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[GIT PULL V10] irq: next irq tracking

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  [GIT PULL V10] irq: next irq tracking Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-06-12 16:00 +0200
    [PATCH V10 2/3] irq: Track the interrupt timings Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-06-12 16:00 +0200
    [PATCH V10 1/3] irq: Allow to pass the IRQF_TIMER flag with percpu irq request Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-06-12 16:00 +0200

#1663520 — [GIT PULL V10] irq: next irq tracking

Hi Thomas,

this pull request contains the next irq prediction as posted for V10
[1] which takes into account all the commments. It is based on top of
v4.12-rc5.

As previously discussed the code is not enabled by default, hence compiled out.

The first patch adds the IRQF_TIMER flag to the timers which are percpu in
order to discard any timing measurement when the interrupt is coming from a
timer.

The second patch adds a circular buffer and the small routine to store the
local time when an interrupt occurs. The t-uple <irq,timestamp> are encoded
together into a single 64bits as suggested by Nicolas Pitre.

The third patch provides the mathematic to compute the regular intervals. The
rational is in changelog and the math is commented in details in the code.

Thanks.

  -- Daniel

[1] https://www.spinics.net/lists/kernel/msg2509177.html


The following changes since commit 32c1431eea4881a6b17bd7c639315010aeefa452:

  Linux 4.12-rc5 (2017-06-11 16:48:20 -0700)

are available in the git repository at:

  http://git@git.linaro.org/people/daniel.lezcano/linux.git next-irq/4.13

for you to fetch changes up to 1ed971bc878ede444d10f8a24bc9963938f0b7c6:

  irq: Compute the periodic interval for interrupts (2017-06-12 15:06:00 +0200)

----------------------------------------------------------------
Daniel Lezcano (3):
      irq: Allow to pass the IRQF_TIMER flag with percpu irq request
      irq: Track the interrupt timings
      irq: Compute the periodic interval for interrupts

 arch/arm/kernel/smp_twd.c                |   3 +-
 drivers/clocksource/arc_timer.c          |   4 +--
 drivers/clocksource/arm_arch_timer.c     |  20 ++++++++-----
 drivers/clocksource/arm_global_timer.c   |   4 +--
 drivers/clocksource/exynos_mct.c         |   7 +++--
 drivers/clocksource/qcom-timer.c         |   4 +--
 drivers/clocksource/time-armada-370-xp.c |   9 +++---
 drivers/clocksource/timer-nps.c          |   6 ++--
 include/linux/interrupt.h                |  17 ++++++++++-
 kernel/irq/Kconfig                       |   3 ++
 kernel/irq/Makefile                      |   1 +
 kernel/irq/handle.c                      |   2 ++
 kernel/irq/internals.h                   | 103 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 kernel/irq/manage.c                      |  18 +++++++----
 kernel/irq/timings.c                     | 366 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 15 files changed, 536 insertions(+), 31 deletions(-)
 create mode 100644 kernel/irq/timings.c

-- 

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#1663521 — [PATCH V10 2/3] irq: Track the interrupt timings

The interrupt framework gives a lot of information about each interrupt.

It does not keep track of when those interrupts occur though.

This patch provides a mean to record the timestamp for each interrupt
occurrences in a per-CPU circular buffer to help with the prediction
of the next occurrence using a statistical model.

Each CPU can store IRQ_TIMINGS_SIZE events <irq, timestamp>, the current
value of IRQ_TIMINGS_SIZE is 32.

Each event is encoded into a single u64, where the 48 bits are used for the
timestamp and the next 16 bits are for the irq number.

A static key is introduced so when the irq prediction is switched off at
runtime, we can reduce the overhead near to zero.

It results in most of the code in internals.h for inline reason and a very
few in the new file timings.c. The latter will contain more in the next patch
which will provide the statistical model for the next event prediction.

