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 686F4C433FE for ; Mon, 21 Nov 2022 08:14:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229575AbiKUIOW (ORCPT ); Mon, 21 Nov 2022 03:14:22 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44648 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229874AbiKUIOU (ORCPT ); Mon, 21 Nov 2022 03:14:20 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9BF6127FCB for ; Mon, 21 Nov 2022 00:13:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1669018401; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=LXlYy9pZM0dbFzL7qiPQerpcjHoHper9o+KpvlsD6jg=; b=Vwa1kOERxQgiyfrevjFJtXVm3wjDU4vPXXtfokKnU1Omh2qDirZs+b5VVNCLKFhsMZmkKg 23anqydOcMTZa+S68D4FDSkRS4BXIFAH9TjrTqgvxEi1wg7LnePjaC8mnYclPQQncJdHUi vxBWgVb6+lJ1bNtq1lHbIUeV5Q0dqPQ= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-12-1i1GLF9IOWKBtLsYoPD4aQ-1; Mon, 21 Nov 2022 03:13:20 -0500 X-MC-Unique: 1i1GLF9IOWKBtLsYoPD4aQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id DD59E38012C8; Mon, 21 Nov 2022 08:13:19 +0000 (UTC) Received: from T590 (ovpn-8-16.pek2.redhat.com [10.72.8.16]) by smtp.corp.redhat.com (Postfix) with ESMTPS id CEEAA2027061; Mon, 21 Nov 2022 08:13:15 +0000 (UTC) Date: Mon, 21 Nov 2022 16:13:10 +0800 From: Ming Lei To: Christoph Hellwig Cc: Damien Le Moal , Andreas Hindborg , Jens Axboe , linux-block@vger.kernel.org, ming.lei@redhat.com Subject: Re: Reordering of ublk IO requests Message-ID: References: <87fseh92aa.fsf@wdc.com> <2f86eb58-148b-03ac-d2bf-d67c5756a7a6@opensource.wdc.com> <8735ag8ueg.fsf@wdc.com> <87v8nc79cv.fsf@wdc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Mon, Nov 21, 2022 at 12:03:02AM -0800, Christoph Hellwig wrote: > I've been wading through this thread a bit, and while I can't follow > everything due some pretty bad reply trimming I'm really really > confused by this whole discussion. > > Every single storage system, be that hard drives, SSDs, file systems > or what else much preferres sequential write. Any code that turns > perfectly sequential writes into reverse sequential writes is a massive > performance bug, zoned or not. > > So totally independent of zone device support in ublk this needs to be > fixed ASAP. I will send one fix soon. BTW, blk-mq has such similar issue, which is reported for while, but not addressed yet. https://lore.kernel.org/linux-nvme/CAHex0coMNvFa1TPzK+5mZHsiie4d1Jd0Z8ejcZk1Vi1_4F7eRg@mail.gmail.com/T/#mbcb9b52ff61aed6fdd1b6630c6e62e55a4ed898f Thanks, Ming