1. 07 5月, 2014 1 次提交
    • A
      genirq: Provide irq_force_affinity fallback for non-SMP · 4c88d7f9
      Arnd Bergmann 提交于
      Patch 01f8fa4f "genirq: Allow forcing cpu affinity of interrupts" added
      an irq_force_affinity() function, and 30ccf03b "clocksource: Exynos_mct:
      Use irq_force_affinity() in cpu bringup" subsequently uses it. However, the
      driver can be used with CONFIG_SMP disabled, but the function declaration
      is only available for CONFIG_SMP, leading to this build error:
      
      drivers/clocksource/exynos_mct.c:431:3: error: implicit declaration of function 'irq_force_affinity' [-Werror=implicit-function-declaration]
         irq_force_affinity(mct_irqs[MCT_L0_IRQ + cpu], cpumask_of(cpu));
      
      This patch introduces a dummy helper function for the non-SMP case
      that always returns success, to get rid of the build error.
      Since the patches causing the problem are marked for stable backports,
      this one should be as well.
      Signed-off-by: NArnd Bergmann <arnd@arndb.de>
      Cc: Krzysztof Kozlowski <k.kozlowski@samsung.com>
      Acked-by: NKukjin Kim <kgene.kim@samsung.com>
      Cc: stable@vger.kernel.org
      Link: http://lkml.kernel.org/r/5619084.0zmrrIUZLV@wuerfelSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
      4c88d7f9
  2. 28 4月, 2014 1 次提交
  3. 18 4月, 2014 1 次提交
    • T
      genirq: Allow forcing cpu affinity of interrupts · 01f8fa4f
      Thomas Gleixner 提交于
      The current implementation of irq_set_affinity() refuses rightfully to
      route an interrupt to an offline cpu.
      
      But there is a special case, where this is actually desired. Some of
      the ARM SoCs have per cpu timers which require setting the affinity
      during cpu startup where the cpu is not yet in the online mask.
      
      If we can't do that, then the local timer interrupt for the about to
      become online cpu is routed to some random online cpu.
      
      The developers of the affected machines tried to work around that
      issue, but that results in a massive mess in that timer code.
      
      We have a yet unused argument in the set_affinity callbacks of the irq
      chips, which I added back then for a similar reason. It was never
      required so it got not used. But I'm happy that I never removed it.
      
      That allows us to implement a sane handling of the above scenario. So
      the affected SoC drivers can add the required force handling to their
      interrupt chip, switch the timer code to irq_force_affinity() and
      things just work.
      
      This does not affect any existing user of irq_set_affinity().
      
      Tagged for stable to allow a simple fix of the affected SoC clock
      event drivers.
      Reported-and-tested-by: NKrzysztof Kozlowski <k.kozlowski@samsung.com>
      Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      Cc: Kyungmin Park <kyungmin.park@samsung.com>
      Cc: Marek Szyprowski <m.szyprowski@samsung.com>
      Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
      Cc: Tomasz Figa <t.figa@samsung.com>,
      Cc: Daniel Lezcano <daniel.lezcano@linaro.org>,
      Cc: Kukjin Kim <kgene.kim@samsung.com>
      Cc: linux-arm-kernel@lists.infradead.org,
      Cc: stable@vger.kernel.org
      Link: http://lkml.kernel.org/r/20140416143315.717251504@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
      01f8fa4f
  4. 20 2月, 2014 1 次提交
    • T
      genirq: Provide irq_wake_thread() · a92444c6
      Thomas Gleixner 提交于
      In course of the sdhci/sdio discussion with Russell about killing the
      sdio kthread hackery we discovered the need to be able to wake an
      interrupt thread from software.
      
      The rationale for this is, that sdio hardware can lack proper
      interrupt support for certain features. So the driver needs to poll
      the status registers, but at the same time it needs to be woken up by
      an hardware interrupt.
      
      To be able to get rid of the home brewn kthread construct of sdio we
      need a way to wake an irq thread independent of an actual hardware
      interrupt.
      