Note this code is by default *not* compiled in the kernel.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
---
V9:
  - Changed indentation level by inverting the static key condition
  - Encoded interrupt and timestamp into a u64 variable
  - Boolean enable instead of refcount for the static key
V8:
  - Replaced percpu field in the irqdesc by a percpu array containing the
    timings and the associated irq. The function irq_timings_get_next() is no
    longer needed, so it is removed
  - Removed all unused code resulting from the conversion irqdesc->percpu
    timings storage
V7:
  - Mentionned in the irq_timings_get_next() function description,
    the function must be called inside a rcu read locked section
V6:
  - Renamed handle_irq_timings to record_irq_time
  - Stored the event time instead of the interval time
  - Removed the 'timestamp' field from the timings structure
  - Moved _handle_irq_timings content inside record_irq_time
V5:
  - Changed comment about 'deterministic' as the comment is confusing
  - Added license comment in the header
  - Replaced irq_timings_get/put by irq_timings_enable/disable
  - Moved IRQS_TIMINGS check in the handle_timings inline function
  - Dropped 'if !prev' as it is pointless
  - Stored time interval in nsec basis with u64 instead of u32
  - Removed redundant store
  - Removed the math
V4:
  - Added a static key
  - Added more comments for irq_timings_get_next()
  - Unified some function names to be prefixed by 'irq_timings_...'
  - Fixed a rebase error
V3:
  - Replaced ktime_get() by local_clock()
  - Shared irq are not handled
  - Simplified code by adding the timing in the irqdesc struct
  - Added a function to browse the irq timings
V2:
  - Fixed kerneldoc comment
  - Removed data field from the struct irq timing
  - Changed the lock section comment
  - Removed semi-colon style with empty stub
  - Replaced macro by static inline
  - Fixed static functions declaration
RFC:
  - initial posting

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 include/linux/interrupt.h |  5 +++
 kernel/irq/Kconfig        |  3 ++
 kernel/irq/Makefile       |  1 +
 kernel/irq/handle.c       |  2 ++
 kernel/irq/internals.h    | 84 +++++++++++++++++++++++++++++++++++++++++++++++
 kernel/irq/manage.c       |  3 ++
 kernel/irq/timings.c      | 30 +++++++++++++++++
 7 files changed, 128 insertions(+)
 create mode 100644 kernel/irq/timings.c

diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 89defd5..4c9d3ca 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -712,6 +712,11 @@ static inline void init_irq_proc(void)
 }
 #endif
 
+#ifdef CONFIG_IRQ_TIMINGS
+void irq_timings_enable(void);
+void irq_timings_disable(void);
+#endif
+
 struct seq_file;
 int show_interrupts(struct seq_file *p, void *v);
 int arch_show_interrupts(struct seq_file *p, int prec);
diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig
index 3bbfd6a..38e551d 100644
--- a/kernel/irq/Kconfig
+++ b/kernel/irq/Kconfig
@@ -81,6 +81,9 @@ config GENERIC_MSI_IRQ_DOMAIN
 config HANDLE_DOMAIN_IRQ
 	bool
 
+config IRQ_TIMINGS
+	bool
+
 config IRQ_DOMAIN_DEBUG
 	bool "Expose hardware/virtual IRQ mapping via debugfs"
 	depends on IRQ_DOMAIN && DEBUG_FS
diff --git a/kernel/irq/Makefile b/kernel/irq/Makefile
index 1d3ee31..efb5f14 100644
--- a/kernel/irq/Makefile
+++ b/kernel/irq/Makefile
@@ -10,3 +10,4 @@ obj-$(CONFIG_PM_SLEEP) += pm.o
 obj-$(CONFIG_GENERIC_MSI_IRQ) += msi.o
 obj-$(CONFIG_GENERIC_IRQ_IPI) += ipi.o
 obj-$(CONFIG_SMP) += affinity.o
+obj-$(CONFIG_IRQ_TIMINGS) += timings.o
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index d3f2490..eb4d3e8 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -138,6 +138,8 @@ irqreturn_t __handle_irq_event_percpu(struct irq_desc *desc, unsigned int *flags
 	unsigned int irq = desc->irq_data.irq;
 	struct irqaction *action;
 
