Messages in this thread | | | Date | Fri, 18 May 2012 16:24:43 +0200 | From | Jan Kara <> | Subject | Re: [PATCH 2/2] block: Convert BDI proportion calculations to flexible proportions |
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On Fri 18-05-12 00:04:33, Peter Zijlstra wrote: > On Tue, 2012-05-15 at 17:43 +0200, Jan Kara wrote: > > +static struct timer_list writeout_period_timer = > > + TIMER_DEFERRED_INITIALIZER(writeout_period, 0, 0); > > So the problem with using a deferred timer is that it 'ignores' idle > time. So if a very busy period is followed by a real quiet period you'd > expect all the proportions to have aged to 0, but they won't have. Ah, I see. Thanks for warning me.
> One way to solve that is to track a jiffies count of the last time the > timer triggered and compute the missed periods from that and extend > fprop_new_period() to deal with period increments of more than 1. Yeah, that should be easy enough so I'll try it that way since I presume it's nicer to power usage to use deferred timers if it's reasonably possible.
Honza -- Jan Kara <jack@suse.cz> SUSE Labs, CR
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