Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH for-5.13/block] blk-iocost: don't ignore vrate_min on QD
 contention
To:     Tejun Heo <tj@kernel.org>
Cc:     linux-block@vger.kernel.org, kernel-team@fb.com, dskarlat@fb.com,
        dschatzberg@fb.com, linux-kernel@vger.kernel.org
References: <YIIo1HuyNmhDeiNx@slm.duckdns.org>
From:   Jens Axboe <axboe@kernel.dk>
Message-ID: <aed2c239-8169-d30f-1410-ac0b5ae10cf1@kernel.dk>
Date:   Fri, 23 Apr 2021 08:55:15 -0600
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101
 Thunderbird/68.10.0
MIME-Version: 1.0
In-Reply-To: <YIIo1HuyNmhDeiNx@slm.duckdns.org>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 4/22/21 7:54 PM, Tejun Heo wrote:
> ioc_adjust_base_vrate() ignored vrate_min when rq_wait_pct indicates that
> there is QD contention. The reasoning was that QD depletion always reliably
> indicates device saturation and thus it's safe to override user specified
> vrate_min. However, this sometimes leads to unnecessary throttling,
> especially on really fast devices, because vrate adjustments have delays and
> inertia. It also confuses users because the behavior violates the explicitly
> specified configuration.
> 
> This patch drops the special case handling so that vrate_min is always
> applied.

Applied, thanks.

-- 
Jens Axboe