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Message-ID: <20250618174014.1168640-16-david@redhat.com>
Date: Wed, 18 Jun 2025 19:39:58 +0200
From: David Hildenbrand <david@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: linux-mm@...ck.org,
linux-doc@...r.kernel.org,
linuxppc-dev@...ts.ozlabs.org,
virtualization@...ts.linux.dev,
linux-fsdevel@...r.kernel.org,
David Hildenbrand <david@...hat.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Jonathan Corbet <corbet@....net>,
Madhavan Srinivasan <maddy@...ux.ibm.com>,
Michael Ellerman <mpe@...erman.id.au>,
Nicholas Piggin <npiggin@...il.com>,
Christophe Leroy <christophe.leroy@...roup.eu>,
Jerrin Shaji George <jerrin.shaji-george@...adcom.com>,
Arnd Bergmann <arnd@...db.de>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
"Michael S. Tsirkin" <mst@...hat.com>,
Jason Wang <jasowang@...hat.com>,
Xuan Zhuo <xuanzhuo@...ux.alibaba.com>,
Eugenio Pérez <eperezma@...hat.com>,
Alexander Viro <viro@...iv.linux.org.uk>,
Christian Brauner <brauner@...nel.org>,
Jan Kara <jack@...e.cz>,
Zi Yan <ziy@...dia.com>,
Matthew Brost <matthew.brost@...el.com>,
Joshua Hahn <joshua.hahnjy@...il.com>,
Rakie Kim <rakie.kim@...com>,
Byungchul Park <byungchul@...com>,
Gregory Price <gourry@...rry.net>,
Ying Huang <ying.huang@...ux.alibaba.com>,
Alistair Popple <apopple@...dia.com>,
Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
"Liam R. Howlett" <Liam.Howlett@...cle.com>,
Vlastimil Babka <vbabka@...e.cz>,
Mike Rapoport <rppt@...nel.org>,
Suren Baghdasaryan <surenb@...gle.com>,
Michal Hocko <mhocko@...e.com>,
"Matthew Wilcox (Oracle)" <willy@...radead.org>,
Minchan Kim <minchan@...nel.org>,
Sergey Senozhatsky <senozhatsky@...omium.org>,
Brendan Jackman <jackmanb@...gle.com>,
Johannes Weiner <hannes@...xchg.org>,
Jason Gunthorpe <jgg@...pe.ca>,
John Hubbard <jhubbard@...dia.com>,
Peter Xu <peterx@...hat.com>,
Xu Xin <xu.xin16@....com.cn>,
Chengming Zhou <chengming.zhou@...ux.dev>,
Miaohe Lin <linmiaohe@...wei.com>,
Naoya Horiguchi <nao.horiguchi@...il.com>,
Oscar Salvador <osalvador@...e.de>,
Rik van Riel <riel@...riel.com>,
Harry Yoo <harry.yoo@...cle.com>,
Qi Zheng <zhengqi.arch@...edance.com>,
Shakeel Butt <shakeel.butt@...ux.dev>
Subject: [PATCH RFC 15/29] mm/migration: remove PageMovable()
As __ClearPageMovable() is gone that would have only made
PageMovable()==false but still __PageMovable()==true, now
PageMovable() == __PageMovable().
So we can replace PageMovable() checks by __PageMovable(). In fact,
__PageMovable() cannot change until a page is freed, so we can turn
some PageMovable() into sanity checks for __PageMovable().
Signed-off-by: David Hildenbrand <david@...hat.com>
---
include/linux/migrate.h | 2 --
mm/compaction.c | 15 ---------------
mm/migrate.c | 18 ++++++++++--------
3 files changed, 10 insertions(+), 25 deletions(-)
diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index fb6e9612e9f0b..204e89eac998f 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -104,10 +104,8 @@ static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
#endif /* CONFIG_MIGRATION */
#ifdef CONFIG_COMPACTION
-bool PageMovable(struct page *page);
void __SetPageMovable(struct page *page, const struct movable_operations *ops);
#else
-static inline bool PageMovable(struct page *page) { return false; }
static inline void __SetPageMovable(struct page *page,
const struct movable_operations *ops)
{
diff --git a/mm/compaction.c b/mm/compaction.c
index 889ec696ba96a..5c37373017014 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -114,21 +114,6 @@ static unsigned long release_free_list(struct list_head *freepages)
}
#ifdef CONFIG_COMPACTION
-bool PageMovable(struct page *page)
-{
- const struct movable_operations *mops;
-
- VM_BUG_ON_PAGE(!PageLocked(page), page);
- if (!__PageMovable(page))
- return false;
-
- mops = page_movable_ops(page);
- if (mops)
- return true;
-
- return false;
-}
-
void __SetPageMovable(struct page *page, const struct movable_operations *mops)
{
VM_BUG_ON_PAGE(!PageLocked(page), page);
diff --git a/mm/migrate.c b/mm/migrate.c
index db807f9bbf975..cf92075108f0c 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -87,9 +87,12 @@ bool isolate_movable_ops_page(struct page *page, isolate_mode_t mode)
goto out;
/*
- * Check movable flag before taking the page lock because
+ * Check for movable_ops pages before taking the page lock because
* we use non-atomic bitops on newly allocated page flags so
* unconditionally grabbing the lock ruins page's owner side.
+ *
+ * Note that once a page has movable_ops, it will stay that way
+ * until the page was freed.
*/
if (unlikely(!__PageMovable(page)))
goto out_putfolio;
@@ -108,7 +111,8 @@ bool isolate_movable_ops_page(struct page *page, isolate_mode_t mode)
if (unlikely(!folio_trylock(folio)))
goto out_putfolio;
- if (!PageMovable(page) || PageIsolated(page))
+ VM_WARN_ON_ONCE_PAGE(!__PageMovable(page), page);
+ if (PageIsolated(page))
goto out_no_isolated;
mops = page_movable_ops(page);
@@ -149,11 +153,10 @@ static void putback_movable_ops_page(struct page *page)
*/
struct folio *folio = page_folio(page);
+ VM_WARN_ON_ONCE_PAGE(!__PageMovable(page), page);
VM_WARN_ON_ONCE_PAGE(!PageIsolated(page), page);
folio_lock(folio);
- /* If the page was released by it's owner, there is nothing to do. */
- if (PageMovable(page))
- page_movable_ops(page)->putback_page(page);
+ page_movable_ops(page)->putback_page(page);
ClearPageIsolated(page);
folio_unlock(folio);
folio_put(folio);
@@ -189,10 +192,9 @@ static int migrate_movable_ops_page(struct page *dst, struct page *src,
{
int rc = MIGRATEPAGE_SUCCESS;
+ VM_WARN_ON_ONCE_PAGE(!__PageMovable(src), src);
VM_WARN_ON_ONCE_PAGE(!PageIsolated(src), src);
- /* If the page was released by it's owner, there is nothing to do. */
- if (PageMovable(src))
- rc = page_movable_ops(src)->migrate_page(dst, src, mode);
+ rc = page_movable_ops(src)->migrate_page(dst, src, mode);
if (rc == MIGRATEPAGE_SUCCESS)
ClearPageIsolated(src);
return rc;
--
2.49.0
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