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

Suren Baghdasaryan
2021-09-06T16:56:28Z

On Mon, Sep 6, 2021 at 5:13 AM Matthew Wilcox <willy@infradead.org> wrote:
>
> 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?

If dropping my patch (1f4c6a1cf274 ("mm, memcg: inline
mem_cgroup_{charge/uncharge} to improve disabled memcg config")) helps
in resolving this, feel free to do that and I'll redo it after folios
are merged.
Thanks,
Suren.