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Commit dcbff5d1 authored by Lai Jiangshan's avatar Lai Jiangshan Committed by Linus Torvalds
Browse files

idr: reorder the fields 



idr_layer->layer is always accessed in read path, move it in the front.

idr_layer->bitmap is moved on the bottom.  And rcu_head shares with
bitmap due to they do not be accessed at the same time.

idr->id_free/id_free_cnt/lock are free list fields, and moved to the
bottom.  They will be removed in near future.

Signed-off-by: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 15f3ec3f

include/linux/idr.h

+8 −5
Original line number Original line Diff line number Diff line
@@ -29,21 +29,24 @@ 




struct idr_layer {

struct idr_layer {

	int			prefix;	/* the ID prefix of this idr_layer */

	int			prefix;	/* the ID prefix of this idr_layer */

	DECLARE_BITMAP(bitmap, IDR_SIZE); /* A zero bit means "space here" */

	int			layer;	/* distance from leaf */

	struct idr_layer __rcu	*ary[1<<IDR_BITS];

	struct idr_layer __rcu	*ary[1<<IDR_BITS];

	int			count;	/* When zero, we can release it */

	int			count;	/* When zero, we can release it */

	int			layer;	/* distance from leaf */

	union {

		/* A zero bit means "space here" */

		DECLARE_BITMAP(bitmap, IDR_SIZE);

		struct rcu_head		rcu_head;

		struct rcu_head		rcu_head;

	};

	};

};





struct idr {

struct idr {

	struct idr_layer __rcu	*hint;	/* the last layer allocated from */

	struct idr_layer __rcu	*hint;	/* the last layer allocated from */

	struct idr_layer __rcu	*top;

	struct idr_layer __rcu	*top;

	struct idr_layer	*id_free;

	int			layers;	/* only valid w/o concurrent changes */

	int			layers;	/* only valid w/o concurrent changes */

	int			id_free_cnt;

	int			cur;	/* current pos for cyclic allocation */

	int			cur;	/* current pos for cyclic allocation */

	spinlock_t		lock;

	spinlock_t		lock;

	int			id_free_cnt;

	struct idr_layer	*id_free;

};

};





#define IDR_INIT(name)							\

#define IDR_INIT(name)							\