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From: Tejun Heo <tj@kernel.org>
To: Hillf Danton <hdanton@sina.com>
Cc: axboe@kernel.dk, newella@fb.com, clm@fb.com,
	josef@toxicpanda.com, dennisz@fb.com, lizefan@huawei.com,
	hannes@cmpxchg.org, linux-kernel@vger.kernel.org,
	linux-block@vger.kernel.org, kernel-team@fb.com,
	cgroups@vger.kernel.org, Josef Bacik <jbacik@fb.com>,
	Rik van Riel <riel@surriel.com>
Subject: Re: [PATCH 08/10] blkcg: implement blk-iocost
Date: Thu, 29 Aug 2019 08:46:09 -0700
Message-ID: <20190829154609.GU2263813@devbig004.ftw2.facebook.com> (raw)
In-Reply-To: <20190829133928.16192-1-hdanton@sina.com>

Hello,

On Thu, Aug 29, 2019 at 09:39:28PM +0800, Hillf Danton wrote:
> > +	on_q_ns = ktime_get_ns() - rq->alloc_time_ns;
> > +	rq_wait_ns = rq->start_time_ns - rq->alloc_time_ns;
> > +
> ehm... alloc_time makes no sense wrt start_time if this is their only
> use. What are you trying to measure with the two stamps if they are
> meaningfully apart?

Queue depth depletion.

> > +	rq_qos_add(q, rqos);
> > +	ret = blkcg_activate_policy(q, &blkcg_policy_iocost);
> > +	if (ret) {
> > +		rq_qos_del(q, rqos);
> 
> 		free_percpu(ioc->pcpu_stat);

Good catch.  Will send a follow up patch.

Thanks.

-- 
tejun

  parent reply index

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-28 22:05 [PATCHSET v3 block/for-linus] IO cost model based work-conserving porportional controller Tejun Heo
2019-08-28 22:05 ` [PATCH 01/10] blkcg: pass @q and @blkcg into blkcg_pol_alloc_pd_fn() Tejun Heo
2019-08-28 22:05 ` [PATCH 02/10] blkcg: make ->cpd_init_fn() optional Tejun Heo
2019-08-28 22:05 ` [PATCH 03/10] blkcg: separate blkcg_conf_get_disk() out of blkg_conf_prep() Tejun Heo
2019-08-28 22:05 ` [PATCH 04/10] block/rq_qos: add rq_qos_merge() Tejun Heo
2019-08-28 22:05 ` [PATCH 05/10] block/rq_qos: implement rq_qos_ops->queue_depth_changed() Tejun Heo
2019-08-28 22:05 ` [PATCH 06/10] blkcg: s/RQ_QOS_CGROUP/RQ_QOS_LATENCY/ Tejun Heo
2019-08-28 22:05 ` [PATCH 07/10] blk-mq: add optional request->alloc_time_ns Tejun Heo
2019-08-28 22:05 ` [PATCH 08/10] blkcg: implement blk-iocost Tejun Heo
2019-08-29 15:53   ` [PATCH] blkcg: fix missing free on error path of blk_iocost_init() Tejun Heo
2019-09-10 12:55   ` [PATCH 08/10] blkcg: implement blk-iocost Michal Koutný
2019-09-10 16:08     ` Tejun Heo
2019-09-11  8:18       ` Paolo Valente
2019-09-11 14:16         ` Tejun Heo
2019-09-11 15:54           ` Tejun Heo
2019-09-11 16:44           ` Paolo Valente
2019-10-03 14:51       ` Michal Koutný
2019-10-03 16:45         ` Tejun Heo
2019-10-09 15:36           ` Michal Koutný
2019-10-14 15:36             ` Tejun Heo
2019-11-01 16:15               ` Michal Koutný
2019-11-01 16:56                 ` Paolo Valente
2019-08-28 22:05 ` [PATCH 09/10] blkcg: add tools/cgroup/iocost_monitor.py Tejun Heo
2019-08-28 22:06 ` [PATCH 10/10] blkcg: add tools/cgroup/iocost_coef_gen.py Tejun Heo
2019-08-29  3:29 ` [PATCHSET v3 block/for-linus] IO cost model based work-conserving porportional controller Jens Axboe
     [not found] ` <20190829082248.6464-1-hdanton@sina.com>
2019-08-29 15:43   ` [PATCH 07/10] blk-mq: add optional request->alloc_time_ns Tejun Heo
     [not found] ` <20190829133928.16192-1-hdanton@sina.com>
2019-08-29 15:46   ` Tejun Heo [this message]
2019-08-29 15:54 ` [PATCHSET v3 block/for-linus] IO cost model based work-conserving porportional controller Paolo Valente
2019-08-29 15:56   ` Tejun Heo
  -- strict thread matches above, loose matches on Subject: below --
2019-07-10 20:51 [PATCHSET v2 " Tejun Heo
2019-07-10 20:51 ` [PATCH 08/10] blkcg: implement blk-iocost Tejun Heo

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