Fatal trap 12: page fault panic with recent kernel with ZFS

Kip Macy kmacy at freebsd.org
Tue May 19 02:03:46 UTC 2009

> Thanks, I appreciate all this work.  Not allowing inactive pages to
> shrink the ARC sounds great as an option.  I would be willing to bet
> that allowing inactive pages to shrink the arc would be far less
> detrimental to most people who aren't running a constant busy file
> server load, and its definitely important to try to protect untuned
> boxes.

Allowing NFS to use ARC buffers might be one solution to that.

> Do you have any suggestions for increasing the amount of memory ARC
> can use?  I've had difficulty increasing kmem past a few gigs on any
> of my recent builds (all past where kmem was changed so it could be
> more than ~2g) because at some point the kernel would stop booting.
> If I increase them too far, a few lines of the booting kernel would
> print, followed by a long stream of page fault panics or something
> with a sudden reboot.  With the recent change allowing the use of
> direct mem, the ARC could easily use ample memory except it turned
> out not to be stable.

As of r192216 that should not be a probably any more. The maximum kmem
is now 512GB.  It will be at least a year or two before anyone bumps
his head against that.

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