890ec60d
"sched/fair: add tunable to force selection at cpu granularity" written
by Juri Lelli <juri.lelli@arm.com>

Change-Id: I4b3d79141fc8e53dc51cd63ac11096c2e3cb10f5
Signed-off-by: Chris Redpath <chris.redpath@arm.com>
(cherry-picked from commit f1ec666a62dec1083ed52fe1ddef093b84373aaf)
[ Moved the feature to find_energy_efficient_cpu() and removed the
  sysctl knob ]
Signed-off-by: Quentin Perret <quentin.perret@arm.com>
2019-10-01 10:36:33 +01:00
Patrick Bellasi
b61876ed12 ANDROID: sched/fair: EAS: Add uclamp support to find_energy_efficient_cpu()
Utilization clamping can be used to boost the utilization of small tasks
or cap that of big tasks. Thus, one of its possible usages is to bias
tasks placement to "promote" small tasks on higher capacity (less energy
efficient) CPUs or "constraint" big tasks on small capacity (more energy
efficient) CPUs.

When the Energy Aware Scheduler (EAS) looks for the most energy
efficient CPU to run a task on, it currently considers only the
effective utiliation estimated for a task.

Fix this by adding an additional check to skip CPUs which capacity is
smaller then the task clamped utilization.

Change-Id: I43fa6fa27e27c1eb5272c6a45d1a6a5b0faae1aa
Signed-off-by: Patrick Bellasi <patrick.bellasi@arm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Quentin Perret <quentin.perret@arm.com>
2019-10-01 10:36:32 +01:00
Linus Torvalds
9c5efe9ae7 Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:

 - Apply a number of membarrier related fixes and cleanups, which fixes
   a use-after-free race in the membarrier code

 - Introduce proper RCU protection for tasks on the runqueue - to get
   rid of the subtle task_rcu_dereference() interface that was easy to
   get wrong

 - Misc fixes, but also an EAS speedup

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/fair: Avoid redundant EAS calculation
  sched/core: Remove double update_max_interval() call on CPU startup
  sched/core: Fix preempt_schedule() interrupt return comment
  sched/fair: Fix -Wunused-but-set-variable warnings
  sched/core: Fix migration to invalid CPU in __set_cpus_allowed_ptr()
  sched/membarrier: Return -ENOMEM to userspace on memory allocation failure
  sched/membarrier: Skip IPIs when mm->mm_users == 1
  selftests, sched/membarrier: Add multi-threaded test
  sched/membarrier: Fix p->mm->membarrier_state racy load
  sched/membarrier: Call sync_core only before usermode for same mm
  sched/membarrier: Remove redundant check
  sched/membarrier: Fix private expedited registration check
  tasks, sched/core: RCUify the assignment of rq->curr
  tasks, sched/core: With a grace period after finish_task_switch(), remove unnecessary code
  tasks, sched/core: Ensure tasks are available for a grace period after leaving the runqueue
  tasks: Add a count of task RCU users
  sched/core: Convert vcpu_is_preempted() from macro to an inline function
  sched/fair: Remove unused cfs_rq_clock_task() function
2019-09-28 12:39:07 -07:00
Quentin Perret
4892f51ad5 sched/fair: Avoid redundant EAS calculation
The EAS wake-up path computes the system energy for several CPU
candidates: the CPU with maximum spare capacity in each performance
domain, and the prev_cpu. However, if prev_cpu also happens to be the
CPU with maximum spare capacity in its performance domain, the energy
calculation is still done twice, unnecessarily.

Add a condition to filter out this corner case before doing the energy
calculation.

Reported-by: Pavan Kondeti <pkondeti@codeaurora.org>
Signed-off-by: Quentin Perret <qperret@qperret.net>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: juri.lelli@redhat.com
Cc: morten.rasmussen@arm.com
Cc: qais.yousef@arm.com
Cc: rjw@rjwysocki.net
Cc: tkjos@google.com
Cc: valentin.schneider@arm.com
Cc: vincent.guittot@linaro.org
Fixes: eb92692b25 ("sched/fair: Speed-up energy-aware wake-ups")
Link: https://lkml.kernel.org/r/20190920094115.GA11503@qperret.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-09-25 17:42:32 +02:00
Valentin Schneider
9fc41acc89 sched/core: Remove double update_max_interval() call on CPU startup
update_max_interval() is called in both CPUHP_AP_SCHED_STARTING's startup
and teardown callbacks, but it turns out it's also called at the end of
the startup callback of CPUHP_AP_ACTIVE (which is further down the
startup sequence).

There's no point in repeating this interval update in the startup sequence
since the CPU will remain online until it goes down the teardown path.

Remove the redundant call in sched_cpu_activate() (CPUHP_AP_ACTIVE).

