Re: [PATCH 1/6] drm/ttm: move the LRU into resource handling v4

[Daniel Vetter <daniel@ffwll.ch>]

On Mon, Mar 21, 2022 at 02:25:56PM +0100, Christian König wrote:
> This way we finally fix the problem that new resource are
> not immediately evict-able after allocation.
> 
> That has caused numerous problems including OOM on GDS handling
> and not being able to use TTM as general resource manager.
> 
> v2: stop assuming in ttm_resource_fini that res->bo is still valid.
> v3: cleanup kerneldoc, add more lockdep annotation
> v4: consistently use res->num_pages
> 
> Signed-off-by: Christian König <christian.koenig@amd.com>
> Tested-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>

> +/**
> + * struct ttm_lru_bulk_move
> + *
> + * @tt: first/last lru entry for resources in the TT domain
> + * @vram: first/last lru entry for resources in the VRAM domain
> + *
> + * Helper structure for bulk moves on the LRU list.
> + */
> +struct ttm_lru_bulk_move {
> +	struct ttm_lru_bulk_move_pos tt[TTM_MAX_BO_PRIORITY];
> +	struct ttm_lru_bulk_move_pos vram[TTM_MAX_BO_PRIORITY];

Not really needed, just a thought: Should we track the associated dma_resv
object here to make sure the locking is all done correctly (and also check
that the bulk move bo have the same dma_resv)? It wouldn't really be any
overhead for the !CONFIG_LOCKDEP case and we could sprinkle a lot more
dma_resv_held all over the place.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch