Re: zero-filed page on VOP_PUTPAGES

[yamt%mwd.biglobe.ne.jp@localhost (YAMAMOTO Takashi)]

hi,

> 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?

i forgot. :-)

> 
> 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

have you tried to analyze the problem with PUFFS_FLAG_OPDUMP?

does your server process requests from kernel simultaneously?
eg. multithread

YAMAMOTO Takashi

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