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: juri.lelli@redhat.com
Cc: vincent.guittot@linaro.org
Link: https://lkml.kernel.org/r/20190923093017.11755-1-valentin.schneider@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-09-25 17:42:32 +02:00
Valentin Schneider
a49b4f4012 sched/core: Fix preempt_schedule() interrupt return comment
preempt_schedule_irq() is the one that should be called on return from
interrupt, clean up the comment to avoid any ambiguity.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-m68k@lists.linux-m68k.org
Cc: linux-riscv@lists.infradead.org
Cc: uclinux-h8-devel@lists.sourceforge.jp
Link: https://lkml.kernel.org/r/20190923143620.29334-2-valentin.schneider@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-09-25 17:42:32 +02:00
Qian Cai
763a9ec06c sched/fair: Fix -Wunused-but-set-variable warnings
Commit:

   de53fd7aed ("sched/fair: Fix low cpu usage with high throttling by removing expiration of cpu-local slices")

introduced a few compilation warnings:

  kernel/sched/fair.c: In function '__refill_cfs_bandwidth_runtime':
  kernel/sched/fair.c:4365:6: warning: variable 'now' set but not used [-Wunused-but-set-variable]
  kernel/sched/fair.c: In function 'start_cfs_bandwidth':
  kernel/sched/fair.c:4992:6: warning: variable 'overrun' set but not used [-Wunused-but-set-variable]

Also, __refill_cfs_bandwidth_runtime() does no longer update the
expiration time, so fix the comments accordingly.

Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ben Segall <bsegall@google.com>
Reviewed-by: Dave Chiluk <chiluk+linux@indeed.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: pauld@redhat.com
Fixes: de53fd7aed ("sched/fair: Fix low cpu usage with high throttling by removing expiration of cpu-local slices")
Link: https://lkml.kernel.org/r/1566326455-8038-1-git-send-email-cai@lca.pw
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-09-25 17:42:31 +02:00
KeMeng Shi
714e501e16 sched/core: Fix migration to invalid CPU in __set_cpus_allowed_ptr()
An oops can be triggered in the scheduler when running qemu on arm64:

 Unable to handle kernel paging request at virtual address ffff000008effe40
 Internal error: Oops: 96000007 [#1] SMP
 Process migration/0 (pid: 12, stack limit = 0x00000000084e3736)
 pstate: 20000085 (nzCv daIf -PAN -UAO)
 pc : __ll_sc___cmpxchg_case_acq_4+0x4/0x20
 lr : move_queued_task.isra.21+0x124/0x298
 ...
 Call trace:
  __ll_sc___cmpxchg_case_acq_4+0x4/0x20
  __migrate_task+0xc8/0xe0
  migration_cpu_stop+0x170/0x180
  cpu_stopper_thread+0xec/0x178
  smpboot_thread_fn+0x1ac/0x1e8
  kthread+0x134/0x138
  ret_from_fork+0x10/0x18

__set_cpus_allowed_ptr() will choose an active dest_cpu in affinity mask to
migrage the process if process is not currently running on any one of the
CPUs specified in affinity mask. __set_cpus_allowed_ptr() will choose an
invalid dest_cpu (dest_cpu >= nr_cpu_ids, 1024 in my virtual machine) if
CPUS in an affinity mask are deactived by cpu_down after cpumask_intersects
check. cpumask_test_cpu() of dest_cpu afterwards is overflown and may pass if
corresponding bit is coincidentally set. As a consequence, kernel will
access an invalid rq address associate with the invalid CPU in
migration_cpu_stop->__migrate_task->move_queued_task and the Oops occurs.

The reproduce the crash:

  1) A process repeatedly binds itself to cpu0 and cpu1 in turn by calling
  sched_setaffinity.

  2) A shell script repeatedly does "echo 0 > /sys/devices/system/cpu/cpu1/online"
  and "echo 1 > /sys/devices/system/cpu/cpu1/online" in turn.

  3) Oops appears if the invalid CPU is set in memory after tested cpumask.

Signed-off-by: KeMeng Shi <shikemeng@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/1568616808-16808-1-git-send-email-shikemeng@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-09-25 17:42:31 +02:00
Mathieu Desnoyers
c172e0a3e8 sched/membarrier: Return -ENOMEM to userspace on memory allocation failure
Remove the IPI fallback code from membarrier to deal with very
infrequent cpumask memory allocation failure. Use GFP_KERNEL rather
than GFP_NOWAIT, and relax the blocking guarantees for the expedited
membarrier system call commands, allowing it to block if waiting for
memory to be made available.

In addition, now -ENOMEM can be returned to user-space if the cpumask
memory allocation fails.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190919173705.2181-8-mathieu.desnoyers@efficios.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-09-25 17:42:31 +02:00
Mathieu Desnoyers
c6d68c1c4a sched/membarrier: Skip IPIs when mm->mm_users == 1
If there is only a single mm_user for the mm, the private expedited
membarrier command can skip the IPIs, because only a single thread
is using the mm.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190919173705.2181-7-mathieu.desnoyers@efficios.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-09-25 17:42:31 +02:00
Mathieu Desnoyers
227a4aadc7 sched/membarrier: Fix p->mm->membarrier_state racy load
The membarrier_state field is located within the mm_struct, which
is not guaranteed to exist when used from runqueue-lock-free iteration
on runqueues by the membarrier system call.

