Messages in this thread | | | Date | Wed, 18 Nov 2009 21:33:55 +0000 | From | Matthew Garrett <> | Subject | Re: [PATCH] [RFC] Add support for uevents on block device idle changes |
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On Wed, Nov 18, 2009 at 10:06:33PM +0100, Kay Sievers wrote:
> That's true, but I think there is a significant difference between > polling every one or two seconds for media changes, and usually one or > two minutes for a disk idle. It's not that we poll in a rather hight > frequency, in an arbitrary interval, and check if some condition is > met.
My use cases are on the order of a second.
> I still don't think that we should add new event interfaces which are > single-subscriber only, and use global values for a specific user. > What if there will be another independent user for this, which might > want a different timeout? They fight over the trigger value to set in > sysfs?
You can trivially multiplex without any additional wakeups. Something like devkit-disks can simply trigger on the lowest requested time and then schedule wakeups for subscribers who want a different timeout.
> From my perspective, the once-at-timeout wakeup is more acceptable > than an in-kernel policy setting for a single-subscriber event > interface.
I'd be open to it being something for multiple subscribers, though that would add to the complexity in the block code and I'm not sure that's needed.
-- Matthew Garrett | mjg59@srcf.ucam.org
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