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From: Thomas Gleixner <tglx@linutronix.de>
To: Waiman Long <longman@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Alexey Dobriyan <adobriyan@gmail.com>,
	Kees Cook <keescook@chromium.org>,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	Davidlohr Bueso <dave@stgolabs.net>,
	Miklos Szeredi <miklos@szeredi.hu>,
	Daniel Colascione <dancol@google.com>,
	Dave Chinner <david@fromorbit.com>,
	Randy Dunlap <rdunlap@infradead.org>,
	Matthew Wilcox <willy@infradead.org>
Subject: Re: [PATCH v3 4/4] /proc/stat: Call kstat_irqs_usr() only for active IRQs
Date: Fri, 11 Jan 2019 20:19:33 +0100 (CET)	[thread overview]
Message-ID: <alpine.DEB.2.21.1901112017000.1661@nanos.tec.linutronix.de> (raw)
In-Reply-To: <alpine.DEB.2.21.1901111750280.4957@nanos.tec.linutronix.de>

On Fri, 11 Jan 2019, Thomas Gleixner wrote:
> --- a/kernel/irq/internals.h
> +++ b/kernel/irq/internals.h
> @@ -246,6 +246,7 @@ static inline void kstat_incr_irqs_this_
>  {
>  	__this_cpu_inc(*desc->kstat_irqs);
>  	__this_cpu_inc(kstat.irqs_sum);
> +	desc->tot_count++;

There is one issue here. True percpu interrupts, like the timer interrupts
on ARM(64), will access that in parallel. But that's not rocket science to
fix.

Thanks,

	tglx



  reply	other threads:[~2019-01-11 19:19 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-09 19:20 [PATCH v3 0/4] /proc/stat: Reduce irqs counting performance overhead Waiman Long
2019-01-09 19:20 ` [PATCH v3 1/4] /proc/stat: Extract irqs counting code into show_stat_irqs() Waiman Long
2019-01-09 19:20 ` [PATCH v3 2/4] /proc/stat: Only do percpu sum of active IRQs Waiman Long
2019-01-09 19:20 ` [PATCH v3 3/4] genirq: Track the number " Waiman Long
2019-01-09 19:20 ` [PATCH v3 4/4] /proc/stat: Call kstat_irqs_usr() only for " Waiman Long
2019-01-11 17:23   ` Thomas Gleixner
2019-01-11 19:19     ` Thomas Gleixner [this message]
2019-01-11 19:23       ` Matthew Wilcox
2019-01-11 21:02         ` Thomas Gleixner
2019-01-14 19:04           ` Waiman Long
2019-01-15  9:24             ` Thomas Gleixner
2019-01-15 15:52               ` Waiman Long

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