Re: [PATCH] mm: memcontrol: remove page_memcg()

[Michal Hocko <mhocko@suse.com>]

On Tue 21-05-24 15:44:21, Matthew Wilcox wrote:
> On Tue, May 21, 2024 at 09:15:56PM +0800, Kefeng Wang wrote:
> > The page_memcg() only called by mod_memcg_page_state(), so squash it to
> > cleanup page_memcg().
> 
> This isn't wrong, except that the entire usage of memcg is wrong in the
> only two callers of mod_memcg_page_state():
> 
> $ git grep mod_memcg_page_state
> include/linux/memcontrol.h:static inline void mod_memcg_page_state(struct page *page,
> include/linux/memcontrol.h:static inline void mod_memcg_page_state(struct page *page,
> mm/vmalloc.c:           mod_memcg_page_state(page, MEMCG_VMALLOC, -1);
> mm/vmalloc.c:                   mod_memcg_page_state(area->pages[i], MEMCG_VMALLOC, 1);
> 
> The memcg should not be attached to the individual pages that make up a
> vmalloc allocation.  Rather, it should be managed by the vmalloc
> allocation itself.  I don't have the knowledge to poke around inside
> vmalloc right now, but maybe somebody else could take that on.

This would make sense as a follow up.

-- 
Michal Hocko
SUSE Labs