[dm-devel] Re: [PATCH 17/19] io-controller: Support per cgroup per device weights and io class

[Gui Jianfeng <guijianfeng cn fujitsu com>]

Vivek Goyal wrote:
...
>  
> @@ -1233,6 +1254,8 @@ struct io_group *io_group_chain_alloc(struct request_queue *q, void *key,
>  		elv_get_iog(iog);
>  
>  		iog->iocg_id = css_id(&iocg->css);
> +		io_group_init_entity(iocg, iog, iog->dev);

Hi Vivek,

A regression occurs in io.policy handling. IO Controller completely stops working when i use 
this interface. 
Make sure that we initialize entity after iog->dev is setting up properly.

Signed-off-by: Gui Jianfeng <guijianfeng cn fujitsu com>
---
 block/elevator-fq.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/block/elevator-fq.c b/block/elevator-fq.c
index 6b30c36..a516dce 100644
--- a/block/elevator-fq.c
+++ b/block/elevator-fq.c
@@ -1451,7 +1451,6 @@ struct io_group *io_group_chain_alloc(struct request_queue *q, void *key,
 		elv_get_iog(iog);
 
 		iog->iocg_id = css_id(&iocg->css);
-		io_group_init_entity(iocg, iog, iog->dev);
 		iog->my_entity = &iog->entity;
 
 		if (bio) {
@@ -1459,6 +1458,8 @@ struct io_group *io_group_chain_alloc(struct request_queue *q, void *key,
 			iog->dev = MKDEV(disk->major, disk->first_minor);
 		}
 
+		io_group_init_entity(iocg, iog, iog->dev);
+
 		blk_init_request_list(&iog->rl);
 #ifdef CONFIG_DEBUG_GROUP_IOSCHED
 		io_group_path(iog, iog->path, sizeof(iog->path));
-- 
1.5.4.rc3