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[2003:d8:2f2d:2400:4052:3b5:fff9:4ed0]) by smtp.gmail.com with UTF8SMTPSA id ffacd0b85a97d-3a568b087b4sm17884528f8f.51.2025.06.18.10.41.05 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 18 Jun 2025 10:41:07 -0700 (PDT) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, linux-doc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, virtualization@lists.linux.dev, linux-fsdevel@vger.kernel.org, David Hildenbrand , Andrew Morton , Jonathan Corbet , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Jerrin Shaji George , Arnd Bergmann , Greg Kroah-Hartman , "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , =?UTF-8?q?Eugenio=20P=C3=A9rez?= , Alexander Viro , Christian Brauner , Jan Kara , Zi Yan , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , "Matthew Wilcox (Oracle)" , Minchan Kim , Sergey Senozhatsky , Brendan Jackman , Johannes Weiner , Jason Gunthorpe , John Hubbard , Peter Xu , Xu Xin , Chengming Zhou , Miaohe Lin , Naoya Horiguchi , Oscar Salvador , Rik van Riel , Harry Yoo , Qi Zheng , Shakeel Butt Subject: [PATCH RFC 19/29] mm: stop storing migration_ops in page->mapping Date: Wed, 18 Jun 2025 19:40:02 +0200 Message-ID: <20250618174014.1168640-20-david@redhat.com> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250618174014.1168640-1-david@redhat.com> References: <20250618174014.1168640-1-david@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" ... 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. Signed-off-by: David Hildenbrand Reviewed-by: Zi Yan --- include/linux/balloon_compaction.h | 2 +- include/linux/migrate.h | 14 ++------------ include/linux/zsmalloc.h | 2 ++ mm/balloon_compaction.c | 1 - mm/compaction.c | 5 ++--- mm/migrate.c | 23 +++++++++++++++++++++++ mm/zpdesc.h | 5 ++--- mm/zsmalloc.c | 8 +++----- 8 files changed, 35 insertions(+), 25 deletions(-) diff --git a/include/linux/balloon_compaction.h b/include/linux/balloon_com= paction.h index 9bce8e9f5018c..a8a1706cc56f3 100644 --- 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 c575778456f97..64639dab92b91 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -104,23 +104,13 @@ static inline int migrate_huge_page_move_mapping(stru= ct address_space *mapping, #endif /* CONFIG_MIGRATION */ =20 #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 =20 -static inline -const struct movable_operations *page_movable_ops(struct page *page) -{ - VM_BUG_ON(!page_has_movable_ops(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 13e9cc5490f71..f3ccff2d966cd 100644 --- 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); =20 +extern const struct movable_operations zsmalloc_mops; + #endif diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c index e4f1a122d786b..2a4a649805c11 100644 --- a/mm/balloon_compaction.c +++ b/mm/balloon_compaction.c @@ -253,6 +253,5 @@ const struct movable_operations balloon_mops =3D { .isolate_page =3D balloon_page_isolate, .putback_page =3D balloon_page_putback, }; -EXPORT_SYMBOL_GPL(balloon_mops); =20 #endif /* CONFIG_BALLOON_COMPACTION */ diff --git a/mm/compaction.c b/mm/compaction.c index f8b7c09e2e48c..a10f23df9396e 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -114,11 +114,10 @@ static unsigned long release_free_list(struct list_he= ad *freepages) } =20 #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 =3D (void *)((unsigned long)mops | PAGE_MAPPING_MOVABLE); + page->mapping =3D (void *)(PAGE_MAPPING_MOVABLE); } EXPORT_SYMBOL(__SetPageMovable); =20 diff --git a/mm/migrate.c b/mm/migrate.c index 37e722fbfee70..a36030de94f30 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -43,6 +43,8 @@ #include #include #include +#include +#include =20 #include =20 @@ -51,6 +53,27 @@ #include "internal.h" #include "swap.h" =20 +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 */ +#ifdef CONFIG_ZSMALLOC + if (PageZsmalloc(page)) + return &zsmalloc_mops; +#endif /* CONFIG_ZSMALLOC */ + 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 5763f36039736..6855d9e2732d8 100644 --- 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)); } =20 -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)); } =20 static inline void __zpdesc_set_zsmalloc(struct zpdesc *zpdesc) diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c index 72c2b7562c511..7192196b9421d 100644 --- a/mm/zsmalloc.c +++ b/mm/zsmalloc.c @@ -1684,8 +1684,6 @@ static void lock_zspage(struct zspage *zspage) =20 #ifdef CONFIG_COMPACTION =20 -static const struct movable_operations zsmalloc_mops; - static void replace_sub_page(struct size_class *class, struct zspage *zspa= ge, struct zpdesc *newzpdesc, struct zpdesc *oldzpdesc) { @@ -1708,7 +1706,7 @@ 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 =3D oldzpdesc->handle; - __zpdesc_set_movable(newzpdesc, &zsmalloc_mops); + __zpdesc_set_movable(newzpdesc); } =20 static bool zs_page_isolate(struct page *page, isolate_mode_t mode) @@ -1815,7 +1813,7 @@ static void zs_page_putback(struct page *page) { } =20 -static const struct movable_operations zsmalloc_mops =3D { +const struct movable_operations zsmalloc_mops =3D { .isolate_page =3D zs_page_isolate, .migrate_page =3D zs_page_migrate, .putback_page =3D zs_page_putback, @@ -1878,7 +1876,7 @@ static void SetZsPageMovable(struct zs_pool *pool, st= ruct zspage *zspage) =20 do { WARN_ON(!zpdesc_trylock(zpdesc)); - __zpdesc_set_movable(zpdesc, &zsmalloc_mops); + __zpdesc_set_movable(zpdesc); zpdesc_unlock(zpdesc); } while ((zpdesc =3D get_next_zpdesc(zpdesc)) !=3D NULL); } --=20 2.49.0