<feed xmlns='http://www.w3.org/2005/Atom'>
<title>user/sven/linux.git/include/linux/interrupt.h, branch v6.1.39</title>
<subtitle>Linux Kernel
</subtitle>
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<updated>2022-05-24T18:11:13Z</updated>
<entry>
<title>Merge tag 'sched-core-2022-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2022-05-24T18:11:13Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-05-24T18:11:13Z</published>
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<id>urn:sha1:6f3f04c19074972ea12edeed23b07a32894e9e03</id>
<content type='text'>
Pull scheduler updates from Ingo Molnar:

 - Updates to scheduler metrics:
     - PELT fixes &amp; enhancements
     - PSI fixes &amp; enhancements
     - Refactor cpu_util_without()

 - Updates to instrumentation/debugging:
     - Remove sched_trace_*() helper functions - can be done via debug
       info
     - Fix double update_rq_clock() warnings

 - Introduce &amp; use "preemption model accessors" to simplify some of the
   Kconfig complexity.

 - Make softirq handling RT-safe.

 - Misc smaller fixes &amp; cleanups.

* tag 'sched-core-2022-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  topology: Remove unused cpu_cluster_mask()
  sched: Reverse sched_class layout
  sched/deadline: Remove superfluous rq clock update in push_dl_task()
  sched/core: Avoid obvious double update_rq_clock warning
  smp: Make softirq handling RT safe in flush_smp_call_function_queue()
  smp: Rename flush_smp_call_function_from_idle()
  sched: Fix missing prototype warnings
  sched/fair: Remove cfs_rq_tg_path()
  sched/fair: Remove sched_trace_*() helper functions
  sched/fair: Refactor cpu_util_without()
  sched/fair: Revise comment about lb decision matrix
  sched/psi: report zeroes for CPU full at the system level
  sched/fair: Delete useless condition in tg_unthrottle_up()
  sched/fair: Fix cfs_rq_clock_pelt() for throttled cfs_rq
  sched/fair: Move calculate of avg_load to a better location
  mailmap: Update my email address to @redhat.com
  MAINTAINERS: Add myself as scheduler topology reviewer
  psi: Fix trigger being fired unexpectedly at initial
  ftrace: Use preemption model accessors for trace header printout
  kcsan: Use preemption model accessors
</content>
</entry>
<entry>
<title>lockdep: Delete local_irq_enable_in_hardirq()</title>
<updated>2022-05-11T14:27:04Z</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@linutronix.de</email>
</author>
<published>2022-05-09T19:03:43Z</published>
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<id>urn:sha1:deaf7c4b4bf8b802cc465bb9b33fe6c76e812924</id>
<content type='text'>
No more users and there is no desire to grow new ones.

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lkml.kernel.org/r/8735hir0j4.ffs@tglx
</content>
</entry>
<entry>
<title>smp: Make softirq handling RT safe in flush_smp_call_function_queue()</title>
<updated>2022-05-01T08:03:43Z</updated>
<author>
<name>Sebastian Andrzej Siewior</name>
<email>bigeasy@linutronix.de</email>
</author>
<published>2022-04-13T13:31:05Z</published>
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<id>urn:sha1:1a90bfd220201fbe050dfc15deaac20ca5f15638</id>
<content type='text'>
flush_smp_call_function_queue() invokes do_softirq() which is not available
on PREEMPT_RT. flush_smp_call_function_queue() is invoked from the idle
task and the migration task with preemption or interrupts disabled.

So RT kernels cannot process soft interrupts in that context as that has to
acquire 'sleeping spinlocks' which is not possible with preemption or
interrupts disabled and forbidden from the idle task anyway.

The currently known SMP function call which raises a soft interrupt is in
the block layer, but this functionality is not enabled on RT kernels due to
latency and performance reasons.

RT could wake up ksoftirqd unconditionally, but this wants to be avoided if
there were soft interrupts pending already when this is invoked in the
context of the migration task. The migration task might have preempted a
threaded interrupt handler which raised a soft interrupt, but did not reach
the local_bh_enable() to process it. The "running" ksoftirqd might prevent
the handling in the interrupt thread context which is causing latency
issues.