      Provide an irq_wake_thread() function which wakes up the thread which
      is associated to a given dev_id. This allows sdio to invoke the irq
      thread from the hardware irq handler via the IRQ_WAKE_THREAD return
      value and provides a possibility to wake it via a timer for the
      polling scenarios. That allows to simplify the sdio logic
      significantly.
      Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      Cc: Russell King <linux@arm.linux.org.uk>
      Cc: Chris Ball <chris@printf.net>
      Acked-by: NPeter Zijlstra <peterz@infradead.org>
      Link: http://lkml.kernel.org/r/20140215003823.772565780@linutronix.de
      a92444c6
  5. 09 2月, 2014 1 次提交
  6. 28 1月, 2014 1 次提交
  7. 15 11月, 2013 1 次提交
  8. 01 10月, 2013 1 次提交
    • F
      irq: Consolidate do_softirq() arch overriden implementations · 7d65f4a6
      Frederic Weisbecker 提交于
      All arch overriden implementations of do_softirq() share the following
      common code: disable irqs (to avoid races with the pending check),
      check if there are softirqs pending, then execute __do_softirq() on
      a specific stack.
      
      Consolidate the common parts such that archs only worry about the
      stack switch.
      Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
      Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Paul Mackerras <paulus@au1.ibm.com>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Paul Mackerras <paulus@au1.ibm.com>
      Cc: James Hogan <james.hogan@imgtec.com>
      Cc: James E.J. Bottomley <jejb@parisc-linux.org>
      Cc: Helge Deller <deller@gmx.de>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
      Cc: David S. Miller <davem@davemloft.net>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      7d65f4a6
  9. 13 9月, 2013 1 次提交
  10. 12 1月, 2013 1 次提交
  11. 23 9月, 2012 1 次提交
    • P
      time: RCU permitted to stop idle entry via softirq · 803b0eba
      Paul E. McKenney 提交于
      The can_stop_idle_tick() function complains if a softirq vector is
      raised too late in the idle-entry process, presumably in order to
      prevent dangling softirq invocations from being delayed across the
      full idle period, which might be indefinitely long -- and if softirq
      was asserted any later than the call to this function, such a delay
      might well happen.
      
      However, RCU needs to be able to use softirq to stop idle entry in
      order to be able to drain RCU callbacks from the current CPU, which in
      turn enables faster entry into dyntick-idle mode, which in turn reduces
      power consumption.  Because RCU takes this action at a well-defined
      point in the idle-entry path, it is safe for RCU to take this approach.
      
      This commit therefore silences the error message that is sometimes
      produced when the going-idle CPU suddenly finds that it has an RCU_SOFTIRQ
      to process.  The error message will continue to be issued for other
      softirq vectors.
      Reported-by: NSedat Dilek <sedat.dilek@gmail.com>
      Signed-off-by: NPaul E. McKenney <paul.mckenney@linaro.org>
      Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      Tested-by: NSedat Dilek <sedat.dilek@gmail.com>
      Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
      803b0eba
  12. 19 7月, 2012 1 次提交
  13. 24 5月, 2012 1 次提交
    • O
      genirq: reimplement exit_irq_thread() hook via task_work_add() · 4d1d61a6
      Oleg Nesterov 提交于
      exit_irq_thread() and task->irq_thread are needed to handle the unexpected
      (and unlikely) exit of irq-thread.
      
      We can use task_work instead and make this all private to
      kernel/irq/manage.c, cleanup plus micro-optimization.
      
      1. rename exit_irq_thread() to irq_thread_dtor(), make it
         static, and move it up before irq_thread().
      
      2. change irq_thread() to do task_work_add(irq_thread_dtor)
         at the start and task_work_cancel() before return.
      
         tracehook_notify_resume() can never play with kthreads,
         only do_exit()->exit_task_work() can call the callback
         and this is what we want.
      
