Re: [PATCH v2 3/9] mm/hugetlb_cgroup: convert set_hugetlb_cgroup*() to folios

[Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx>]

On 11/1/22 11:45 PM, Muchun Song wrote:
> > On Nov 2, 2022, at 06:30, Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx> wrote:
> >
> > Allows __prep_new_huge_page() to operate on a folio by converting
> > set_hugetlb_cgroup*() to take in a folio.
> >
> > Signed-off-by: Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx>
> > ---
> > include/linux/hugetlb_cgroup.h | 12 ++++++------
> > mm/hugetlb.c                   | 33 +++++++++++++++++++--------------
> > mm/hugetlb_cgroup.c            | 11 ++++++-----
> > 3 files changed, 31 insertions(+), 25 deletions(-)
> >
> > diff --git a/include/linux/hugetlb_cgroup.h b/include/linux/hugetlb_cgroup.h
> > index feb2edafc8b6..a7e3540f7f38 100644
> > --- a/include/linux/hugetlb_cgroup.h
> > +++ b/include/linux/hugetlb_cgroup.h
> > @@ -112,16 +112,16 @@ static inline void __set_hugetlb_cgroup(struct folio *folio,
> > (unsigned long)h_cg);
> > }
> >
> > -static inline void set_hugetlb_cgroup(struct page *page,
> > +static inline void set_hugetlb_cgroup(struct folio *folio,
> >      struct hugetlb_cgroup *h_cg)
> > {
> > - __set_hugetlb_cgroup(page_folio(page), h_cg, false);
> > + __set_hugetlb_cgroup(folio, h_cg, false);
> > }
> >
> > -static inline void set_hugetlb_cgroup_rsvd(struct page *page,
> > +static inline void set_hugetlb_cgroup_rsvd(struct folio *folio,
> >   struct hugetlb_cgroup *h_cg)
> > {
> > - __set_hugetlb_cgroup(page_folio(page), h_cg, true);
> > + __set_hugetlb_cgroup(folio, h_cg, true);
> > }
> >
> > static inline bool hugetlb_cgroup_disabled(void)
> > @@ -199,12 +199,12 @@ hugetlb_cgroup_from_folio_rsvd(struct folio *folio)
> > return NULL;
> > }
> >
> > -static inline void set_hugetlb_cgroup(struct page *page,
> > +static inline void set_hugetlb_cgroup(struct folio *folio,
> >      struct hugetlb_cgroup *h_cg)
> > {
> > }
> >
> > -static inline void set_hugetlb_cgroup_rsvd(struct page *page,
> > +static inline void set_hugetlb_cgroup_rsvd(struct folio *folio,
> >   struct hugetlb_cgroup *h_cg)
> > {
> > }
> > diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> > index 27b87dc85c48..a6384fb0b57f 100644
> > --- a/mm/hugetlb.c
> > +++ b/mm/hugetlb.c
> > @@ -1758,19 +1758,21 @@ static void __prep_account_new_huge_page(struct hstate *h, int nid)
> > h->nr_huge_pages_node[nid]++;
> > }
> >
> > -static void __prep_new_huge_page(struct hstate *h, struct page *page)
> > +static void __prep_new_hugetlb_folio(struct hstate *h, struct folio *folio)
> > {
> > - hugetlb_vmemmap_optimize(h, page);
> > - INIT_LIST_HEAD(&page->lru);
> > - set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
> > - hugetlb_set_page_subpool(page, NULL);
> > - set_hugetlb_cgroup(page, NULL);
> > - set_hugetlb_cgroup_rsvd(page, NULL);
> > + hugetlb_vmemmap_optimize(h, &folio->page);
> > + INIT_LIST_HEAD(&folio->lru);
> > + folio->_folio_dtor = HUGETLB_PAGE_DTOR;
> Seems like a variant of set_compound_page_dtor() for folio is missing,
> e.g. set_large_folio_dtor(). It's better to add it in this series.
>
> Thanks.

Hi Muchun thanks for taking a look,

Would it be ok to add this functionality in a separate patch series? 
Some of the earlier patches in this series were modified by Hugh's 
series[1] so I'm not sure how a v3 of this series would look now. Let me 
know which approach you would prefer.


