Before commit 076cbf5d2163 ("x86/xen: don't let xen_pv_play_dead()
return"), in Xen, when a previously offlined CPU was brought back
online, it unexpectedly resumed execution where it left off in the
middle of the idle loop.
There were some hacks to make that work, but the behavior was surprising
as do_idle() doesn't expect an offlined CPU to return from the dead (in
arch_cpu_idle_dead()).
Now that Xen has been fixed, and the arch-specific implementations of
arch_cpu_idle_dead() also don't return, give it a __noreturn attribute.
This will cause the compiler to complain if an arch-specific
implementation might return. It also improves code generation for both
caller and callee.
Also fixes the following warning:
vmlinux.o: warning: objtool: do_idle+0x25f: unreachable instruction
Reported-by: Paul E. McKenney <paulmck@kernel.org>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/60d527353da8c99d4cf13b6473131d46719ed16d.1676358308.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Current arch_cpu_idle() is called with IRQs disabled, but will return
with IRQs enabled.
However, the very first thing the generic code does after calling
arch_cpu_idle() is raw_local_irq_disable(). This means that
architectures that can idle with IRQs disabled end up doing a
pointless 'enable-disable' dance.
Therefore, push this IRQ disabling into the idle function, meaning
that those architectures can avoid the pointless IRQ state flipping.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Acked-by: Mark Rutland <mark.rutland@arm.com> [arm64]
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Guo Ren <guoren@kernel.org>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20230112195540.618076436@infradead.org
The whole disable-RCU, enable-IRQS dance is very intricate since
changing IRQ state is traced, which depends on RCU.
Add two helpers for the cpuidle case that mirror the entry code:
ct_cpuidle_enter()
ct_cpuidle_exit()
And fix all the cases where the enter/exit dance was buggy.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20230112195540.130014793@infradead.org
The RCU dynticks counter is going to be merged into the context tracking
subsystem. Start with moving the idle extended quiescent states
entrypoints to context tracking. For now those are dumb redirections to
existing RCU calls.
[ paulmck: Apply kernel test robot feedback. ]
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com>
Cc: Uladzislau Rezki <uladzislau.rezki@sony.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Nicolas Saenz Julienne <nsaenz@kernel.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Cc: Yu Liao <liaoyu15@huawei.com>
Cc: Phil Auld <pauld@redhat.com>
Cc: Paul Gortmaker<paul.gortmaker@windriver.com>
Cc: Alex Belits <abelits@marvell.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
- rwsem cleanups & optimizations/fixes:
- Conditionally wake waiters in reader/writer slowpaths
- Always try to wake waiters in out_nolock path
- Add try_cmpxchg64() implementation, with arch optimizations - and use it to
micro-optimize sched_clock_{local,remote}()
- Various force-inlining fixes to address objdump instrumentation-check warnings
- Add lock contention tracepoints:
lock:contention_begin
lock:contention_end
- Misc smaller fixes & cleanups
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'locking-core-2022-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
- rwsem cleanups & optimizations/fixes:
- Conditionally wake waiters in reader/writer slowpaths
- Always try to wake waiters in out_nolock path
- Add try_cmpxchg64() implementation, with arch optimizations - and use
it to micro-optimize sched_clock_{local,remote}()
- Various force-inlining fixes to address objdump instrumentation-check
warnings
- Add lock contention tracepoints:
lock:contention_begin
lock:contention_end
- Misc smaller fixes & cleanups
* tag 'locking-core-2022-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/clock: Use try_cmpxchg64 in sched_clock_{local,remote}
locking/atomic/x86: Introduce arch_try_cmpxchg64
locking/atomic: Add generic try_cmpxchg64 support
futex: Remove a PREEMPT_RT_FULL reference.
locking/qrwlock: Change "queue rwlock" to "queued rwlock"
lockdep: Delete local_irq_enable_in_hardirq()
locking/mutex: Make contention tracepoints more consistent wrt adaptive spinning
locking: Apply contention tracepoints in the slow path
locking: Add lock contention tracepoints
locking/rwsem: Always try to wake waiters in out_nolock path
locking/rwsem: Conditionally wake waiters in reader/writer slowpaths
locking/rwsem: No need to check for handoff bit if wait queue empty
lockdep: Fix -Wunused-parameter for _THIS_IP_
x86/mm: Force-inline __phys_addr_nodebug()
x86/kvm/svm: Force-inline GHCB accessors
task_stack, x86/cea: Force-inline stack helpers
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Merge tag 'v5.18-rc5' into sched/core to pull in fixes & to resolve a conflict
- sched/core is on a pretty old -rc1 base - refresh it to include recent fixes.
- this also allows up to resolve a (trivial) .mailmap conflict
Conflicts:
.mailmap
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This is invoked from the stopper thread too, which is definitely not idle.
Rename it to flush_smp_call_function_queue() and fixup the callers.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220413133024.305001096@linutronix.de
While looking into a bug related to the compiler's handling of addresses
of labels, I noticed some uses of _THIS_IP_ seemed unused in lockdep.
Drive by cleanup.
