[PATCH 4/6] drm/radeon: add buffers to the LRU list from smallest to largest

[Marek Olšák]

Only the VMWare driver uses ttm_eu_fence_buffer_objects. Cc'ing
Thomas. What do you think about this, Thomas?

Marek

On Thu, Feb 27, 2014 at 2:22 AM, Michel Dänzer <michel at daenzer.net> wrote:
> On Mit, 2014-02-26 at 19:25 +0100, Marek Olšák wrote:
>>
>> diff --git a/drivers/gpu/drm/radeon/radeon_cs.c b/drivers/gpu/drm/radeon/radeon_cs.c
>> index f28a8d8..d49a3f7 100644
>> --- a/drivers/gpu/drm/radeon/radeon_cs.c
>> +++ b/drivers/gpu/drm/radeon/radeon_cs.c
>> [...]
>> @@ -303,6 +314,18 @@ static void radeon_cs_parser_fini(struct radeon_cs_parser *parser, int error, bo
>>       unsigned i;
>>
>>       if (!error) {
>> +             /* Sort the buffer list from the smallest to largest buffer,
>> +              * which affects the order of buffers in the LRU list.
>> +              * This assures that the smallest buffers are added first
>> +              * to the LRU list, so they are likely to be later evicted
>> +              * first, instead of large buffers whose eviction is more
>> +              * expensive.
>> +              *
>> +              * This slightly lowers the number of bytes moved by TTM
>> +              * per frame under memory pressure.
>> +              */
>> +             list_sort(NULL, &parser->validated, cmp_size_smaller_first);
>> +
>>               ttm_eu_fence_buffer_objects(&parser->ticket,
>>                                           &parser->validated,
>>                                           parser->ib.fence);
>
> This seems like a good idea in general, so maybe it should be done in
> ttm_eu_fence_buffer_objects() instead, and possibly also in the callers
> of ttm_eu_backoff_reservation_locked().
>
>
> --
> Earthling Michel Dänzer            |                  http://www.amd.com
> Libre software enthusiast          |                Mesa and X developer
>