Messages in this thread | | | From | "Rafael J. Wysocki" <> | Subject | Re: [linux-pm] [PATCH 0/8] Suspend block api (version 8) | Date | Mon, 31 May 2010 23:38:55 +0200 |
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On Monday 31 May 2010, Arve Hjønnevåg wrote: > 2010/5/29 Alan Stern <stern@rowland.harvard.edu>: > > On Sat, 29 May 2010, Arve Hjønnevåg wrote: > > > >> > In place of in-kernel suspend blockers, there will be a new type of QoS > >> > constraint -- call it QOS_EVENTUALLY. It's a very weak constraint, > >> > compatible with all cpuidle modes in which runnable threads are allowed > >> > to run (which is all of them), but not compatible with suspend. > >> > > >> This sound just like another API rename. It will work, but given that > >> suspend blockers was the name least objectionable last time around, > >> I'm not sure what this would solve. > > > > It's not just a rename. By changing this into a QoS constraint, we > > make it more generally useful. Instead of standing on its own, it > > becomes part of the PM-QOS framework. > > > > We cannot use the existing pm-qos framework. It is not safe to call > from atomic context.
We've just merged a patch that fixed that if I'm not mistaken. Mark, did your PM QoS update fix that?
> Also, it does not have any state constraints, so it iterates over every > registered constraint each time one of them changes.
That's fixable IMO.
> Nor does is currently provide any stats for debugging.
That's why Alan is proposing to add that.
> The original wakelock patchset supported a wakelock type so it could > be used to block more then suspend, but I had to remove this because > it "overlapped" with pm-qos. So, yes I do consider this just another > rename.
It's an extension of an existing framework rather than an addition of a new one, with entirely new API and so on. Extending existing APIs is much preferred to adding new ones, in general.
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