-Wunused-parameter:
kernel/locking/lockdep.c:1383:22: warning: unused parameter 'ip'
kernel/locking/lockdep.c:4246:48: warning: unused parameter 'ip'
kernel/locking/lockdep.c:4844:19: warning: unused parameter 'ip'
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Waiman Long <longman@redhat.com>
Link: https://lore.kernel.org/r/20220314221909.2027027-1-ndesaulniers@google.com
Steve reported that ChromeOS encounters the forceidle balancer being
ran from rt_mutex_setprio()'s balance_callback() invocation and
explodes.
Now, the forceidle balancer gets queued every time the idle task gets
selected, set_next_task(), which is strictly too often.
rt_mutex_setprio() also uses set_next_task() in the 'change' pattern:
queued = task_on_rq_queued(p); /* p->on_rq == TASK_ON_RQ_QUEUED */
running = task_current(rq, p); /* rq->curr == p */
if (queued)
dequeue_task(...);
if (running)
put_prev_task(...);
/* change task properties */
if (queued)
enqueue_task(...);
if (running)
set_next_task(...);
However, rt_mutex_setprio() will explicitly not run this pattern on
the idle task (since priority boosting the idle task is quite insane).
Most other 'change' pattern users are pidhash based and would also not
apply to idle.
Also, the change pattern doesn't contain a __balance_callback()
invocation and hence we could have an out-of-band balance-callback,
which *should* trigger the WARN in rq_pin_lock() (which guards against
this exact anti-pattern).
So while none of that explains how this happens, it does indicate that
having it in set_next_task() might not be the most robust option.
Instead, explicitly queue the forceidle balancer from pick_next_task()
when it does indeed result in forceidle selection. Having it here,
ensures it can only be triggered under the __schedule() rq->lock
instance, and hence must be ran from that context.
This also happens to clean up the code a little, so win-win.
Fixes: d2dfa17bc7 ("sched: Trivial forced-newidle balancer")
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: T.J. Alumbaugh <talumbau@chromium.org>
Link: https://lkml.kernel.org/r/20220330160535.GN8939@worktop.programming.kicks-ass.net
Similarly to kernel/sched/build_utility.c, collect all 'scheduling policy' related
source code files into kernel/sched/build_policy.c:
kernel/sched/idle.c
kernel/sched/rt.c
kernel/sched/cpudeadline.c
kernel/sched/pelt.c
kernel/sched/cputime.c
kernel/sched/deadline.c
With the exception of fair.c, which we continue to build as a separate file
for build efficiency and parallelism reasons.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Peter Zijlstra <peterz@infradead.org>
The intel powerclamp driver will setup a per-CPU worker with RT
priority. The worker will then invoke play_idle() in which it remains in
the idle poll loop until it is stopped by the timer it started earlier.
That timer needs to expire in hard interrupt context on PREEMPT_RT.
Otherwise the timer will expire in ksoftirqd as a SOFT timer but that task
won't be scheduled on the CPU because its priority is lower than the
priority of the worker which is in the idle loop.
Always expire the idle timer in hard interrupt context.
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210906113034.jgfxrjdvxnjqgtmc@linutronix.de
When a sibling is forced-idle to match the core-cookie; search for
matching tasks to fill the core.
rcu_read_unlock() can incur an infrequent deadlock in
sched_core_balance(). Fix this by using the RCU-sched flavor instead.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Don Hiatt <dhiatt@digitalocean.com>
Tested-by: Hongyu Ning <hongyu.ning@linux.intel.com>
Tested-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20210422123308.800048269@infradead.org
Because sched_class::pick_next_task() also implies
sched_class::set_next_task() (and possibly put_prev_task() and
newidle_balance) it is not state invariant. This makes it unsuitable
for remote task selection.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
[Vineeth: folded fixes]
Signed-off-by: Vineeth Remanan Pillai <viremana@linux.microsoft.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Don Hiatt <dhiatt@digitalocean.com>
Tested-by: Hongyu Ning <hongyu.ning@linux.intel.com>
Tested-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20210422123308.437092775@infradead.org
In preparation of playing games with rq->lock, abstract the thing
using an accessor.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Don Hiatt <dhiatt@digitalocean.com>
Tested-by: Hongyu Ning <hongyu.ning@linux.intel.com>
Tested-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20210422123308.136465446@infradead.org
Fix ~42 single-word typos in scheduler code comments.
We have accumulated a few fun ones over the years. :-)
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ben Segall <bsegall@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: linux-kernel@vger.kernel.org
Instead of waking up a random and already idle CPU, we can take advantage
of this_cpu being about to enter idle to run the ILB and update the
blocked load.
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Link: https://lkml.kernel.org/r/20210224133007.28644-7-vincent.guittot@linaro.org
Entering RCU idle mode may cause a deferred wake up of an RCU NOCB_GP
kthread (rcuog) to be serviced.
Usually a local wake up happening while running the idle task is handled
in one of the need_resched() checks carefully placed within the idle
loop that can break to the scheduler.