Copy the membarrier_state from the mm_struct into the scheduler runqueue
when the scheduler switches between mm.

When registering membarrier for mm, after setting the registration bit
in the mm membarrier state, issue a synchronize_rcu() to ensure the
scheduler observes the change. In order to take care of the case
where a runqueue keeps executing the target mm without swapping to
other mm, iterate over each runqueue and issue an IPI to copy the
membarrier_state from the mm_struct into each runqueue which have the
same mm which state has just been modified.

Move the mm membarrier_state field closer to pgd in mm_struct to use
a cache line already touched by the scheduler switch_mm.

The membarrier_execve() (now membarrier_exec_mmap) hook now needs to
clear the runqueue's membarrier state in addition to clear the mm
membarrier state, so move its implementation into the scheduler
membarrier code so it can access the runqueue structure.

Add memory barrier in membarrier_exec_mmap() prior to clearing
the membarrier state, ensuring memory accesses executed prior to exec
are not reordered with the stores clearing the membarrier state.

As suggested by Linus, move all membarrier.c RCU read-side locks outside
of the for each cpu loops.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190919173705.2181-5-mathieu.desnoyers@efficios.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-09-25 17:42:30 +02:00
Mathieu Desnoyers
09554009c0 sched/membarrier: Remove redundant check
Checking that the number of threads is 1 is redundant with checking
mm_users == 1.

No change in functionality intended.

Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190919173705.2181-3-mathieu.desnoyers@efficios.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-09-25 17:42:30 +02:00
Mathieu Desnoyers
fc0d77387c sched/membarrier: Fix private expedited registration check
Fix a logic flaw in the way membarrier_register_private_expedited()
handles ready state checks for private expedited sync core and private
expedited registrations.

If a private expedited membarrier registration is first performed, and
then a private expedited sync_core registration is performed, the ready
state check will skip the second registration when it really should not.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190919173705.2181-2-mathieu.desnoyers@efficios.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-09-25 17:42:30 +02:00
Eric W. Biederman
5311a98fef tasks, sched/core: RCUify the assignment of rq->curr
The current task on the runqueue is currently read with rcu_dereference().

To obtain ordinary RCU semantics for an rcu_dereference() of rq->curr it needs
to be paired with rcu_assign_pointer() of rq->curr.  Which provides the
memory barrier necessary to order assignments to the task_struct
and the assignment to rq->curr.

Unfortunately the assignment of rq->curr in __schedule is a hot path,
and it has already been show that additional barriers in that code
will reduce the performance of the scheduler.  So I will attempt to
describe below why you can effectively have ordinary RCU semantics
without any additional barriers.

The assignment of rq->curr in init_idle is a slow path called once
per cpu and that can use rcu_assign_pointer() without any concerns.

As I write this there are effectively two users of rcu_dereference() on
rq->curr.  There is the membarrier code in kernel/sched/membarrier.c
that only looks at "->mm" after the rcu_dereference().  Then there is
task_numa_compare() in kernel/sched/fair.c.  My best reading of the
code shows that task_numa_compare only access: "->flags",
"->cpus_ptr", "->numa_group", "->numa_faults[]",
"->total_numa_faults", and "->se.cfs_rq".

The code in __schedule() essentially does:
	rq_lock(...);
	smp_mb__after_spinlock();

	next = pick_next_task(...);
	rq->curr = next;

	context_switch(prev, next);

At the start of the function the rq_lock/smp_mb__after_spinlock
pair provides a full memory barrier.  Further there is a full memory barrier
in context_switch().

This means that any task that has already run and modified itself (the
common case) has already seen two memory barriers before __schedule()
runs and begins executing.  A task that modifies itself then sees a
third full memory barrier pair with the rq_lock();

For a brand new task that is enqueued with wake_up_new_task() there
are the memory barriers present from the taking and release the
pi_lock and the rq_lock as the processes is enqueued as well as the
full memory barrier at the start of __schedule() assuming __schedule()
happens on the same cpu.

This means that by the time we reach the assignment of rq->curr
except for values on the task struct modified in pick_next_task
the code has the same guarantees as if it used rcu_assign_pointer().

Reading through all of the implementations of pick_next_task it
appears pick_next_task is limited to modifying the task_struct fields
"->se", "->rt", "->dl".  These fields are the sched_entity structures
of the varies schedulers.

Further "->se.cfs_rq" is only changed in cgroup attach/move operations
initialized by userspace.

Unless I have missed something this means that in practice that the
users of "rcu_dereference(rq->curr)" get normal RCU semantics of
rcu_dereference() for the fields the care about, despite the
assignment of rq->curr in __schedule() ot using rcu_assign_pointer.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20190903200603.GW2349@hirez.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-09-25 17:42:29 +02:00
Eric W. Biederman
154abafc68 tasks, sched/core: With a grace period after finish_task_switch(), remove unnecessary code
Remove work arounds that were written before there was a grace period
after tasks left the runqueue in finish_task_switch().

