Re: VOP_GETATTR: locking protocol change proposal

[Mindaugas Rasiukevicius <rmind%netbsd.org@localhost>]

yamt%mwd.biglobe.ne.jp@localhost (YAMAMOTO Takashi) wrote:
> > <...>
> > 
> > With the attached diff the locking protocol requests at least a shared
> > lock and all calls to VOP_GETATTR() outside of file systems respect it.
> > 
> > <...>
> 
> postgresql assumes instant lseek(SEEK_END) to get the size of
> their heap files.
> 
>       http://rhaas.blogspot.com/2011/11/linux-lseek-scalability.html
> 
> as fsync etc keeps the vnode lock during i/o, it might cause severe
> performance regression.

I wonder if it is worth having a separate VOP for that, which would
retrieve a subset of vattr without lock held.  There are potentially
more uses in the tree.

-- 
Mindaugas