Unfortunately the call to rcu_idle_enter() is already beyond the last
generic need_resched() check and we may halt the CPU with a resched
request unhandled, leaving the task hanging.
Fix this with splitting the rcuog wakeup handling from rcu_idle_enter()
and place it before the last generic need_resched() check in the idle
loop. It is then assumed that no call to call_rcu() will be performed
after that in the idle loop until the CPU is put in low power mode.
Fixes: 96d3fd0d31 (rcu: Break call_rcu() deadlock involving scheduler and perf)
Reported-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20210131230548.32970-3-frederic@kernel.org
- migrate_disable/enable() support which originates from the RT tree and
is now a prerequisite for the new preemptible kmap_local() API which aims
to replace kmap_atomic().
- A fair amount of topology and NUMA related improvements
- Improvements for the frequency invariant calculations
- Enhanced robustness for the global CPU priority tracking and decision
making
- The usual small fixes and enhancements all over the place
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Merge tag 'sched-core-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Thomas Gleixner:
- migrate_disable/enable() support which originates from the RT tree
and is now a prerequisite for the new preemptible kmap_local() API
which aims to replace kmap_atomic().
- A fair amount of topology and NUMA related improvements
- Improvements for the frequency invariant calculations
- Enhanced robustness for the global CPU priority tracking and decision
making
- The usual small fixes and enhancements all over the place
* tag 'sched-core-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (61 commits)
sched/fair: Trivial correction of the newidle_balance() comment
sched/fair: Clear SMT siblings after determining the core is not idle
sched: Fix kernel-doc markup
x86: Print ratio freq_max/freq_base used in frequency invariance calculations
x86, sched: Use midpoint of max_boost and max_P for frequency invariance on AMD EPYC
x86, sched: Calculate frequency invariance for AMD systems
irq_work: Optimize irq_work_single()
smp: Cleanup smp_call_function*()
irq_work: Cleanup
sched: Limit the amount of NUMA imbalance that can exist at fork time
sched/numa: Allow a floating imbalance between NUMA nodes
sched: Avoid unnecessary calculation of load imbalance at clone time
sched/numa: Rename nr_running and break out the magic number
sched: Make migrate_disable/enable() independent of RT
sched/topology: Condition EAS enablement on FIE support
arm64: Rebuild sched domains on invariance status changes
sched/topology,schedutil: Wrap sched domains rebuild
sched/uclamp: Allow to reset a task uclamp constraint value
sched/core: Fix typos in comments
Documentation: scheduler: fix information on arch SD flags, sched_domain and sched_debug
...
We call arch_cpu_idle() with RCU disabled, but then use
local_irq_{en,dis}able(), which invokes tracing, which relies on RCU.
Switch all arch_cpu_idle() implementations to use
raw_local_irq_{en,dis}able() and carefully manage the
lockdep,rcu,tracing state like we do in entry.
(XXX: we really should change arch_cpu_idle() to not return with
interrupts enabled)
Reported-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lkml.kernel.org/r/20201120114925.594122626@infradead.org
Only select_task_rq_fair() uses that parameter to do an actual domain
search, other classes only care about what kind of wakeup is happening
(fork, exec, or "regular") and thus just translate the flag into a wakeup
type.
WF_TTWU and WF_EXEC have just been added, use these along with WF_FORK to
encode the wakeup types we care about. For select_task_rq_fair(), we can
simply use the shiny new WF_flag : SD_flag mapping.
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20201102184514.2733-3-valentin.schneider@arm.com
Florian reported that all of kernel/sched/ is rebuild when
CONFIG_BLK_DEV_INITRD is changed, which, while not a bug is
unexpected. This is due to us including vmlinux.lds.h.
Jakub explained that the problem is that we put the alignment
requirement on the type instead of on a variable. Type alignment is a
minimum, the compiler is free to pick any larger alignment for a
specific instance of the type (eg. the variable).
So force the type alignment on all individual variable definitions and
remove the undesired dependency on vmlinux.lds.h.
Fixes: 85c2ce9104 ("sched, vmlinux.lds: Increase STRUCT_ALIGNMENT to 64 bytes for GCC-4.9")
Reported-by: Florian Fainelli <f.fainelli@gmail.com>
Suggested-by: Jakub Jelinek <jakub@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Add comments and memory barrier to kthread_use_mm and kthread_unuse_mm
to allow the effect of membarrier(2) to apply to kthreads accessing
user-space memory as well.
Given that no prior kthread use this guarantee and that it only affects
kthreads, adding this guarantee does not affect user-space ABI.
Refine the check in membarrier_global_expedited to exclude runqueues
running the idle thread rather than all kthreads from the IPI cpumask.
Now that membarrier_global_expedited can IPI kthreads, the scheduler
also needs to update the runqueue's membarrier_state when entering lazy
TLB state.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20201020134715.13909-3-mathieu.desnoyers@efficios.com
Use a more generic form for __section that requires quotes to avoid
complications with clang and gcc differences.
Remove the quote operator # from compiler_attributes.h __section macro.
Convert all unquoted __section(foo) uses to quoted __section("foo").