In particular now that there tasks exiting the runqueue exprience
a RCU grace period none of the work performed by task_rcu_dereference()
excpet the rcu_dereference() is necessary so replace task_rcu_dereference()
with rcu_dereference().

Remove the code in rcuwait_wait_event() that checks to ensure the current
task has not exited.  It is no longer necessary as it is guaranteed
that any running task will experience a RCU grace period after it
leaves the run queueue.

Remove the comment in rcuwait_wake_up() as it is no longer relevant.

Ref: 8f95c90ceb ("sched/wait, RCU: Introduce rcuwait machinery")
Ref: 150593bf86 ("sched/api: Introduce task_rcu_dereference() and try_get_task_struct()")
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/87lfurdpk9.fsf_-_@x220.int.ebiederm.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-09-25 17:42:29 +02:00
Eric W. Biederman
0ff7b2cfba tasks, sched/core: Ensure tasks are available for a grace period after leaving the runqueue
In the ordinary case today the RCU grace period for a task_struct is
triggered when another process wait's for it's zombine and causes the
kernel to call release_task().  As the waiting task has to receive a
signal and then act upon it before this happens, typically this will
occur after the original task as been removed from the runqueue.

Unfortunaty in some cases such as self reaping tasks it can be shown
that release_task() will be called starting the grace period for
task_struct long before the task leaves the runqueue.

Therefore use put_task_struct_rcu_user() in finish_task_switch() to
guarantee that the there is a RCU lifetime after the task
leaves the runqueue.

Besides the change in the start of the RCU grace period for the
task_struct this change may cause perf_event_delayed_put and
trace_sched_process_free.  The function perf_event_delayed_put boils
down to just a WARN_ON for cases that I assume never show happen.  So
I don't see any problem with delaying it.

The function trace_sched_process_free is a trace point and thus
visible to user space.  Occassionally userspace has the strangest
dependencies so this has a miniscule chance of causing a regression.
This change only changes the timing of when the tracepoint is called.
The change in timing arguably gives userspace a more accurate picture
of what is going on.  So I don't expect there to be a regression.

In the case where a task self reaps we are pretty much guaranteed that
the RCU grace period is delayed.  So we should get quite a bit of
coverage in of this worst case for the change in a normal threaded
workload.  So I expect any issues to turn up quickly or not at all.

I have lightly tested this change and everything appears to work
fine.

Inspired-by: Linus Torvalds <torvalds@linux-foundation.org>
Inspired-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/87r24jdpl5.fsf_-_@x220.int.ebiederm.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-09-25 17:42:29 +02:00
Nicholas Piggin
13224794cb mm: remove quicklist page table caches
Patch series "mm: remove quicklist page table caches".

A while ago Nicholas proposed to remove quicklist page table caches [1].

I've rebased his patch on the curren upstream and switched ia64 and sh to
use generic versions of PTE allocation.

[1] https://lore.kernel.org/linux-mm/20190711030339.20892-1-npiggin@gmail.com

This patch (of 3):

Remove page table allocator "quicklists".  These have been around for a
long time, but have not got much traction in the last decade and are only
used on ia64 and sh architectures.

The numbers in the initial commit look interesting but probably don't
apply anymore.  If anybody wants to resurrect this it's in the git
history, but it's unhelpful to have this code and divergent allocator
behaviour for minor archs.

Also it might be better to instead make more general improvements to page
allocator if this is still so slow.

Link: http://lkml.kernel.org/r/1565250728-21721-2-git-send-email-rppt@linux.ibm.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-24 15:54:09 -07:00
Greg Kroah-Hartman
896be8f44d Merge 5.4-rc1-prereleae into android-mainline
To make the 5.4-rc1 merge easier, merge at a prerelease point in time
before the final release happens.

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I29b683c837ed1a3324644dbf9bf863f30740cd0b
2019-09-23 14:14:08 +02:00
Linus Torvalds
84da111de0 hmm related patches for 5.4
This is more cleanup and consolidation of the hmm APIs and the very
 strongly related mmu_notifier interfaces. Many places across the tree
 using these interfaces are touched in the process. Beyond that a cleanup
 to the page walker API and a few memremap related changes round out the
 series:
 
 - General improvement of hmm_range_fault() and related APIs, more
   documentation, bug fixes from testing, API simplification &
   consolidation, and unused API removal
 
 - Simplify the hmm related kconfigs to HMM_MIRROR and DEVICE_PRIVATE, and
   make them internal kconfig selects
 
 - Hoist a lot of code related to mmu notifier attachment out of drivers by
   using a refcount get/put attachment idiom and remove the convoluted
   mmu_notifier_unregister_no_release() and related APIs.
 