      3. remove task_struct->irq_thread and the special hook
         in do_exit().
      Signed-off-by: NOleg Nesterov <oleg@redhat.com>
      Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
      Cc: David Howells <dhowells@redhat.com>
      Cc: Richard Kuo <rkuo@codeaurora.org>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Alexander Gordeev <agordeev@redhat.com>
      Cc: Chris Zankel <chris@zankel.net>
      Cc: David Smith <dsmith@redhat.com>
      Cc: "Frank Ch. Eigler" <fche@redhat.com>
      Cc: Geert Uytterhoeven <geert@linux-m68k.org>
      Cc: Larry Woodman <lwoodman@redhat.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: Ingo Molnar <mingo@elte.hu>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      4d1d61a6
  14. 19 4月, 2012 1 次提交
  15. 29 3月, 2012 1 次提交
  16. 03 2月, 2012 1 次提交
  17. 17 10月, 2011 1 次提交
  18. 03 10月, 2011 2 次提交
    • M
      genirq: percpu: allow interrupt type to be set at enable time · 1e7c5fd2
      Marc Zyngier 提交于
      As request_percpu_irq() doesn't allow for a percpu interrupt to have
      its type configured (it is generally impossible to configure it on all
      CPUs at once), add a 'type' argument to enable_percpu_irq().
      
      This allows some low-level, board specific init code to be switched to
      a generic API.
      
      [ tglx: Added WARN_ON argument ]
      Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>
      Cc: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
      Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      1e7c5fd2
    • M
      genirq: Add support for per-cpu dev_id interrupts · 31d9d9b6
      Marc Zyngier 提交于
      The ARM GIC interrupt controller offers per CPU interrupts (PPIs),
      which are usually used to connect local timers to each core. Each CPU
      has its own private interface to the GIC, and only sees the PPIs that
      are directly connect to it.
      
      While these timers are separate devices and have a separate interrupt
      line to a core, they all use the same IRQ number.
      
      For these devices, request_irq() is not the right API as it assumes
      that an IRQ number is visible by a number of CPUs (through the
      affinity setting), but makes it very awkward to express that an IRQ
      number can be handled by all CPUs, and yet be a different interrupt
      line on each CPU, requiring a different dev_id cookie to be passed
      back to the handler.
      
      The *_percpu_irq() functions is designed to overcome these
      limitations, by providing a per-cpu dev_id vector:
      
      int request_percpu_irq(unsigned int irq, irq_handler_t handler,
      		   const char *devname, void __percpu *percpu_dev_id);
      void free_percpu_irq(unsigned int, void __percpu *);
      int setup_percpu_irq(unsigned int irq, struct irqaction *new);
      void remove_percpu_irq(unsigned int irq, struct irqaction *act);
      void enable_percpu_irq(unsigned int irq);
      void disable_percpu_irq(unsigned int irq);
      
      The API has a number of limitations:
      - no interrupt sharing
      - no threading
      - common handler across all the CPUs
      
      Once the interrupt is requested using setup_percpu_irq() or
      request_percpu_irq(), it must be enabled by each core that wishes its
      local interrupt to be delivered.
      
      Based on an initial patch by Thomas Gleixner.
      Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>
      Cc: linux-arm-kernel@lists.infradead.org
      Link: http://lkml.kernel.org/r/1316793788-14500-2-git-send-email-marc.zyngier@arm.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
      31d9d9b6
  19. 27 7月, 2011 1 次提交
  20. 15 6月, 2011 1 次提交
    • S
      rcu: Use softirq to address performance regression · 09223371
      Shaohua Li 提交于
      Commit a26ac245(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: NShaohua Li <shaohua.li@intel.com>
      Tested-by: N"Alex,Shi" <alex.shi@intel.com>
      Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      09223371
  21. 06 5月, 2011 1 次提交
  22. 31 3月, 2011 1 次提交
  23. 30 3月, 2011 1 次提交
  24. 26 2月, 2011 3 次提交
    • T
      genirq: Provide forced interrupt threading · 8d32a307
      Thomas Gleixner 提交于
      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: NThomas Gleixner <tglx@linutronix.de>
      Cc: Peter Zijlstra <peterz@infradead.org>
      LKML-Reference: <20110223234956.772668648@linutronix.de>
      8d32a307
    • T
      genirq: Add IRQF_NO_THREAD · 0c4602ff
      Thomas Gleixner 提交于
      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: NThomas Gleixner <tglx@linutronix.de>
      Cc: Peter Zijlstra <peterz@infradead.org>
      LKML-Reference: <20110223234956.578893460@linutronix.de>
      0c4602ff
    • T
      genirq: Prepare the handling of shared oneshot interrupts · b5faba21
      Thomas Gleixner 提交于
      For level type interrupts we need to track how many threads are on
      flight to avoid useless interrupt storms when not all thread handlers
      have finished yet. Keep track of the woken threads and only unmask
      when there are no more threads in flight.
      
