ZFS: Deadlock during vnode recycling

Andriy Gapon avg at FreeBSD.org
Tue Oct 9 09:11:41 UTC 2012


on 07/10/2012 21:44 Justin T. Gibbs said the following:
> On Oct 7, 2012, at 9:32 AM, Andriy Gapon <avg at FreeBSD.org> wrote:
> 
>> In fact here is a real patch that I would like to propose:
>> http://people.freebsd.org/~avg/zfs-getnewvnode_reserve.diff
> 
> OS-X has these same types of problems and I talked with Don Brady
> of the OS-X ZFS port about them during ZFS day.  It sounds like he
> explicitly pre-allocates vnodes in these code paths instead of
> relying on a reserve pool.

How is pre-allocation different from reservation?
Terminologically it looks like different words for the same thing.

> I plan to review his work since I expect
> he's found and fixed problems we don't even know we have yet.

That would be very interesting to learn.

> My only complaint with this patch is that it doesn't include stats
> counters for these rare conditions so that I can validate that the
> code is exercised during a test suite.  Can you merge in the kstat
> portion of the change I proposed?

Umm, I was not planning on doing that...  Your last patch looked rather big.
If we decide that including those stats in that way into the tree is a way to
go, then I will try to look into doing that.  Unless you beat me to it.

P.S. it is not fact that the patch of mine could go into the tree, of course :-)

-- 
Andriy Gapon


More information about the freebsd-fs mailing list