Re: [PATCH 1/2] pci: Block config access during BIST (resend)

Grant Grundler
2005-09-07T14:52:22Z

On Wed, Sep 07, 2005 at 03:49:37PM +1000, Paul Mackerras wrote:
> Maybe, but it seems like a bad idea to me. It's longer, it's less
> obvious what's happening,

I would argue it more obvious. People looking at the code
are immediately going to realize it was a deliberate choice to
not use a spinlock.

> and it precludes the sorts of optimization
> that we do on ppc64 where a cpu that is waiting for a lock can tell
> give its time slice to the cpu that is holding the lock (on systems
> where the hypervisor time-slices multiple virtual cpus on one physical
> cpu).

relax_cpu() doesn't do that?

> What's wrong with just doing spin_lock/spin_unlock?

it's not wrong - just misleading IMHO. There is no
"critical section" in that particular chunk of code.

If relax_cpu doesn't allow time-slice donation, then I guess
spinlock/unlock with only a comment inside it explain why
would be ok too.

thanks,
grant