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

[Sidhartha Kumar <sidhartha.kumar@oracle.com>]

On 11/1/22 11:45 PM, Muchun Song wrote:
>
>> On Nov 2, 2022, at 06:30, Sidhartha Kumar <sidhartha.kumar@oracle.com> 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@oracle.com>
>> ---
>> 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@google.com/

>> + 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
>>
>>
>