linux-toradex.git/include/linux/interrupt.h, branch Colibri_T30_LinuxImageV2.1Beta2_20140206

genirq: Add IRQF_RESUME_EARLY and resume such IRQs earlier

2011-11-11T17:43:13+00:00

commit 9bab0b7fbaceec47d32db51cd9e59c82fb071f5a upstream.

This adds a mechanism to resume selected IRQs during syscore_resume
instead of dpm_resume_noirq.

Under Xen we need to resume IRQs associated with IPIs early enough
that the resched IPI is unmasked and we can therefore schedule
ourselves out of the stop_machine where the suspend/resume takes
place.

This issue was introduced by 676dc3cf5bc3 "xen: Use IRQF_FORCE_RESUME".

Signed-off-by: Ian Campbell 
Cc: Rafael J. Wysocki 
Cc: Jeremy Fitzhardinge 
Cc: xen-devel 
Cc: Konrad Rzeszutek Wilk 
Link: http://lkml.kernel.org/r/1318713254.11016.52.camel@dagon.hellion.org.uk
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

atomic: use

2011-07-26T23:49:47+00:00

This allows us to move duplicated code in 
(atomic_inc_not_zero() for now) to 

Signed-off-by: Arun Sharma 
Reviewed-by: Eric Dumazet 
Cc: Ingo Molnar 
Cc: David Miller 
Cc: Eric Dumazet 
Acked-by: Mike Frysinger 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

rcu: Use softirq to address performance regression

2011-06-14T22:25:39+00:00

Commit a26ac2455ffcf3(rcu: move TREE_RCU from softirq to kthread)
introduced performance regression. In an AIM7 test, this commit degraded
performance by about 40%.

The commit runs rcu callbacks in a kthread instead of softirq. We observed
high rate of context switch which is caused by this. Out test system has
64 CPUs and HZ is 1000, so we saw more than 64k context switch per second
which is caused by RCU's per-CPU kthread.  A trace showed that most of
the time the RCU per-CPU kthread doesn't actually handle any callbacks,
but instead just does a very small amount of work handling grace periods.
This means that RCU's per-CPU kthreads are making the scheduler do quite
a bit of work in order to allow a very small amount of RCU-related
processing to be done.

Alex Shi's analysis determined that this slowdown is due to lock
contention within the scheduler.  Unfortunately, as Peter Zijlstra points
out, the scheduler's real-time semantics require global action, which
means that this contention is inherent in real-time scheduling.  (Yes,
perhaps someone will come up with a workaround -- otherwise, -rt is not
going to do well on large SMP systems -- but this patch will work around
this issue in the meantime.  And "the meantime" might well be forever.)

This patch therefore re-introduces softirq processing to RCU, but only
for core RCU work.  RCU callbacks are still executed in kthread context,
so that only a small amount of RCU work runs in softirq context in the
common case.  This should minimize ksoftirqd execution, allowing us to
skip boosting of ksoftirqd for CONFIG_RCU_BOOST=y kernels.

Signed-off-by: Shaohua Li 
Tested-by: "Alex,Shi" 
Signed-off-by: Paul E. McKenney

rcu: move TREE_RCU from softirq to kthread

2011-05-06T06:16:54+00:00

If RCU priority boosting is to be meaningful, callback invocation must
be boosted in addition to preempted RCU readers.  Otherwise, in presence
of CPU real-time threads, the grace period ends, but the callbacks don't
get invoked.  If the callbacks don't get invoked, the associated memory
doesn't get freed, so the system is still subject to OOM.

But it is not reasonable to priority-boost RCU_SOFTIRQ, so this commit
moves the callback invocations to a kthread, which can be boosted easily.

Also add comments and properly synchronized all accesses to
rcu_cpu_kthread_task, as suggested by Lai Jiangshan.

Signed-off-by: Paul E. McKenney 
Signed-off-by: Paul E. McKenney 
Reviewed-by: Josh Triplett

Fix common misspellings

2011-03-31T14:26:23+00:00

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi

genirq: Remove now obsolete set_irq_wake()

