block: move .bd_inode into 1st cacheline of block_device

The .bd_inode field of block_device is used in IO fast path of blkdev_write_iter() and blkdev_llseek(), so it is more efficient to keep it into the 1st cacheline. .bd_openers is only touched in open()/close(), and .bd_size_lock is only for updating bdev capacity, which is in slow path too. So swap .bd_inode layout with .bd_openers & .bd_size_lock to move .bd_inode into the 1st cache line.

Ming Lei committed 2 years ago

Commit fad907c1 parent bb6cc251 file · +2 −1Browse files

Showing the changes to include/linux (1 of 1 file). Show all

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include/linux/blk_types.h+2−1

@@ -49,9 +49,10 @@ struct block_device { · 48 unmodified lines
49	49	bool bd_write_holder;
50	50	bool bd_has_submit_bio;
51	51	dev_t bd_dev;
	52	+ struct inode bd_inode; / will die */
	53	+
52	54	atomic_t bd_openers;
53	55	spinlock_t bd_size_lock; /* for bd_inode->i_size updates */
54		− struct inode * bd_inode; /* will die */
55	56	void * bd_claiming;
56	57	void * bd_holder;
57	58	const struct blk_holder_ops *bd_holder_ops;