[PATCH v2 2/6] mm/hugetlb: rename isolate_hugetlb() to folio_isolate_hugetlb()

David Hildenbrand
2025-01-13T13:16:49Z

Let's make the function name match "folio_isolate_lru()", and add some
kernel doc.

Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
include/linux/hugetlb.h | 4 ++--
mm/gup.c | 2 +-
mm/hugetlb.c | 23 ++++++++++++++++++++---
mm/mempolicy.c | 2 +-
mm/migrate.c | 6 +++---
5 files changed, 27 insertions(+), 10 deletions(-)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 49ec2362ce926..c95ad5cd7894d 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -153,7 +153,7 @@ bool hugetlb_reserve_pages(struct inode *inode, long from, long to,
vm_flags_t vm_flags);
long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
long freed);
-bool isolate_hugetlb(struct folio *folio, struct list_head *list);
+bool folio_isolate_hugetlb(struct folio *folio, struct list_head *list);
int get_hwpoison_hugetlb_folio(struct folio *folio, bool *hugetlb, bool unpoison);
int get_huge_page_for_hwpoison(unsigned long pfn, int flags,
bool *migratable_cleared);
@@ -414,7 +414,7 @@ static inline pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr,
return NULL;
}

-static inline bool isolate_hugetlb(struct folio *folio, struct list_head *list)
+static inline bool folio_isolate_hugetlb(struct folio *folio, struct list_head *list)
{
return false;
}
diff --git a/mm/gup.c b/mm/gup.c
index 00a1269cbee0a..2cc3a9d28e70e 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2344,7 +2344,7 @@ static unsigned long collect_longterm_unpinnable_folios(
continue;

if (folio_test_hugetlb(folio)) {
- isolate_hugetlb(folio, movable_folio_list);
+ folio_isolate_hugetlb(folio, movable_folio_list);
continue;
}

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 9a5596022c4b3..a93b508bc0e0e 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2808,7 +2808,7 @@ static int alloc_and_dissolve_hugetlb_folio(struct hstate *h,
* Fail with -EBUSY if not possible.
*/
spin_unlock_irq(&hugetlb_lock);
- isolated = isolate_hugetlb(old_folio, list);
+ isolated = folio_isolate_hugetlb(old_folio, list);
ret = isolated ? 0 : -EBUSY;
spin_lock_irq(&hugetlb_lock);
goto free_new;
@@ -2893,7 +2893,7 @@ int isolate_or_dissolve_huge_page(struct page *page, struct list_head *list)
if (hstate_is_gigantic(h))
return -ENOMEM;

- if (folio_ref_count(folio) && isolate_hugetlb(folio, list))
+ if (folio_ref_count(folio) && folio_isolate_hugetlb(folio, list))
ret = 0;
else if (!folio_ref_count(folio))
ret = alloc_and_dissolve_hugetlb_folio(h, folio, list);
@@ -7417,7 +7417,24 @@ __weak unsigned long hugetlb_mask_last_page(struct hstate *h)

#endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */

-bool isolate_hugetlb(struct folio *folio, struct list_head *list)
+/**
+ * folio_isolate_hugetlb - try to isolate an allocated hugetlb folio
+ * @folio: the folio to isolate
+ * @list: the list to add the folio to on success
+ *
+ * Isolate an allocated (refcount > 0) hugetlb folio, marking it as
+ * isolated/non-migratable, and moving it from the active list to the
+ * given list.
+ *
+ * Isolation will fail if @folio is not an allocated hugetlb folio, or if
+ * it is already isolated/non-migratable.
+ *
+ * On success, an additional folio reference is taken that must be dropped
+ * using folio_putback_active_hugetlb() to undo the isolation.
+ *
+ * Return: True if isolation worked, otherwise False.
+ */
+bool folio_isolate_hugetlb(struct folio *folio, struct list_head *list)
{
bool ret = true;

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index f83b73236ffe7..bbaadbeeb2919 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -647,7 +647,7 @@ static int queue_folios_hugetlb(pte_t *pte, unsigned long hmask,
*/
if ((flags & MPOL_MF_MOVE_ALL) ||
(!folio_likely_mapped_shared(folio) && !hugetlb_pmd_shared(pte)))
- if (!isolate_hugetlb(folio, qp->pagelist))
+ if (!folio_isolate_hugetlb(folio, qp->pagelist))
qp->nr_failed++;
unlock:
spin_unlock(ptl);
diff --git a/mm/migrate.c b/mm/migrate.c
index caadbe393aa21..80887cadb2774 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -128,7 +128,7 @@ static void putback_movable_folio(struct folio *folio)
*
* This function shall be used whenever the isolated pageset has been
* built from lru, balloon, hugetlbfs page. See isolate_migratepages_range()
- * and isolate_hugetlb().
+ * and folio_isolate_hugetlb().
*/
void putback_movable_pages(struct list_head *l)
{
@@ -169,7 +169,7 @@ bool isolate_folio_to_list(struct folio *folio, struct list_head *list)
bool isolated, lru;

if (folio_test_hugetlb(folio))
- return isolate_hugetlb(folio, list);
+ return folio_isolate_hugetlb(folio, list);

lru = !__folio_test_movable(folio);
if (lru)
@@ -2203,7 +2203,7 @@ static int __add_folio_for_migration(struct folio *folio, int node,
return -EACCES;

if (folio_test_hugetlb(folio)) {
- if (isolate_hugetlb(folio, pagelist))
+ if (folio_isolate_hugetlb(folio, pagelist))
return 1;
} else if (folio_isolate_lru(folio)) {
list_add_tail(&folio->lru, pagelist);
--
2.47.1