From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D0FC3C433EF for ; Tue, 17 May 2022 06:12:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234879AbiEQGL7 (ORCPT ); Tue, 17 May 2022 02:11:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42234 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231979AbiEQGL6 (ORCPT ); Tue, 17 May 2022 02:11:58 -0400 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 320D743AFA; Mon, 16 May 2022 23:11:57 -0700 (PDT) Received: by verein.lst.de (Postfix, from userid 2407) id 5145968AA6; Tue, 17 May 2022 08:11:52 +0200 (CEST) Date: Tue, 17 May 2022 08:11:52 +0200 From: Christoph Hellwig To: Khazhy Kumykov Cc: Tejun Heo , Jens Axboe , Christoph Hellwig , linux-block@vger.kernel.org, w.bumiller@proxmox.com, cgroups@vger.kernel.org Subject: Re: Issue with 252c651a4c85 ("blk-cgroup: stop using seq_get_buf") Message-ID: <20220517061152.GA4789@lst.de> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Thu, May 12, 2022 at 03:42:54PM -0700, Khazhy Kumykov wrote: > I can see in the latest tip, if we have devices with no statistics, > we'll print the maj:min and then nothing else, which can end up > looking weird, (e.g. like below.) I see that in older kernels, we > avoided printing the device name at all if there were no stats, and it > looks like this behavior was silently broken by 252c651a4c85 > ("blk-cgroup: stop using seq_get_buf"), where before we prepared the > whole line then decided at the end whether to commit it or not. > > I do see a patch "blk-cgroup: always terminate io.stat lines" that > addresses this by just unconditionally printing the newline (though it > looks like that patch never landed). It should really go in, I just sent a ping for it.