Re: [PATCH EDAC 07/13] edac: add support for raw error reports

[Mauro Carvalho Chehab <mchehab@redhat.com>]

Em Fri, 15 Feb 2013 16:41:23 +0100
Borislav Petkov <bp@alien8.de> escreveu:

> On Fri, Feb 15, 2013 at 01:25:30PM -0200, Mauro Carvalho Chehab wrote:
> > Well, for sure using an structure will help to avoid missing a
> > parameter or exchanging its order. The stack usage won't reduce,
> > though, because the structure will keep using the stack.
> 
> If you allocate it on the stack of the caller, yes. If you kmalloc it,
> no.

Sure, but calling kmalloc while handling a memory error doesn't seem
a very good idea, IMHO. So, better to either use an already allocated
space (or the stack).
> 
> In any case, passing a pointer to struct edac_raw_error_desc only will
> allow on x86_64 (and i386 AFAICT) to use only registers to pass callee
> function arguments. Which is always a win. You probably need to stare at
> compiler output to see what gcc actually does with -O2 optimizations.

Yes, I know, but, on the other hand, there's the additional cost of
copying almost all data into the structure.

> > As I can't foresee the usage of this function call outside the core
> > and by the GHES driver, I'm not sure what would be the better.
> 
> Having an error descriptor is always better, even if it were only for
> clarity's and simplicity's sake.

Yes, the code is now clearer.

Ok, I'll keep this patch on my git. I'll likely fold it with the previous 
one on the final patchset.

-- 

Cheers,
Mauro