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Ian Campbell

2010-Jul-28 10:54 UTC

[Xen-devel] [GIT/PATCH 0/4] Do not use IRQF_TIMER for non timer interrupts

Hi Thomas,

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 the following series renames the IRQF_TIMER flag to
IRQF_NO_SUSPEND and updates the users which are not timer interrupts to
use the new name. IRQF_TIMER is retained as an alias for
IRQF_NO_SUSPEND.

The final patch in the series adds a new user the flag which disables
suspend of Xen IPI IRQs.

Ian.

The following changes since commit fc0f5ac8fe693d1b05f5a928cc48135d1c8b7f2e:
  Linus Torvalds (1):
        Merge branch ''for-linus'' of
git://git.kernel.org/.../ericvh/v9fs

are available in the git repository at:

  git://xenbits.xensource.com/people/ianc/linux-2.6.git for-irq/irqf-no-suspend

Ian Campbell (4):
      irq: rename IRQF_TIMER to IRQF_NO_SUSPEND
      ixp4xx-beeper: Use IRQF_NO_SUSPEND not IRQF_TIMER for non-timer interrupt
      powerpc: Use IRQF_NO_SUSPEND not IRQF_TIMER for non-timer interrupts
      xen: do not suspend IPI IRQs.

 arch/powerpc/platforms/powermac/low_i2c.c |    4 ++--
 drivers/input/misc/ixp4xx-beeper.c        |    2 +-
 drivers/macintosh/via-pmu.c               |    4 ++--
 drivers/xen/events.c                      |    1 +
 include/linux/interrupt.h                 |    8 ++++++--
 kernel/irq/manage.c                       |    2 +-
 6 files changed, 13 insertions(+), 8 deletions(-)



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Ian Campbell

2010-Jul-28 10:54 UTC

head link

[Xen-devel] [PATCH 1/4] irq: rename IRQF_TIMER to IRQF_NO_SUSPEND

Continue to provide IRQF_TIMER as an alias to IRQF_NO_SUSPEND since I
think it is worth preserving the nice self-documenting name (where it
is used appropriately). It also avoid needing to patch all the many
users who are using the flag for an actual timer interrupt.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
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
---
 include/linux/interrupt.h |    8 ++++++--
 kernel/irq/manage.c       |    2 +-
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index c233113..b9bedd5 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -44,7 +44,7 @@
  * IRQF_SAMPLE_RANDOM - irq is used to feed the random generator
  * IRQF_SHARED - allow sharing the irq among several devices
  * IRQF_PROBE_SHARED - set by callers when they expect sharing mismatches to
occur
- * IRQF_TIMER - Flag to mark this interrupt as timer interrupt
+ * IRQF_NO_SUSPEND - Do not disable this IRQ during suspend
  * IRQF_PERCPU - Interrupt is per cpu
  * IRQF_NOBALANCING - Flag to exclude this interrupt from irq balancing
  * IRQF_IRQPOLL - Interrupt is used for polling (only the interrupt that is
@@ -53,17 +53,21 @@
  * IRQF_ONESHOT - Interrupt is not reenabled after the hardirq handler
finished.
  *                Used by threaded interrupts which need to keep the
  *                irq line disabled until the threaded handler has been run.
+ *
+ * IRQF_TIMER - Flag to mark this interrupt as timer interrupt
  */
 #define IRQF_DISABLED		0x00000020
 #define IRQF_SAMPLE_RANDOM	0x00000040
 #define IRQF_SHARED		0x00000080
 #define IRQF_PROBE_SHARED	0x00000100
-#define IRQF_TIMER		0x00000200
+#define IRQF_NO_SUSPEND		0x00000200
 #define IRQF_PERCPU		0x00000400
 #define IRQF_NOBALANCING	0x00000800
 #define IRQF_IRQPOLL		0x00001000
 #define IRQF_ONESHOT		0x00002000
 
+#define IRQF_TIMER		(IRQF_NO_SUSPEND)
+
 /*
  * Bits used by threaded handlers:
  * IRQTF_RUNTHREAD - signals that the interrupt handler thread should run
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index e149748..c3003e9 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -216,7 +216,7 @@ static inline int setup_affinity(unsigned int irq, struct
irq_desc *desc)
 void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
 {
 	if (suspend) {
-		if (!desc->action || (desc->action->flags & IRQF_TIMER))
+		if (!desc->action || (desc->action->flags & IRQF_NO_SUSPEND))
 			return;
 		desc->status |= IRQ_SUSPENDED;
 	}
-- 
1.5.6.5


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Ian Campbell

2010-Jul-28 10:54 UTC

head link

[Xen-devel] [PATCH 4/4] xen: do not suspend IPI IRQs.