      Yes, I'm lazy and using a bitfield. But not only because I'm lazy, the
      main reason is that it's way simpler than using a refcount. A refcount
      based solution would need to keep track of various things like
      crashing the irq thread, spurious interrupts coming in,
      disables/enables, free_irq() and some more. The bitfield keeps the
      tracking simple and makes things just work. It's also nicely confined
      to the thread code pathes and does not require additional checks all
      over the place.
      Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      Cc: Peter Zijlstra <peterz@infradead.org>
      LKML-Reference: <20110223234956.388095876@linutronix.de>
      b5faba21
  25. 19 2月, 2011 3 次提交
  26. 08 2月, 2011 1 次提交
  27. 26 1月, 2011 1 次提交
  28. 23 1月, 2011 1 次提交
    • B
      genirq: Add IRQ affinity notifiers · cd7eab44
      Ben Hutchings 提交于
      When initiating I/O on a multiqueue and multi-IRQ device, we may want
      to select a queue for which the response will be handled on the same
      or a nearby CPU.  This requires a reverse-map of IRQ affinity.  Add a
      notification mechanism to support this.
      
      This is based closely on work by Thomas Gleixner <tglx@linutronix.de>.
      Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
      Cc: linux-net-drivers@solarflare.com
      Cc: Tom Herbert <therbert@google.com>
      Cc: David Miller <davem@davemloft.net>
      LKML-Reference: <1295470904.11126.84.camel@bwh-desktop>
      Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      cd7eab44
  29. 10 11月, 2010 1 次提交
  30. 21 10月, 2010 1 次提交
    • T
      tracing: Cleanup the convoluted softirq tracepoints · f4bc6bb2
      Thomas Gleixner 提交于
      With the addition of trace_softirq_raise() the softirq tracepoint got
      even more convoluted. Why the tracepoints take two pointers to assign
      an integer is beyond my comprehension.
      
      But adding an extra case which treats the first pointer as an unsigned
      long when the second pointer is NULL including the back and forth
      type casting is just horrible.
      
      Convert the softirq tracepoints to take a single unsigned int argument
      for the softirq vector number and fix the call sites.
      Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      LKML-Reference: <alpine.LFD.2.00.1010191428560.6815@localhost6.localdomain6>
      Acked-by: NPeter Zijlstra <peterz@infradead.org>
      Acked-by: mathieu.desnoyers@efficios.com
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      f4bc6bb2
  31. 12 10月, 2010 1 次提交
  32. 22 9月, 2010 1 次提交
  33. 07 9月, 2010 1 次提交
  34. 29 7月, 2010 1 次提交
    • I
      irq: Add new IRQ flag IRQF_NO_SUSPEND · 685fd0b4
      Ian Campbell 提交于
      A small number of users of IRQF_TIMER are using it for the implied no
      suspend behaviour on interrupts which are not timer interrupts.
      
      Therefore add a new IRQF_NO_SUSPEND flag, rename IRQF_TIMER to
      __IRQF_TIMER and redefine IRQF_TIMER in terms of these new flags.
      Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
      Cc: Jeremy Fitzhardinge <jeremy@goop.org>
      Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Grant Likely <grant.likely@secretlab.ca>
      Cc: xen-devel@lists.xensource.com
      Cc: linux-input@vger.kernel.org
      Cc: linuxppc-dev@ozlabs.org
      Cc: devicetree-discuss@lists.ozlabs.org
      LKML-Reference: <1280398595-29708-1-git-send-email-ian.campbell@citrix.com>
      Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      685fd0b4
  35. 22 5月, 2010 1 次提交