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

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().