+	record_irq_time(desc);
+
 	for_each_action_of_desc(desc, action) {
 		irqreturn_t res;
 
diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h
index bc226e7..df51b5e0 100644
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -8,6 +8,7 @@
 #include <linux/irqdesc.h>
 #include <linux/kernel_stat.h>
 #include <linux/pm_runtime.h>
+#include <linux/sched/clock.h>
 
 #ifdef CONFIG_SPARSE_IRQ
 # define IRQ_BITMAP_BITS	(NR_IRQS + 8196)
@@ -57,6 +58,7 @@ enum {
 	IRQS_WAITING		= 0x00000080,
 	IRQS_PENDING		= 0x00000200,
 	IRQS_SUSPENDED		= 0x00000800,
+	IRQS_TIMINGS		= 0x00001000,
 };
 
 #include "debug.h"
@@ -226,3 +228,85 @@ irq_pm_install_action(struct irq_desc *desc, struct irqaction *action) { }
 static inline void
 irq_pm_remove_action(struct irq_desc *desc, struct irqaction *action) { }
 #endif
+
+#ifdef CONFIG_IRQ_TIMINGS
+
+#define IRQ_TIMINGS_SHIFT	5
+#define IRQ_TIMINGS_SIZE	(1 << IRQ_TIMINGS_SHIFT)
+#define IRQ_TIMINGS_MASK	(IRQ_TIMINGS_SIZE - 1)
+
+struct irq_timings {
+	u64 values[IRQ_TIMINGS_SIZE]; /* our circular buffer */
+	unsigned int count; /* Number of interruptions since last inspection */
+};
+
+DECLARE_PER_CPU(struct irq_timings, irq_timings);
+
+static inline void remove_timings(struct irq_desc *desc)
+{
+	desc->istate &= ~IRQS_TIMINGS;
+}
+
+static inline void setup_timings(struct irq_desc *desc, struct irqaction *act)
+{
+	/*
+	 * We don't need the measurement because the idle code already
+	 * knows the next expiry event.
+	 */
+	if (act->flags & __IRQF_TIMER)
+		return;
+
+	desc->istate |= IRQS_TIMINGS;
+}
+
+extern void irq_timings_enable(void);
+extern void irq_timings_disable(void);
+
+extern struct static_key_false irq_timing_enabled;
+
+/*
+ * The interrupt number and the timestamp are encoded into a single
+ * u64 variable to optimize the size.
+ * 48 bit time stamp and 16 bit IRQ number is way sufficient.
+ *  Who cares an IRQ after 78 hours of idle time?
+ */
+static inline u64 irq_timing_encode(u64 timestamp, int irq)
+{
+	return (timestamp << 16) | irq;
+}
+
+static inline void irq_timing_decode(u64 value, u64 *timestamp, int *irq)
+{
+	*timestamp = value >> 16;
+	*irq = value & U16_MAX;
+}
+
+/*
+ * The function record_irq_time is only called in one place in the
+ * interrupts handler. We want this function always inline so the code
+ * inside is embedded in the function and the static key branching
+ * code can act at the higher level. Without the explicit
+ * __always_inline we can end up with a function call and a small
+ * overhead in the hotpath for nothing.
+ */
+static __always_inline void record_irq_time(struct irq_desc *desc)
+{
+	if (!static_branch_likely(&irq_timing_enabled))
+		return;
+
+	if (desc->istate & IRQS_TIMINGS) {
+		struct irq_timings *timings = this_cpu_ptr(&irq_timings);
+
+		timings->values[timings->count & IRQ_TIMINGS_MASK] =
+			irq_timing_encode(local_clock(),
+					  irq_desc_get_irq(desc));
+
+		timings->count++;
+	}
+}
+#else
+static inline void remove_timings(struct irq_desc *desc) {}
+static inline void setup_timings(struct irq_desc *desc,
+				 struct irqaction *act) {};
+static inline void record_irq_time(struct irq_desc *desc) {}
+#endif /* CONFIG_IRQ_TIMINGS */
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 057fde8..5dfa63d 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1372,6 +1372,8 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
 
 	raw_spin_unlock_irqrestore(&desc->lock, flags);
 
