Messages in this thread | | | Date | Sat, 22 Feb 2014 18:03:04 -0500 (EST) | From | Alan Stern <> | Subject | Re: [PATCH v2 5/9] usb: don't use PREPARE_DELAYED_WORK |
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On Sat, 22 Feb 2014, Tejun Heo wrote:
> On Sat, Feb 22, 2014 at 10:14:48AM -0500, Alan Stern wrote: > > Is the cancel_delayed_work_sync(&hub->init_work) call in hub_quiesce() > > going to get confused by all this? > > Yeah, you can't cancel a work item which hasn't been initialzed. > Maybe move init of the first work function there? I don't think it > really matters tho. > > > It's worth mentioning that the only reason for the hub_init_func3 stuff > > is, as the comment says, to avoid a long sleep (100 ms) inside a work > > routine. With all the changes to the work queue infrastructure, maybe > > this doesn't matter so much any more. If we got rid of it then there > > wouldn't be any multiplexing, and this whole issue would become moot. > > I don't really think that'd be necessary. Just sleeping synchronously > should be fine. How many threads are we talking about?
One thread per hub (no more than 10 on a typical system). The code in question is part of the hub driver's probe sequence.
On Sat, 22 Feb 2014, Peter Hurley wrote:
> If a running hub init does not need to be single-threaded wrt > a different running hub init,
I'm not quite sure what that means, but the hub init threads are indeed independent of each other.
> then a single init work could be queued to > the system_unbound_wq which doesn't care about running times.
This sort of thing sounds like the best approach. Tejun, do you want to rewrite the patch, getting rid of the hub_init_func3 and HUB_INIT3 business entirely? Or would you like me to do it?
Alan Stern
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