Commit 3838c406 authored by Jens Axboe's avatar Jens Axboe
Browse files

block: re-arrange the struct block_device fields for better layout 



This moves struct device out-of-line as it's just used at open/close
time, so we can keep some of the commonly used fields closer together.
On a standard setup, it also reduces the size from 864 bytes to 848
bytes. Yes, struct device is a pig...

Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 310e9c85

include/linux/blk_types.h

+12 −8
Original line number Diff line number Diff line
@@ -40,26 +40,25 @@ struct bio_crypt_ctx; 
struct block_device {

	sector_t		bd_start_sect;

	sector_t		bd_nr_sectors;

	struct gendisk *	bd_disk;

	struct request_queue *	bd_queue;

	struct disk_stats __percpu *bd_stats;

	unsigned long		bd_stamp;

	bool			bd_read_only;	/* read-only policy */

	u8			bd_partno;

	bool			bd_write_holder;

	dev_t			bd_dev;

	atomic_t		bd_openers;

	spinlock_t		bd_size_lock; /* for bd_inode->i_size updates */

	struct inode *		bd_inode;	/* will die */

	struct super_block *	bd_super;

	void *			bd_claiming;

	struct device		bd_device;

	void *			bd_holder;

	/* The counter of freeze processes */

	int			bd_fsfreeze_count;

	int			bd_holders;

	bool			bd_write_holder;

	struct kobject		*bd_holder_dir;

	u8			bd_partno;

	spinlock_t		bd_size_lock; /* for bd_inode->i_size updates */

	struct gendisk *	bd_disk;

	struct request_queue *	bd_queue;



	/* The counter of freeze processes */

	int			bd_fsfreeze_count;

	/* Mutex for freeze */

	struct mutex		bd_fsfreeze_mutex;

	struct super_block	*bd_fsfreeze_sb;
@@ -68,6 +67,11 @@ struct block_device { 
#ifdef CONFIG_FAIL_MAKE_REQUEST

	bool			bd_make_it_fail;

#endif

	/*

	 * keep this out-of-line as it's both big and not needed in the fast

	 * path

	 */

	struct device		bd_device;

} __randomize_layout;



#define bdev_whole(_bdev) \