+	setup_timings(desc, new);
+
 	/*
 	 * Strictly no need to wake it up, but hung_task complains
 	 * when no hard interrupt wakes the thread up.
@@ -1500,6 +1502,7 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
 		irq_settings_clr_disable_unlazy(desc);
 		irq_shutdown(desc);
 		irq_release_resources(desc);
+		remove_timings(desc);
 	}
 
 #ifdef CONFIG_SMP
diff --git a/kernel/irq/timings.c b/kernel/irq/timings.c
new file mode 100644
index 0000000..56cf687
--- /dev/null
+++ b/kernel/irq/timings.c
@@ -0,0 +1,30 @@
+/*
+ * linux/kernel/irq/timings.c
+ *
+ * Copyright (C) 2016, Linaro Ltd - Daniel Lezcano <daniel.lezcano@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+#include <linux/percpu.h>
+#include <linux/static_key.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+
+#include "internals.h"
+
+DEFINE_STATIC_KEY_FALSE(irq_timing_enabled);
+
+DEFINE_PER_CPU(struct irq_timings, irq_timings);
+
+void irq_timings_enable(void)
+{
+	static_branch_enable(&irq_timing_enabled);
+}
+
+void irq_timings_disable(void)
+{
+	static_branch_disable(&irq_timing_enabled);
+}
-- 
2.7.4

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#1663522 — [PATCH V10 1/3] irq: Allow to pass the IRQF_TIMER flag with percpu irq request

In the next changes, we track when the interrupts occur in order to
statistically compute when is supposed to happen the next interrupt.

In all the interruptions, it does not make sense to store the timer interrupt
occurences and try to predict the next interrupt as when know the expiration
time.

The request_irq() has a irq flags parameter and the timer drivers use it to
pass the IRQF_TIMER flag, letting us know the interrupt is coming from a timer.
Based on this flag, we can discard these interrupts when tracking them.

But, the API request_percpu_irq does not allow to pass a flag, hence specifying
if the interrupt type is a timer.

Add a function request_percpu_irq_flags() where we can specify the flags. The
request_percpu_irq() function is changed to be a wrapper to
request_percpu_irq_flags() passing a zero flag parameter.

Change the timers using request_percpu_irq() to use request_percpu_irq_flags()
instead with the IRQF_TIMER flag set.

For now, in order to prevent a misusage of this parameter, only the IRQF_TIMER
flag (or zero) is a valid parameter to be passed to the
request_percpu_irq_flags() function.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Patrice Chotard <patrice.chotard@st.com>
Cc: Kukjin Kim <kgene@kernel.org>
Cc: Javier Martinez Canillas <javier@osg.samsung.com>
Cc: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Acked-by: Krzysztof Kozlowski <krzk@kernel.org>
---
Changelog:

   V10:
	- Drop the change for arch arm virtual timer
	  https://lkml.org/lkml/2017/4/25/184
   V9:
	- Clarified the patch description
	- Fixed EXPORT_SYMBOL_GPL(request_percpu_irq_flags)

