mm: stop storing migration_ops in page->mapping

...  instead, look them up statically based on the page type.  Maybe in
the future we want a registration interface?  At least for now, it can be
easily handled using the two page types that actually support page
migration.

The remaining usage of page->mapping is to flag such pages as actually
being movable (having movable_ops), which we will change next.

Link: https://lkml.kernel.org/r/20250704102524.326966-20-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Harry Yoo <harry.yoo@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: "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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/balloon_compaction.h b/include/linux/balloon_compaction.h
index 9bce8e9f5018cd9b40dd374d707779c46f4eda02..a8a1706cc56f35c0474596c67bc7d254b283ae1e 100644 (file)
--- a/include/linux/balloon_compaction.h
+++ b/include/linux/balloon_compaction.h
@@ -92,7 +92,7 @@ static inline void balloon_page_insert(struct balloon_dev_info *balloon,
                                       struct page *page)
 {
        __SetPageOffline(page);
-       __SetPageMovable(page, &balloon_mops);
+       __SetPageMovable(page);
        set_page_private(page, (unsigned long)balloon);
        list_add(&page->lru, &balloon->pages);
 }

diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index e04035f70e36faf1752065f856b79fd3f36a3bf1..6aece3f3c8be8a13c63ff73894d704f9296e392c 100644 (file)
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -104,23 +104,13 @@ static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
 #endif /* CONFIG_MIGRATION */
 
 #ifdef CONFIG_COMPACTION
-void __SetPageMovable(struct page *page, const struct movable_operations *ops);
+void __SetPageMovable(struct page *page);
 #else
-static inline void __SetPageMovable(struct page *page,
-               const struct movable_operations *ops)
+static inline void __SetPageMovable(struct page *page)
 {
 }
 #endif
 
-static inline
-const struct movable_operations *page_movable_ops(struct page *page)
-{
-       VM_WARN_ON_ONCE_PAGE(!page_has_movable_ops(page), page);
-
-       return (const struct movable_operations *)
-               ((unsigned long)page->mapping - PAGE_MAPPING_MOVABLE);
-}
-
 #ifdef CONFIG_NUMA_BALANCING
 int migrate_misplaced_folio_prepare(struct folio *folio,
                struct vm_area_struct *vma, int node);

diff --git a/include/linux/zsmalloc.h b/include/linux/zsmalloc.h
index 13e9cc5490f71bc87964c9e530420716487ba634..f3ccff2d966cd59dd2b5bef3ceaf334be0cc9018 100644 (file)
--- a/include/linux/zsmalloc.h
+++ b/include/linux/zsmalloc.h
@@ -46,4 +46,6 @@ void zs_obj_read_end(struct zs_pool *pool, unsigned long handle,
 void zs_obj_write(struct zs_pool *pool, unsigned long handle,
                  void *handle_mem, size_t mem_len);
 
+extern const struct movable_operations zsmalloc_mops;
+
 #endif

diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c
index e4f1a122d786b2ae0e0e3e7f10f53ac1d20b97d2..2a4a649805c11c55b6dfb2f8c0af9d7458f487b3 100644 (file)
--- a/mm/balloon_compaction.c
+++ b/mm/balloon_compaction.c
@@ -253,6 +253,5 @@ const struct movable_operations balloon_mops = {
        .isolate_page = balloon_page_isolate,
        .putback_page = balloon_page_putback,
 };
-EXPORT_SYMBOL_GPL(balloon_mops);
 
 #endif /* CONFIG_BALLOON_COMPACTION */

diff --git a/mm/compaction.c b/mm/compaction.c
index 41fd6a1fe9a3371df6e5653e2ae12f8953a12ac7..348eb754cb2274e0a689adc60b645cf2784c23dc 100644 (file)
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -114,11 +114,10 @@ static unsigned long release_free_list(struct list_head *freepages)
 }
 
 #ifdef CONFIG_COMPACTION
-void __SetPageMovable(struct page *page, const struct movable_operations *mops)
+void __SetPageMovable(struct page *page)
 {
        VM_BUG_ON_PAGE(!PageLocked(page), page);
-       VM_BUG_ON_PAGE((unsigned long)mops & PAGE_MAPPING_MOVABLE, page);
-       page->mapping = (void *)((unsigned long)mops | PAGE_MAPPING_MOVABLE);
+       page->mapping = (void *)(PAGE_MAPPING_MOVABLE);
 }
 EXPORT_SYMBOL(__SetPageMovable);
 

diff --git a/mm/migrate.c b/mm/migrate.c
index aec0774d3da32c2ef51b542d0cdf9cf2b1dec2c4..90ddf906d70698b00c5d3492eec64f05f6440877 100644 (file)
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -43,6 +43,8 @@
 #include <linux/sched/sysctl.h>
 #include <linux/memory-tiers.h>
 #include <linux/pagewalk.h>
+#include <linux/balloon_compaction.h>
+#include <linux/zsmalloc.h>
 
