Re: linux-next: manual merge of the akpm-current tree with the folio tree

Matthew Wilcox
2021-09-07T13:50:23Z

On Mon, Sep 06, 2021 at 02:48:07PM +1000, Stephen Rothwell wrote:
> Hi all,
>
> On Wed, 21 Jul 2021 16:31:18 +1000 Stephen Rothwell <sfr@canb.auug.org.au> wrote:
> >
> > Today's linux-next merge of the akpm-current tree got conflicts in:
> >
> > include/linux/memcontrol.h
> > mm/memcontrol.c
> >
> > between commits:
> >
> > 05bb7bbab428 ("mm/memcg: Convert mem_cgroup_charge() to take a folio")
> > 8b2afb6a1c34 ("mm/memcg: Convert mem_cgroup_uncharge() to take a folio")
> >
> > from the folio tree and commit:
> >
> > 1f4c6a1cf274 ("mm, memcg: inline mem_cgroup_{charge/uncharge} to improve disabled memcg config")
> >
> > from the akpm-current tree.
> >
> > I fixed it up (see below) and can carry the fix as necessary. This
> > is now fixed as far as linux-next is concerned, but any non trivial
> > conflicts should be mentioned to your upstream maintainer when your tree
> > is submitted for merging. You may also want to consider cooperating
> > with the maintainer of the conflicting tree to minimise any particularly
> > complex conflicts.
> >
> > diff --cc include/linux/memcontrol.h
> > index af9c44bb1e42,406058a0c480..000000000000
> > --- a/include/linux/memcontrol.h
> > +++ b/include/linux/memcontrol.h
> > @@@ -704,15 -691,37 +702,36 @@@ static inline bool mem_cgroup_below_min
> > page_counter_read(&memcg->memory);
> > }
> >
> > - int mem_cgroup_charge(struct folio *folio, struct mm_struct *mm, gfp_t gfp);
> > -int __mem_cgroup_charge(struct page *page, struct mm_struct *mm,
> > - gfp_t gfp_mask);
> > -static inline int mem_cgroup_charge(struct page *page, struct mm_struct *mm,
> > - gfp_t gfp_mask)
> > ++int __mem_cgroup_charge(struct folio *folio, struct mm_struct *mm, gfp_t gfp);
> > ++static inline int mem_cgroup_charge(struct folio *folio, struct mm_struct *mm,
> > ++ gfp_t gfp)
> > + {
> > + if (mem_cgroup_disabled())
> > + return 0;
> > - return __mem_cgroup_charge(page, mm, gfp_mask);
> > ++ return __mem_cgroup_charge(folio, mm, gfp);
> > + }
> > +
> > int mem_cgroup_swapin_charge_page(struct page *page, struct mm_struct *mm,
> > gfp_t gfp, swp_entry_t entry);
> > void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry);
> >
> > - void mem_cgroup_uncharge(struct folio *folio);
> > - void mem_cgroup_uncharge_list(struct list_head *page_list);
> > -void __mem_cgroup_uncharge(struct page *page);
> > -static inline void mem_cgroup_uncharge(struct page *page)
> > ++void __mem_cgroup_uncharge(struct folio *folio);
> > ++static inline void mem_cgroup_uncharge(struct folio *folio)
> > + {
> > + if (mem_cgroup_disabled())
> > + return;
> > - __mem_cgroup_uncharge(page);
> > ++ __mem_cgroup_uncharge(folio);
> > + }
> > +
> > + void __mem_cgroup_uncharge_list(struct list_head *page_list);
> > + static inline void mem_cgroup_uncharge_list(struct list_head *page_list)
> > + {
> > + if (mem_cgroup_disabled())
> > + return;
> > + __mem_cgroup_uncharge_list(page_list);
> > + }
> >
> > -void mem_cgroup_migrate(struct page *oldpage, struct page *newpage);
> > +void mem_cgroup_migrate(struct folio *old, struct folio *new);
> >
> > /**
> > * mem_cgroup_lruvec - get the lru list vector for a memcg & node
> > diff --cc mm/memcontrol.c
> > index 1d77c873463c,c010164172dd..000000000000
> > --- a/mm/memcontrol.c
> > +++ b/mm/memcontrol.c
> > @@@ -6712,29 -6718,27 +6708,26 @@@ out
> > }
> >
> > /**
> > - * mem_cgroup_charge - Charge a newly allocated folio to a cgroup.
