Re: zero-filed page on VOP_PUTPAGES

[manu%netbsd.org@localhost (Emmanuel Dreyfus)]

Emmanuel Dreyfus <manu%netbsd.org@localhost> 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
http://hcpnet.free.fr/pubz
manu%netbsd.org@localhost