 - General API improvement for the migrate_vma API and revision of its only
   user in nouveau
 
 - Annotate mmu_notifiers with lockdep and sleeping region debugging
 
 Two series unrelated to HMM or mmu_notifiers came along due to
 dependencies:
 
 - Allow pagemap's memremap_pages family of APIs to work without providing
   a struct device
 
 - Make walk_page_range() and related use a constant structure for function
   pointers
 -----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCgAdFiEEfB7FMLh+8QxL+6i3OG33FX4gmxoFAl1/nnkACgkQOG33FX4g
 mxqaRg//c6FqowV1pQlLutvAOAgMdpzfZ9eaaDKngy9RVQxz+k/MmJrdRH/p/mMA
 Pq93A1XfwtraGKErHegFXGEDk4XhOustVAVFwvjyXO41dTUdoFVUkti6ftbrl/rS
 6CT+X90jlvrwdRY7QBeuo7lxx7z8Qkqbk1O1kc1IOracjKfNJS+y6LTamy6weM3g
 tIMHI65PkxpRzN36DV9uCN5dMwFzJ73DWHp1b0acnDIigkl6u5zp6orAJVWRjyQX
 nmEd3/IOvdxaubAoAvboNS5CyVb4yS9xshWWMbH6AulKJv3Glca1Aa7QuSpBoN8v
 wy4c9+umzqRgzgUJUe1xwN9P49oBNhJpgBSu8MUlgBA4IOc3rDl/Tw0b5KCFVfkH
 yHkp8n6MP8VsRrzXTC6Kx0vdjIkAO8SUeylVJczAcVSyHIo6/JUJCVDeFLSTVymh
 EGWJ7zX2iRhUbssJ6/izQTTQyCH3YIyZ5QtqByWuX2U7ZrfkqS3/EnBW1Q+j+gPF
 Z2yW8iT6k0iENw6s8psE9czexuywa/Lttz94IyNlOQ8rJTiQqB9wLaAvg9hvUk7a
 kuspL+JGIZkrL3ouCeO/VA6xnaP+Q7nR8geWBRb8zKGHmtWrb5Gwmt6t+vTnCC2l
 olIDebrnnxwfBQhEJ5219W+M1pBpjiTpqK/UdBd92A4+sOOhOD0=
 =FRGg
 -----END PGP SIGNATURE-----

Merge tag 'for-linus-hmm' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma

Pull hmm updates from Jason Gunthorpe:
 "This is more cleanup and consolidation of the hmm APIs and the very
  strongly related mmu_notifier interfaces. Many places across the tree
  using these interfaces are touched in the process. Beyond that a
  cleanup to the page walker API and a few memremap related changes
  round out the series:

   - General improvement of hmm_range_fault() and related APIs, more
     documentation, bug fixes from testing, API simplification &
     consolidation, and unused API removal

   - Simplify the hmm related kconfigs to HMM_MIRROR and DEVICE_PRIVATE,
     and make them internal kconfig selects

   - Hoist a lot of code related to mmu notifier attachment out of
     drivers by using a refcount get/put attachment idiom and remove the
     convoluted mmu_notifier_unregister_no_release() and related APIs.

   - General API improvement for the migrate_vma API and revision of its
     only user in nouveau

   - Annotate mmu_notifiers with lockdep and sleeping region debugging

  Two series unrelated to HMM or mmu_notifiers came along due to
  dependencies:

   - Allow pagemap's memremap_pages family of APIs to work without
     providing a struct device

   - Make walk_page_range() and related use a constant structure for
     function pointers"

* tag 'for-linus-hmm' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma: (75 commits)
  libnvdimm: Enable unit test infrastructure compile checks
  mm, notifier: Catch sleeping/blocking for !blockable
  kernel.h: Add non_block_start/end()
  drm/radeon: guard against calling an unpaired radeon_mn_unregister()
  csky: add missing brackets in a macro for tlb.h
  pagewalk: use lockdep_assert_held for locking validation
  pagewalk: separate function pointers from iterator data
  mm: split out a new pagewalk.h header from mm.h
  mm/mmu_notifiers: annotate with might_sleep()
  mm/mmu_notifiers: prime lockdep
  mm/mmu_notifiers: add a lockdep map for invalidate_range_start/end
  mm/mmu_notifiers: remove the __mmu_notifier_invalidate_range_start/end exports
  mm/hmm: hmm_range_fault() infinite loop
  mm/hmm: hmm_range_fault() NULL pointer bug
  mm/hmm: fix hmm_range_fault()'s handling of swapped out pages
  mm/mmu_notifiers: remove unregister_no_release
  RDMA/odp: remove ib_ucontext from ib_umem
  RDMA/odp: use mmu_notifier_get/put for 'struct ib_ucontext_per_mm'
  RDMA/mlx5: Use odp instead of mr->umem in pagefault_mr
  RDMA/mlx5: Use ib_umem_start instead of umem.address
  ...
2019-09-21 10:07:42 -07:00
Greg Kroah-Hartman
bfa0399bc8 Merge Linus's 5.4-rc1-prerelease branch into android-mainline
This merges Linus's tree as of commit b41dae061b ("Merge tag
'xfs-5.4-merge-7' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux")
into android-mainline.

