[PATCH 04/10] softirq: Consolidate default local_softirq_pending() implementations

From: Frederic Weisbecker
Date: Wed Mar 28 2018 - 22:27:36 EST


Consolidate and optimize default softirq mask API implementations.
Per-CPU operations are expected to be faster and a few architectures
already rely on them to implement local_softirq_pending() and related
accessors/mutators. Those will be migrated to the new generic code.

Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: David S. Miller <davem@xxxxxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: James E.J. Bottomley <jejb@xxxxxxxxxxxxxxxx>
Cc: Helge Deller <deller@xxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx>
---
include/linux/interrupt.h | 14 ++++++++++++++
include/linux/irq_cpustat.h | 6 +-----
2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 69c2382..01caeca 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -434,11 +434,25 @@ extern bool force_irqthreads;
#define force_irqthreads (0)
#endif

+#ifndef local_softirq_pending
+
+#ifndef local_softirq_pending_ref
+#define local_softirq_pending_ref irq_stat.__softirq_pending
+#endif
+
+#define local_softirq_pending() (__this_cpu_read(local_softirq_pending_ref))
+#define set_softirq_pending(x) (__this_cpu_write(local_softirq_pending_ref, (x)))
+#define or_softirq_pending(x) (__this_cpu_or(local_softirq_pending_ref, (x)))
+
+#else /* local_softirq_pending */
+
#ifndef __ARCH_SET_SOFTIRQ_PENDING
#define set_softirq_pending(x) (local_softirq_pending() = (x))
#define or_softirq_pending(x) (local_softirq_pending() |= (x))
#endif

+#endif /* local_softirq_pending */
+
/* Some architectures might implement lazy enabling/disabling of
* interrupts. In some cases, such as stop_machine, we might want
* to ensure that after a local_irq_disable(), interrupts have
diff --git a/include/linux/irq_cpustat.h b/include/linux/irq_cpustat.h
index ddea03c..6e8895c 100644
--- a/include/linux/irq_cpustat.h
+++ b/include/linux/irq_cpustat.h
@@ -22,11 +22,7 @@ DECLARE_PER_CPU_ALIGNED(irq_cpustat_t, irq_stat); /* defined in asm/hardirq.h */
#define __IRQ_STAT(cpu, member) (per_cpu(irq_stat.member, cpu))
#endif

- /* arch independent irq_stat fields */
-#define local_softirq_pending() \
- __IRQ_STAT(smp_processor_id(), __softirq_pending)
-
- /* arch dependent irq_stat fields */
+/* arch dependent irq_stat fields */
#define nmi_count(cpu) __IRQ_STAT((cpu), __nmi_count) /* i386 */

#endif /* __irq_cpustat_h */
--
2.7.4