Also convert __attribute__((section("foo"))) uses to __section("foo")
even if the __attribute__ has multiple list entry forms.
Conversion done using the script at:
https://lore.kernel.org/lkml/75393e5ddc272dc7403de74d645e6c6e0f4e70eb.camel@perches.com/2-convert_section.pl
Signed-off-by: Joe Perches <joe@perches.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@gooogle.com>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove trace_cpu_idle() from the arch_cpu_idle() implementations and
put it in the generic code, right before disabling RCU. Gets rid of
more trace_*_rcuidle() users.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Marco Elver <elver@google.com>
Link: https://lkml.kernel.org/r/20200821085348.428433395@infradead.org
Lots of things take locks, due to a wee bug, rcu_lockdep didn't notice
that the locking tracepoints were using RCU.
Push rcu_idle_{enter,exit}() as deep as possible into the idle paths,
this also resolves a lot of _rcuidle()/RCU_NONIDLE() usage.
Specifically, sched_clock_idle_wakeup_event() will use ktime which
will use seqlocks which will tickle lockdep, and
stop_critical_timings() uses lock.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Marco Elver <elver@google.com>
Link: https://lkml.kernel.org/r/20200821085348.310943801@infradead.org
Implement call_cpuidle_s2idle() in analogy with call_cpuidle()
for the s2idle-specific idle state entry and invoke it from
cpuidle_idle_call() to make the s2idle-specific idle entry code
path look more similar to the "regular" idle entry one.
No intentional functional impact.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Chen Yu <yu.c.chen@intel.com>
Now that the sched_class descriptors are defined in order via the linker
script vmlinux.lds.h, there's no reason to have a "next" pointer to the
previous priroity structure. The order of the sturctures can be aligned as
an array, and used to index and find the next sched_class descriptor.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20191219214558.845353593@goodmis.org
In order to make a micro optimization in pick_next_task(), the order of the
sched class descriptor address must be in the same order as their priority
to each other. That is:
&idle_sched_class < &fair_sched_class < &rt_sched_class <
&dl_sched_class < &stop_sched_class
In order to guarantee this order of the sched class descriptors, add each
one into their own data section and force the order in the linker script.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/157675913272.349305.8936736338884044103.stgit@localhost.localdomain
The idle task and stop task sched_classes return 0 in this function.
The single call site in sched_rr_get_interval() calls
p->sched_class->get_rr_interval() only conditional in case it is
defined. Otherwise time_slice=0 will be used.
The deadline sched class does not define it. Commit a57beec5d4
("sched: Make sched_class::get_rr_interval() optional") introduced
the default time-slice=0 for sched classes which do not provide this
function.
So .get_rr_interval for idle and stop sched_class can be removed to
shrink the code a little.
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200603080304.16548-4-dietmar.eggemann@arm.com
The recent commit: 90b5363acd ("sched: Clean up scheduler_ipi()")
got smp_call_function_single_async() subtly wrong. Even though it will
return -EBUSY when trying to re-use a csd, that condition is not
atomic and still requires external serialization.
The change in ttwu_queue_remote() got this wrong.
While on first reading ttwu_queue_remote() has an atomic test-and-set
that appears to serialize the use, the matching 'release' is not in
the right place to actually guarantee this serialization.
The actual race is vs the sched_ttwu_pending() call in the idle loop;
that can run the wakeup-list without consuming the CSD.
Instead of trying to chain the lists, merge them.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200526161908.129371594@infradead.org
Just like the ttwu_queue_remote() IPI, make use of _TIF_POLLING_NRFLAG
to avoid sending IPIs to idle CPUs.
[ mingo: Fix UP build bug. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200526161907.953304789@infradead.org
There is a spelling misake in comments of cpuidle_idle_call. Fix it.
Signed-off-by: Hewenliang <hewenliang4@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: https://lkml.kernel.org/r/20200110025604.34373-1-hewenliang4@huawei.com
- Use nanoseconds (instead of microseconds) as the unit of time in
the cpuidle core and simplify checks for disabled idle states in
the idle loop (Rafael Wysocki).
- Fix and clean up the teo cpuidle governor (Rafael Wysocki).
- Fix the cpuidle registration error code path (Zhenzhong Duan).
- Avoid excessive vmexits in the ACPI cpuidle driver (Yin Fengwei).
- Extend the idle injection infrastructure to be able to measure the
requested duration in nanoseconds and to allow an exit latency
limit for idle states to be specified (Daniel Lezcano).
- Fix cpufreq driver registration and clarify a comment in the
cpufreq core (Viresh Kumar).
- Add NULL checks to the show() and store() methods of sysfs
attributes exposed by cpufreq (Kai Shen).
- Update cpufreq drivers:
* Fix for a plain int as pointer warning from sparse in
intel_pstate (Jamal Shareef).
* Fix for a hardcoded number of CPUs and stack bloat in the
powernv driver (John Hubbard).
* Updates to the ti-cpufreq driver and DT files to support new
platforms and migrate bindings from opp-v1 to opp-v2 (Adam Ford,
H. Nikolaus Schaller).
* Merging of the arm_big_little and vexpress-spc drivers and
related cleanup (Sudeep Holla).
