Save some bytes removing unused attributes of struct brd_device.
Before:
[arighi@linux: linux-2.6]$ pahole --cacheline 32 -C brd_device drivers/block/brd.o
struct brd_device {
int brd_number; /* 0 4 */
int brd_refcnt; /* 4 4 */
loff_t brd_offset; /* 8 8 */
loff_t brd_sizelimit; /* 16 8 */
unsigned int brd_blocksize; /* 24 4 */
/* XXX 4 bytes hole, try to pack */
/* --- cacheline 1 boundary (32 bytes) --- */
struct request_queue * brd_queue; /* 32 8 */
struct gendisk * brd_disk; /* 40 8 */
struct list_head brd_list; /* 48 16 */
/* --- cacheline 2 boundary (64 bytes) --- */
spinlock_t brd_lock; /* 64 4 */
/* XXX 4 bytes hole, try to pack */
struct radix_tree_root brd_pages; /* 72 16 */
/* size: 88, cachelines: 3 */
/* sum members: 80, holes: 2, sum holes: 8 */
/* last cacheline: 24 bytes */
};
After:
[arighi@linux: linux-2.6]$ pahole --cacheline 32 -C brd_device drivers/block/brd.o
struct brd_device {
struct list_head brd_list; /* 0 16 */
struct request_queue * brd_queue; /* 16 8 */
struct gendisk * brd_disk; /* 24 8 */
/* --- cacheline 1 boundary (32 bytes) --- */
struct radix_tree_root brd_pages; /* 32 16 */
spinlock_t brd_lock; /* 48 4 */
int brd_number; /* 52 4 */
/* size: 56, cachelines: 2 */
/* last cacheline: 24 bytes */
};
Signed-off-by: Andrea Righi <[email protected]>
---
drivers/block/brd.c | 17 +++++++----------
1 files changed, 7 insertions(+), 10 deletions(-)
diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index 1c7f637..5044f8c 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -34,22 +34,19 @@
* device).
*/
struct brd_device {
- int brd_number;
- int brd_refcnt;
- loff_t brd_offset;
- loff_t brd_sizelimit;
- unsigned brd_blocksize;
-
- struct request_queue *brd_queue;
- struct gendisk *brd_disk;
- struct list_head brd_list;
/*
* Backing store of pages and lock to protect it. This is the contents
* of the block device.
*/
- spinlock_t brd_lock;
+ struct list_head brd_list;
+
+ struct request_queue *brd_queue;
+ struct gendisk *brd_disk;
struct radix_tree_root brd_pages;
+ /* Protect access to the radix tree */
+ spinlock_t brd_lock;
+ int brd_number;
};
/*
--
1.7.0.4