Re: [PATCH v2 1/2] mm/memcontrol: add dmem charge/uncharge functions

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

On Tue, May 19, 2026 at 11:59:01AM -0400, Eric Chanudet wrote:
> Add mem_cgroup_dmem_charge() and mem_cgroup_dmem_uncharge() to allow
> dmem pool allocations to optionally be double-charged against the memory
> controller. Take the struct cgroup from the dmem pool's css as there is
> no convenient object exported to represent these allocations. These will
> resolve the effective memory css from that cgroup and perform the
> charge.
> 
> Introduce a MEMCG_DMEM stat counter to memory.stat to make the cgroup's
> dmem charge visible.
> 
> Signed-off-by: Eric Chanudet <echanude@redhat.com>
> ---
>  include/linux/memcontrol.h | 16 ++++++++++++
>  mm/memcontrol.c            | 65 ++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 81 insertions(+)
> 
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index dc3fa687759b45748b2acee6d7f43da325eb50c1..8e1d49b87fb64e6114f3eb920293e14920290fe7 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -39,6 +39,7 @@ enum memcg_stat_item {
>  	MEMCG_ZSWAP_B,
>  	MEMCG_ZSWAPPED,
>  	MEMCG_ZSWAP_INCOMP,
> +	MEMCG_DMEM,
>  	MEMCG_NR_STAT,
>  };
>  
> @@ -1872,6 +1873,21 @@ static inline bool mem_cgroup_zswap_writeback_enabled(struct mem_cgroup *memcg)
>  }
>  #endif
>  
> +#if defined(CONFIG_MEMCG) && defined(CONFIG_CGROUP_DMEM)
> +bool mem_cgroup_dmem_charge(struct cgroup *cgrp, unsigned int nr_pages,
> +			    gfp_t gfp_mask);
> +void mem_cgroup_dmem_uncharge(struct cgroup *cgrp, unsigned int nr_pages);
> +#else
> +static inline bool mem_cgroup_dmem_charge(struct cgroup *cgrp,
> +					  unsigned int nr_pages, gfp_t gfp_mask)

Please follow Johannes's request to pass the actually memory object instead of
naked numbers.