This "early" merge makes it easier to test and handle merge conflicts
instead of having to wait until the "end" of the merge window and handle
all 10000+ commits at once.

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I6bebf55e5e2353f814e3c87f5033607b1ae5d812
2019-09-20 16:07:54 -07:00
Greg Kroah-Hartman
cae5e9966d Revert "ANDROID: sched/fair: add arch scaling function for max frequency capping"
This reverts commit ff481da636.

We want to back-out the eas-dev merge that happened in the tree after
5.3-rc1 as those patches "should" all be in Linus's tree now.

This is done to handle the merge conflicts with 5.4-rc1.

Cc: Todd Kjos <tkjos@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I0152003c46113569f4e92823254d2f4af8a30a6f
2019-09-20 16:07:05 -07:00
Greg Kroah-Hartman
fe764fe4c7 Revert "ANDROID: sched: Update max cpu capacity in case of max frequency constraints"
This reverts commit bfc73d1830.

We want to back-out the eas-dev merge that happened in the tree after
5.3-rc1 as those patches "should" all be in Linus's tree now.

This is done to handle the merge conflicts with 5.4-rc1.

Cc: Todd Kjos <tkjos@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I6e5f8f45be6a2ea01446dd2cea0e3da1fa839404
2019-09-20 16:07:05 -07:00
Greg Kroah-Hartman
e99623b31d Revert "ANDROID: sched: Prevent unnecessary active balance of single task in sched group"
This reverts commit 7846cccba0.

We want to back-out the eas-dev merge that happened in the tree after
5.3-rc1 as those patches "should" all be in Linus's tree now.

This is done to handle the merge conflicts with 5.4-rc1.

Cc: Todd Kjos <tkjos@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Idb2a1eeb907c2ecbf29c71462594f5966a268a5a
2019-09-20 16:07:05 -07:00
Greg Kroah-Hartman
9212f0e499 Revert "ANDROID: sched: Enable idle balance to pull single task towards cpu with higher capacity"
This reverts commit f2fce2f48c.

We want to back-out the eas-dev merge that happened in the tree after
5.3-rc1 as those patches "should" all be in Linus's tree now.

This is done to handle the merge conflicts with 5.4-rc1.

Cc: Todd Kjos <tkjos@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: If826caad4ed3ffb42e9401ba8863669b999bbffb
2019-09-20 16:07:05 -07:00
Greg Kroah-Hartman
390260086c Revert "ANDROID: sched/fair: Attempt to improve throughput for asym cap systems"
This reverts commit 1a1d22a3d8.

We want to back-out the eas-dev merge that happened in the tree after
5.3-rc1 as those patches "should" all be in Linus's tree now.

This is done to handle the merge conflicts with 5.4-rc1.

Cc: Todd Kjos <tkjos@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I4f3a3b047d2c81f2f6de6da633964f009717a1cf
2019-09-20 16:07:04 -07:00
Greg Kroah-Hartman
504e400e6c Revert "ANDROID: sched/fair: Don't balance misfits if it would overload local group"
This reverts commit 67de53b177.

We want to back-out the eas-dev merge that happened in the tree after
5.3-rc1 as those patches "should" all be in Linus's tree now.

This is done to handle the merge conflicts with 5.4-rc1.

Cc: Todd Kjos <tkjos@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I8b1a8909ce8d5eb8d1660586a8706fb6a674d751
2019-09-20 16:07:04 -07:00
Greg Kroah-Hartman
ede4c83add Revert "ANDROID: sched/fair: Also do misfit in overloaded groups"
This reverts commit c3a40105da.

We want to back-out the eas-dev merge that happened in the tree after
5.3-rc1 as those patches "should" all be in Linus's tree now.

This is done to handle the merge conflicts with 5.4-rc1.

Cc: Todd Kjos <tkjos@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I12de178caa24b1b3b8158c7c466a0110b03c234a
2019-09-20 16:07:04 -07:00
Linus Torvalds
77dcfe2b9e Power management updates for 5.4-rc1
- Rework the main suspend-to-idle control flow to avoid repeating
    "noirq" device resume and suspend operations in case of spurious
    wakeups from the ACPI EC and decouple the ACPI EC wakeups support
    from the LPS0 _DSM support (Rafael Wysocki).
 
  - Extend the wakeup sources framework to expose wakeup sources as
    device objects in sysfs (Tri Vo, Stephen Boyd).
 
  - Expose system suspend statistics in sysfs (Kalesh Singh).
 
  - Introduce a new haltpoll cpuidle driver and a new matching
    governor for virtualized guests wanting to do guest-side polling
    in the idle loop (Marcelo Tosatti, Joao Martins, Wanpeng Li,
    Stephen Rothwell).
 
  - Fix the menu and teo cpuidle governors to allow the scheduler tick
    to be stopped if PM QoS is used to limit the CPU idle state exit
    latency in some cases (Rafael Wysocki).
 
  - Increase the resolution of the play_idle() argument to microseconds
    for more fine-grained injection of CPU idle cycles (Daniel Lezcano).
 
