[PATCH 08/17] memcg: add support for GPU page counters.

[Shakeel Butt]

On Mon, Jun 30, 2025 at 02:49:27PM +1000, Dave Airlie wrote:
> From: Dave Airlie <airlied at redhat.com>
> 
> This introduces 2 new statistics and 3 new memcontrol APIs for dealing
> with GPU system memory allocations.
> 
> The stats corresponds to the same stats in the global vmstat,
> for number of active GPU pages, and number of pages in pools that
> can be reclaimed.
> 
> The first API charges a order of pages to a objcg, and sets
> the objcg on the pages like kmem does, and updates the active/reclaim
> statistic.
> 
> The second API uncharges a page from the obj cgroup it is currently charged
> to.
> 
> The third API allows moving a page to/from reclaim and between obj cgroups.
> When pages are added to the pool lru, this just updates accounting.
> When pages are being removed from a pool lru, they can be taken from
> the parent objcg so this allows them to be uncharged from there and transferred
> to a new child objcg.
> 
> Signed-off-by: Dave Airlie <airlied at redhat.com>
> ---
>  Documentation/admin-guide/cgroup-v2.rst |   6 ++
>  include/linux/memcontrol.h              |  14 +++
>  mm/memcontrol.c                         | 110 ++++++++++++++++++++++++
>  3 files changed, 130 insertions(+)
> 
> diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
> index 0cc35a14afbe..d6f057c4fe2e 100644
> --- a/Documentation/admin-guide/cgroup-v2.rst
> +++ b/Documentation/admin-guide/cgroup-v2.rst
> @@ -1542,6 +1542,12 @@ The following nested keys are defined.
>  	  vmalloc (npn)
>  		Amount of memory used for vmap backed memory.
>  
> +	  gpu (npn)
> +		Amount of system memory used for GPU devices.
> +
> +	  gpu_reclaim (npn)
> +		Amount of system memory cached for GPU devices.
> +
>  	  shmem
>  		Amount of cached filesystem data that is swap-backed,
>  		such as tmpfs, shm segments, shared anonymous mmap()s
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index 87b6688f124a..ff82d603910d 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -36,6 +36,8 @@ enum memcg_stat_item {
>  	MEMCG_SOCK,
>  	MEMCG_PERCPU_B,
>  	MEMCG_VMALLOC,
> +	MEMCG_GPU,
> +	MEMCG_GPU_RECLAIM,

You already added node level counters i.e. GPUActive & GPUReclaim, just
use those instead of these. Add them to memcg_node_stat_items[].