Re: [PATCH v14 040/138] mm/memcg: Convert mem_cgroup_charge() to take a folio

Vlastimil Babka
2021-08-11T10:54:12Z

On 7/15/21 5:35 AM, Matthew Wilcox (Oracle) wrote:
> Convert all callers of mem_cgroup_charge() to call page_folio() on the
> page they're currently passing in. Many of them will be converted to
> use folios themselves soon.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> Reviewed-by: Christoph Hellwig <hch@lst.de>

Acked-by: Vlastimil Babka <vbabka@suse.cz>

> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index c2ffad021e09..03283d97b62a 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -6681,10 +6681,9 @@ void mem_cgroup_calculate_protection(struct mem_cgroup *root,
> atomic_long_read(&parent->memory.children_low_usage)));
> }
>
> -static int __mem_cgroup_charge(struct page *page, struct mem_cgroup *memcg,
> +static int __mem_cgroup_charge(struct folio *folio, struct mem_cgroup *memcg,
> gfp_t gfp)

The git/next version also renames this function to charge_memcg(), why? The new
name doesn't look that internal as the old one. I don't have a strong opinion
but CCing memcg maintainers who might.

> {
> - struct folio *folio = page_folio(page);
> unsigned int nr_pages = folio_nr_pages(folio);
> int ret;
>
> @@ -6697,27 +6696,27 @@ static int __mem_cgroup_charge(struct page *page, struct mem_cgroup *memcg,
>
> local_irq_disable();
> mem_cgroup_charge_statistics(memcg, nr_pages);
> - memcg_check_events(memcg, page_to_nid(page));
> + memcg_check_events(memcg, folio_nid(folio));
> local_irq_enable();
> out:
> return ret;
> }
>