Re: would a mutex_wait be useful?

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

Matt Thomas <matt%3am-software.com@localhost> wrote:
> > Where/when do you need interruptible mutex?
> 
> I was replacing code in arm32/mem.c with a home grown lock with  
> mutex_enter.
> Relatively easy to do except it no longer does PCATCH.

I agree with Antti that code asks for condvar(9), at least.

> > That does not sound like a good API. If specific synchronisation is  
> > needed,
> > I think wrappers with mutex_tryenter() could be used for that.
> 
> Not easily.  And rolling your own seems wrong.  Hence the proposal  
> for a common method to do it.

Why wrong? If somebody holds your mutex for a long time, then it is not
MP-friendly and needs fixing/improving. In a case of coarse-grained locking,
long holds and contention are expected, and wrappers might have a use here.

-- 
Best regards,
Mindaugas