2011-03-29T22:35:34+00:00

Missed that one in the big compat remval patch

Signed-off-by: Thomas Gleixner

Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2011-03-16T02:23:40+00:00

* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (116 commits)
  x86: Enable forced interrupt threading support
  x86: Mark low level interrupts IRQF_NO_THREAD
  x86: Use generic show_interrupts
  x86: ioapic: Avoid redundant lookup of irq_cfg
  x86: ioapic: Use new move_irq functions
  x86: Use the proper accessors in fixup_irqs()
  x86: ioapic: Use irq_data->state
  x86: ioapic: Simplify irq chip and handler setup
  x86: Cleanup the genirq name space
  genirq: Add chip flag to force mask on suspend
  genirq: Add desc->irq_data accessor
  genirq: Add comments to Kconfig switches
  genirq: Fixup fasteoi handler for oneshot mode
  genirq: Provide forced interrupt threading
  sched: Switch wait_task_inactive to schedule_hrtimeout()
  genirq: Add IRQF_NO_THREAD
  genirq: Allow shared oneshot interrupts
  genirq: Prepare the handling of shared oneshot interrupts
  genirq: Make warning in handle_percpu_event useful
  x86: ioapic: Move trigger defines to io_apic.h
  ...

Fix up trivial(?) conflicts in arch/x86/pci/xen.c due to genirq name
space changes clashing with the Xen cleanups.  The set_irq_msi() had
moved to xen_bind_pirq_msi_to_irq().

Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2011-03-16T01:37:30+00:00

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (26 commits)
  sched: Resched proper CPU on yield_to()
  sched: Allow users with sufficient RLIMIT_NICE to change from SCHED_IDLE policy
  sched: Allow SCHED_BATCH to preempt SCHED_IDLE tasks
  sched: Clean up the IRQ_TIME_ACCOUNTING code
  sched: Add #ifdef around irq time accounting functions
  sched, autogroup: Stop claiming ownership of the root task group
  sched, autogroup: Stop going ahead if autogroup is disabled
  sched, autogroup, sysctl: Use proc_dointvec_minmax() instead
  sched: Fix the group_imb logic
  sched: Clean up some f_b_g() comments
  sched: Clean up remnants of sd_idle
  sched: Wholesale removal of sd_idle logic
  sched: Add yield_to(task, preempt) functionality
  sched: Use a buddy to implement yield_task_fair()
  sched: Limit the scope of clear_buddies
  sched: Check the right ->nr_running in yield_task_fair()
  sched: Avoid expensive initial update_cfs_load(), on UP too
  sched: Fix switch_from_fair()
  sched: Simplify the idle scheduling class
  softirqs: Account ksoftirqd time as cpustat softirq
  ...

genirq: Provide forced interrupt threading

2011-02-26T10:57:18+00:00

Add a commandline parameter "threadirqs" which forces all interrupts except
those marked IRQF_NO_THREAD to run threaded. That's mostly a debug option to
allow retrieving better debug data from crashing interrupt handlers. If
"threadirqs" is not enabled on the kernel command line, then there is no
impact in the interrupt hotpath.

Architecture code needs to select CONFIG_IRQ_FORCED_THREADING after
marking the interrupts which cant be threaded IRQF_NO_THREAD. All
interrupts which have IRQF_TIMER set are implict marked
IRQF_NO_THREAD. Also all PER_CPU interrupts are excluded.

Forced threading hard interrupts also forces all soft interrupt
handling into thread context.

When enabled it might slow down things a bit, but for debugging problems in
interrupt code it's a reasonable penalty as it does not immediately
crash and burn the machine when an interrupt handler is buggy.

Some test results on a Core2Duo machine:

Cache cold run of:
 # time git grep irq_desc

      non-threaded       threaded
 real 1m18.741s          1m19.061s
 user 0m1.874s           0m1.757s
 sys  0m5.843s           0m5.427s

 # iperf -c server
non-threaded
[  3]  0.0-10.0 sec  1.09 GBytes   933 Mbits/sec
[  3]  0.0-10.0 sec  1.09 GBytes   934 Mbits/sec
[  3]  0.0-10.0 sec  1.09 GBytes   933 Mbits/sec
threaded
[  3]  0.0-10.0 sec  1.09 GBytes   939 Mbits/sec
[  3]  0.0-10.0 sec  1.09 GBytes   934 Mbits/sec
[  3]  0.0-10.0 sec  1.09 GBytes   937 Mbits/sec

Signed-off-by: Thomas Gleixner 
Cc: Peter Zijlstra 
LKML-Reference: <20110223234956.772668648@linutronix.de>

genirq: Add IRQF_NO_THREAD

2011-02-25T19:24:22+00:00

Some low level interrupts cannot be threaded even when we force thread
all interrupt handlers. Add a flag to annotate such interrupts. Add
all timer interrupts to this category by default.

Signed-off-by: Thomas Gleixner 
Cc: Peter Zijlstra 
LKML-Reference: <20110223234956.578893460@linutronix.de>