Re: [PATCH 13/17] ttm/pool: enable memcg tracking and shrinker.

[Shakeel Butt <shakeel.butt@linux.dev>]

On Mon, Jun 30, 2025 at 02:49:32PM +1000, Dave Airlie wrote:
> From: Dave Airlie <airlied@redhat.com>
> 
> This enables all the backend code to use the list lru in memcg mode,
> and set the shrinker to be memcg aware.
> 
> It adds the loop case for when pooled pages end up being reparented
> to a higher memcg group, that newer memcg can search for them there
> and take them back.
> 
> Signed-off-by: Dave Airlie <airlied@redhat.com>
> ---
>  drivers/gpu/drm/ttm/ttm_pool.c | 123 ++++++++++++++++++++++++++++-----
>  1 file changed, 105 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/gpu/drm/ttm/ttm_pool.c b/drivers/gpu/drm/ttm/ttm_pool.c
> index 210f4ac4de67..49e92f40ab23 100644
> --- a/drivers/gpu/drm/ttm/ttm_pool.c
> +++ b/drivers/gpu/drm/ttm/ttm_pool.c
> @@ -143,7 +143,9 @@ static int ttm_pool_nid(struct ttm_pool *pool) {
>  }
>  
>  /* Allocate pages of size 1 << order with the given gfp_flags */
> -static struct page *ttm_pool_alloc_page(struct ttm_pool *pool, gfp_t gfp_flags,
> +static struct page *ttm_pool_alloc_page(struct ttm_pool *pool,
> +					struct obj_cgroup *objcg,
> +					gfp_t gfp_flags,
>  					unsigned int order)
>  {
>  	unsigned long attr = DMA_ATTR_FORCE_CONTIGUOUS;
> @@ -163,6 +165,10 @@ static struct page *ttm_pool_alloc_page(struct ttm_pool *pool, gfp_t gfp_flags,
>  		p = alloc_pages_node(pool->nid, gfp_flags, order);

Here I am wondering if we should introduce something like
__GFP_ACCOUNT_NOKMEM to avoid kmem counters but still charge to the
memcg and along with set_active_memcg(), we can avoid introducing gpu
specific memcg charging interfaces.