linux-kernel - [PATCH 04/10] softirq: Consolidate default local_softirq

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Date:   Tue, 24 Apr 2018 16:09:09 +0200
From:   Frederic Weisbecker <frederic@...nel.org>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...nel.org>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Frederic Weisbecker <frederic@...nel.org>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Tony Luck <tony.luck@...el.com>,
        Peter Zijlstra <peterz@...radead.org>,
        "David S . Miller" <davem@...emloft.net>,
        Michael Ellerman <mpe@...erman.id.au>,
        Helge Deller <deller@....de>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Martin Schwidefsky <schwidefsky@...ibm.com>,
        Fenghua Yu <fenghua.yu@...el.com>,
        Heiko Carstens <heiko.carstens@...ibm.com>,
        "James E . J . Bottomley" <jejb@...isc-linux.org>
Subject: [PATCH 04/10] softirq: Consolidate default local_softirq_pending() implementations

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@...nel.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Ingo Molnar <mingo@...nel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Cc: David S. Miller <davem@...emloft.net>
Cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>
Cc: Paul Mackerras <paulus@...ba.org>
Cc: Michael Ellerman <mpe@...erman.id.au>
Cc: James E.J. Bottomley <jejb@...isc-linux.org>
Cc: Helge Deller <deller@....de>
Cc: Tony Luck <tony.luck@...el.com>
Cc: Fenghua Yu <fenghua.yu@...el.com>
Cc: Martin Schwidefsky <schwidefsky@...ibm.com>
Cc: Heiko Carstens <heiko.carstens@...ibm.com>
---
 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 5426627..7a11f73 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -432,11 +432,25 @@ 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