block: reorder request_queue to remove 64 bit alignment padding
Reorder request_queue to remove 16 bytes of alignment padding in 64 bit
builds.
On my config this shrinks the size of this structure from 1608 to 1592
bytes and therefore needs one fewer cachelines.
Also trivially move the open bracket { to be on the same line as the
structure name to make it easier to grep.
Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 6dcea68..c0cd9a2 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -260,8 +260,7 @@
unsigned char discard_zeroes_data;
};
-struct request_queue
-{
+struct request_queue {
/*
* Together with queue_head for cacheline sharing
*/
@@ -304,16 +303,16 @@
void *queuedata;
/*
- * queue needs bounce pages for pages above this limit
- */
- gfp_t bounce_gfp;
-
- /*
* various queue flags, see QUEUE_* below
*/
unsigned long queue_flags;
/*
+ * queue needs bounce pages for pages above this limit
+ */
+ gfp_t bounce_gfp;
+
+ /*
* protects queue structures from reentrancy. ->__queue_lock should
* _never_ be used directly, it is queue private. always use
* ->queue_lock.
@@ -334,8 +333,8 @@
unsigned int nr_congestion_off;
unsigned int nr_batching;
- void *dma_drain_buffer;
unsigned int dma_drain_size;
+ void *dma_drain_buffer;
unsigned int dma_pad_mask;
unsigned int dma_alignment;