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Date: Fri, 10 May 2024 04:18:21 +0100
From: Matthew Wilcox <willy@infradead.org>
To: Zhaoyang Huang <huangzhaoyang@gmail.com>
Cc: "zhaoyang.huang" <zhaoyang.huang@unisoc.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Jens Axboe <axboe@kernel.dk>, Tejun Heo <tj@kernel.org>,
	Josef Bacik <josef@toxicpanda.com>,
	Baolin Wang <baolin.wang@linux.alibaba.com>, linux-mm@kvack.org,
	linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
	cgroups@vger.kernel.org, steve.kang@unisoc.com
Subject: Re: [RFC PATCH 2/2] mm: introduce budgt control in readahead
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On Fri, May 10, 2024 at 10:43:20AM +0800, Zhaoyang Huang wrote:
> Thanks for the prompt. I did some basic research on soft RAID and
> wonder if applying the bps limit on /dev/md0 like below could make
> this work.

No.  Look at btrfs' raid support, for example.  it doesn't use md0.

> I didn't find information about 'RAID internally'. Could we set the
> limit on the root device(the one used for mount) to manage the whole
> partition without caring about where the bio finally goes? Or ask the
> user to decide if to use by making sure the device they apply will not
> do RAID?

No.