genirq: Speedup show_interrupts()

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Since commit 425a5072dc ("genirq: Free irq_desc with rcu"),
show_interrupts() can be switched to rcu locking, which removes possible
contention on sparse_irq_lock.

The per_cpu count scan and print can be done without holding desc spinlock.

And there is no need to call kstat_irqs_cpu() and abuse irq_to_desc() while
holding rcu read lock, since desc and desc->kstat_irqs wont disappear or
change.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Link: https://lkml.kernel.org/r/20180620150332.163320-1-edumazet@google.com

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Eric Dumazet 2018-06-20 08:03:32 -07:00 • committed by Thomas Gleixner

parent 0a13ec0bbc

commit 74bdf7815d

1 changed files with 12 additions and 10 deletions

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kernel/irq/proc.c

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