[PATCH 1/4] irq: Support to compute context on top of a given preempt_count offset

From: Frederic Weisbecker
Date: Fri May 21 2010 - 10:05:20 EST


This brings the support to compute irq/preempt contexts on top
of a a given preempt count offset instead of the current one.

This is going to be useful for perf that needs to know the
preempt_count() of the context that an event has interrupted.

Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
---
include/linux/hardirq.h | 17 +++++++++++++----
1 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h
index d5b3876..0195547 100644
--- a/include/linux/hardirq.h
+++ b/include/linux/hardirq.h
@@ -58,6 +58,7 @@
#define SOFTIRQ_MASK (__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT)
#define HARDIRQ_MASK (__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)
#define NMI_MASK (__IRQ_MASK(NMI_BITS) << NMI_SHIFT)
+#define IRQ_MASK (SOFTIRQ_MASK | HARDIRQ_MASK | NMI_MASK)

#define PREEMPT_OFFSET (1UL << PREEMPT_SHIFT)
#define SOFTIRQ_OFFSET (1UL << SOFTIRQ_SHIFT)
@@ -74,15 +75,23 @@
#error PREEMPT_ACTIVE is too low!
#endif

-#define hardirq_count() (preempt_count() & HARDIRQ_MASK)
-#define softirq_count() (preempt_count() & SOFTIRQ_MASK)
-#define irq_count() (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK \
- | NMI_MASK))
+#define hardirq_count_offset(offset) ((offset) & HARDIRQ_MASK)
+#define softirq_count_offset(offset) ((offset) & SOFTIRQ_MASK)
+#define irq_count_offset(offset) ((offset) & IRQ_MASK)
+
+#define hardirq_count() hardirq_count_offset(preempt_count())
+#define softirq_count() softirq_count_offset(preempt_count())
+#define irq_count() irq_count_offset(preempt_count())

/*
* Are we doing bottom half or hardware interrupt processing?
* Are we in a softirq context? Interrupt context?
*/
+#define in_irq_offset(offset) (hardirq_count_offset(offset))
+#define in_softirq_offset(offset) (softirq_count_offset(offset))
+#define in_interrupt_offset(offset) (irq_count_offset(offset))
+
+
#define in_irq() (hardirq_count())
#define in_softirq() (softirq_count())
#define in_interrupt() (irq_count())
--
1.6.2.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/