Add a new function which handles this case explicitely for RT and falls
back to do_softirq() on !RT kernels. In the RT case this warns when one of
the flushed SMP function calls raised a soft interrupt so this can be
investigated.

[ tglx: Moved the RT part out of SMP code ]

Signed-off-by: Sebastian Andrzej Siewior &lt;bigeasy@linutronix.de&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Acked-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lore.kernel.org/r/YgKgL6aPj8aBES6G@linutronix.de
Link: https://lore.kernel.org/r/20220413133024.356509586@linutronix.de

</content>
</entry>
<entry>
<title>lib/irq_poll: Declare IRQ_POLL softirq vector as ksoftirqd-parking safe</title>
<updated>2022-03-07T22:53:50Z</updated>
<author>
<name>Frederic Weisbecker</name>
<email>frederic@kernel.org</email>
</author>
<published>2022-02-08T16:16:35Z</published>
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<id>urn:sha1:f96272a90d9eaea9933aaab704ddbd258feb3841</id>
<content type='text'>
The following warning may appear while setting a CPU down:

	NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #20!!!

The IRQ_POLL_SOFTIRQ vector can be raised during the hotplug cpu_down()
path after ksoftirqd is parked and before the CPU actually dies. However
this is handled afterward at the CPUHP_IRQ_POLL_DEAD stage where the
queue gets migrated.

Hence this warning can be considered spurious and the vector can join
the "hotplug-safe" list.

Reported-and-tested-by: Paul Menzel &lt;pmenzel@molgen.mpg.de&gt;
Signed-off-by: Frederic Weisbecker &lt;frederic@kernel.org&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Paul E. McKenney &lt;paulmck@kernel.org&gt;
Cc: Paul Menzel &lt;pmenzel@molgen.mpg.de&gt;
</content>
</entry>
<entry>
<title>tick/rcu: Stop allowing RCU_SOFTIRQ in idle</title>
<updated>2022-03-07T22:01:34Z</updated>
<author>
<name>Frederic Weisbecker</name>
<email>frederic@kernel.org</email>
</author>
<published>2022-02-08T16:16:34Z</published>
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<id>urn:sha1:0345691b24c076655ce8f0f4bfd24cba3467ccbd</id>
<content type='text'>
RCU_SOFTIRQ used to be special in that it could be raised on purpose
within the idle path to prevent from stopping the tick. Some code still
prevents from unnecessary warnings related to this specific behaviour
while entering in dynticks-idle mode.

However the nohz layout has changed quite a bit in ten years, and the
removal of CONFIG_RCU_FAST_NO_HZ has been the final straw to this
safe-conduct. Now the RCU_SOFTIRQ vector is expected to be raised from
sane places.

A remaining corner case is admitted though when the vector is invoked
in fragile hotplug path.

Signed-off-by: Frederic Weisbecker &lt;frederic@kernel.org&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Paul E. McKenney &lt;paulmck@kernel.org&gt;
Cc: Paul Menzel &lt;pmenzel@molgen.mpg.de&gt;
</content>
</entry>
<entry>
<title>genirq: Provide new interfaces for affinity hints</title>
<updated>2021-12-10T19:47:38Z</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@linutronix.de</email>
</author>
<published>2021-09-03T15:24:17Z</published>
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<id>urn:sha1:65c7cdedeb3026fabcc967a7aae2f755ad4d0783</id>
<content type='text'>
The discussion about removing the side effect of irq_set_affinity_hint() of
actually applying the cpumask (if not NULL) as affinity to the interrupt,
unearthed a few unpleasantries:

  1) The modular perf drivers rely on the current behaviour for the very
     wrong reasons.

  2) While none of the other drivers prevents user space from changing
     the affinity, a cursorily inspection shows that there are at least
     expectations in some drivers.

#1 needs to be cleaned up anyway, so that's not a problem

#2 might result in subtle regressions especially when irqbalanced (which
   nowadays ignores the affinity hint) is disabled.