In general the semantics of IPIs are that they are are expected to
continue functioning after dpm_suspend_noirq().

Specifically I have seen a deadlock between the callfunc IPI and the
stop machine used by xen''s do_suspend() routine. If one CPU has already
called dpm_suspend_noirq() then there is a window where it can be sent
a callfunc IPI before all the other CPUs have entered stop_cpu().

If this happens then the first CPU ends up spinning in stop_cpu()
waiting for the other to rendezvous in state STOPMACHINE_PREPARE while
the other is spinning in csd_lock_wait().

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: xen-devel@lists.xensource.com
Cc: <stable@kernel.org> # .32.x+: 517d6934: irq: rename IRQF_TIMER to
IRQF_NO_SUSPEND
Cc: <stable@kernel.org> # .32.x+
---
 drivers/xen/events.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index db8f506..28f133a 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -536,6 +536,7 @@ int bind_ipi_to_irqhandler(enum ipi_vector ipi,
 	if (irq < 0)
 		return irq;
 
+	irqflags |= IRQF_NO_SUSPEND;
 	retval = request_irq(irq, handler, irqflags, devname, dev_id);
 	if (retval != 0) {
 		unbind_from_irq(irq);
-- 
1.5.6.5


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Thomas Gleixner

2010-Jul-29 08:49 UTC

head link

[Xen-devel] Re: [PATCH 1/4] irq: rename IRQF_TIMER to IRQF_NO_SUSPEND

On Wed, 28 Jul 2010, Ian Campbell wrote:
> Continue to provide IRQF_TIMER as an alias to IRQF_NO_SUSPEND since I
> think it is worth preserving the nice self-documenting name (where it
> is used appropriately). It also avoid needing to patch all the many
> users who are using the flag for an actual timer interrupt.
I''m not happy about the alias. What about:

#define __IRQF_TIMER		0x00000200
#define IRQF_NO_SUSPEND		0x00000400

#define IRQF_TIMER    (__IRQF_TIMER | IRQF_NO_SUSPEND)

Thanks,

	tglx

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Ian Campbell

2010-Jul-29 09:03 UTC

head link

[Xen-devel] Re: [PATCH 1/4] irq: rename IRQF_TIMER to IRQF_NO_SUSPEND

On Thu, 2010-07-29 at 09:49 +0100, Thomas Gleixner
wrote:> On Wed, 28 Jul 2010, Ian Campbell wrote:
> 
> > Continue to provide IRQF_TIMER as an alias to IRQF_NO_SUSPEND since I
> > think it is worth preserving the nice self-documenting name (where it
> > is used appropriately). It also avoid needing to patch all the many
> > users who are using the flag for an actual timer interrupt.
> 
> I''m not happy about the alias. What about:
> 
> #define __IRQF_TIMER		0x00000200
> #define IRQF_NO_SUSPEND		0x00000400
> 
> #define IRQF_TIMER    (__IRQF_TIMER | IRQF_NO_SUSPEND)
Sure, I''ll rework along those lines.

Ian.




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Ian Campbell

2010-Jul-29 10:16 UTC

head link

[Xen-devel] [GIT/PATCH 0/4] Do not use IRQF_TIMER for non timer interrupts

On Thu, 2010-07-29 at 09:49 +0100, Thomas Gleixner
wrote:> On Wed, 28 Jul 2010, Ian Campbell wrote:
> 
> > Continue to provide IRQF_TIMER as an alias to IRQF_NO_SUSPEND since I
> > think it is worth preserving the nice self-documenting name (where it
> > is used appropriately). It also avoid needing to patch all the many
> > users who are using the flag for an actual timer interrupt.
> 
> I''m not happy about the alias. What about:
> 
> #define __IRQF_TIMER		0x00000200
> #define IRQF_NO_SUSPEND		0x00000400
> 
> #define IRQF_TIMER    (__IRQF_TIMER | IRQF_NO_SUSPEND)
Resending with this change. Plus I ran checkpatch on the whole lot (I
previously managed to run it only on the first patch) and fixed the
complaints.