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 arch/arm/kernel/smp_twd.c                |  3 ++-
 drivers/clocksource/arc_timer.c          |  4 ++--
 drivers/clocksource/arm_arch_timer.c     | 20 ++++++++++++--------
 drivers/clocksource/arm_global_timer.c   |  4 ++--
 drivers/clocksource/exynos_mct.c         |  7 ++++---
 drivers/clocksource/qcom-timer.c         |  4 ++--
 drivers/clocksource/time-armada-370-xp.c |  9 +++++----
 drivers/clocksource/timer-nps.c          |  6 +++---
 include/linux/interrupt.h                | 11 ++++++++++-
 kernel/irq/manage.c                      | 15 ++++++++++-----
 10 files changed, 52 insertions(+), 31 deletions(-)

diff --git a/arch/arm/kernel/smp_twd.c b/arch/arm/kernel/smp_twd.c
index 895ae51..ce9fdcf 100644
--- a/arch/arm/kernel/smp_twd.c
+++ b/arch/arm/kernel/smp_twd.c
@@ -332,7 +332,8 @@ static int __init twd_local_timer_common_register(struct device_node *np)
 		goto out_free;
 	}
 
-	err = request_percpu_irq(twd_ppi, twd_handler, "twd", twd_evt);
+	err = request_percpu_irq_flags(twd_ppi, twd_handler, IRQF_TIMER, "twd",
+				       twd_evt);
 	if (err) {
 		pr_err("twd: can't register interrupt %d (%d)\n", twd_ppi, err);
 		goto out_free;
diff --git a/drivers/clocksource/arc_timer.c b/drivers/clocksource/arc_timer.c
index 2164973..66f2632 100644
--- a/drivers/clocksource/arc_timer.c
+++ b/drivers/clocksource/arc_timer.c
@@ -301,8 +301,8 @@ static int __init arc_clockevent_setup(struct device_node *node)
 	}
 
 	/* Needs apriori irq_set_percpu_devid() done in intc map function */
-	ret = request_percpu_irq(arc_timer_irq, timer_irq_handler,
-				 "Timer0 (per-cpu-tick)", evt);
+	ret = request_percpu_irq_flags(arc_timer_irq, timer_irq_handler, IRQF_TIMER,
+				       "Timer0 (per-cpu-tick)", evt);
 	if (ret) {
 		pr_err("clockevent: unable to request irq\n");
 		return ret;
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index 4bed671..22646b5 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -980,25 +980,29 @@ static int __init arch_timer_register(void)
 	ppi = arch_timer_ppi[arch_timer_uses_ppi];
 	switch (arch_timer_uses_ppi) {
 	case ARCH_TIMER_VIRT_PPI:
-		err = request_percpu_irq(ppi, arch_timer_handler_virt,
-					 "arch_timer", arch_timer_evt);
+		err = request_percpu_irq_flags(ppi, arch_timer_handler_virt,
+					       IRQF_TIMER, "arch_timer",
+					       arch_timer_evt);
 		break;
 	case ARCH_TIMER_PHYS_SECURE_PPI:
 	case ARCH_TIMER_PHYS_NONSECURE_PPI:
-		err = request_percpu_irq(ppi, arch_timer_handler_phys,
-					 "arch_timer", arch_timer_evt);
+		err = request_percpu_irq_flags(ppi, arch_timer_handler_phys,
+					       IRQF_TIMER, "arch_timer",
+					       arch_timer_evt);
 		if (!err && arch_timer_has_nonsecure_ppi()) {
 			ppi = arch_timer_ppi[ARCH_TIMER_PHYS_NONSECURE_PPI];
-			err = request_percpu_irq(ppi, arch_timer_handler_phys,
-						 "arch_timer", arch_timer_evt);
+			err = request_percpu_irq_flags(ppi, arch_timer_handler_phys,
+						       IRQF_TIMER, "arch_timer",
+						       arch_timer_evt);
 			if (err)
 				free_percpu_irq(arch_timer_ppi[ARCH_TIMER_PHYS_SECURE_PPI],
 						arch_timer_evt);
 		}
 		break;
 	case ARCH_TIMER_HYP_PPI:
-		err = request_percpu_irq(ppi, arch_timer_handler_phys,
-					 "arch_timer", arch_timer_evt);
+		err = request_percpu_irq_flags(ppi, arch_timer_handler_phys,
+					       IRQF_TIMER, "arch_timer",
+					       arch_timer_evt);
 		break;
 	default:
 		BUG();
diff --git a/drivers/clocksource/arm_global_timer.c b/drivers/clocksource/arm_global_timer.c
index 123ed20..5a72ec1 100644
--- a/drivers/clocksource/arm_global_timer.c
+++ b/drivers/clocksource/arm_global_timer.c
@@ -302,8 +302,8 @@ static int __init global_timer_of_register(struct device_node *np)
 		goto out_clk;
 	}
 