Provide new interfaces:

  irq_update_affinity_hint()  - Only sets the affinity hint pointer
  irq_set_affinity_and_hint() - Set the pointer and apply the affinity to
                                the interrupt

Make irq_set_affinity_hint() a wrapper around irq_apply_affinity_hint() and
document it to be phased out.

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Nitesh Narayan Lal &lt;nitesh@redhat.com&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Ming Lei &lt;ming.lei@redhat.com&gt;
Link: https://lore.kernel.org/r/20210501021832.743094-1-jesse.brandeburg@intel.com
Link: https://lore.kernel.org/r/20210903152430.244937-2-nitesh@redhat.com

</content>
</entry>
<entry>
<title>genirq: Change force_irqthreads to a static key</title>
<updated>2021-08-10T20:50:07Z</updated>
<author>
<name>Tanner Love</name>
<email>tannerlove@google.com</email>
</author>
<published>2021-06-02T18:03:38Z</published>
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<id>urn:sha1:91cc470e797828d779cd4c1efbe8519bcb358bae</id>
<content type='text'>
With CONFIG_IRQ_FORCED_THREADING=y, testing the boolean force_irqthreads
could incur a cache line miss in invoke_softirq() and other places.

Replace the test with a static key to avoid the potential cache miss.

[ tglx: Dropped the IDE part, removed the export and updated blk-mq ]

Suggested-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: Tanner Love &lt;tannerlove@google.com&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Eric Dumazet &lt;edumazet@google.com&gt;
Reviewed-by: Kees Cook &lt;keescook@chromium.org&gt;
Link: https://lore.kernel.org/r/20210602180338.3324213-1-tannerlove.kernel@gmail.com

</content>
</entry>
<entry>
<title>Merge branch 'irq/affinity' into irq/core</title>
<updated>2021-05-19T09:04:47Z</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@linutronix.de</email>
</author>
<published>2021-05-19T09:04:47Z</published>
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<id>urn:sha1:006ae1970a8cde1d3e92da69b324d12880133a13</id>
<content type='text'>
Merge the export of irq_set_affinity() which is a standalone commit so it
can be pulled into other trees.
</content>
</entry>
<entry>
<title>genirq: Export affinity setter for modules</title>
<updated>2021-05-19T09:01:51Z</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@linutronix.de</email>
</author>
<published>2021-05-18T09:17:26Z</published>
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<id>urn:sha1:4d80d6ca5d77fde9880da8466e5b64f250e5bf82</id>
<content type='text'>
Perf modules abuse irq_set_affinity_hint() to set the affinity of system
PMU interrupts just because irq_set_affinity() was not exported.

The fact that irq_set_affinity_hint() actually sets the affinity is a
non-documented side effect and the name is clearly saying it's a hint.

To clean this up, export the real affinity setter.

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Acked-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Link: https://lore.kernel.org/r/20210518093117.968251441@linutronix.de
</content>
</entry>
<entry>
<title>genirq: Add a IRQF_NO_DEBUG flag</title>
<updated>2021-05-17T18:01:35Z</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@linutronix.de</email>
</author>
<published>2021-04-02T06:23:25Z</published>
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<id>urn:sha1:c2b1063e8feb2115537addce10f36c0c82d11d9b</id>
<content type='text'>
The whole call to note_interrupt() can be avoided or return early when
interrupts would be marked accordingly. For IPI handlers which always
return HANDLED the whole procedure is pretty pointless to begin with.

Add a IRQF_NO_DEBUG flag and mark the interrupt accordingly if supplied
when the interrupt is requested.

When noirqdebug is set on the kernel commandline, then the interrupt is
marked unconditionally so that there is only one condition in the hotpath
to evaluate.

 [ clg: Add changelog ]

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Cédric Le Goater &lt;clg@kaod.org&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Link: https://lore.kernel.org/r/7a8ad02f-63a8-c1aa-fdd1-39d973593d02@kaod.org
</content>
</entry>
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