[PATCH v2 89/89] fs: move i_generation into new hole created after timestamp conversion

Jeff Layton
2023-10-04T18:56:17Z

The recent change to use discrete integers instead of struct timespec64
shaved 8 bytes off of struct inode, but it also moves the i_lock
into the previous cacheline, away from the fields that it protects.

Move i_generation above the i_lock, which moves the new 4 byte hole to
just after the i_fsnotify_mask in my setup.

Suggested-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
include/linux/fs.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 485b5e21c8e5..686c9f33e725 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -677,6 +677,7 @@ struct inode {
u32 i_atime_nsec;
u32 i_mtime_nsec;
u32 i_ctime_nsec;
+ u32 i_generation;
spinlock_t i_lock; /* i_blocks, i_bytes, maybe i_size */
unsigned short i_bytes;
u8 i_blkbits;
@@ -733,7 +734,6 @@ struct inode {
unsigned i_dir_seq;
};

- __u32 i_generation;

#ifdef CONFIG_FSNOTIFY
__u32 i_fsnotify_mask; /* all events this inode cares about */
--
2.41.0