RE: [PATCH 1/4][Xen-devel] X86 microcode: cancel redundant input parameter of microcode functions

Liu, Jinsong
2009-01-22T10:54:15Z

Christoph Egger wrote:
> On Thursday 22 January 2009 04:08:21 Liu, Jinsong wrote:
>> X86 microcode: cancel redundant input parameter of microcode
>> functions
>>
>> Cancel redundant input parameter ''uci'', since it can
get from
>> another input parameter ''cpu'' as index.
>>
>> Signed-off-by: Liu, Jinsong <jinsong.liu@intel.com>
>
> I added the parameter ''uci'' to reduce dependency on a
global variable.
> That improves reentrancy and cache locality.
>
> If you want to go a step forward rather back, then remove the
''cpu''
> parameter instead.
>
> Christoph

I think the input parameter ''cpu'' is better than
''uci'' since ''cpu'' is much clear to developer
with explicit meaning, so between the 2 redundant parameters
''uci'' and ''cpu'', we should remove
''uci'', just like what native linux microcode functions do.

As for cache locality, it''s not important for microcode functions since
it''s not in key path, seldom be called. BTW, we''d better keep
consistent with native linux code for the sake of futher porting and upgrade,
you know, the latest linux kernel (2.6.28) still has some issues for microcode
...

Thanks,
Jinsong