Linux-Block Archive on lore.kernel.org
 help / color / Atom feed
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


  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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=A69EF8D0-8156-46DB-A4DA-C5334764116E@linaro.org \
    --to=paolo.valente@linaro.org \
    --cc=axboe@kernel.dk \
    --cc=cgroups@vger.kernel.org \
    --cc=clm@fb.com \
    --cc=dennisz@fb.com \
    --cc=hannes@cmpxchg.org \
    --cc=jbacik@fb.com \
    --cc=josef@toxicpanda.com \
    --cc=kernel-team@fb.com \
    --cc=linux-block@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=lizefan@huawei.com \
    --cc=mkoutny@suse.com \
    --cc=newella@fb.com \
    --cc=riel@surriel.com \
    --cc=tj@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-Block Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-block/0 linux-block/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-block linux-block/ https://lore.kernel.org/linux-block \
		linux-block@vger.kernel.org
	public-inbox-index linux-block

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-block


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git