Re: [PATCH] cfq-iosched: don't check cfqg in choose_service_tree()

Vivek Goyal
2010-12-14T22:25:27Z

On Tue, Dec 14, 2010 at 02:32:28PM +0800, Gui Jianfeng wrote:
> When cfq_choose_cfqg() is called in select_queue(), there must be at least one
> backlogged CFQ queue waiting for dispatching, hence there must be at least one
> backlogged CFQ group on service tree. So we never call choose_service_tree()
> with cfqg == NULL.
>
> Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
> ---

Thanks Gui for the cleanup. This patch looks good to me.

Acked-by: Vivek Goyal <vgoyal@redhat.com>

Vivek

> block/cfq-iosched.c | 6 ------
> 1 files changed, 0 insertions(+), 6 deletions(-)
>
> diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
> index 9b186fd..c19d015 100644
> --- a/block/cfq-iosched.c
> +++ b/block/cfq-iosched.c
> @@ -2103,12 +2103,6 @@ static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg)
> unsigned group_slice;
> enum wl_prio_t original_prio = cfqd->serving_prio;
>
> - if (!cfqg) {
> - cfqd->serving_prio = IDLE_WORKLOAD;
> - cfqd->workload_expires = jiffies + 1;
> - return;
> - }
> -
> /* Choose next priority. RT > BE > IDLE */
> if (cfq_group_busy_queues_wl(RT_WORKLOAD, cfqd, cfqg))
> cfqd->serving_prio = RT_WORKLOAD;
> --
> 1.6.5.2
>