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From: Vivek Goyal on 24 Mar 2010 21:10
On Wed, Mar 24, 2010 at 01:52:03PM -0700, Divyesh Shah wrote:
> even if they are found to be co-operating.
>
> The prio_trees do not have any IDLE cfqqs on them. cfq_close_cooperator()
> is called from cfq_select_queue() and cfq_completed_request(). The latter
> ensures that the close cooperator code does not get invoked if the current
> cfqq is of class IDLE but the former doesn't seem to have any such checks.
> So an IDLE cfqq may get merged with a BE cfqq from the same group which
> should be avoided.
>
> Signed-off-by: Divyesh Shah<dpshah(a)google.com>
> ---

Looks good to me.

Acked-by: Vivek Goyal <vgoyal(a)redhat.com>

Vivek

>
> block/cfq-iosched.c | 2 ++
> 1 files changed, 2 insertions(+), 0 deletions(-)
>
> diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
> index dee9d93..e6910dc 100644
> --- a/block/cfq-iosched.c
> +++ b/block/cfq-iosched.c
> @@ -1721,6 +1721,8 @@ static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd,
> {
> struct cfq_queue *cfqq;
>
> + if (cfq_class_idle(cur_cfqq))
> + return NULL;
> if (!cfq_cfqq_sync(cur_cfqq))
> return NULL;
> if (CFQQ_SEEKY(cur_cfqq))
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From: Jens Axboe on 25 Mar 2010 10:50
On Wed, Mar 24 2010, Divyesh Shah wrote:
> even if they are found to be co-operating.
>
> The prio_trees do not have any IDLE cfqqs on them. cfq_close_cooperator()
> is called from cfq_select_queue() and cfq_completed_request(). The latter
> ensures that the close cooperator code does not get invoked if the current
> cfqq is of class IDLE but the former doesn't seem to have any such checks.
> So an IDLE cfqq may get merged with a BE cfqq from the same group which
> should be avoided.

Thanks, applied.

--
Jens Axboe

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Prev: [PATCH 1/2] tracing: Reduce overhead of module tracepoints
Next: [PATCH][v2] cfq-iosched: Add additional blktrace log messages in CFQ for easier debugging.