Ian.

The following changes since commit fc0f5ac8fe693d1b05f5a928cc48135d1c8b7f2e:
  Linus Torvalds (1):
        Merge branch ''for-linus'' of
git://git.kernel.org/.../ericvh/v9fs

are available in the git repository at:

  git://xenbits.xensource.com/people/ianc/linux-2.6.git for-irq/irqf-no-suspend

Ian Campbell (4):
      irq: Add new IRQ flag IRQF_NO_SUSPEND
      ixp4xx-beeper: Use IRQF_NO_SUSPEND not IRQF_TIMER for non-timer interrupt
      powerpc: Use IRQF_NO_SUSPEND not IRQF_TIMER for non-timer interrupts
      xen: do not suspend IPI IRQs.

 arch/powerpc/platforms/powermac/low_i2c.c |    5 +++--
 drivers/input/misc/ixp4xx-beeper.c        |    3 ++-
 drivers/macintosh/via-pmu.c               |    9 +++++----
 drivers/xen/events.c                      |    1 +
 include/linux/interrupt.h                 |    7 ++++++-
 kernel/irq/manage.c                       |    2 +-
 6 files changed, 18 insertions(+), 9 deletions(-)



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Ian Campbell

2010-Jul-29 10:16 UTC

head link

[Xen-devel] [PATCH 1/4] irq: Add new IRQ flag IRQF_NO_SUSPEND

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: Ian Campbell <ian.campbell@citrix.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
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
---
 include/linux/interrupt.h |    7 ++++++-
 kernel/irq/manage.c       |    2 +-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index c233113..a0384a4 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -53,16 +53,21 @@
  * IRQF_ONESHOT - Interrupt is not reenabled after the hardirq handler
finished.
  *                Used by threaded interrupts which need to keep the
  *                irq line disabled until the threaded handler has been run.
+ * IRQF_NO_SUSPEND - Do not disable this IRQ during suspend
+ *
  */
 #define IRQF_DISABLED		0x00000020
 #define IRQF_SAMPLE_RANDOM	0x00000040
 #define IRQF_SHARED		0x00000080
 #define IRQF_PROBE_SHARED	0x00000100
-#define IRQF_TIMER		0x00000200
+#define __IRQF_TIMER		0x00000200
 #define IRQF_PERCPU		0x00000400
 #define IRQF_NOBALANCING	0x00000800
 #define IRQF_IRQPOLL		0x00001000
 #define IRQF_ONESHOT		0x00002000
+#define IRQF_NO_SUSPEND		0x00004000
+
+#define IRQF_TIMER		(__IRQF_TIMER | IRQF_NO_SUSPEND)
 
 /*
  * Bits used by threaded handlers:
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index e149748..c3003e9 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -216,7 +216,7 @@ static inline int setup_affinity(unsigned int irq, struct
irq_desc *desc)
 void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
 {
 	if (suspend) {
-		if (!desc->action || (desc->action->flags & IRQF_TIMER))
+		if (!desc->action || (desc->action->flags & IRQF_NO_SUSPEND))
 			return;
 		desc->status |= IRQ_SUSPENDED;
 	}
-- 
1.5.6.5


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Ian Campbell

2010-Jul-29 10:16 UTC

head link

[Xen-devel] [PATCH 4/4] xen: do not suspend IPI IRQs.

In general the semantics of IPIs are that they are are expected to
continue functioning after dpm_suspend_noirq().

Specifically I have seen a deadlock between the callfunc IPI and the
stop machine used by xen''s do_suspend() routine. If one CPU has already
called dpm_suspend_noirq() then there is a window where it can be sent
a callfunc IPI before all the other CPUs have entered stop_cpu().

If this happens then the first CPU ends up spinning in stop_cpu()
waiting for the other to rendezvous in state STOPMACHINE_PREPARE while
the other is spinning in csd_lock_wait().

