[PATCH 87/87] fs: move i_blocks up a few places in struct inode

Jeff Layton <[email protected]> Thu, 28 Sep 2023 07:05:54 -0400
Newsgroups gmane.linux.kernel.bpf,gmane.linux.file-systems,gmane.linux.kernel,gmane.linux.kernel.mm,gmane.linux.ports.ppc64.devel,gmane.linux.drivers.platform.x86.devel,gmane.linux.drivers.rdma,gmane.linux.serial,gmane.linux.usb.general,gmane.linux.kernel.autofs,gmane.comp.file-systems.btrfs,gmane.comp.file-systems.ceph.devel,gmane.comp.file-systems.coda.general,gmane.linux.kernel.efi,gmane.comp.file-systems.ext4,gmane.linux.file-systems.f2fs,gmane.linux.uml.devel,gmane.linux.drivers.mtd,gmane.linux.nfs,gmane.comp.file-systems.nilfs.user,gmane.linux.file-systems.ntfs.devel,gmane.linux.hardware.karma.devel,gmane.linux.file-systems.union,gmane.comp.file-systems.reiserfs.general,gmane.linux.kernel.cifs,gmane.network.samba.internals,gmane.linux.network,gmane.comp.security.apparmor,gmane.linux.kernel.lsm
Message-ID <[email protected]>
The recent change to use discrete integers instead of struct timespec64
in struct inode shaved 8 bytes off of it, but it also moves the i_lock
into the previous cacheline, away from the fields that it protects.

Move i_blocks up above the i_lock, which moves the new 4 byte hole to
just after the timestamps, without changing the size of the structure.

Signed-off-by: Jeff Layton <[email protected]>
---
 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 de902ff2938b..3e0fe0f52e7c 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -677,11 +677,11 @@ struct inode {
 	u32			i_atime_nsec;
 	u32			i_mtime_nsec;
 	u32			i_ctime_nsec;
+	blkcnt_t		i_blocks;
 	spinlock_t		i_lock;	/* i_blocks, i_bytes, maybe i_size */
 	unsigned short          i_bytes;
 	u8			i_blkbits;
 	u8			i_write_hint;
-	blkcnt_t		i_blocks;
 
 #ifdef __NEED_I_SIZE_ORDERED
 	seqcount_t		i_size_seqcount;
-- 
2.41.0