Commit e6a1c874 authored by Jens Axboe's avatar Jens Axboe Committed by Jens Axboe
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[PATCH] struct request: shrink and optimize some more 



Move some members around and unionize completion_data and rb_node since
they cannot ever be used at the same time.

Signed-off-by: default avatarJens Axboe <axboe@suse.de>
parent 51da90fc

include/linux/blkdev.h

+13 −7
Original line number Diff line number Diff line
@@ -211,6 +211,8 @@ struct request { 
	struct list_head queuelist;

	struct list_head donelist;



	request_queue_t *q;



	unsigned int cmd_flags;

	enum rq_cmd_type_bits cmd_type;
@@ -219,12 +221,12 @@ struct request { 
	 */



	sector_t sector;		/* next sector to submit */

	sector_t hard_sector;		/* next sector to complete */

	unsigned long nr_sectors;	/* no. of sectors left to submit */

	unsigned long hard_nr_sectors;	/* no. of sectors left to complete */

	/* no. of sectors left to submit in the current segment */

	unsigned int current_nr_sectors;



	sector_t hard_sector;		/* next sector to complete */

	unsigned long hard_nr_sectors;	/* no. of sectors left to complete */

	/* no. of sectors left to complete in the current segment */

	unsigned int hard_cur_sectors;
@@ -232,7 +234,15 @@ struct request { 
	struct bio *biotail;



	struct hlist_node hash;	/* merge hash */

	/*

	 * The rb_node is only used inside the io scheduler, requests

	 * are pruned when moved to the dispatch queue. So let the

	 * completion_data share space with the rb_node.

	 */

	union {

		struct rb_node rb_node;	/* sort/lookup */

		void *completion_data;

	};



	/*

	 * two pointers are available for the IO schedulers, if they need
@@ -241,8 +251,6 @@ struct request { 
	void *elevator_private;

	void *elevator_private2;



	void *completion_data;



	struct gendisk *rq_disk;

	unsigned long start_time;
@@ -260,8 +268,6 @@ struct request { 


	unsigned short ioprio;



	request_queue_t *q;



	void *special;

	char *buffer;