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| author | Lai Jiangshan <laijs@cn.fujitsu.com> | 2014-06-06 14:37:15 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-06-06 16:08:13 -0700 |
| commit | dcbff5d1effbbd52be1ed9f2efb6c8d0445ad188 (patch) | |
| tree | 461ec0551ce11d4fa387a7c93ed317e836697a34 /include/linux/idr.h | |
| parent | 15f3ec3f238a44181e1ae85b3cc2c27b9fece01b (diff) | |
| download | lwn-dcbff5d1effbbd52be1ed9f2efb6c8d0445ad188.tar.gz lwn-dcbff5d1effbbd52be1ed9f2efb6c8d0445ad188.zip | |
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: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/idr.h')
| -rw-r--r-- | include/linux/idr.h | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/include/linux/idr.h b/include/linux/idr.h index 6af3400b9b2f..013fd9bc4cb6 100644 --- a/include/linux/idr.h +++ b/include/linux/idr.h @@ -29,21 +29,24 @@ struct 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]; int count; /* When zero, we can release it */ - int layer; /* distance from leaf */ - struct rcu_head rcu_head; + union { + /* A zero bit means "space here" */ + DECLARE_BITMAP(bitmap, IDR_SIZE); + struct rcu_head rcu_head; + }; }; struct idr { struct idr_layer __rcu *hint; /* the last layer allocated from */ struct idr_layer __rcu *top; - struct idr_layer *id_free; int layers; /* only valid w/o concurrent changes */ - int id_free_cnt; int cur; /* current pos for cyclic allocation */ spinlock_t lock; + int id_free_cnt; + struct idr_layer *id_free; }; #define IDR_INIT(name) \ |