Date: Wed, 23 Nov 2016 17:06:30 -0800
From: Shaohua Li <shli@fb.com>
To: Tejun Heo <tj@kernel.org>
CC: <linux-block@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <Kernel-team@fb.com>, <axboe@fb.com>, <vgoyal@redhat.com>
Subject: Re: [PATCH V4 11/15] blk-throttle: add interface to configure think
 time threshold
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On Wed, Nov 23, 2016 at 04:32:43PM -0500, Tejun Heo wrote:
> On Mon, Nov 14, 2016 at 02:22:18PM -0800, Shaohua Li wrote:
> > Add interface to configure the threshold
> > 
> > Signed-off-by: Shaohua Li <shli@fb.com>
> > ---
> >  block/blk-sysfs.c    |  7 +++++++
> >  block/blk-throttle.c | 25 +++++++++++++++++++++++++
> >  block/blk.h          |  4 ++++
> >  3 files changed, 36 insertions(+)
> > 
> > diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
> > index 3e284e4..f15aeed 100644
> > --- a/block/blk-sysfs.c
> > +++ b/block/blk-sysfs.c
> > @@ -532,6 +532,12 @@ static struct queue_sysfs_entry throtl_slice_entry = {
> >  	.show = blk_throtl_slice_show,
> >  	.store = blk_throtl_slice_store,
> >  };
> > +
> > +static struct queue_sysfs_entry throtl_idle_threshold_entry = {
> > +	.attr = {.name = "throttling_idle_threshold", .mode = S_IRUGO | S_IWUSR },
> > +	.show = blk_throtl_idle_threshold_show,
> > +	.store = blk_throtl_idle_threshold_store,
> > +};
> 
> Shouldn't this be a per-cgroup setting along with latency target?
> These two are the parameters which define how the cgroup should be
> treated time-wise.

It should be easy to make it per-cgroup. Just not sure if it should be
per-cgroup. The logic is if the disk is faster, wait time should be shorter to
not harm performance. So it sounds like a per-disk characteristic.

Thanks,
Shaohua