* Fix for imx's default speed grade value (Anson Huang).
* Minor cleanup of the s3c64xx driver (Nathan Chancellor).
* CPU speed bin detection fix for sun50i (Ondrej Jirman).
- Appoint Chanwoo Choi as the new devfreq maintainer.
- Update the devfreq core:
* Check NULL governor in available_governors_show sysfs to prevent
showing wrong governor information and fix a race condition
between devfreq_update_status() and trans_stat_show() (Leonard
Crestez).
* Add new 'interrupt-driven' flag for devfreq governors to allow
interrupt-driven governors to prevent the devfreq core from
polling devices for status (Dmitry Osipenko).
* Improve an error message in devfreq_add_device() (Matthias
Kaehlcke).
- Update devfreq drivers:
* tegra30 driver fixes and cleanups (Dmitry Osipenko).
* Removal of unused property from dt-binding documentation for
the exynos-bus driver (Kamil Konieczny).
* exynos-ppmu cleanup and DT bindings update (Lukasz Luba, Marek
Szyprowski).
- Add new CPU IDs for CometLake Mobile and Desktop to the Intel RAPL
power capping driver (Zhang Rui).
- Allow device initialization in the generic power domains (genpd)
framework to be more straightforward and clean it up (Ulf Hansson).
- Add support for adjusting OPP voltages at run time to the OPP
framework (Stephen Boyd).
- Avoid freeing memory that has never been allocated in the
hibernation core (Andy Whitcroft).
- Clean up function headers in a header file and coding style in the
wakeup IRQs handling code (Ulf Hansson, Xiaofei Tan).
- Clean up the SmartReflex adaptive voltage scaling (AVS) driver for
ARM (Ben Dooks, Geert Uytterhoeven).
- Wrap power management documentation to fit in 80 columns (Bjorn
Helgaas).
- Add pm-graph utility entry to MAINTAINERS (Todd Brandt).
- Update the cpupower utility:
* Fix the handling of set and info subcommands (Abhishek Goel).
* Fix build warnings (Nathan Chancellor).
* Improve mperf_monitor handling (Janakarajan Natarajan).
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Merge tag 'pm-5.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management updates from Rafael Wysocki:
"These include cpuidle changes to use nanoseconds (instead of
microseconds) as the unit of time and to simplify checks for disabled
idle states in the idle loop, some cpuidle fixes and governor updates,
assorted cpufreq updates (driver updates mostly and a few core fixes
and cleanups), devfreq updates (dominated by the tegra30 driver
changes), new CPU IDs for the RAPL power capping driver, relatively
minor updates of the generic power domains (genpd) and operation
performance points (OPP) frameworks, and assorted fixes and cleanups.
There are also two maintainer information updates: Chanwoo Choi will
be maintaining the devfreq subsystem going forward and Todd Brandt is
going to maintain the pm-graph utility (created by him).
Specifics:
- Use nanoseconds (instead of microseconds) as the unit of time in
the cpuidle core and simplify checks for disabled idle states in
the idle loop (Rafael Wysocki)
- Fix and clean up the teo cpuidle governor (Rafael Wysocki)
- Fix the cpuidle registration error code path (Zhenzhong Duan)
- Avoid excessive vmexits in the ACPI cpuidle driver (Yin Fengwei)
- Extend the idle injection infrastructure to be able to measure the
requested duration in nanoseconds and to allow an exit latency
limit for idle states to be specified (Daniel Lezcano)
- Fix cpufreq driver registration and clarify a comment in the
cpufreq core (Viresh Kumar)
- Add NULL checks to the show() and store() methods of sysfs
attributes exposed by cpufreq (Kai Shen)
- Update cpufreq drivers:
* Fix for a plain int as pointer warning from sparse in
intel_pstate (Jamal Shareef)
* Fix for a hardcoded number of CPUs and stack bloat in the
powernv driver (John Hubbard)
* Updates to the ti-cpufreq driver and DT files to support new
platforms and migrate bindings from opp-v1 to opp-v2 (Adam Ford,
H. Nikolaus Schaller)
* Merging of the arm_big_little and vexpress-spc drivers and
related cleanup (Sudeep Holla)
* Fix for imx's default speed grade value (Anson Huang)
* Minor cleanup of the s3c64xx driver (Nathan Chancellor)
* CPU speed bin detection fix for sun50i (Ondrej Jirman)
- Appoint Chanwoo Choi as the new devfreq maintainer.