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: xen-devel@lists.xensource.com
Cc: <stable@kernel.org> # .32.x+: ab68ca3d: irq: Add new IRQ flag
IRQF_NO_SUSPEND
Cc: <stable@kernel.org> # .32.x+
---
 drivers/xen/events.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index db8f506..28f133a 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -536,6 +536,7 @@ int bind_ipi_to_irqhandler(enum ipi_vector ipi,
 	if (irq < 0)
 		return irq;
 
+	irqflags |= IRQF_NO_SUSPEND;
 	retval = request_irq(irq, handler, irqflags, devname, dev_id);
 	if (retval != 0) {
 		unbind_from_irq(irq);
-- 
1.5.6.5


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Benjamin Herrenschmidt

2010-Jul-30 10:29 UTC

head link

[Xen-devel] Re: [PATCH 1/4] irq: Add new IRQ flag IRQF_NO_SUSPEND

On Thu, 2010-07-29 at 11:16 +0100, Ian Campbell wrote:> 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: Ian Campbell <ian.campbell@citrix.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Jeremy Fitzhardinge <jeremy@goop.org>
> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: 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
> ---
>  include/linux/interrupt.h |    7 ++++++-
>  kernel/irq/manage.c       |    2 +-
>  2 files changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
> index c233113..a0384a4 100644
> --- a/include/linux/interrupt.h
> +++ b/include/linux/interrupt.h
> @@ -53,16 +53,21 @@
>   * IRQF_ONESHOT - Interrupt is not reenabled after the hardirq handler
finished.
>   *                Used by threaded interrupts which need to keep the
>   *                irq line disabled until the threaded handler has been
run.
> + * IRQF_NO_SUSPEND - Do not disable this IRQ during suspend
> + *
>   */
>  #define IRQF_DISABLED		0x00000020
>  #define IRQF_SAMPLE_RANDOM	0x00000040
>  #define IRQF_SHARED		0x00000080
>  #define IRQF_PROBE_SHARED	0x00000100
> -#define IRQF_TIMER		0x00000200
> +#define __IRQF_TIMER		0x00000200
>  #define IRQF_PERCPU		0x00000400
>  #define IRQF_NOBALANCING	0x00000800
>  #define IRQF_IRQPOLL		0x00001000
>  #define IRQF_ONESHOT		0x00002000
> +#define IRQF_NO_SUSPEND		0x00004000
> +
> +#define IRQF_TIMER		(__IRQF_TIMER | IRQF_NO_SUSPEND)
>  
>  /*
>   * Bits used by threaded handlers:
> diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
> index e149748..c3003e9 100644
> --- a/kernel/irq/manage.c
> +++ b/kernel/irq/manage.c
> @@ -216,7 +216,7 @@ static inline int setup_affinity(unsigned int irq,
struct irq_desc *desc)
>  void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
>  {
>  	if (suspend) {
> -		if (!desc->action || (desc->action->flags & IRQF_TIMER))
> +		if (!desc->action || (desc->action->flags &
IRQF_NO_SUSPEND))
>  			return;
>  		desc->status |= IRQ_SUSPENDED;
>  	}


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Xen devel - Jul 2010 - [GIT/PATCH 0/4] Do not use IRQF_TIMER for non timer interrupts

[Xen-devel] [GIT/PATCH 0/4] Do not use IRQF_TIMER for non timer interrupts

[Xen-devel] [PATCH 1/4] irq: rename IRQF_TIMER to IRQF_NO_SUSPEND

[Xen-devel] [PATCH 4/4] xen: do not suspend IPI IRQs.

[Xen-devel] Re: [PATCH 1/4] irq: rename IRQF_TIMER to IRQF_NO_SUSPEND

[Xen-devel] Re: [PATCH 1/4] irq: rename IRQF_TIMER to IRQF_NO_SUSPEND

[Xen-devel] [GIT/PATCH 0/4] Do not use IRQF_TIMER for non timer interrupts

[Xen-devel] [PATCH 1/4] irq: Add new IRQ flag IRQF_NO_SUSPEND

[Xen-devel] [PATCH 4/4] xen: do not suspend IPI IRQs.

[Xen-devel] Re: [PATCH 1/4] irq: Add new IRQ flag IRQF_NO_SUSPEND