Thanks,

Sidhartha Kumar

[1] 
https://lore.kernel.org/linux-mm/3818cc9a-9999-d064-d778-9c94c5911e6@xxxxxxxxxx/

> > + hugetlb_set_folio_subpool(folio, NULL);
> > + set_hugetlb_cgroup(folio, NULL);
> > + set_hugetlb_cgroup_rsvd(folio, NULL);
> > }
> >
> > static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
> > {
> > - __prep_new_huge_page(h, page);
> > + struct folio *folio = page_folio(page);
> > +
> > + __prep_new_hugetlb_folio(h, folio);
> > spin_lock_irq(&hugetlb_lock);
> > __prep_account_new_huge_page(h, nid);
> > spin_unlock_irq(&hugetlb_lock);
> > @@ -2731,8 +2733,10 @@ static int alloc_and_dissolve_huge_page(struct hstate *h, struct page *old_page,
> > struct list_head *list)
> > {
> > gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
> > - int nid = page_to_nid(old_page);
> > + struct folio *old_folio = page_folio(old_page);
> > + int nid = folio_nid(old_folio);
> > struct page *new_page;
> > + struct folio *new_folio;
> > int ret = 0;
> >
> > /*
> > @@ -2745,16 +2749,17 @@ static int alloc_and_dissolve_huge_page(struct hstate *h, struct page *old_page,
> > new_page = alloc_buddy_huge_page(h, gfp_mask, nid, NULL, NULL);
> > if (!new_page)
> > return -ENOMEM;
> > - __prep_new_huge_page(h, new_page);
> > + new_folio = page_folio(new_page);
> > + __prep_new_hugetlb_folio(h, new_folio);
> >
> > retry:
> > spin_lock_irq(&hugetlb_lock);
> > - if (!PageHuge(old_page)) {
> > + if (!folio_test_hugetlb(old_folio)) {
> > /*
> > * Freed from under us. Drop new_page too.
> > */
> > goto free_new;
> > - } else if (page_count(old_page)) {
> > + } else if (folio_ref_count(old_folio)) {
> > /*
> > * Someone has grabbed the page, try to isolate it here.
> > * Fail with -EBUSY if not possible.
> > @@ -2763,7 +2768,7 @@ static int alloc_and_dissolve_huge_page(struct hstate *h, struct page *old_page,
> > ret = isolate_hugetlb(old_page, list);
> > spin_lock_irq(&hugetlb_lock);
> > goto free_new;
> > - } else if (!HPageFreed(old_page)) {
> > + } else if (!folio_test_hugetlb_freed(old_folio)) {
> > /*
> > * Page's refcount is 0 but it has not been enqueued in the
> > * freelist yet. Race window is small, so we can succeed here if
> > @@ -2801,7 +2806,7 @@ static int alloc_and_dissolve_huge_page(struct hstate *h, struct page *old_page,
> > free_new:
> > spin_unlock_irq(&hugetlb_lock);
> > /* Page has a zero ref count, but needs a ref to be freed */
> > - set_page_refcounted(new_page);
> > + folio_ref_unfreeze(new_folio, 1);
> > update_and_free_page(h, new_page, false);
> >
> > return ret;
> > diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
> > index 600c98560a0f..692b23b5d423 100644
> > --- a/mm/hugetlb_cgroup.c
> > +++ b/mm/hugetlb_cgroup.c
> > @@ -212,7 +212,7 @@ static void hugetlb_cgroup_move_parent(int idx, struct hugetlb_cgroup *h_cg,
> > /* Take the pages off the local counter */
> > page_counter_cancel(counter, nr_pages);
> >
> > - set_hugetlb_cgroup(page, parent);
> > + set_hugetlb_cgroup(folio, parent);
> > out:
> > return;
> > }
> > @@ -894,6 +894,7 @@ void hugetlb_cgroup_migrate(struct page *oldhpage, struct page *newhpage)
> > struct hugetlb_cgroup *h_cg_rsvd;
> > struct hstate *h = page_hstate(oldhpage);
> > struct folio *old_folio = page_folio(oldhpage);
> > + struct folio *new_folio = page_folio(newhpage);
> >
> > if (hugetlb_cgroup_disabled())
> > return;
> > @@ -901,12 +902,12 @@ void hugetlb_cgroup_migrate(struct page *oldhpage, struct page *newhpage)
> > spin_lock_irq(&hugetlb_lock);
> > h_cg = hugetlb_cgroup_from_folio(old_folio);
> > h_cg_rsvd = hugetlb_cgroup_from_folio_rsvd(old_folio);
> > - set_hugetlb_cgroup(oldhpage, NULL);
> > - set_hugetlb_cgroup_rsvd(oldhpage, NULL);
> > + set_hugetlb_cgroup(old_folio, NULL);
> > + set_hugetlb_cgroup_rsvd(old_folio, NULL);
> >
> > /* move the h_cg details to new cgroup */
> > - set_hugetlb_cgroup(newhpage, h_cg);
> > - set_hugetlb_cgroup_rsvd(newhpage, h_cg_rsvd);
> > + set_hugetlb_cgroup(new_folio, h_cg);
> > + set_hugetlb_cgroup_rsvd(new_folio, h_cg_rsvd);
> > list_move(&newhpage->lru, &h->hugepage_activelist);
> > spin_unlock_irq(&hugetlb_lock);
> > return;
> > --
> > 2.31.1