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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>
This commit is contained in:
Miao Xie 2014-07-24 11:37:10 +08:00 committed by Chris Mason
parent 5f546063ce
commit d5ee37bcb1
1 changed files with 12 additions and 13 deletions
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25
fs/btrfs/volumes.h
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@ -36,30 +36,31 @@ struct btrfs_device {
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 @@ struct btrfs_device {
/* 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 btrfs_device {
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;