From: Jens Axboe <axboe@kernel.dk>
To: Shaohua Li <shli@fb.com>, linux-block@vger.kernel.org
Cc: Kernel-team@fb.com
Subject: Re: [PATCH] blk-throttle: ignore discard request size
Date: Fri, 18 Aug 2017 09:35:01 -0600 [thread overview]
Message-ID: <e2144181-6129-96e2-0e44-66625da2f04a@kernel.dk> (raw)
In-Reply-To: <67ffcf14c2d15622b84c60a493b590dd81a07f51.1503068984.git.shli@fb.com>
On 08/18/2017 09:13 AM, Shaohua Li wrote:
> discard request usually is very big and easily use all bandwidth budget
> of a cgroup. discard request size doesn't really mean the size of data
> written, so it doesn't make sense to account it into bandwidth budget.
> This patch ignores discard requests size. It makes sense to account
> discard request into iops budget though.
Some (most) devices to touch media for a discard operation, but the
cost tends to be fairly constant and independent of discard size.
Would it make sense to just treat it as a constant cost? Zero
cost seems wrong.
--
Jens Axboe
next prev parent reply other threads:[~2017-08-18 15:35 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-18 15:13 [PATCH] blk-throttle: ignore discard request size Shaohua Li
2017-08-18 15:35 ` Jens Axboe [this message]
2017-08-18 16:28 ` Shaohua Li
2017-08-18 19:06 ` Jens Axboe
2017-08-18 19:12 ` Shaohua Li
2017-08-18 19:15 ` Jens Axboe
2017-08-18 19:19 ` Shaohua Li
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