Re: [PATCH 2/2] Arm32: tidy the memset() macro

[Julien Grall <julien@xxxxxxx>]

Hi Jan,

On 19/08/2022 09:11, Jan Beulich wrote:
> On 19.08.2022 10:06, Julien Grall wrote:
> > On 19/08/2022 09:02, Jan Beulich wrote:
> > > On 19.08.2022 09:58, Julien Grall wrote:
> > > > On 19/08/2022 08:50, Jan Beulich wrote:
> > > > > - add parentheses where they were missing (MISRA)
> > > > > - make sure to evaluate also v exactly once (MISRA)
> > > > > - remove excess parentheses
> > > > > - rename local variables to not have leading underscores
> > > > > - apply Xen coding style
> > > > This code has been taken from Linux. From you write above, I don't see
> > > > any strong reason for us to modify it (even if it is small).
> > > At least the MISRA issues want addressing, I suppose. Plus I wasn't
> > > able to spot the macro in Linux anymore (nor __memzero()), so to me
> > > there seemed to be little point to consider keeping anything "in sync"
> > > here.
> > I read the last part as we want a re-sync of the code (we haven't done
> > one in the past couple of years).
> I'm afraid I'm now really confused: Which last part? I don't see how
> any of what I have said could be read that way. Quite the opposite:
> By stating that Linux doesn't have this macro anymore, isn't it quite
> clear that there's nothing to re-sync against?
Your view here if we will never re-sync the code. This is incorrect, we 
still want to keep it close so we can benefit from improvement in the 
Linux code. So if you start tweaking the code just for coding style 
purpose, it will just make it more difficult for us (I appreciate this 
is limited here).
In this case, Linux has removed __memzero() is patch ff5fdafc9e97 "ARM: 
8745/1: get rid of __memzero()" because the performance difference with 
memset() was limited. For Xen, I think we should also remove the function.
With that, this patch becomes pointless.

Cheers,

--
Julien Grall