linsched: add check on invoke tick_nohz_irq_exit() in irq_exit()

RFC PATCH New Michael Wang 1 participant 1 message Sep 3, 2012

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Michael Wang

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2012-09-03 03:58 UTC #0 lore raw

RFC PATCH 2/4 linsched: add check on invoke tick_nohz_irq_exit() in irq_exit()

From: Michael Wang <[email protected]>

tick_nohz_irq_exit() will make sure the tick timer reprogram correctly after cpu enter idle.

With out this check, after the interrupt, tick timer will be enabled even cpu is still in idle, this will cause inaccuracy.

Signed-off-by Michael Wang <[email protected]>

---
 arch/linsched/kernel/irq.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

arch/linsched/kernel/irq.c +4 -0

index 3000d47..5f88af4 100644
@@ -2,6 +2,7 @@
 #include <asm/hardirq.h>
 #include <linux/sched.h>
 #include <linux/irq_work.h>
+#include <linux/tick.h>
 
 unsigned long linsched_irq_flags = ARCH_IRQ_ENABLED;

@@ -87,6 +88,9 @@ void irq_exit(void)
        sub_preempt_count(IRQ_EXIT_OFFSET);
        if (!in_interrupt() && local_softirq_pending())
                do_softirq();
+
+       if (idle_cpu(smp_processor_id()) && !in_interrupt() && !need_resched())
+               tick_nohz_irq_exit();
 }
 
 void local_bh_enable_ip(unsigned long ip)

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