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Subject: Re: [linux-pm] [PATCH 0/8] Suspend block api (version 8)
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Date: Fri, 28 May 2010 09:43:43 +0200
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On Thu, 2010-05-27 at 17:45 -0700, Arve Hjønnevåg wrote:
> What happens if the user presses the button right before you set QoS
> of 'user apps' to  QS_NONE?
> To me it looks like this solution would result in this sequence which
> may ignore the button press:
>         Button pushed
>         Button driver sets QoS of app it wakes to QS_ABOVESUSPEND
>         Set QoS of 'user apps' to QS_NONE 

I don't think we should change app QoS parameters, but change service
provider parameters.

For instance, suppose the filesystem-IO QoS has 3 levels: 
  High, Normal and Idle.

Then if we assign Idle to updatedb, we'll service it as long as the
filesystem-server QoS has a higher level (High and Normal). When we
change the filesystem-serves' QoS to idle, it finds there is nothing to
keep it servicing stuff and it'll block pending requests, updatedb stops
being runnable and we're good.