Btrfs: make the device lock and its protected data in the same cacheline
The lock in btrfs_device structure was far away from its protected data, it would
make CPU load the cache line twice when we accessed them, move them together.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 2aaa00c..6fcc8ea 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -36,30 +36,31 @@
struct list_head dev_list;
struct list_head dev_alloc_list;
struct btrfs_fs_devices *fs_devices;
+
struct btrfs_root *dev_root;
+ struct rcu_string *name;
+
+ u64 generation;
+
+ spinlock_t io_lock ____cacheline_aligned;
+ int running_pending;
/* regular prio bios */
struct btrfs_pending_bios pending_bios;
/* WRITE_SYNC bios */
struct btrfs_pending_bios pending_sync_bios;
- u64 generation;
- int running_pending;
+ struct block_device *bdev;
+
+ /* the mode sent to blkdev_get */
+ fmode_t mode;
+
int writeable;
int in_fs_metadata;
int missing;
int can_discard;
int is_tgtdev_for_dev_replace;
- spinlock_t io_lock;
- /* the mode sent to blkdev_get */
- fmode_t mode;
-
- struct block_device *bdev;
-
-
- struct rcu_string *name;
-
/* the internal btrfs device id */
u64 devid;
@@ -83,7 +84,6 @@
/* minimal io size for this device */
u32 sector_size;
-
/* physical drive uuid (or lvm uuid) */
u8 uuid[BTRFS_UUID_SIZE];
@@ -107,7 +107,6 @@
struct radix_tree_root reada_zones;
struct radix_tree_root reada_extents;
-
/* disk I/O failure stats. For detailed description refer to
* enum btrfs_dev_stat_values in ioctl.h */
int dev_stats_valid;
