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[2003:d8:2f40:b300:53f7:d260:aff4:7256]) by smtp.gmail.com with UTF8SMTPSA id 5b1f17b1804b1-4538a406489sm136741305e9.27.2025.06.30.06.00.31 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 30 Jun 2025 06:00:33 -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 v1 07/29] mm/migrate: rename isolate_movable_page() to isolate_movable_ops_page() Date: Mon, 30 Jun 2025 14:59:48 +0200 Message-ID: <20250630130011.330477-8-david@redhat.com> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250630130011.330477-1-david@redhat.com> References: <20250630130011.330477-1-david@redhat.com> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit ... and start moving back to per-page things that will absolutely not be folio things in the future. Add documentation and a comment that the remaining folio stuff (lock, refcount) will have to be reworked as well. While at it, convert the VM_BUG_ON() into a WARN_ON_ONCE() and handle it gracefully (relevant with further changes), and convert a WARN_ON_ONCE() into a VM_WARN_ON_ONCE_PAGE(). Note that we will leave anything that needs a rework (lock, refcount, ->lru) to be using folios for now: that perfectly highlights the problematic bits. Reviewed-by: Zi Yan Reviewed-by: Harry Yoo Signed-off-by: David Hildenbrand --- include/linux/migrate.h | 4 ++-- mm/compaction.c | 2 +- mm/migrate.c | 39 +++++++++++++++++++++++++++++---------- 3 files changed, 32 insertions(+), 13 deletions(-) diff --git a/include/linux/migrate.h b/include/linux/migrate.h index aaa2114498d6d..c0ec7422837bd 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -69,7 +69,7 @@ int migrate_pages(struct list_head *l, new_folio_t new, free_folio_t free, unsigned long private, enum migrate_mode mode, int reason, unsigned int *ret_succeeded); struct folio *alloc_migration_target(struct folio *src, unsigned long private); -bool isolate_movable_page(struct page *page, isolate_mode_t mode); +bool isolate_movable_ops_page(struct page *page, isolate_mode_t mode); bool isolate_folio_to_list(struct folio *folio, struct list_head *list); int migrate_huge_page_move_mapping(struct address_space *mapping, @@ -90,7 +90,7 @@ static inline int migrate_pages(struct list_head *l, new_folio_t new, static inline struct folio *alloc_migration_target(struct folio *src, unsigned long private) { return NULL; } -static inline bool isolate_movable_page(struct page *page, isolate_mode_t mode) +static inline bool isolate_movable_ops_page(struct page *page, isolate_mode_t mode) { return false; } static inline bool isolate_folio_to_list(struct folio *folio, struct list_head *list) { return false; } diff --git a/mm/compaction.c b/mm/compaction.c index 3925cb61dbb8f..17455c5a4be05 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -1093,7 +1093,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, locked = NULL; } - if (isolate_movable_page(page, mode)) { + if (isolate_movable_ops_page(page, mode)) { folio = page_folio(page); goto isolate_success; } diff --git a/mm/migrate.c b/mm/migrate.c index 767f503f08758..d4b4a7eefb6bd 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -51,8 +51,26 @@ #include "internal.h" #include "swap.h" -bool isolate_movable_page(struct page *page, isolate_mode_t mode) +/** + * isolate_movable_ops_page - isolate a movable_ops page for migration + * @page: The page. + * @mode: The isolation mode. + * + * Try to isolate a movable_ops page for migration. Will fail if the page is + * not a movable_ops page, if the page is already isolated for migration + * or if the page was just was released by its owner. + * + * Once isolated, the page cannot get freed until it is either putback + * or migrated. + * + * Returns true if isolation succeeded, otherwise false. + */ +bool isolate_movable_ops_page(struct page *page, isolate_mode_t mode) { + /* + * TODO: these pages will not be folios in the future. All + * folio dependencies will have to be removed. + */ struct folio *folio = folio_get_nontail_page(page); const struct movable_operations *mops; @@ -73,7 +91,7 @@ bool isolate_movable_page(struct page *page, isolate_mode_t mode) * we use non-atomic bitops on newly allocated page flags so * unconditionally grabbing the lock ruins page's owner side. */ - if (unlikely(!__folio_test_movable(folio))) + if (unlikely(!__PageMovable(page))) goto out_putfolio; /* @@ -90,18 +108,19 @@ bool isolate_movable_page(struct page *page, isolate_mode_t mode) if (unlikely(!folio_trylock(folio))) goto out_putfolio; - if (!folio_test_movable(folio) || folio_test_isolated(folio)) + if (!PageMovable(page) || PageIsolated(page)) goto out_no_isolated; - mops = folio_movable_ops(folio); - VM_BUG_ON_FOLIO(!mops, folio); + mops = page_movable_ops(page); + if (WARN_ON_ONCE(!mops)) + goto out_no_isolated; - if (!mops->isolate_page(&folio->page, mode)) + if (!mops->isolate_page(page, mode)) goto out_no_isolated; /* Driver shouldn't use the isolated flag */ - WARN_ON_ONCE(folio_test_isolated(folio)); - folio_set_isolated(folio); + VM_WARN_ON_ONCE_PAGE(PageIsolated(page), page); + SetPageIsolated(page); folio_unlock(folio); return true; @@ -175,8 +194,8 @@ bool isolate_folio_to_list(struct folio *folio, struct list_head *list) if (lru) isolated = folio_isolate_lru(folio); else - isolated = isolate_movable_page(&folio->page, - ISOLATE_UNEVICTABLE); + isolated = isolate_movable_ops_page(&folio->page, + ISOLATE_UNEVICTABLE); if (!isolated) return false; -- 2.49.0