- Update the devfreq core:
* Check NULL governor in available_governors_show sysfs to prevent
showing wrong governor information and fix a race condition
between devfreq_update_status() and trans_stat_show() (Leonard
Crestez)
* Add new 'interrupt-driven' flag for devfreq governors to allow
interrupt-driven governors to prevent the devfreq core from
polling devices for status (Dmitry Osipenko)
* Improve an error message in devfreq_add_device() (Matthias
Kaehlcke)
- Update devfreq drivers:
* tegra30 driver fixes and cleanups (Dmitry Osipenko)
* Removal of unused property from dt-binding documentation for the
exynos-bus driver (Kamil Konieczny)
* exynos-ppmu cleanup and DT bindings update (Lukasz Luba, Marek
Szyprowski)
- Add new CPU IDs for CometLake Mobile and Desktop to the Intel RAPL
power capping driver (Zhang Rui)
- Allow device initialization in the generic power domains (genpd)
framework to be more straightforward and clean it up (Ulf Hansson)
- Add support for adjusting OPP voltages at run time to the OPP
framework (Stephen Boyd)
- Avoid freeing memory that has never been allocated in the
hibernation core (Andy Whitcroft)
- Clean up function headers in a header file and coding style in the
wakeup IRQs handling code (Ulf Hansson, Xiaofei Tan)
- Clean up the SmartReflex adaptive voltage scaling (AVS) driver for
ARM (Ben Dooks, Geert Uytterhoeven)
- Wrap power management documentation to fit in 80 columns (Bjorn
Helgaas)
- Add pm-graph utility entry to MAINTAINERS (Todd Brandt)
- Update the cpupower utility:
* Fix the handling of set and info subcommands (Abhishek Goel)
* Fix build warnings (Nathan Chancellor)
* Improve mperf_monitor handling (Janakarajan Natarajan)"
* tag 'pm-5.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (83 commits)
PM: Wrap documentation to fit in 80 columns
cpuidle: Pass exit latency limit to cpuidle_use_deepest_state()
cpuidle: Allow idle injection to apply exit latency limit
cpuidle: Introduce cpuidle_driver_state_disabled() for driver quirks
cpuidle: teo: Avoid code duplication in conditionals
cpufreq: Register drivers only after CPU devices have been registered
cpuidle: teo: Avoid using "early hits" incorrectly
cpuidle: teo: Exclude cpuidle overhead from computations
PM / Domains: Convert to dev_to_genpd_safe() in genpd_syscore_switch()
mmc: tmio: Avoid boilerplate code in ->runtime_suspend()
PM / Domains: Implement the ->start() callback for genpd
PM / Domains: Introduce dev_pm_domain_start()
ARM: OMAP2+: SmartReflex: add omap_sr_pdata definition
PM / wakeirq: remove unnecessary parentheses
power: avs: smartreflex: Remove superfluous cast in debugfs_create_file() call
cpuidle: Use nanoseconds as the unit of time
PM / OPP: Support adjusting OPP voltages at runtime
PM / core: Clean up some function headers in power.h
cpufreq: Add NULL checks to show() and store() methods of cpufreq
cpufreq: intel_pstate: Fix plain int as pointer warning from sparse
...
* pm-cpuidle:
cpuidle: Pass exit latency limit to cpuidle_use_deepest_state()
cpuidle: Allow idle injection to apply exit latency limit
cpuidle: Introduce cpuidle_driver_state_disabled() for driver quirks
cpuidle: teo: Avoid code duplication in conditionals
cpuidle: teo: Avoid using "early hits" incorrectly
cpuidle: teo: Exclude cpuidle overhead from computations
cpuidle: Use nanoseconds as the unit of time
cpuidle: Consolidate disabled state checks
ACPI: processor_idle: Skip dummy wait if kernel is in guest
cpuidle: Do not unset the driver if it is there already
cpuidle: teo: Fix "early hits" handling for disabled idle states
cpuidle: teo: Consider hits and misses metrics of disabled states
cpuidle: teo: Rename local variable in teo_select()
cpuidle: teo: Ignore disabled idle states that are too deep
Modify cpuidle_use_deepest_state() to take an additional exit latency
limit argument to be passed to find_deepest_idle_state() and make
cpuidle_idle_call() pass dev->forced_idle_latency_limit_ns to it for
forced idle.
Suggested-by: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
[ rjw: Rebase and rearrange code, subject & changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
In some cases it may be useful to specify an exit latency limit for
the idle state to be used during CPU idle time injection.
Instead of duplicating the information in struct cpuidle_device
or propagating the latency limit in the call stack, replace the
use_deepest_state field with forced_latency_limit_ns to represent
that limit, so that the deepest idle state with exit latency within
that limit is forced (i.e. no governors) when it is set.
A zero exit latency limit for forced idle means to use governors in
the usual way (analogous to use_deepest_state equal to "false" before
this change).
Additionally, add play_idle_precise() taking two arguments, the
duration of forced idle and the idle state exit latency limit, both
in nanoseconds, and redefine play_idle() as a wrapper around that
new function.
This change is preparatory, no functional impact is expected.
Suggested-by: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
[ rjw: Subject, changelog, cpuidle_use_deepest_state() kerneldoc, whitespace ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Currently, the cpuidle subsystem uses microseconds as the unit of
time which (among other things) causes the idle loop to incur some
integer division overhead for no clear benefit.
In order to allow cpuidle to measure time in nanoseconds, add two
new fields, exit_latency_ns and target_residency_ns, to represent the
exit latency and target residency of an idle state in nanoseconds,
respectively, to struct cpuidle_state and initialize them with the
help of the corresponding values in microseconds provided by drivers.
