Problem with skiplist

[Bron Gondwana]

On Thu, Sep 11, 2008 at 03:48:25PM +0200, DEMBKOWSKI, Henryk (Henryk) wrote:
> Bron,
> 
> Thank you for help.

No problem.

You may have noticed, I sent the wrong version of cyrusdb_skiplist.c.
The one I sent was still stable, but had two more patches that aren't
candidates for upstream at this point.

I've posted the new version to the list now.

> Do you think that we should also change linux kernel to  2.6.19.2 or
> higher?

Yes.  That's getting pretty old!  We're running 2.6.26.1 on most of
our servers.  In particular, there's a nasty mmap bug on 64 bit for
quite a few earlier versions.  .22 => .25 are quite broken.  My bug
report to LKML triggered quite a flamewar about it, and Linus came up
with a patch that worked nicely.

Ahh, I see the thread you referenced has a link to my post.

On the other hand:

"VM: Fix nasty and subtle race in shared mmap'ed page writeback"

This is unlikely to be the cause.  Cyrus doesn't use mmap writes,
only reads.  While we don't run kernels that old any more, the
skiplist problems are much more likely to be related to bugs in
the older skiplist code than kernel issues.

Bron.