From 50e1dab86aa2c10cbca2f754aae9542169403141 Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@fb.com>
Date: Thu, 26 Jan 2017 14:42:34 -0700
Subject: blk-mq-sched: fix starvation for multiple hardware queues and shared
tags
If we have both multiple hardware queues and shared tag map between
devices, we need to ensure that we propagate the hardware queue
restart bit higher up. This is because we can get into a situation
where we don't have any IO pending on a hardware queue, yet we fail
getting a tag to start new IO. If that happens, it's not enough to
mark the hardware queue as needing a restart, we need to bubble
that up to the higher level queue as well.
Signed-off-by: Jens Axboe <axboe@fb.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Tested-by: Hannes Reinecke <hare@suse.com>
---
include/linux/blkdev.h | 1 +
1 file changed, 1 insertion(+)
(limited to 'include')
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 0ee283f3cffe..883b8abe4305 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -607,6 +607,7 @@ struct request_queue {
#define QUEUE_FLAG_FLUSH_NQ 25 /* flush not queueuable */
#define QUEUE_FLAG_DAX 26 /* device supports DAX */
#define QUEUE_FLAG_STATS 27 /* track rq completion times */
+#define QUEUE_FLAG_RESTART 28 /* queue needs restart at completion */
#define QUEUE_FLAG_DEFAULT ((1 << QUEUE_FLAG_IO_STAT) | \
(1 << QUEUE_FLAG_STACKABLE) | \
--
cgit