  - Switch over some users of cpuidle notifiers to the new QoS-based
    frequency limits and drop the CPUFREQ_ADJUST and CPUFREQ_NOTIFY
    policy notifier events (Viresh Kumar).
 
  - Add new cpufreq driver based on nvmem for sun50i (Yangtao Li).
 
  - Add support for MT8183 and MT8516 to the mediatek cpufreq driver
    (Andrew-sh.Cheng, Fabien Parent).
 
  - Add i.MX8MN support to the imx-cpufreq-dt cpufreq driver (Anson
    Huang).
 
  - Add qcs404 to cpufreq-dt-platdev blacklist (Jorge Ramirez-Ortiz).
 
  - Update the qcom cpufreq driver (among other things, to make it
    easier to extend and to use kryo cpufreq for other nvmem-based
    SoCs) and add qcs404 support to it  (Niklas Cassel, Douglas
    RAILLARD, Sibi Sankar, Sricharan R).
 
  - Fix assorted issues and make assorted minor improvements in the
    cpufreq code (Colin Ian King, Douglas RAILLARD, Florian Fainelli,
    Gustavo Silva, Hariprasad Kelam).
 
  - Add new devfreq driver for NVidia Tegra20 (Dmitry Osipenko, Arnd
    Bergmann).
 
  - Add new Exynos PPMU events to devfreq events and extend that
    mechanism (Lukasz Luba).
 
  - Fix and clean up the exynos-bus devfreq driver (Kamil Konieczny).
 
  - Improve devfreq documentation and governor code, fix spelling
    typos in devfreq (Ezequiel Garcia, Krzysztof Kozlowski, Leonard
    Crestez, MyungJoo Ham, Gaël PORTAY).
 
  - Add regulators enable and disable to the OPP (operating performance
    points) framework (Kamil Konieczny).
 
  - Update the OPP framework to support multiple opp-suspend properties
    (Anson Huang).
 
  - Fix assorted issues and make assorted minor improvements in the OPP
    code (Niklas Cassel, Viresh Kumar, Yue Hu).
 
  - Clean up the generic power domains (genpd) framework (Ulf Hansson).
 
  - Clean up assorted pieces of power management code and documentation
    (Akinobu Mita, Amit Kucheria, Chuhong Yuan).
 
  - Update the pm-graph tool to version 5.5 including multiple fixes
    and improvements (Todd Brandt).
 
  - Update the cpupower utility (Benjamin Weis, Geert Uytterhoeven,
    Sébastien Szymanski).
 -----BEGIN PGP SIGNATURE-----
 
 iQJGBAABCAAwFiEE4fcc61cGeeHD/fCwgsRv/nhiVHEFAl2ArZ4SHHJqd0Byand5
 c29ja2kubmV0AAoJEILEb/54YlRxgfYQAK80hs43vWQDmp7XKrN4pQe8+qYULAGO
 fBfrFl+NG9y/cnuqnt3NtA8MoyNsMMkMLkpkEDMfSbYqqH5ehEzX5+uGJWiWx8+Y
 oH5KU8MH7Tj/utYaalGzDt0AHfHZDIGC0NCUNQJVtE/4mOANFabwsCwscp4MrD5Q
 WjFN8U4BrsmWgJdZ/U9QIWcDZ0I+1etCF+rZG2yxSv31FMq2Zk/Qm4YyobqCvQFl
 TR9rxl08wqUmIYIz5cDjt/3AKH7NLLDqOTstbCL7cmufM5XPFc1yox69xc89UrIa
 4AMgmDp7SMwFG/gdUPof0WQNmx7qxmiRAPleAOYBOZW/8jPNZk2y+RhM5NeF72m7
 AFqYiuxqatkSb4IsT8fLzH9IUZOdYr8uSmoMQECw+MHdApaKFjFV8Lb/qx5+AwkD
 y7pwys8dZSamAjAf62eUzJDWcEwkNrujIisGrIXrVHb7ISbweskMOmdAYn9p4KgP
 dfRzpJBJ45IaMIdbaVXNpg3rP7Apfs7X1X+/ZhG6f+zHH3zYwr8Y81WPqX8WaZJ4
 qoVCyxiVWzMYjY2/1lzjaAdqWojPWHQ3or3eBaK52DouyG3jY6hCDTLwU7iuqcCX
 jzAtrnqrNIKufvaObEmqcmYlIIOFT7QaJCtGUSRFQLfSon8fsVSR7LLeXoAMUJKT
 JWQenuNaJngK
 =TBDQ
 -----END PGP SIGNATURE-----

Merge tag 'pm-5.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management updates from Rafael Wysocki:
 "These include a rework of the main suspend-to-idle code flow (related
  to the handling of spurious wakeups), a switch over of several users
  of cpufreq notifiers to QoS-based limits, a new devfreq driver for
  Tegra20, a new cpuidle driver and governor for virtualized guests, an
  extension of the wakeup sources framework to expose wakeup sources as
  device objects in sysfs, and more.