-	err = request_percpu_irq(gt_ppi, gt_clockevent_interrupt,
-				 "gt", gt_evt);
+	err = request_percpu_irq_flags(gt_ppi, gt_clockevent_interrupt,
+				       IRQF_TIMER, "gt", gt_evt);
 	if (err) {
 		pr_warn("global-timer: can't register interrupt %d (%d)\n",
 			gt_ppi, err);
diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c
index 670ff0f..a48ca0f 100644
--- a/drivers/clocksource/exynos_mct.c
+++ b/drivers/clocksource/exynos_mct.c
@@ -524,9 +524,10 @@ static int __init exynos4_timer_resources(struct device_node *np, void __iomem *
 
 	if (mct_int_type == MCT_INT_PPI) {
 
-		err = request_percpu_irq(mct_irqs[MCT_L0_IRQ],
-					 exynos4_mct_tick_isr, "MCT",
-					 &percpu_mct_tick);
+		err = request_percpu_irq_flags(mct_irqs[MCT_L0_IRQ],
+					       exynos4_mct_tick_isr,
+					       IRQF_TIMER, "MCT",
+					       &percpu_mct_tick);
 		WARN(err, "MCT: can't request IRQ %d (%d)\n",
 		     mct_irqs[MCT_L0_IRQ], err);
 	} else {
diff --git a/drivers/clocksource/qcom-timer.c b/drivers/clocksource/qcom-timer.c
index ee358cd..8e876fc 100644
--- a/drivers/clocksource/qcom-timer.c
+++ b/drivers/clocksource/qcom-timer.c
@@ -174,8 +174,8 @@ static int __init msm_timer_init(u32 dgt_hz, int sched_bits, int irq,
 	}
 
 	if (percpu)
-		res = request_percpu_irq(irq, msm_timer_interrupt,
-					 "gp_timer", msm_evt);
+		res = request_percpu_irq_flags(irq, msm_timer_interrupt,
+					       IRQF_TIMER, "gp_timer", msm_evt);
 
 	if (res) {
 		pr_err("request_percpu_irq failed\n");
diff --git a/drivers/clocksource/time-armada-370-xp.c b/drivers/clocksource/time-armada-370-xp.c
index aea4380..fea81ad 100644
--- a/drivers/clocksource/time-armada-370-xp.c
+++ b/drivers/clocksource/time-armada-370-xp.c
@@ -309,10 +309,11 @@ static int __init armada_370_xp_timer_common_init(struct device_node *np)
 	/*
 	 * Setup clockevent timer (interrupt-driven).
 	 */
-	res = request_percpu_irq(armada_370_xp_clkevt_irq,
-				armada_370_xp_timer_interrupt,
-				"armada_370_xp_per_cpu_tick",
-				armada_370_xp_evt);
+	res = request_percpu_irq_flags(armada_370_xp_clkevt_irq,
+				       armada_370_xp_timer_interrupt,
+				       IRQF_TIMER,
+				       "armada_370_xp_per_cpu_tick",
+				       armada_370_xp_evt);
 	/* Immediately configure the timer on the boot CPU */
 	if (res) {
 		pr_err("Failed to request percpu irq\n");
diff --git a/drivers/clocksource/timer-nps.c b/drivers/clocksource/timer-nps.c
index e74ea17..a83b6a4 100644
--- a/drivers/clocksource/timer-nps.c
+++ b/drivers/clocksource/timer-nps.c
@@ -256,9 +256,9 @@ static int __init nps_setup_clockevent(struct device_node *node)
 		return ret;
 
