[dm-devel] Re: [PATCH] io-controller: implement per group request allocation limitation

[Munehiro Ikeda <m-ikeda ds jp nec com>]

Gui Jianfeng wrote, on 07/09/2009 09:56 PM:
> Hi Vivek,
>
> This patch exports a cgroup based per group request limits interface.
> and removes the global one. Now we can use this interface to perform
> different request allocation limitation for different groups.
>
> Signed-off-by: Gui Jianfeng<guijianfeng cn fujitsu com>
> ---
(snip)

Hi Jianfeng,

If this helps.

If calling elv_io_group_congestion_threshold() before
setting iog->iocg_id, iocg->nr_group_requests cannot be
referred.  As a result of it, iog->nr_congestion_on is
always misculculated as 0.
This patch moves the calling of
elv_io_group_congestion_threshold() after setting
iog->iocg_id.

Signed-off-by: Munehiro "Muuhh" Ikeda <m-ikeda ds jp nec 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 7c83d1e..3368a7f 100644
--- a/block/elevator-fq.c
+++ b/block/elevator-fq.c
@@ -2195,7 +2195,6 @@ static struct io_group *io_alloc_root_group(struct request_queue *q,
 		iog->sched_data.service_tree[i] = IO_SERVICE_TREE_INIT;
 
 	blk_init_request_list(&iog->rl);
-	elv_io_group_congestion_threshold(q, iog);
 
 	iocg = &io_root_cgroup;
 	spin_lock_irq(&iocg->lock);
@@ -2204,6 +2203,8 @@ static struct io_group *io_alloc_root_group(struct request_queue *q,
 	iog->iocg_id = css_id(&iocg->css);
 	spin_unlock_irq(&iocg->lock);
 
+	elv_io_group_congestion_threshold(q, iog);
+
 #ifdef CONFIG_DEBUG_GROUP_IOSCHED
 	io_group_path(iog, iog->path, sizeof(iog->path));
 #endif
--
1.6.2.5




--
IKEDA, Munehiro
  NEC Corporation of America
    m-ikeda ds jp nec com