[PATCH RFC 3/7] mm: Add PG_atomic

[John Garry <john.g.garry@oracle.com>]

Add page flag PG_atomic, meaning that a folio needs to be written back
atomically.

Signed-off-by: John Garry <john.g.garry@oracle.com>
---
 include/linux/page-flags.h     | 5 +++++
 include/trace/events/mmflags.h | 3 ++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 652d77805e99..e777b2e7daaf 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -119,6 +119,7 @@ enum pageflags {
 	PG_reclaim,		/* To be reclaimed asap */
 	PG_swapbacked,		/* Page is backed by RAM/swap */
 	PG_unevictable,		/* Page is "unevictable"  */
+	PG_atomic,
 #ifdef CONFIG_MMU
 	PG_mlocked,		/* Page is vma mlocked */
 #endif
@@ -579,6 +580,10 @@ PAGEFLAG(Unevictable, unevictable, PF_HEAD)
 	__CLEARPAGEFLAG(Unevictable, unevictable, PF_HEAD)
 	TESTCLEARFLAG(Unevictable, unevictable, PF_HEAD)
 
+PAGEFLAG(Atomic, atomic, PF_HEAD)
+	__CLEARPAGEFLAG(Atomic, atomic, PF_HEAD)
+	TESTCLEARFLAG(Atomic, atomic, PF_HEAD)
+
 #ifdef CONFIG_MMU
 PAGEFLAG(Mlocked, mlocked, PF_NO_TAIL)
 	__CLEARPAGEFLAG(Mlocked, mlocked, PF_NO_TAIL)
diff --git a/include/trace/events/mmflags.h b/include/trace/events/mmflags.h
index d801409b33cf..3c83e7b93898 100644
--- a/include/trace/events/mmflags.h
+++ b/include/trace/events/mmflags.h
@@ -118,7 +118,8 @@
 	DEF_PAGEFLAG_NAME(mappedtodisk),				\
 	DEF_PAGEFLAG_NAME(reclaim),					\
 	DEF_PAGEFLAG_NAME(swapbacked),					\
-	DEF_PAGEFLAG_NAME(unevictable)					\
+	DEF_PAGEFLAG_NAME(unevictable),					\
+	DEF_PAGEFLAG_NAME(atomic)					\
 IF_HAVE_PG_MLOCK(mlocked)						\
 IF_HAVE_PG_UNCACHED(uncached)						\
 IF_HAVE_PG_HWPOISON(hwpoison)						\
-- 
2.31.1