Re: [PATCH 08/13] drm/xe/sa: Allow creating suballocator with custom guard size

[Michal Wajdeczko <michal.wajdeczko@intel.com>]

On 12.12.2024 04:23, Matthew Brost wrote:
> On Thu, Dec 12, 2024 at 02:01:36AM +0100, Michal Wajdeczko wrote:

...

>>  
>> +static inline struct xe_sa_manager *xe_sa_bo_manager_init(struct xe_tile *tile, u32 size, u32 align)
>> +{
>> +	return __xe_sa_bo_manager_init(tile, size, SZ_4K, align);
> 
> So why is this guard needed? I'm reasoning this was for CS prefetches
> but all current uses of the SA (xe_bb.c) do suballocations with CS
> prefetch padding. We likely don't need to do this in both places.
> 
> I'd say drop prefetch padding from xe_bb.c and move the prefetch
> calculation size to here.
> 
> Can be done in a follow up but before RBing let's make sure we
> understand exactly why this is needed and develop a follow up plan as
> the code as is doesn't look right / necessary.
> 

since none of SA functions were documented, same with BB code, I just
wanted to preserve existing usage without going too deep into a "why"

to get right answers we need original author(s), but since code was part
of the initial submission, I can't tell who is it