 #include <asm/tlbflush.h>
 
@@ -51,6 +53,27 @@
 #include "internal.h"
 #include "swap.h"
 
+static const struct movable_operations *page_movable_ops(struct page *page)
+{
+       VM_WARN_ON_ONCE_PAGE(!page_has_movable_ops(page), page);
+
+       /*
+        * If we enable page migration for a page of a certain type by marking
+        * it as movable, the page type must be sticky until the page gets freed
+        * back to the buddy.
+        */
+#ifdef CONFIG_BALLOON_COMPACTION
+       if (PageOffline(page))
+               /* Only balloon compaction sets PageOffline pages movable. */
+               return &balloon_mops;
+#endif /* CONFIG_BALLOON_COMPACTION */
+#if defined(CONFIG_ZSMALLOC) && defined(CONFIG_COMPACTION)
+       if (PageZsmalloc(page))
+               return &zsmalloc_mops;
+#endif /* defined(CONFIG_ZSMALLOC) && defined(CONFIG_COMPACTION) */
+       return NULL;
+}
+
 /**
  * isolate_movable_ops_page - isolate a movable_ops page for migration
  * @page: The page.

diff --git a/mm/zpdesc.h b/mm/zpdesc.h
index 5763f3603973604660280372d3cc2eabc04ef681..6855d9e2732d895d94da6731659bf1dbaabe53a9 100644 (file)
--- a/mm/zpdesc.h
+++ b/mm/zpdesc.h
@@ -152,10 +152,9 @@ static inline struct zpdesc *pfn_zpdesc(unsigned long pfn)
        return page_zpdesc(pfn_to_page(pfn));
 }
 
-static inline void __zpdesc_set_movable(struct zpdesc *zpdesc,
-                                       const struct movable_operations *mops)
+static inline void __zpdesc_set_movable(struct zpdesc *zpdesc)
 {
-       __SetPageMovable(zpdesc_page(zpdesc), mops);
+       __SetPageMovable(zpdesc_page(zpdesc));
 }
 
 static inline void __zpdesc_set_zsmalloc(struct zpdesc *zpdesc)

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index b12250e219bb704fe4c5fb43c80ddfe819a5a809..4aaff7c26ea9670961298c4f15f1b3f130b5a30e 100644 (file)
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -1685,8 +1685,6 @@ static void lock_zspage(struct zspage *zspage)
 
 #ifdef CONFIG_COMPACTION
 
-static const struct movable_operations zsmalloc_mops;
-
 static void replace_sub_page(struct size_class *class, struct zspage *zspage,
                                struct zpdesc *newzpdesc, struct zpdesc *oldzpdesc)
 {
@@ -1709,7 +1707,7 @@ static void replace_sub_page(struct size_class *class, struct zspage *zspage,
        set_first_obj_offset(newzpdesc, first_obj_offset);
        if (unlikely(ZsHugePage(zspage)))
                newzpdesc->handle = oldzpdesc->handle;
-       __zpdesc_set_movable(newzpdesc, &zsmalloc_mops);
+       __zpdesc_set_movable(newzpdesc);
 }
 
 static bool zs_page_isolate(struct page *page, isolate_mode_t mode)
@@ -1819,7 +1817,7 @@ static void zs_page_putback(struct page *page)
 {
 }
 
-static const struct movable_operations zsmalloc_mops = {
+const struct movable_operations zsmalloc_mops = {
        .isolate_page = zs_page_isolate,
        .migrate_page = zs_page_migrate,
        .putback_page = zs_page_putback,
@@ -1882,7 +1880,7 @@ static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage)
 
        do {
                WARN_ON(!zpdesc_trylock(zpdesc));
-               __zpdesc_set_movable(zpdesc, &zsmalloc_mops);
+               __zpdesc_set_movable(zpdesc);
                zpdesc_unlock(zpdesc);
        } while ((zpdesc = get_next_zpdesc(zpdesc)) != NULL);
 }