Re: mutexes, locks and so on...

[Johnny Billquist <bqt%softjar.se@localhost>]

On 11/14/10 20:16, David Holland wrote:
> On Sat, Nov 13, 2010 at 01:45:40AM +0900, Izumi Tsutsui wrote:
>   >  >  Wow. I guess you can add me to the list of people leaving.
>   >
>   >  There is no perfect world and we don't have enough resources.
>   >
>   >  Any help to keep support for ancient machines are appreciate, but
>   >  complaints like "we should support it" which prevents improvements
>   >  of mainstream will just make NetBSD rotten.
>
> What "prevents improvements of mainstream" are we talking about here?
> We have someone who wants to provide tuned vax-specific locking
> primitives. The absolute worst possible cost to the "mainstream" that
> this incurs is a bit of extra cpp and config hackery.
>
> (Can we all please get a grip?)

Yes, please.

And... Wow, just for my seaching for a spin mutex lock against myself at 
boot time, I started counting the number of times the uvm_fpageqlock 
spin mutex is taken. By the time the
"boot device: xxx" is printed out, that spin-mutex have been taken 
423137 times.

That looked like a big number to me atleast. (And yes, it is that mutex 
that is taken twice, which traps me right now. Still looking at why it 
happens, but I know that the "normal" code does not in fact check for 
this condition, and happily just accept that you take a spin-lock that 
is already taken, when you're not multiprocessor.)

        Johnny