Help with filing a [maybe] ZFS/mmap bug.

[Andriy Gapon]

on 23/09/2013 02:52 George Hartzell said the following:
> This weekend I built up a system using the 10.0 beta 2 dvd, then
> updated /usr/src from head.
> 
> I grabbed a fresh copy of your patch this afternoon.
> 
> I applied your patch with no problems.  I was unable to build a new
> kernel though, you have one reference to m->busy, where m is a
> vm_page_t (if I remember correctly).  I dug around a bit and decided
> that you meant m->busy_lock, which let me build a usable kernel.
> 
> It looks like INVARIANTS and INVARIANT_SUPPORT are included in the
> GENERIC conf file.
> 
> I ran through my test routine with the original system and was able to
> reproduce the problem.
> 
> After building and installing a kernel with your patch I was still
> able to trigger the problem.  If anything it was worse (sample size =
> 1, I know...).
> 
> I did not see any interesting output in /var/log/messages or to the
> console or anywhere else obvious.
> 
> I'm not sure what to do next.  It's likely that my m->busy to
> m->busy_lock change was not The Right Thing to Do and might have
> invalidated what the patch was trying to do.
> 
> In any case, I now have a system running HEAD and should be able to
> test things more easily.

George,

thank you very much for the test!  And sorry for the "delay" with my reply.
I was out of new ideas at first and then very busy.  But now Steve has woken me
up :-)

The busy -> busy_lock change was not entirely correct, but it is pretty harmless.

I will probably commit the putpages patch anyway soon.  But your test confirms
that the pageout logic was not related to the bug.

I think I now have an idea of what could be wrong.
I will follow up in the other thread.

-- 
Andriy Gapon