[dm-devel] [PATCH 4/7] dm mpath: remove process_queued_ios()

[Mike Snitzer]

On Tue, Feb 11 2014 at  4:46am -0500,
Hannes Reinecke <hare at suse.de> wrote:

> On 02/10/2014 02:30 PM, Mike Snitzer wrote:
> > 
> > Just to verify, this seems to be the only outstanding question for this
> > patchset?
> > 
> > What value are you using for HZ?  If this portion of the change does
> > turn out to be meaningul: Rather than tieing to HZ should we just use an
> > explicitly non-zero value for __pg_init_all_paths()'s @min_delay?
> > 
> The actual amount here is irrelevant, as long as it's non-zero.
> It's just there to force execution of the work item off the current
> thread.

I'm aware we just need a non-zero value.  My concern, as originally
raised by Junichi in an earlier reply when you had it as HZ/50, is that
the value could be 0 if HZ is really small.  While unlikely I see no
point allowing the variable nature of HZ compromise passing a non-zero
value here.  Best to just be explicit by passing 1 or something.

All said, the question of why this is actually needed remains.  I trust
you're working on answering that via reproducer (by not forcing the use
of workqueue context)?