From: Paolo Valente <paolo.valente@linaro.org>
To: Tejun Heo <tj@kernel.org>
Cc: "Michal Koutný" <mkoutny@suse.com>,
"Johannes Weiner" <hannes@cmpxchg.org>,
clm@fb.com, dennisz@fb.com, newella@fb.com,
"Li Zefan" <lizefan@huawei.com>, "Jens Axboe" <axboe@kernel.dk>,
"Josef Bacik" <josef@toxicpanda.com>,
"Josef Bacik" <jbacik@fb.com>,
kernel-team@fb.com, "Rik van Riel" <riel@surriel.com>,
cgroups@vger.kernel.org, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 08/10] blkcg: implement blk-iocost
Date: Wed, 11 Sep 2019 10:18:53 +0200
Message-ID: <A69EF8D0-8156-46DB-A4DA-C5334764116E@linaro.org> (raw)
In-Reply-To: <20190910160855.GS2263813@devbig004.ftw2.facebook.com>
> Il giorno 10 set 2019, alle ore 18:08, Tejun Heo <tj@kernel.org> ha scritto:
>
> Hello, Michal.
>
> On Tue, Sep 10, 2019 at 02:55:14PM +0200, Michal Koutný wrote:
>> This adds the generic io.weight attribute. How will this compose with
>> the weight from IO schedulers? (AFAIK, only BFQ allows proportional
>> control as of now. +CC Paolo.)
>
> The two being enabled at the same time doesn't make sense, so we can
> just switch over to bfq when bfq is selected as the iosched. I asked
> what Paolo wanted to do in terms of interface a couple times now but
> didn't get an answer and he posted a patch which makes the two
> controllers conflict, so.... Paolo, so it looks like you want to
> rename all bfq files to drop the bfq prefix, right?
Yep, mainly because ... this is the solution you voted and you
yourself proposed [1] :)
[1] https://patchwork.kernel.org/patch/10988261/
> I can implement
> the switching if so.
>
That would be perfect.
Thanks,
Paolo
>> I see this attributes are effectively per-cgroup per-device. Apparently,
>> one device should have only one weight across hierarchy. Would it make
>> sense to have io.bfq.weight and io.cost.weight with disjunctive devices?
>
> It never makes sense to have both enabled, so I don't think that
> interface makes sense.
>
>>> + .name = "cost.qos",
>>> + .flags = CFTYPE_ONLY_ON_ROOT,
>>> [...]
>>> + .name = "cost.model",
>>> + .flags = CFTYPE_ONLY_ON_ROOT,
>> I'm concerned that these aren't true cgroup attributes. The root cgroup
>> would act as container for global configuration options. Wouldn't these
>> values better fit as (configurable) attributes of the respective
>> devices?
>
> Initially, I put them under block device sysfs but it was too clumsy
> with different config file formats and all. I think it's better to
> have global controller configs at the root cgroup.
>
>> Secondly, how is CFTYPE_ONLY_ON_ROOT supposed to be presented in cgroup
>> namespaces?
>
> Not at all. These are system-wide configs. cgroup namespaces
> shouldn't have anything which aren't in non-root cgroups.
>
> Thanks.
>
> --
> tejun
next prev 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 [this message]
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 ` [PATCH 08/10] blkcg: implement blk-iocost Tejun Heo
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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