Re: [PATCH 1/2] i386: mce cleanup part1: functional change

Joerg Roedel
2007-10-09T17:28:17Z

On Tue, Oct 09, 2007 at 06:32:30PM +0200, Oleg Verych wrote:
> On Tue, Oct 09, 2007 at 06:06:05PM +0200, Joerg Roedel wrote:
> > > cpu_has() returns int,
> > > but would it be better to have something like
> > >
> > > if (!mce_disabled &&
> > > !(c->x86_capability & (X86_FEATURE_MCA | X86_FEATURE_MCE)) {
> > > printk(KERN_INFO "CPU%i: No machine check support available\n",
> > > smp_processor_id());
> >
> > This looks complicated and is harder to read. Its exactly the purpose of the
> > cpu_has() macro to avoid such constructs.
>
> It is done via test_bit(), which is designed for IO access with all that
> `const volatile' stuff, 2 x unnecessary, can't be optimized here (IMHO).

This code runs only on bootup and once per cpu. I think readable code
is more important here than make it a few cycles faster.

--
| AMD Saxony Limited Liability Company & Co. KG
Operating | Wilschdorfer Landstr. 101, 01109 Dresden, Germany
System | Register Court Dresden: HRA 4896
Research | General Partner authorized to represent:
Center | AMD Saxony LLC (Wilmington, Delaware, US)
| General Manager of AMD Saxony LLC: Dr. Hans-R. Deppe, Thomas McCoy