From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 2008127FD52; Wed, 4 Mar 2026 16:48:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772642899; cv=none; b=LemKnc4NKnOH1H7qAFDFU9zWOQcIJxzNH2d4UgoBKX8dlOSFQkE6jmuRcTfmsqaD7Ri9jk7x1tctf0Q4OQAelKmVsvzCf4Ot9CXm8J1WsW/8SFbICHimiFUApRez5u4Oafx/EC/Mf8pu7uFFUaf0vmzKUbc9DlVhTWu9MAYcjDo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772642899; c=relaxed/simple; bh=5BbHZMLyY1O+x4P9MgQ1WppXPdBOTizCZSh/gDLkd+Y=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=qedjvXr9x92ucfczLiEpcTXJmdvVIrSn04s+hget2oSQsovTwRKrAboXab7kVLW+bwxOI4gWN6/D+gBzCobcek3p3PYn/bv+rgzOokSjURcqDfAKdpSxIHtTLkNt4CyjIhKoO5EspMv2p8ad4ZBFSItJWSJRIDV9JKMzU7mC30Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Ps/UMxSo; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Ps/UMxSo" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 90772C19425; Wed, 4 Mar 2026 16:48:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772642898; bh=5BbHZMLyY1O+x4P9MgQ1WppXPdBOTizCZSh/gDLkd+Y=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Ps/UMxSoCn8YIhEWM20xB+ijaCPxzG7qeMx5ATR1V//dcYK0jlwTzSEmWRert7lEq 5LXSK8u+N39MA9/1fKhw8V+cIUPWdl8103WvD+g96QiTnRNEcfEmdPmXJ1qZ1EVQis mxXGW1AV45Bjsyo9xy0mMci+8sswcSsqNcHn/+LqDSW8U8WGHjirxf5uEqI0YUks2f yB3yiPShcNJEt25AwWEgDwfAzFCPXShWjC20pka0L98FJi1YOsl8xHdKegjC7Ru/To V0rCLie9Cf+bX6OCjV7irAvbjqBBxysNte8WgcrbJhbXBXY4nw2VFAFwqmDQNhJHnW fRUo653P/uujg== Date: Wed, 4 Mar 2026 06:48:17 -1000 From: Tejun Heo To: Breno Leitao Cc: Jens Axboe , Josef Bacik , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, thevlad@meta.com, kernel-team@meta.com, Michal =?iso-8859-1?Q?Koutn=FD?= Subject: Re: [PATCH v2] blk-cgroup: always display debug stats in io.stat Message-ID: References: <20260303-blk_cgroup_debug_stats-v2-1-196c713cb762@debian.org> Precedence: bulk X-Mailing-List: linux-kernel@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: Hello, Breno. On Wed, Mar 04, 2026 at 01:56:43AM -0800, Breno Leitao wrote: > > Given that they haven't changed for a long time, maybe it's okay to expose > > them by default, but why? This is something which can be toggled on easily > > at any time. > > My goal is to ship a kernel that exposes these detailed io stats by > default, without requiring any runtime configuration. The stats should > simply be available out of the box. This is a pretty trivial patch to carry, right? Or just do it as a part of boot system config? > > What's the benefit of exposing these extra numbers which > > probably don't mean much for most people? > > My original plan was to introduce a Kconfig option for this. In v1 (about a > month ago), Michal suggested removing the toggle entirely and always exposing > the stats, which seemed reasonable to me and received no objections, so I > went ahead with that approach. > > To be clear: is your position that we should not support building a kernel > that always exposes the detailed stats in io.stat? As a debug option maybe but I'd prefer if vendors (including us) that want to permanently enable these debug stats carried the patch in their trees. I think that these are a bit too tied to the specifics of the current implementation and it's not very difficult to imagine at least some of the keys changing or getting dropped in the future, so I'm reluctant to export them by default. Thanks. -- tejun