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 BB956C07E9D for ; Mon, 26 Sep 2022 15:56:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234536AbiIZP4q (ORCPT ); Mon, 26 Sep 2022 11:56:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35316 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234488AbiIZP40 (ORCPT ); Mon, 26 Sep 2022 11:56:26 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6031C18B39 for ; Mon, 26 Sep 2022 07:43:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; 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=yd+7xPXxutp7BMz4CBbE8owqija+W0l0RgE5zhq40bw=; b=IhEc7ztHXDV+p89G2zat6RrXXl ZEQOl7wpL4a9ZiA2aFW01gJkUXQIZSapKtXsEPQzgi2GpJhRBxZmJ3nxfbDZgIZAgor+u3OucfUi7 JHZZ51Y5yS7fP8qB5gvUyNlj4Rte7QZg7zxHqnTYJlz/4TrmLTCmjaJ5Veu9PPO8+FVOtP4+dVNP7 Bt7e9s2vpZwLDOAAShXXEzrpbQXudfb9x9awttp/Cr7eR4vk8glEFVN/YnpC7ETR29zDfUwvv/4Zi aMjtjmMZOdXrGCKWda3fZNW5S4DpMqx15zguXyryDyOYwlKFeDqfjcHDrQawSQDyN5PES+TaSabeJ xyidgwpw==; Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1ocpK9-005QwG-Aw; Mon, 26 Sep 2022 14:43:09 +0000 Date: Mon, 26 Sep 2022 07:43:09 -0700 From: Christoph Hellwig To: Jens Axboe Cc: Christoph Hellwig , Pankaj Raghav , linux-block@vger.kernel.org, damien.lemoal@opensource.wdc.com, gost.dev@samsung.com Subject: Re: [PATCH 1/2] block: modify blk_mq_plug() to allow only reads for zoned block devices Message-ID: References: <20220925185348.120964-1-p.raghav@samsung.com> <20220925185348.120964-2-p.raghav@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Mon, Sep 26, 2022 at 08:40:54AM -0600, Jens Axboe wrote: > On 9/26/22 8:37 AM, Christoph Hellwig wrote: > > On Sun, Sep 25, 2022 at 08:53:46PM +0200, Pankaj Raghav wrote: > >> Modify blk_mq_plug() to allow plugging only for read operations in zoned > >> block devices as there are alternative IO paths in the linux block > >> layer which can end up doing a write via driver private requests in > >> sequential write zones. > > > > We should be able to plug for all operations that are not > > REQ_OP_ZONE_APPEND just fine. > > Agree, I think we just want to make this about someone doing a series > of appends. If you mix-and-match with passthrough you will have a bad > time anyway. Err, sorry - what I wrote about is compelte garbage. I initially wanted to say you can plug for REQ_OP_ZONE_APPEND just fine, and then realized that we also want various other ones that have the write bit set batched. So I suspect we really want to explicitly check for REQ_OP_WRITE here.