Commit 88e740f1 authored Oct 27, 2008 by Fernando Luis Vázquez Cao Committed by Jens Axboe Dec 29, 2008

block: add queue flag for paravirt frontend drivers



As is the case with SSD devices, we do not want to idle in AS/CFQ when
the block device is a paravirt front-end driver. This patch adds a flag
(QUEUE_FLAG_VIRT) which should be used by front-end drivers such as
virtio_blk and xen-blkfront to indicate a paravirtualized device.

Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

parent 3c92ec8a

include/linux/blkdev.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -449,6 +449,7 @@ struct request_queue
		#define QUEUE_FLAG_FAIL_IO 12 /* fake timeout */
		#define QUEUE_FLAG_STACKABLE 13 /* supports request stacking */
		#define QUEUE_FLAG_NONROT 14 /* non-rotational device (SSD) */
		#define QUEUE_FLAG_VIRT QUEUE_FLAG_NONROT /* paravirt device */

		static inline int queue_is_locked(struct request_queue *q)
		{