diff options
| author | Luiz Capitulino <luizcap@redhat.com> | 2025-07-14 09:16:52 -0400 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2025-07-24 19:12:35 -0700 |
| commit | d863a12108f24c5f0b49f99f328e33371bd7c69d (patch) | |
| tree | d2327d8a0632c458dc71ab7e09bb79027a6e6762 /include | |
| parent | 92c99fc614737eaa99125283c306d2ebb13b101a (diff) | |
mm/util: introduce snapshot_page()
This commit refactors __dump_page() into snapshot_page().
snapshot_page() tries to take a faithful snapshot of a page and its folio
representation. The snapshot is returned in the struct page_snapshot
parameter along with additional flags that are best retrieved at snapshot
creation time to reduce race windows.
This function is intended to be used by callers that need a stable
representation of a struct page and struct folio so that pointers or page
information doesn't change while working on a page.
The idea and original implementation of snapshot_page() comes from Matthew
Wilcox with suggestions for improvements from David Hildenbrand. All bugs
and misconceptions are mine.
[luizcap@redhat.com: fix set_ps_flags() commentary]
Link: https://lkml.kernel.org/r/d5c75701-b353-4536-a306-187fab0655b3@redhat.com
Link: https://lkml.kernel.org/r/637a03a05cb2e3df88f84ff9e9f9642374ef813a.1752499009.git.luizcap@redhat.com
Signed-off-by: Luiz Capitulino <luizcap@redhat.com>
Reviewed-by: Shivank Garg <shivankg@amd.com>
Tested-by: Harry Yoo <harry.yoo@oracle.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/mm.h | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index 805108d7bbc3..8e3a4c5b78ff 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -4199,4 +4199,23 @@ static inline bool page_pool_page_is_pp(struct page *page) } #endif +#define PAGE_SNAPSHOT_FAITHFUL (1 << 0) +#define PAGE_SNAPSHOT_PG_BUDDY (1 << 1) +#define PAGE_SNAPSHOT_PG_IDLE (1 << 2) + +struct page_snapshot { + struct folio folio_snapshot; + struct page page_snapshot; + unsigned long pfn; + unsigned long idx; + unsigned long flags; +}; + +static inline bool snapshot_page_is_faithful(const struct page_snapshot *ps) +{ + return ps->flags & PAGE_SNAPSHOT_FAITHFUL; +} + +void snapshot_page(struct page_snapshot *ps, const struct page *page); + #endif /* _LINUX_MM_H */ |