mm/balloon_compaction: stop using __ClearPageMovable()

We can just look at the balloon device (stored in page->private), to see
if the page is still part of the balloon.

As isolated balloon pages cannot get released (they are taken off the
balloon list while isolated), we don't have to worry about this case in
the putback and migration callback.  Add a WARN_ON_ONCE for now.

Link: https://lkml.kernel.org/r/20250704102524.326966-14-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Eugenio Pé rez <eperezma@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Gregory Price <gourry@gourry.net>
Cc: Harry Yoo <harry.yoo@oracle.com>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jerrin Shaji George <jerrin.shaji-george@broadcom.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/balloon_compaction.h b/include/linux/balloon_compaction.h
index bfc6e50bd004b7b4bf0973172a8fca432ad8802a..9bce8e9f5018cd9b40dd374d707779c46f4eda02 100644 (file)
--- a/include/linux/balloon_compaction.h
+++ b/include/linux/balloon_compaction.h
@@ -136,10 +136,8 @@ static inline gfp_t balloon_mapping_gfp_mask(void)
  */
 static inline void balloon_page_finalize(struct page *page)
 {
-       if (IS_ENABLED(CONFIG_BALLOON_COMPACTION)) {
-               __ClearPageMovable(page);
+       if (IS_ENABLED(CONFIG_BALLOON_COMPACTION))
                set_page_private(page, 0);
-       }
        /* PageOffline is sticky until the page is freed to the buddy. */
 }
 

diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c
index ec176bdb8a78b79e285f57adfd410b950f90c9fc..e4f1a122d786b2ae0e0e3e7f10f53ac1d20b97d2 100644 (file)
--- a/mm/balloon_compaction.c
+++ b/mm/balloon_compaction.c
@@ -206,6 +206,9 @@ static bool balloon_page_isolate(struct page *page, isolate_mode_t mode)
        struct balloon_dev_info *b_dev_info = balloon_page_device(page);
        unsigned long flags;
 
+       if (!b_dev_info)
+               return false;
+
        spin_lock_irqsave(&b_dev_info->pages_lock, flags);
        list_del(&page->lru);
        b_dev_info->isolated_pages++;
@@ -219,6 +222,10 @@ static void balloon_page_putback(struct page *page)
        struct balloon_dev_info *b_dev_info = balloon_page_device(page);
        unsigned long flags;
 
+       /* Isolated balloon pages cannot get deflated. */
+       if (WARN_ON_ONCE(!b_dev_info))
+               return;
+
        spin_lock_irqsave(&b_dev_info->pages_lock, flags);
        list_add(&page->lru, &b_dev_info->pages);
        b_dev_info->isolated_pages--;
@@ -234,6 +241,10 @@ static int balloon_page_migrate(struct page *newpage, struct page *page,
        VM_BUG_ON_PAGE(!PageLocked(page), page);
        VM_BUG_ON_PAGE(!PageLocked(newpage), newpage);
 
+       /* Isolated balloon pages cannot get deflated. */
+       if (WARN_ON_ONCE(!balloon))
+               return -EAGAIN;
+
        return balloon->migratepage(balloon, newpage, page, mode);
 }