Additionally, change cpuidle_governor_latency_req() to return the
idle state exit latency constraint in nanoseconds.
Also meeasure idle state residency (last_residency_ns in struct
cpuidle_device and time_ns in struct cpuidle_driver) in nanoseconds
and update the cpuidle core and governors accordingly.
However, the menu governor still computes typical intervals in
microseconds to avoid integer overflows.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Doug Smythies <dsmythies@telus.net>
Tested-by: Doug Smythies <dsmythies@telus.net>
Ever since we moved the sched_class definitions into their own files,
the constant expression {fair,idle}_sched_class.pick_next_task() is
not in fact a compile time constant anymore and results in an indirect
call (barring LTO).
Fix that by exposing pick_next_task_{fair,idle}() directly, this gets
rid of the indirect call (and RETPOLINE) on the fast path.
Also remove the unlikely() from the idle case, it is in fact /the/ way
we select idle -- and that is a very common thing to do.
Performance for will-it-scale/sched_yield improves by 2% (as reported
by 0-day).
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: bsegall@google.com
Cc: dietmar.eggemann@arm.com
Cc: juri.lelli@redhat.com
Cc: ktkhai@virtuozzo.com
Cc: mgorman@suse.de
Cc: qais.yousef@arm.com
Cc: qperret@google.com
Cc: rostedt@goodmis.org
Cc: valentin.schneider@arm.com
Cc: vincent.guittot@linaro.org
Link: https://lkml.kernel.org/r/20191108131909.603037345@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Commit 67692435c4 ("sched: Rework pick_next_task() slow-path")
inadvertly introduced a race because it changed a previously
unexplored dependency between dropping the rq->lock and
sched_class::put_prev_task().
The comments about dropping rq->lock, in for example
newidle_balance(), only mentions the task being current and ->on_cpu
being set. But when we look at the 'change' pattern (in for example
sched_setnuma()):
queued = task_on_rq_queued(p); /* p->on_rq == TASK_ON_RQ_QUEUED */
running = task_current(rq, p); /* rq->curr == p */
if (queued)
dequeue_task(...);
if (running)
put_prev_task(...);
/* change task properties */
if (queued)
enqueue_task(...);
if (running)
set_next_task(...);
It becomes obvious that if we do this after put_prev_task() has
already been called on @p, things go sideways. This is exactly what
the commit in question allows to happen when it does:
prev->sched_class->put_prev_task(rq, prev, rf);
if (!rq->nr_running)
newidle_balance(rq, rf);
The newidle_balance() call will drop rq->lock after we've called
put_prev_task() and that allows the above 'change' pattern to
interleave and mess up the state.
Furthermore, it turns out we lost the RT-pull when we put the last DL
task.
Fix both problems by extracting the balancing from put_prev_task() and
doing a multi-class balance() pass before put_prev_task().
Fixes: 67692435c4 ("sched: Rework pick_next_task() slow-path")
Reported-by: Quentin Perret <qperret@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Quentin Perret <qperret@google.com>
Tested-by: Valentin Schneider <valentin.schneider@arm.com>
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>
- 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).
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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()
...
Pull scheduler updates from Ingo Molnar:
- MAINTAINERS: Add Mark Rutland as perf submaintainer, Juri Lelli and
Vincent Guittot as scheduler submaintainers. Add Dietmar Eggemann,
Steven Rostedt, Ben Segall and Mel Gorman as scheduler reviewers.
As perf and the scheduler is getting bigger and more complex,
document the status quo of current responsibilities and interests,
and spread the review pain^H^H^H^H fun via an increase in the Cc:
linecount generated by scripts/get_maintainer.pl. :-)
- Add another series of patches that brings the -rt (PREEMPT_RT) tree
closer to mainline: split the monolithic CONFIG_PREEMPT dependencies
into a new CONFIG_PREEMPTION category that will allow the eventual
introduction of CONFIG_PREEMPT_RT. Still a few more hundred patches
to go though.
- Extend the CPU cgroup controller with uclamp.min and uclamp.max to
allow the finer shaping of CPU bandwidth usage.
- Micro-optimize energy-aware wake-ups from O(CPUS^2) to O(CPUS).
- Improve the behavior of high CPU count, high thread count
applications running under cpu.cfs_quota_us constraints.
- Improve balancing with SCHED_IDLE (SCHED_BATCH) tasks present.
- Improve CPU isolation housekeeping CPU allocation NUMA locality.
- Fix deadline scheduler bandwidth calculations and logic when cpusets
rebuilds the topology, or when it gets deadline-throttled while it's
being offlined.
- Convert the cpuset_mutex to percpu_rwsem, to allow it to be used from
setscheduler() system calls without creating global serialization.
Add new synchronization between cpuset topology-changing events and
the deadline acceptance tests in setscheduler(), which were broken
before.
- Rework the active_mm state machine to be less confusing and more
optimal.
- Rework (simplify) the pick_next_task() slowpath.
