[dm-devel] [PATCH 05/24] dm cache policy mq: implement writeback_work() and mq_{set, clear}_dirty()

[Mike Snitzer]

On Fri, Oct 25 2013 at 12:06pm -0400,
Alasdair G Kergon <agk at redhat.com> wrote:

> On Thu, Oct 24, 2013 at 02:30:18PM -0400, Mike Snitzer wrote:
> > From: Joe Thornber <ejt at redhat.com>
>  
> > --- a/drivers/md/dm-cache-policy-mq.c
> 
> > -	 * We maintain two queues of entries.  The cache proper contains
> 
> > +	 * We maintain three queues of entries.  The cache proper,
> 
> Does the Documentation file need updating too?

will fix.

> : The multiqueue policy has two sets of 16 queues: one set for entries
> : waiting for the cache and another one for those in the cache.
> 
> > @@ -580,7 +585,16 @@ static void check_generation(struct mq_policy *mq)
> 
> Is the comment about this function no longer accurate?
> 
> : * At the moment the threshold is taken by averaging the hit counts of some
> : * of the entries in the cache (the first 20 entries of the first level).
> 
> - It looks at clean before dirty?

yes, that is new.  will fix.

> - It looks at more than just the first level if it needs to?

was always the case, so docs were already stale.  will fix.

> > +// FIXME: can __mq_set_clear_dirty block?
> 
> Still to check this before inclusion upstream?

yeah, Joe said he'd have a look.