Re: [GIT PULL tip/genirq] Please pull from lost-spurious-irq

From: Thomas Gleixner
Date: Tue Aug 03 2010 - 07:44:01 EST


On Tue, 3 Aug 2010, Tejun Heo wrote:
> I agree that timer multiplexing is a rather ugly thing and it would be
> great to remove it. You're right that it doesn't make whole lot of
> difference whether the timer is global or local if it's low frequency
> and in fast paths expect/unexpect would be able to just test its list
> entry and set/clear currently expecting status without messing with
> the global timer or lock. Then, we can have a single low freq timer
> for expect/unexpect and the other for actual polling.

And the third one for watch, right ? That would give us separate timer
functions which each serve a particular purpose.

When you go for it, can you please simplify all the heuristics?

spurious poll:

One fixed poll interval is enough. The retry logic can be made
simple, just set it back to interrupt delivery once per minute and
limit the storm to 10.


Get rid of the interrupt context work and do all the work in the
timer. Use a fixed interval and either keep it forever or remove it.


Use a slow fixed interval and just do the expect/unexpect fast
marking. A nice thing would be to have a counter of expect calls so
we can switch off the timer when there is no activity within 10

> How does that sound to you?

Way better. :)


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