- Improve load-balancing on AMD EPYC systems.
- ... and misc cleanups, smaller fixes and improvements - please see
the Git log for more details.
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (53 commits)
sched/psi: Correct overly pessimistic size calculation
sched/fair: Speed-up energy-aware wake-ups
sched/uclamp: Always use 'enum uclamp_id' for clamp_id values
sched/uclamp: Update CPU's refcount on TG's clamp changes
sched/uclamp: Use TG's clamps to restrict TASK's clamps
sched/uclamp: Propagate system defaults to the root group
sched/uclamp: Propagate parent clamps
sched/uclamp: Extend CPU's cgroup controller
sched/topology: Improve load balancing on AMD EPYC systems
arch, ia64: Make NUMA select SMP
sched, perf: MAINTAINERS update, add submaintainers and reviewers
sched/fair: Use rq_lock/unlock in online_fair_sched_group
cpufreq: schedutil: fix equation in comment
sched: Rework pick_next_task() slow-path
sched: Allow put_prev_task() to drop rq->lock
sched/fair: Expose newidle_balance()
sched: Add task_struct pointer to sched_class::set_curr_task
sched: Rework CPU hotplug task selection
sched/{rt,deadline}: Fix set_next_task vs pick_next_task
sched: Fix kerneldoc comment for ia64_set_curr_task
...
The play_idle resolution is 1ms. The intel_powerclamp bases the idle
duration on jiffies. The idle injection API is also using msec based
duration but has no user yet.
Unfortunately, msec based time does not fit well when we want to
inject idle cycle precisely with shallow idle state.
In order to set the scene for the incoming idle injection user, move
the precision up to usec when calling play_idle.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Scheduling-clock interrupts can arrive late in the CPU-offline process,
after idle entry and the subsequent call to cpuhp_report_idle_dead().
Once execution passes the call to rcu_report_dead(), RCU is ignoring
the CPU, which results in lockdep complaints when the interrupt handler
uses RCU:
------------------------------------------------------------------------
=============================
WARNING: suspicious RCU usage
5.2.0-rc1+ #681 Not tainted
-----------------------------
kernel/sched/fair.c:9542 suspicious rcu_dereference_check() usage!
other info that might help us debug this:
RCU used illegally from offline CPU!
rcu_scheduler_active = 2, debug_locks = 1
no locks held by swapper/5/0.
stack backtrace:
CPU: 5 PID: 0 Comm: swapper/5 Not tainted 5.2.0-rc1+ #681
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS Bochs 01/01/2011
Call Trace:
<IRQ>
dump_stack+0x5e/0x8b
trigger_load_balance+0xa8/0x390
? tick_sched_do_timer+0x60/0x60
update_process_times+0x3b/0x50
tick_sched_handle+0x2f/0x40
tick_sched_timer+0x32/0x70
__hrtimer_run_queues+0xd3/0x3b0
hrtimer_interrupt+0x11d/0x270
? sched_clock_local+0xc/0x74
smp_apic_timer_interrupt+0x79/0x200
apic_timer_interrupt+0xf/0x20
</IRQ>
RIP: 0010:delay_tsc+0x22/0x50
Code: ff 0f 1f 80 00 00 00 00 65 44 8b 05 18 a7 11 48 0f ae e8 0f 31 48 89 d6 48 c1 e6 20 48 09 c6 eb 0e f3 90 65 8b 05 fe a6 11 48 <41> 39 c0 75 18 0f ae e8 0f 31 48 c1 e2 20 48 09 c2 48 89 d0 48 29
RSP: 0000:ffff8f92c0157ed0 EFLAGS: 00000212 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000005 RBX: ffff8c861f356400 RCX: ffff8f92c0157e64
RDX: 000000321214c8cc RSI: 00000032120daa7f RDI: 0000000000260f15
RBP: 0000000000000005 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000000 R14: ffff8c861ee18000 R15: ffff8c861ee18000
cpuhp_report_idle_dead+0x31/0x60
do_idle+0x1d5/0x200
? _raw_spin_unlock_irqrestore+0x2d/0x40
cpu_startup_entry+0x14/0x20
start_secondary+0x151/0x170
secondary_startup_64+0xa4/0xb0
------------------------------------------------------------------------
This happens rarely, but can be forced by happen more often by
placing delays in cpuhp_report_idle_dead() following the call to
rcu_report_dead(). With this in place, the following rcutorture
scenario reproduces the problem within a few minutes:
tools/testing/selftests/rcutorture/bin/kvm.sh --cpus 8 --duration 5 --kconfig "CONFIG_DEBUG_LOCK_ALLOC=y CONFIG_PROVE_LOCKING=y" --configs "TREE04"
This commit uses the crude but effective expedient of moving the disabling
of interrupts within the idle loop to precede the cpu_is_offline()
check. It also invokes tick_nohz_idle_stop_tick() instead of
tick_nohz_idle_stop_tick_protected() to shut off the scheduling-clock
interrupt.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
[ paulmck: Revert tick_nohz_idle_stop_tick_protected() removal, new callers. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
