Subject: Re: FreeBSD's /dev on NetBSD
To: None <email@example.com>
From: Hans Petter Selasky <firstname.lastname@example.org>
Date: 08/14/2005 00:09:59
On Saturday 13 August 2005 21:29, Nathan J. Williams wrote:
> Hans Petter Selasky <email@example.com> writes:
> > Maybe I am a little too quick to say this, but doesn't the whole USB
> > system just use splnet/splx to protect data structures? On a
> > multiprocessor system, isn't things going to crash after a while, hence
> > more than one CPU can enter into the code that is protected by
> > splnet/splx ? So actually it is time they implement mutexes in NetBSD
> > too?
> NetBSD's SMP kernel is under a big-lock, so this isn't a problem for
> the time being.
This almost sounds like the Giant lock on FreeBSD. But then, actually
splnet/splx and simple_lock/simple_unlock does not have any effect at all?
What happens on NetBSD if a process calls "tsleep()" while holding a
simple_lock()? Is there any code to do extra checking like on FreeBSD ?
I've heard that NetBSD is very against mutexes. Is this true? Will NetBSD
always use one lock for the whole kernel?