Re: [PATCH v8 1/5] mm: introduce a common interface for balloonpages mobility

[Michael S. Tsirkin]

On Thu, Aug 23, 2012 at 01:06:48PM -0300, Rafael Aquini wrote:
> On Thu, Aug 23, 2012 at 12:03:15PM -0400, Rik van Riel wrote:
> > >
> > >Not "longer" - apparently forever unless user resend the leak command.
> > >It's wrong - it should
> > >1. not tell host if nothing was done
> > >2. after migration finished leak and tell host
> > 
> > Agreed.  If the balloon is told to leak N pages, and could
> > not do so because those pages were locked, the balloon driver
> > needs to retry (maybe waiting on a page lock?) and not signal
> > completion until after the job has been completed.
> > 
> > Having the balloon driver wait on the page lock should be
> > fine, because compaction does not hold the page lock for
> > long.
> 
> And that is precisely what leak_balloon is doing. When it stumbles across a
> locked page it gets rid of that leak round to give a shot for compaction to
> finish its task.
> 

Yes but I do not see where it will retry.
If it does, please add a comment pointing out where it happens.

-- 
MST
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