[PATCH v2] fs: pack fields `i_state` and `i_fsnotify_mask`

[Max Kellermann <max.kellermann@ionos.com>]

Both were 32 bit fields followed by a 32 bit hole.  This reduces size
of `struct inode` by 8 bytes.

Moving `i_fsnotify_marks` there as well so they can be in the same
cacheline.

Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
---
v1->v2: move `i_fsnotify_marks` up as well because "should better be
  in the same cacheline because these two are accessed on some
  performance sensitive paths" (Jan Kara)
---
 include/linux/fs.h | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 5b3a100aba77..fec047cc3327 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -813,7 +813,13 @@ struct inode {
 
 	/* Misc */
 	struct inode_state_flags i_state;
-	/* 32-bit hole */
+
+#ifdef CONFIG_FSNOTIFY
+	__u32			i_fsnotify_mask; /* all events this inode cares about */
+
+	struct fsnotify_mark_connector __rcu	*i_fsnotify_marks;
+#endif
+
 	struct rw_semaphore	i_rwsem;
 
 	/* Timestamp for writeback list ordering and age checks (jiffies). */
@@ -863,13 +869,6 @@ struct inode {
 		unsigned		i_dir_seq;
 	};
 
-
-#ifdef CONFIG_FSNOTIFY
-	__u32			i_fsnotify_mask; /* all events this inode cares about */
-	/* 32-bit hole reserved for expanding i_fsnotify_mask */
-	struct fsnotify_mark_connector __rcu	*i_fsnotify_marks;
-#endif
-
 	void			*i_private; /* fs or device private pointer */
 } __randomize_layout;
 
-- 
2.53.0