From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D60D533CD1; Fri, 10 May 2024 03:18:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715311122; cv=none; b=qapqURuMdyvd+/Zlv6ggWNMxASLtf6XwekPYnXotBAhoz1EP4dqlj7wLi2+e/CorUsFYwOmgPQYFp9XZvrC8hw8gZaVOhHtRTr9w8/bTc0ATW7G4vRNfeaxDLQdBFCfO2sGsT9ugJnqvJL+XmNbrN99ApocSlYfPWPtfgvqaBiw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715311122; c=relaxed/simple; bh=foVyNGlbXIYrxPutsdsOkKH+iikzAmbsemiAiJGyawg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=tJuroIIFrnukH7eB1CFepQNEhPkbj6dN631NTRLw8NII46PUItRMS/eMcSrhd3dORijSWDIfMAiBgkoiODsiT7Qnfj2F/AV6+/wwPV6euPuMSRhJNLxoz/K6IbsMRyMAG09utih7SxOloeSSqx8F4UzsMevBZJ340Hw2+hQ4yr0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=JahM9Gxa; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="JahM9Gxa" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=3fHRsZcdj/tgFnGrPHUfac5A7YiWSFy0VDkIhuxQvAY=; b=JahM9GxavFkcw1GiYwoFbeXZo7 hcFNrP15sZGp+j0vhmRQ0G6ZfKgP9dPPg5G5l0K/IDzIuSD6+IfKkPzZqiIV9pMRybFuy/1XSpjFU Qx60+DMZCAP/zLSQ7HilZ/jnUvLLmCXs9FnvdPd2KRQC4EY2nT/Q2bMA/uxgsypurem2mODz7kCiH 2vtMDgsB/2uHmynZbK1izGb+ni5nMu+FvFSQQdtFSiK1ZJiRCI1GqRpOE1jI22vOCDCTstvWgEHM6 hGYHAHhCnkMzIbsq+Nf9QMw6hO503eLiFNengNrvlafcNlzHgWNEUlfQzvPtQcFaC7G6FywWLgQ0T gAEtjbYQ==; Received: from willy by casper.infradead.org with local (Exim 4.97.1 #2 (Red Hat Linux)) id 1s5Gm5-000000027Oc-3RIv; Fri, 10 May 2024 03:18:22 +0000 Date: Fri, 10 May 2024 04:18:21 +0100 From: Matthew Wilcox To: Zhaoyang Huang Cc: "zhaoyang.huang" , Andrew Morton , Jens Axboe , Tejun Heo , Josef Bacik , Baolin Wang , 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 Message-ID: References: <20240509023937.1090421-1-zhaoyang.huang@unisoc.com> <20240509023937.1090421-3-zhaoyang.huang@unisoc.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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.