tech-kern archive

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Old Index]

Re: zero-filed page on VOP_PUTPAGES

Emmanuel Dreyfus <> wrote:

> > i found the following patch in my tree.
> > unfortunately i forgot details and if there were more cases which needs
> > similar barriers.
> This fixes the problem with no detectable  performance hit. Is there
> any reason why it should not be committed?

Extensive testing shows that the same kind of bug exists if puffs_init()
is called without PUFFS_KFLAG_WTCACHE. This happens on netbsd-5 with and
without your patch.

The difference is that the chunk of zero spans multiple pages (but its
length is not page-aligned) and is always located at offset 0. Example
of output from my test case ( size of zero-filled chunk @ offset )
21071 @ 0
9145 @ 0
26493 @ 0
20772 @ 0
Emmanuel Dreyfus

Home | Main Index | Thread Index | Old Index