Re: Replace lockmgr for vnodes

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

> On Tue, Jan 29, 2008 at 03:06:08PM +0900, YAMAMOTO Takashi wrote:
>  > > No, they don't. In the long run I'm intending to fix at least the
>  > > vnode locks, because IMO they should be interruptible, but that'll
>  > > likely be a slow process.
>  > 
>  > i believe vnode locks should not be interruptible.
> 
> ok then...
> 
> My reasoning is that all sleeps should be interruptible where
> reasonably possible, because it increases the chance of being able to
> recover in a semi-controlled fashion from a big deadlock or other
> similar situation. This is particularly true of locks that might be
> held during I/Os that might go off and never come back, and also
> particularly true of locks that are manipulated by bodgy code that has
> a record of causing trouble. Both these cases apply to vnode locks.
> Meanwhile, the worst case for recovery is rename, and I've just been
> over that code and I don't anticipate serious problems.
> 
> Your turn :-)
> 
> -- 
> David A. Holland
> dholland%netbsd.org@localhost

- what making troubles in your examples are I/Os which never come back
 and bodgy code.  they should be fixed instead of locks.

- interruptible locks are actually harder to manipulate correctly,
 esp. for bodgy code. :)

YAMAMOTO Takashi