> > - * __mem_cgroup_charge - charge a newly allocated page to a cgroup
> > - * @page: page to charge
> > - * @mm: mm context of the victim
> > - * @gfp_mask: reclaim mode
> > ++ * __mem_cgroup_charge - Charge a newly allocated folio to a cgroup.
> > + * @folio: Folio to charge.
> > + * @mm: mm context of the allocating task.
> > + * @gfp: Reclaim mode.
> > *
> > - * Try to charge @page to the memcg that @mm belongs to, reclaiming
> > - * pages according to @gfp_mask if necessary. if @mm is NULL, try to
> > + * Try to charge @folio to the memcg that @mm belongs to, reclaiming
> > + * pages according to @gfp if necessary. If @mm is NULL, try to
> > * charge to the active memcg.
> > *
> > - * Do not use this for pages allocated for swapin.
> > + * Do not use this for folios allocated for swapin.
> > *
> > - * Returns 0 on success. Otherwise, an error code is returned.
> > + * Return: 0 on success. Otherwise, an error code is returned.
> > */
> > - int mem_cgroup_charge(struct folio *folio, struct mm_struct *mm, gfp_t gfp)
> > -int __mem_cgroup_charge(struct page *page, struct mm_struct *mm,
> > - gfp_t gfp_mask)
> > ++int __mem_cgroup_charge(struct folio *folio, struct mm_struct *mm, gfp_t gfp)
> > {
> > struct mem_cgroup *memcg;
> > int ret;
> >
> > - if (mem_cgroup_disabled())
> > - return 0;
> > -
> > memcg = get_mem_cgroup_from_mm(mm);
> > - ret = charge_memcg(page, memcg, gfp_mask);
> > + ret = charge_memcg(folio, memcg, gfp);
> > css_put(&memcg->css);
> >
> > return ret;
> > @@@ -6906,20 -6909,17 +6899,17 @@@ static void uncharge_folio(struct foli
> > }
> >
> > /**
> > - * mem_cgroup_uncharge - Uncharge a folio.
> > - * __mem_cgroup_uncharge - uncharge a page
> > - * @page: page to uncharge
> > ++ * __mem_cgroup_uncharge - Uncharge a folio.
> > + * @folio: Folio to uncharge.
> > *
> > - * Uncharge a page previously charged with __mem_cgroup_charge().
> > + * Uncharge a folio previously charged with mem_cgroup_charge().
> > */
> > - void mem_cgroup_uncharge(struct folio *folio)
> > -void __mem_cgroup_uncharge(struct page *page)
> > ++void __mem_cgroup_uncharge(struct folio *folio)
> > {
> > struct uncharge_gather ug;
> >
> > - if (mem_cgroup_disabled())
> > - return;
> > -
> > - /* Don't touch page->lru of any random page, pre-check: */
> > - if (!page_memcg(page))
> > + /* Don't touch folio->lru of any random page, pre-check: */
> > + if (!folio_memcg(folio))
> > return;
> >
> > uncharge_gather_clear(&ug);
> > @@@ -6932,19 -6932,16 +6922,16 @@@
> > * @page_list: list of pages to uncharge
> > *
> > * Uncharge a list of pages previously charged with
> > - * mem_cgroup_charge().
> > + * __mem_cgroup_charge().
> > */
> > - void mem_cgroup_uncharge_list(struct list_head *page_list)
> > + void __mem_cgroup_uncharge_list(struct list_head *page_list)
> > {
> > struct uncharge_gather ug;
> > - struct page *page;
> > + struct folio *folio;
> >
> > - if (mem_cgroup_disabled())
> > - return;
> > -
> > uncharge_gather_clear(&ug);
> > - list_for_each_entry(page, page_list, lru)
> > - uncharge_page(page, &ug);
> > + list_for_each_entry(folio, page_list, lru)
> > + uncharge_folio(folio, &ug);
> > if (ug.memcg)
> > uncharge_batch(&ug);
> > }
>
> This is now a conflict between the folio tree and Linus' tree.

Quite. Linus, how do you want to handle this? Pull the folio-5.15 tag
I originally sent you? Pull the pageset-5.15 tag? Tell me you'll never
accept this and drop the entire idea?

Do you need anything from me?