folio->private != NULL indicates a folio carries private data, replacing PG_private. All PG_private users are converted. Remove PG_private and reserve the space as __PG_folio for future use. __DEF_PAGEFLAG_NAME() is added to show __PG_folio. Also update files in Documentation. hugetlbfs_reserv.rst is outdated and left unchanged. It should be rewritten. Assisted-by: Claude:claude-opus-4-8 Assisted-by: Codex:gpt-5 Signed-off-by: Zi Yan To: Andrew Morton To: Baoquan He To: Mike Rapoport To: Pasha Tatashin To: Pratyush Yadav To: Jonathan Corbet To: "Matthew Wilcox (Oracle)" To: Jan Kara To: David Hildenbrand To: Steven Rostedt To: Masami Hiramatsu Cc: Dave Young Cc: Shuah Khan Cc: Lorenzo Stoakes Cc: "Liam R. Howlett" Cc: Vlastimil Babka Cc: Suren Baghdasaryan Cc: Michal Hocko Cc: Mathieu Desnoyers Cc: kexec@lists.infradead.org Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-trace-kernel@vger.kernel.org --- Documentation/admin-guide/kdump/vmcoreinfo.rst | 2 +- Documentation/filesystems/vfs.rst | 6 +++--- include/linux/page-flags.h | 19 ++----------------- include/trace/events/mmflags.h | 3 ++- kernel/vmcore_info.c | 1 - 5 files changed, 8 insertions(+), 23 deletions(-) diff --git a/Documentation/admin-guide/kdump/vmcoreinfo.rst b/Documentation/admin-guide/kdump/vmcoreinfo.rst index 7663c610fe901..5f1df6d080508 100644 --- a/Documentation/admin-guide/kdump/vmcoreinfo.rst +++ b/Documentation/admin-guide/kdump/vmcoreinfo.rst @@ -325,7 +325,7 @@ NR_FREE_PAGES On linux-2.6.21 or later, the number of free pages is in vm_stat[NR_FREE_PAGES]. Used to get the number of free pages. -PG_lru|PG_private|PG_swapcache|PG_swapbacked|PG_hwpoison|PG_head_mask +PG_lru|PG_swapcache|PG_swapbacked|PG_hwpoison|PG_head_mask -------------------------------------------------------------------------- Page attributes. These flags are used to filter various unnecessary for diff --git a/Documentation/filesystems/vfs.rst b/Documentation/filesystems/vfs.rst index d3a93eec3945f..dec7816303c6a 100644 --- a/Documentation/filesystems/vfs.rst +++ b/Documentation/filesystems/vfs.rst @@ -649,8 +649,8 @@ Writeback. The first can be used independently to the others. The VM can try to release clean pages in order to reuse them. To do this it can call -->release_folio on clean folios with the private -flag set. Clean pages without PagePrivate and with no external references +->release_folio on clean folios with folio->private set. Clean pages +without folio->private set and with no external references will be released without notice being given to the address_space. To achieve this functionality, pages need to be placed on an LRU with @@ -674,7 +674,7 @@ filemap_fdatawait_range, to wait for all writeback to complete. An address_space handler may attach extra information to a page, typically using the 'private' field in the 'struct page'. If such -information is attached, the PG_Private flag should be set. This will +information is attached, non-NULL 'private' field will cause various VM routines to make extra calls into the address_space handler to deal with that data. diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index ce7fccd90367b..7b7783c0a5216 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -44,10 +44,6 @@ * Consequently, PG_reserved for a page mapped into user space can indicate * the zero page, the vDSO, MMIO pages or device memory. * - * The PG_private bitflag is set on pagecache pages if they contain filesystem - * specific data (which is normally at page->private). It can be used by - * private allocations for its own usage. - * * During initiation of disk I/O, PG_locked is set. This bit is set before I/O * and cleared when writeback _starts_ or when read _completes_. PG_writeback * is set before writeback starts and cleared when it finishes. @@ -105,7 +101,7 @@ enum pageflags { PG_owner_2, /* Owner use. If pagecache, fs may use */ PG_arch_1, PG_reserved, - PG_private, /* If pagecache, has fs-private data */ + __PG_folio, /* Do not use: reserved for folio identification */ PG_private_2, /* If pagecache, has fs aux data */ PG_reclaim, /* To be reclaimed asap */ PG_swapbacked, /* Page is backed by RAM/swap */ @@ -576,7 +572,7 @@ FOLIO_FLAG(swapbacked, FOLIO_HEAD_PAGE) /* * Private page markings that may be used by the filesystem that owns the page * for its own purposes. - * - PG_private and PG_private_2 cause release_folio() and co to be invoked + * - folio->private and PG_private_2 cause release_folio() and co to be invoked */ static __always_inline bool folio_test_private(const struct folio *folio) @@ -584,17 +580,6 @@ static __always_inline bool folio_test_private(const struct folio *folio) return folio->private; } -static __always_inline int PagePrivate(const struct page *page) -{ - return !!page->private; -} - -/* no-ops during transition */ -static __always_inline void folio_set_private(struct folio *folio) { } -static __always_inline void folio_clear_private(struct folio *folio) { } -static __always_inline void SetPagePrivate(struct page *page) { } -static __always_inline void ClearPagePrivate(struct page *page) { } - FOLIO_FLAG(private_2, FOLIO_HEAD_PAGE) /* owner_2 can be set on tail pages for anon memory */ diff --git a/include/trace/events/mmflags.h b/include/trace/events/mmflags.h index ef9aa388b84f7..38a2d30230443 100644 --- a/include/trace/events/mmflags.h +++ b/include/trace/events/mmflags.h @@ -130,6 +130,7 @@ TRACE_DEFINE_ENUM(___GFP_LAST_BIT); #endif #define DEF_PAGEFLAG_NAME(_name) { 1UL << PG_##_name, __stringify(_name) } +#define __DEF_PAGEFLAG_NAME(_name) { 1UL << __PG_##_name, __stringify(_name) } #define __def_pageflag_names \ DEF_PAGEFLAG_NAME(locked), \ @@ -144,7 +145,7 @@ TRACE_DEFINE_ENUM(___GFP_LAST_BIT); DEF_PAGEFLAG_NAME(owner_2), \ DEF_PAGEFLAG_NAME(arch_1), \ DEF_PAGEFLAG_NAME(reserved), \ - DEF_PAGEFLAG_NAME(private), \ + __DEF_PAGEFLAG_NAME(folio), \ DEF_PAGEFLAG_NAME(private_2), \ DEF_PAGEFLAG_NAME(writeback), \ DEF_PAGEFLAG_NAME(head), \ diff --git a/kernel/vmcore_info.c b/kernel/vmcore_info.c index 8614430ca212a..5a417f8a922ab 100644 --- a/kernel/vmcore_info.c +++ b/kernel/vmcore_info.c @@ -216,7 +216,6 @@ static int __init crash_save_vmcoreinfo_init(void) VMCOREINFO_LENGTH(free_area.free_list, MIGRATE_TYPES); VMCOREINFO_NUMBER(NR_FREE_PAGES); VMCOREINFO_NUMBER(PG_lru); - VMCOREINFO_NUMBER(PG_private); VMCOREINFO_NUMBER(PG_swapcache); VMCOREINFO_NUMBER(PG_swapbacked); #define PAGE_SLAB_MAPCOUNT_VALUE (PGTY_slab << 24) -- 2.53.0