 	/* Needs apriori irq_set_percpu_devid() done in intc map function */
-	ret = request_percpu_irq(nps_timer0_irq, timer_irq_handler,
-				 "Timer0 (per-cpu-tick)",
-				 &nps_clockevent_device);
+	ret = request_percpu_irq_flags(nps_timer0_irq, timer_irq_handler,
+				       IRQF_TIMER, "Timer0 (per-cpu-tick)",
+				       &nps_clockevent_device);
 	if (ret) {
 		pr_err("Couldn't request irq\n");
 		clk_disable_unprepare(clk);
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index a6fba48..89defd5 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -152,8 +152,17 @@ request_any_context_irq(unsigned int irq, irq_handler_t handler,
 			unsigned long flags, const char *name, void *dev_id);
 
 extern int __must_check
+request_percpu_irq_flags(unsigned int irq, irq_handler_t handler,
+			 unsigned long flags, const char *devname,
+			 void __percpu *percpu_dev_id);
+
+static inline int __must_check
 request_percpu_irq(unsigned int irq, irq_handler_t handler,
-		   const char *devname, void __percpu *percpu_dev_id);
+		   const char *devname, void __percpu *percpu_dev_id)
+{
+	return request_percpu_irq_flags(irq, handler, 0,
+					devname, percpu_dev_id);
+}
 
 extern const void *free_irq(unsigned int, void *);
 extern void free_percpu_irq(unsigned int, void __percpu *);
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 070be98..057fde8 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1958,9 +1958,10 @@ int setup_percpu_irq(unsigned int irq, struct irqaction *act)
 }
 
 /**
- *	request_percpu_irq - allocate a percpu interrupt line
+ *	request_percpu_irq_flags - allocate a percpu interrupt line
  *	@irq: Interrupt line to allocate
  *	@handler: Function to be called when the IRQ occurs.
+ *	@flags: Interrupt type flags (IRQF_TIMER only)
  *	@devname: An ascii name for the claiming device
  *	@dev_id: A percpu cookie passed back to the handler function
  *
@@ -1973,8 +1974,9 @@ int setup_percpu_irq(unsigned int irq, struct irqaction *act)
  *	the handler gets called with the interrupted CPU's instance of
  *	that variable.
  */
-int request_percpu_irq(unsigned int irq, irq_handler_t handler,
-		       const char *devname, void __percpu *dev_id)
+int request_percpu_irq_flags(unsigned int irq, irq_handler_t handler,
+			     unsigned long flags, const char *devname,
+			     void __percpu *dev_id)
 {
 	struct irqaction *action;
 	struct irq_desc *desc;
@@ -1988,12 +1990,15 @@ int request_percpu_irq(unsigned int irq, irq_handler_t handler,
 	    !irq_settings_is_per_cpu_devid(desc))
 		return -EINVAL;
 
+	if (flags && flags != IRQF_TIMER)
+		return -EINVAL;
+
 	action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
 	if (!action)
 		return -ENOMEM;
 
 	action->handler = handler;
-	action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND;
+	action->flags = flags | IRQF_PERCPU | IRQF_NO_SUSPEND;
 	action->name = devname;
 	action->percpu_dev_id = dev_id;
 
@@ -2014,7 +2019,7 @@ int request_percpu_irq(unsigned int irq, irq_handler_t handler,
 
 	return retval;
 }
-EXPORT_SYMBOL_GPL(request_percpu_irq);
+EXPORT_SYMBOL_GPL(request_percpu_irq_flags);
 
 /**
  *	irq_get_irqchip_state - returns the irqchip state of a interrupt.
-- 
2.7.4

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