Re: [PATCH v2 1/2] mm: memcontrol: use memcg_kmem_enabled in count_objcg_event

[Muchun Song <muchun.song-fxUVXftIFDnyG1zEObXtfA@public.gmane.org>]

> On Sep 20, 2022, at 02:06, Kairui Song <ryncsn-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> 
> From: Kairui Song <kasong-1Nz4purKYjRBDgjK7y7TUQ@public.gmane.org>
> 
> There are currently two helpers for checking if cgroup kmem
> accounting is enabled:
> 
> - mem_cgroup_kmem_disabled
> - memcg_kmem_enabled
> 
> mem_cgroup_kmem_disabled is a simple helper that returns true
> if cgroup.memory=nokmem is specified, otherwise returns false.
> 
> memcg_kmem_enabled is a bit different, it returns true if
> cgroup.memory=nokmem is not specified and there was at least one
> non-root memory control enabled cgroup ever created. This help improve
> performance when kmem accounting was not actually activated. And it's
> optimized with static branch.
> 
> The usage of mem_cgroup_kmem_disabled is for sub-systems that need to
> preallocate data for kmem accounting since they could be initialized
> before kmem accounting is activated. But count_objcg_event doesn't
> need that, so using memcg_kmem_enabled is better here.
> 
> Signed-off-by: Kairui Song <kasong-1Nz4purKYjRBDgjK7y7TUQ@public.gmane.org>

Acked-by: Muchun Song <songmuchun-EC8Uxl6Npydl57MIdRCFDg@public.gmane.org>

Thanks.