[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 org.kernel.vger.reiserfs-devel,dev.linux.lists.gfs2,dev.linux.lists.ntfs3,dev.linux.lists.ocfs2-devel,dev.linux.lists.v9fs,net.sourceforge.lists.linux-f2fs-devel,org.infradead.lists.linux-mtd,org.infradead.lists.linux-um,org.kernel.vger.autofs,org.kernel.vger.bpf,org.kernel.vger.ceph-devel,org.kernel.vger.linux-btrfs,org.kernel.vger.linux-cifs,org.kernel.vger.linux-efi,org.kernel.vger.linux-ext4,org.kernel.vger.linux-fsdevel,org.kernel.vger.linux-hardening,org.kernel.vger.linux-kernel,org.kernel.vger.linux-nfs,org.kernel.vger.linux-nilfs,org.kernel.vger.linux-rdma,org.kernel.vger.linux-s390,org.kernel.vger.linux-security-module,org.kernel.vger.linux-serial,org.kernel.vger.linux-trace-kernel,org.kernel.vger.linux-unionfs,org.kernel.vger.linux-usb,org.kernel.vger.linux-xfs,org.kernel.vger.netdev,org.kernel.vger.platform-driver-x86,org.kernel.vger.selinux,org.kvack.linux-mm,org.ozlabs.lists.linux-erofs,org.ozlabs.lists.linuxppc-dev
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