On 14 Feb 2024, at 4:34, David Hildenbrand wrote: > On 13.02.24 22:55, Zi Yan wrote: >> From: Zi Yan <[email protected]> >> >> It adds a new_order parameter to set new page order in page owner. >> It prepares for upcoming changes to support split huge page to any >> lower order. >> >> Signed-off-by: Zi Yan <[email protected]> >> --- >> include/linux/page_owner.h | 10 +++++----- >> mm/huge_memory.c | 2 +- >> mm/page_alloc.c | 4 ++-- >> mm/page_owner.c | 9 +++++---- >> 4 files changed, 13 insertions(+), 12 deletions(-) >> >> diff --git a/include/linux/page_owner.h b/include/linux/page_owner.h >> index d7878523adfc..a784ba69f67f 100644 >> --- a/include/linux/page_owner.h >> +++ b/include/linux/page_owner.h >> @@ -11,7 +11,7 @@ extern struct page_ext_operations page_owner_ops; >> extern void __reset_page_owner(struct page *page, unsigned short order); >> extern void __set_page_owner(struct page *page, >> unsigned short order, gfp_t gfp_mask); >> -extern void __split_page_owner(struct page *page, int order); >> +extern void __split_page_owner(struct page *page, int old_order, int >> new_order); >> extern void __folio_copy_owner(struct folio *newfolio, struct folio *old); >> extern void __set_page_owner_migrate_reason(struct page *page, int reason); >> extern void __dump_page_owner(const struct page *page); >> @@ -31,10 +31,10 @@ static inline void set_page_owner(struct page *page, >> __set_page_owner(page, order, gfp_mask); >> } >> -static inline void split_page_owner(struct page *page, int order) >> +static inline void split_page_owner(struct page *page, int old_order, int >> new_order) >> { >> if (static_branch_unlikely(&page_owner_inited)) >> - __split_page_owner(page, order); >> + __split_page_owner(page, old_order, new_order); >> } >> static inline void folio_copy_owner(struct folio *newfolio, struct folio >> *old) >> { >> @@ -56,11 +56,11 @@ static inline void reset_page_owner(struct page *page, >> unsigned short order) >> { >> } >> static inline void set_page_owner(struct page *page, >> - unsigned int order, gfp_t gfp_mask) >> + unsigned short order, gfp_t gfp_mask) >> { >> } >> static inline void split_page_owner(struct page *page, >> - int order) >> + int old_order, int new_order) >> { >> } >> static inline void folio_copy_owner(struct folio *newfolio, struct folio >> *folio) >> diff --git a/mm/huge_memory.c b/mm/huge_memory.c >> index 3d30eccd3a7f..ad7133c97428 100644 >> --- a/mm/huge_memory.c >> +++ b/mm/huge_memory.c >> @@ -2919,7 +2919,7 @@ static void __split_huge_page(struct page *page, >> struct list_head *list, >> unlock_page_lruvec(lruvec); >> /* Caller disabled irqs, so they are still disabled here */ >> - split_page_owner(head, order); >> + split_page_owner(head, order, 0); >> /* See comment in __split_huge_page_tail() */ >> if (PageAnon(head)) { >> diff --git a/mm/page_alloc.c b/mm/page_alloc.c >> index 9d4dd41d0647..e0f107b21c98 100644 >> --- a/mm/page_alloc.c >> +++ b/mm/page_alloc.c >> @@ -2652,7 +2652,7 @@ void split_page(struct page *page, unsigned int order) >> for (i = 1; i < (1 << order); i++) >> set_page_refcounted(page + i); >> - split_page_owner(page, order); >> + split_page_owner(page, order, 0); >> split_page_memcg(page, order, 0); >> } >> EXPORT_SYMBOL_GPL(split_page); >> @@ -4837,7 +4837,7 @@ static void *make_alloc_exact(unsigned long addr, >> unsigned int order, >> struct page *page = virt_to_page((void *)addr); >> struct page *last = page + nr; >> - split_page_owner(page, order); >> + split_page_owner(page, order, 0); >> split_page_memcg(page, order, 0); >> while (page < --last) >> set_page_refcounted(last); >> diff --git a/mm/page_owner.c b/mm/page_owner.c >> index 1319e402c2cf..ebbffa0501db 100644 >> --- a/mm/page_owner.c >> +++ b/mm/page_owner.c >> @@ -292,19 +292,20 @@ void __set_page_owner_migrate_reason(struct page >> *page, int reason) >> page_ext_put(page_ext); >> } >> -void __split_page_owner(struct page *page, int order) >> +void __split_page_owner(struct page *page, int old_order, int new_order) >> { >> int i; >> struct page_ext *page_ext = page_ext_get(page); >> struct page_owner *page_owner; >> - unsigned int nr = 1 << order; >> + unsigned int old_nr = 1 << old_order; >> + unsigned int new_nr = 1 << new_order; >> if (unlikely(!page_ext)) >> return; >> - for (i = 0; i < nr; i++) { >> + for (i = 0; i < old_nr; i += new_nr) { >> page_owner = get_page_owner(page_ext); >> - page_owner->order = 0; >> + page_owner->order = new_order; >> page_ext = page_ext_next(page_ext); > > Staring at __set_page_owner_handle(), we do set all 1<<order page_exts > (corresponding to 1<<order "struct page"s) to have ->order set. > > Wouldn't you have to do the same here? > > for (i = 0; i < 1 << old_order; i++) { > page_owner = get_page_owner(page_ext); > page_owner->order = new_order; > page_ext = page_ext_next(page_ext); > }
You are right. So page owner is per struct page. I misunderstood the code. Thank you for pointing this out. Will fix it. -- Best Regards, Yan, Zi
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