From: Tejun Heo <tj@kernel.org>
To: Paolo Valente <paolo.valente@linaro.org>
Cc: Angelo Ruocco <angelo.ruocco.90@gmail.com>,
'Paolo Valente' via bfq-iosched <bfq-iosched@googlegroups.com>,
Jens Axboe <axboe@kernel.dk>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Li Zefan <lizefan@huawei.com>,
Angelo Ruocco <angeloruocco90@gmail.com>,
Dennis Zhou <dennis@kernel.org>,
Josef Bacik <josef@toxicpanda.com>,
Liu Bo <bo.liu@linux.alibaba.com>,
Bart Van Assche <bvanassche@acm.org>,
Johannes Weiner <hannes@cmpxchg.org>,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
ulf.hansson@linaro.org, linus.walleij@linaro.org,
broonie@kernel.org, oleksandr@natalenko.name,
cgroups@vger.kernel.org, linux-doc@vger.kernel.org,
Jonathan Corbet <corbet@lwn.net>
Subject: Re: [PATCH V2 00/10] unify the interface of the proportional-share policy in blkio/io
Date: Tue, 18 Dec 2018 08:41:26 -0800 [thread overview]
Message-ID: <20181218164126.GX2509588@devbig004.ftw2.facebook.com> (raw)
In-Reply-To: <874A0232-2103-4364-BD88-F33B85D6A764@linaro.org>
Hello, Paolo.
On Tue, Dec 18, 2018 at 08:48:10AM +0100, Paolo Valente wrote:
> If Tejun cannot see any solution to his concern, then can we just
> switch to this extension, considering that
> - for non-shared names the interface is *identical* to the current
> one;
> - by using this new interface, and getting feedback we could
> understand how to better handle Tejun's concern?
> A lot of systems do use weights, and people don't even know that these
> systems don't work correctly in blk-mq. And they won't work correctly
> in any available configuration from 4.21, if we don't fix this problem.
So, when seen from userland, how it should behave isn't vague or
complicated. For a given device and policy type, there can be only
one implementation active. It doesn't make sense to have two weight
mechanisms active on one device, right? So, the interface should only
present what makes sense to the user for both configuration knobs and
statistics, and that'd be a hard requirement because we don't want to
present confusing spurious information to userspace.
There seemd to have been significant misunderstandings as to what the
requirements are when this was discussed way back, so idk what the
good path forward is at this point. Just keep the current names?
Thanks.
--
tejun
next prev parent reply other threads:[~2018-12-18 16:43 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-19 10:34 [PATCH V2 00/10] unify the interface of the proportional-share policy in blkio/io Paolo Valente
2018-11-19 10:34 ` [PATCH V2 01/10] cgroup: add hook seq_show_cft with also the owning cftype as parameter Paolo Valente
2018-11-19 10:34 ` [PATCH V2 02/10] block, cgroup: pass cftype to functions that need to use it Paolo Valente
2018-11-19 10:34 ` [PATCH V2 03/10] cgroup: link cftypes of the same subsystem with the same name Paolo Valente
2018-11-19 10:34 ` [PATCH V2 04/10] cgroup: add owner name to cftypes Paolo Valente
2018-11-19 10:34 ` [PATCH V2 05/10] block, bfq: align min and default weights with the old cfq default Paolo Valente
2018-11-19 10:34 ` [PATCH V2 06/10] cgroup: make all functions of all cftypes be invoked Paolo Valente
2018-11-19 10:34 ` [PATCH V2 07/10] block, bfq: use standard file names for the proportional-share policy Paolo Valente
2018-11-19 10:34 ` [PATCH V2 08/10] block, throttle: allow sharing cgroup statistic files Paolo Valente
2018-11-19 10:34 ` [PATCH V2 09/10] doc, bfq-iosched: fix a few clerical errors Paolo Valente
2018-11-19 10:34 ` [PATCH V2 10/10] doc, bfq-iosched: make it consistent with the new cgroup interface Paolo Valente
2018-11-20 16:28 ` [PATCH V2 00/10] unify the interface of the proportional-share policy in blkio/io Tejun Heo
2018-11-20 16:50 ` Paolo Valente
2018-11-30 18:23 ` Paolo Valente
2018-11-30 18:42 ` Tejun Heo
2018-11-30 18:53 ` Paolo Valente
2018-12-10 13:45 ` Angelo Ruocco
2018-12-18 7:48 ` Paolo Valente
2018-12-18 16:41 ` Tejun Heo [this message]
2018-12-18 17:22 ` Paolo Valente
2018-12-18 18:05 ` Paolo Valente
2018-12-23 11:00 ` Paolo Valente
2018-12-27 23:41 ` Tejun Heo
2018-12-30 10:25 ` Paolo Valente
2019-01-02 16:03 ` Tejun Heo
2019-01-02 16:28 ` Paolo Valente
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