  Specifics:

   - Rework the main suspend-to-idle control flow to avoid repeating
     "noirq" device resume and suspend operations in case of spurious
     wakeups from the ACPI EC and decouple the ACPI EC wakeups support
     from the LPS0 _DSM support (Rafael Wysocki).

   - Extend the wakeup sources framework to expose wakeup sources as
     device objects in sysfs (Tri Vo, Stephen Boyd).

   - Expose system suspend statistics in sysfs (Kalesh Singh).

   - Introduce a new haltpoll cpuidle driver and a new matching governor
     for virtualized guests wanting to do guest-side polling in the idle
     loop (Marcelo Tosatti, Joao Martins, Wanpeng Li, Stephen Rothwell).

   - Fix the menu and teo cpuidle governors to allow the scheduler tick
     to be stopped if PM QoS is used to limit the CPU idle state exit
     latency in some cases (Rafael Wysocki).

   - Increase the resolution of the play_idle() argument to microseconds
     for more fine-grained injection of CPU idle cycles (Daniel
     Lezcano).

   - Switch over some users of cpuidle notifiers to the new QoS-based
     frequency limits and drop the CPUFREQ_ADJUST and CPUFREQ_NOTIFY
     policy notifier events (Viresh Kumar).

   - Add new cpufreq driver based on nvmem for sun50i (Yangtao Li).

   - Add support for MT8183 and MT8516 to the mediatek cpufreq driver
     (Andrew-sh.Cheng, Fabien Parent).

   - Add i.MX8MN support to the imx-cpufreq-dt cpufreq driver (Anson
     Huang).

   - Add qcs404 to cpufreq-dt-platdev blacklist (Jorge Ramirez-Ortiz).

   - Update the qcom cpufreq driver (among other things, to make it
     easier to extend and to use kryo cpufreq for other nvmem-based
     SoCs) and add qcs404 support to it (Niklas Cassel, Douglas
     RAILLARD, Sibi Sankar, Sricharan R).

   - Fix assorted issues and make assorted minor improvements in the
     cpufreq code (Colin Ian King, Douglas RAILLARD, Florian Fainelli,
     Gustavo Silva, Hariprasad Kelam).

   - Add new devfreq driver for NVidia Tegra20 (Dmitry Osipenko, Arnd
     Bergmann).

   - Add new Exynos PPMU events to devfreq events and extend that
     mechanism (Lukasz Luba).

   - Fix and clean up the exynos-bus devfreq driver (Kamil Konieczny).

   - Improve devfreq documentation and governor code, fix spelling typos
     in devfreq (Ezequiel Garcia, Krzysztof Kozlowski, Leonard Crestez,
     MyungJoo Ham, Gaël PORTAY).

   - Add regulators enable and disable to the OPP (operating performance
     points) framework (Kamil Konieczny).

   - Update the OPP framework to support multiple opp-suspend properties
     (Anson Huang).

   - Fix assorted issues and make assorted minor improvements in the OPP
     code (Niklas Cassel, Viresh Kumar, Yue Hu).

   - Clean up the generic power domains (genpd) framework (Ulf Hansson).

   - Clean up assorted pieces of power management code and documentation
     (Akinobu Mita, Amit Kucheria, Chuhong Yuan).

   - Update the pm-graph tool to version 5.5 including multiple fixes
     and improvements (Todd Brandt).

   - Update the cpupower utility (Benjamin Weis, Geert Uytterhoeven,
     Sébastien Szymanski)"

* tag 'pm-5.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (126 commits)
  cpuidle-haltpoll: Enable kvm guest polling when dedicated physical CPUs are available
  cpuidle-haltpoll: do not set an owner to allow modunload
  cpuidle-haltpoll: return -ENODEV on modinit failure
  cpuidle-haltpoll: set haltpoll as preferred governor
  cpuidle: allow governor switch on cpuidle_register_driver()
  PM: runtime: Documentation: add runtime_status ABI document
  pm-graph: make setVal unbuffered again for python2 and python3
  powercap: idle_inject: Use higher resolution for idle injection
  cpuidle: play_idle: Increase the resolution to usec
  cpuidle-haltpoll: vcpu hotplug support
  cpufreq: Add qcs404 to cpufreq-dt-platdev blacklist
  cpufreq: qcom: Add support for qcs404 on nvmem driver
  cpufreq: qcom: Refactor the driver to make it easier to extend
  cpufreq: qcom: Re-organise kryo cpufreq to use it for other nvmem based qcom socs
  dt-bindings: opp: Add qcom-opp bindings with properties needed for CPR
  dt-bindings: opp: qcom-nvmem: Support pstates provided by a power domain
  Documentation: cpufreq: Update policy notifier documentation
  cpufreq: Remove CPUFREQ_ADJUST and CPUFREQ_NOTIFY policy notifier events
  PM / Domains: Verify PM domain type in dev_pm_genpd_set_performance_state()
  PM / Domains: Simplify genpd_lookup_dev()
  ...
2019-09-17 19:15:14 -07:00