Re: [PATCH v6 32/33] mm: memcontrol: eliminate the problem of dying memory cgroup for LRU folios

[Joshua Hahn]

On Thu,  5 Mar 2026 19:52:50 +0800 Qi Zheng <qi.zheng@xxxxxxxxx> wrote:

> From: Muchun Song <songmuchun@xxxxxxxxxxxxx>
> 
> Now that everything is set up, switch folio->memcg_data pointers to
> objcgs, update the accessors, and execute reparenting on cgroup death.
> 
> Finally, folio->memcg_data of LRU folios and kmem folios will always
> point to an object cgroup pointer. The folio->memcg_data of slab
> folios will point to an vector of object cgroups.
> 
> Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
> Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
> Acked-by: Shakeel Butt <shakeel.butt@xxxxxxxxx>
> ---

Hello Qi, thank you for this series!

>  static void memcg_online_kmem(struct mem_cgroup *memcg)
> @@ -4949,16 +4985,20 @@ void mem_cgroup_calculate_protection(struct mem_cgroup *root,
>  static int charge_memcg(struct folio *folio, struct mem_cgroup *memcg,
>  			gfp_t gfp)
>  {
> -	int ret;
> -
> -	ret = try_charge(memcg, gfp, folio_nr_pages(folio));

While developing on top of mm-new I found that this was the last caller of
try_charge(). I was thinking that it might be a nice opportunity to just
remove the definition of try_charge() as well, maybe as a clean up patch
at the end of the series.

I see there are many acks on the entire series as well, and I don't think
it is worth doing a new version just for this. But if you are planning on
submitting a new version, I hope that you can consider this.

Thank you! Have a great day : -)
Joshua