2023-07-19 18:09:01

by Sidhartha Kumar

Subject: [PATCH] mm/hugetlb: get rid of page_hstate()

Converts the last page_hstate() user to use folio_hstate() so
page_hstate() can be safely removed.

Signed-off-by: Sidhartha Kumar <[email protected]>
---
include/linux/hugetlb.h | 10 ----------
mm/hugetlb.c | 6 +++---
mm/page_isolation.c | 8 ++++----
3 files changed, 7 insertions(+), 17 deletions(-)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 57f21279c529f..3d4de9c7326bb 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -847,11 +847,6 @@ static inline struct hstate *folio_hstate(struct folio *folio)
return size_to_hstate(folio_size(folio));
}

-static inline struct hstate *page_hstate(struct page *page)
-{
- return folio_hstate(page_folio(page));
-}
-
static inline unsigned hstate_index_to_shift(unsigned index)
{
return hstates[index].order + PAGE_SHIFT;
@@ -1088,11 +1083,6 @@ static inline struct hstate *folio_hstate(struct folio *folio)
return NULL;
}

-static inline struct hstate *page_hstate(struct page *page)
-{
- return NULL;
-}
-
static inline struct hstate *size_to_hstate(unsigned long size)
{
return NULL;
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 71d18bb76b4df..b15ae05819a8a 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1785,10 +1785,10 @@ static void free_hpage_workfn(struct work_struct *work)
node = node->next;
page->mapping = NULL;
/*
- * The VM_BUG_ON_PAGE(!PageHuge(page), page) in page_hstate()
- * is going to trigger because a previous call to
+ * The VM_BUG_ON_FOLIO(!folio_test_hugetlb(folio), folio) in
+ * folio_hstate() is going to trigger because a previous call to
* remove_hugetlb_folio() will call folio_set_compound_dtor
- * (folio, NULL_COMPOUND_DTOR), so do not use page_hstate()
+ * (folio, NULL_COMPOUND_DTOR), so do not use folio_hstate()
* directly.
*/
h = size_to_hstate(page_size(page));
diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index 6599cc965e216..cd36b9998483d 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -79,17 +79,17 @@ static struct page *has_unmovable_pages(unsigned long start_pfn, unsigned long e
* handle each tail page individually in migration.
*/
if (PageHuge(page) || PageTransCompound(page)) {
- struct page *head = compound_head(page);
+ struct folio *folio = page_folio(page);
unsigned int skip_pages;

if (PageHuge(page)) {
- if (!hugepage_migration_supported(page_hstate(head)))
+ if (!hugepage_migration_supported(folio_hstate(folio)))
return page;
- } else if (!PageLRU(head) && !__PageMovable(head)) {
+ } else if (!folio_test_lru(folio) && !__folio_test_movable(folio)) {
return page;
}

- skip_pages = compound_nr(head) - (page - head);
+ skip_pages = folio_nr_pages(folio) - (page - &folio->page);
pfn += skip_pages - 1;
continue;
}
--
2.41.0

2023-07-19 18:36:01

by Matthew Wilcox

Subject: Re: [PATCH] mm/hugetlb: get rid of page_hstate()

On Wed, Jul 19, 2023 at 10:59:44AM -0700, Sidhartha Kumar wrote:
> - skip_pages = compound_nr(head) - (page - head);
> + skip_pages = folio_nr_pages(folio) - (page - &folio->page);

It turns out that you can't do (page - head) under all configs. It
works on all common ones, but the safe way to do what you want here is:

skip_pages = folio_nr_pages(folio) -
folio_page_idx(folio, page);