Re: [RFC PATCH 05/14] memcg: Add mem_cgroup_uncharge_folios()

[Ryan Roberts <ryan.roberts@arm.com>]

On 25/08/2023 14:59, Matthew Wilcox (Oracle) wrote:
> Almost identical to mem_cgroup_uncharge_list(), except it takes a
> folio_batch instead of a list_head.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>

> ---
>  include/linux/memcontrol.h | 12 ++++++++++++
>  mm/memcontrol.c            | 13 +++++++++++++
>  2 files changed, 25 insertions(+)
> 
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index ab94ad4597d0..d0caeb1c1136 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -713,6 +713,14 @@ static inline void mem_cgroup_uncharge_list(struct list_head *page_list)
>  	__mem_cgroup_uncharge_list(page_list);
>  }
>  
> +void __mem_cgroup_uncharge_folios(struct folio_batch *folios);
> +static inline void mem_cgroup_uncharge_folios(struct folio_batch *folios)
> +{
> +	if (mem_cgroup_disabled())
> +		return;
> +	__mem_cgroup_uncharge_folios(folios);
> +}
> +
>  void mem_cgroup_migrate(struct folio *old, struct folio *new);
>  
>  /**
> @@ -1273,6 +1281,10 @@ static inline void mem_cgroup_uncharge_list(struct list_head *page_list)
>  {
>  }
>  
> +static inline void mem_cgroup_uncharge_folios(struct folio_batch *folios)
> +{
> +}
> +
>  static inline void mem_cgroup_migrate(struct folio *old, struct folio *new)
>  {
>  }
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 26ba9d1a66d1..a0fb008afa23 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -33,6 +33,7 @@
>  #include <linux/shmem_fs.h>
>  #include <linux/hugetlb.h>
>  #include <linux/pagemap.h>
> +#include <linux/pagevec.h>
>  #include <linux/vm_event_item.h>
>  #include <linux/smp.h>
>  #include <linux/page-flags.h>
> @@ -7190,6 +7191,18 @@ void __mem_cgroup_uncharge_list(struct list_head *page_list)
>  		uncharge_batch(&ug);
>  }
>  
> +void __mem_cgroup_uncharge_folios(struct folio_batch *folios)
> +{
> +	struct uncharge_gather ug;
> +	unsigned int i;
> +
> +	uncharge_gather_clear(&ug);
> +	for (i = 0; i < folios->nr; i++)
> +		uncharge_folio(folios->folios[i], &ug);
> +	if (ug.memcg)
> +		uncharge_batch(&ug);
> +}
> +
>  /**
>   * mem_cgroup_migrate - Charge a folio's replacement.
>   * @old: Currently circulating folio.