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-rw-r--r--include/linux/mount.h10
1 files changed, 8 insertions, 2 deletions
diff --git a/include/linux/mount.h b/include/linux/mount.h
index 1b7e178b0d84..dab69afee2fa 100644
--- a/include/linux/mount.h
+++ b/include/linux/mount.h
@@ -43,9 +43,8 @@ struct vfsmount {
struct super_block *mnt_sb; /* pointer to superblock */
struct list_head mnt_mounts; /* list of children, anchored here */
struct list_head mnt_child; /* and going through their mnt_child */
- atomic_t mnt_count;
int mnt_flags;
- int mnt_expiry_mark; /* true if marked for expiry */
+ /* 4 bytes hole on 64bits arches */
char *mnt_devname; /* Name of device e.g. /dev/dsk/hda1 */
struct list_head mnt_list;
struct list_head mnt_expire; /* link in fs-specific expiry list */
@@ -54,6 +53,13 @@ struct vfsmount {
struct list_head mnt_slave; /* slave list entry */
struct vfsmount *mnt_master; /* slave is on master->mnt_slave_list */
struct mnt_namespace *mnt_ns; /* containing namespace */
+ /*
+ * We put mnt_count & mnt_expiry_mark at the end of struct vfsmount
+ * to let these frequently modified fields in a separate cache line
+ * (so that reads of mnt_flags wont ping-pong on SMP machines)
+ */
+ atomic_t mnt_count;
+ int mnt_expiry_mark; /* true if marked for expiry */
int mnt_pinned;
};