[PATCH 1/3] block: add queue flag for paravirt frontend drivers

[Fernando Luis Vázquez Cao]

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@xxxxxxxxxxxxx>
---

diff -urNp linux-2.6.28-rc2-orig/include/linux/blkdev.h linux-2.6.28-rc2/include/linux/blkdev.h
--- linux-2.6.28-rc2-orig/include/linux/blkdev.h	2008-10-27 17:41:58.000000000 +0900
+++ linux-2.6.28-rc2/include/linux/blkdev.h	2008-10-27 17:34:49.000000000 +0900
@@ -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)
 {


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/