Re: [RFC][PATCH] create workqueue threads only when needed

From: Oliver Neukum
Date: Mon Feb 02 2009 - 05:03:16 EST


Am Monday 02 February 2009 10:46:33 schrieb Benjamin Herrenschmidt:
> On Mon, 2009-02-02 at 10:14 +0100, Oliver Neukum wrote:
> > Am Monday 02 February 2009 10:05:28 schrieb Benjamin Herrenschmidt:
> > > > Work which /may/ sleep longer, for example performs SCSI transactions,
> > > > needs to go into a private workqueue or other kind of context.
> > >
> > > Well, it's a bit silly to allocate a private workqueue with all it's
> > > associated per CPU kernel threads for something as rare as resetting
> > > your eth NIC ... or even SCSI error handling in fact.
> >
> > How do you avoid a deadlock if SCSI error handling doesn't use
> > a dedicated workqueue?
>
> Something such as slow-work or async funcs (not sure about the later, I
> have to look at the implementation) but the basic idea is to have a pool
> of threads for "generic" delayed work, when its busy, pick another one,
> and the pool itself should resize if there's too much pressure.

And all that without using GFP_KERNEL?

Regards
Oliver
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