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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2E2BCC433F7 for ; Fri, 10 Jul 2020 13:58:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0A46F207D0 for ; Fri, 10 Jul 2020 13:58:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="rzyk22Li" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728125AbgGJN6H (ORCPT ); Fri, 10 Jul 2020 09:58:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39062 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727999AbgGJN6H (ORCPT ); Fri, 10 Jul 2020 09:58:07 -0400 Received: from mail-wr1-x442.google.com (mail-wr1-x442.google.com [IPv6:2a00:1450:4864:20::442]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B85AFC08C5CE; Fri, 10 Jul 2020 06:58:06 -0700 (PDT) Received: by mail-wr1-x442.google.com with SMTP id r12so6007064wrj.13; Fri, 10 Jul 2020 06:58:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=qGTdmZTNycuSsZdYyd+aOzaPH9cISwBzNXZdZyFF4OI=; b=rzyk22Li/x8K4ZYEuz81gQfs0qxf588SLcl4ZiGskAdILv8F4NmLTti5Y5MNLsqX4A cVRiD2BKx6SKDbwn9iDnKIyVf8XWOJ7lC8ioWjj+ojQj1STT3efceKA+V3idbqE+g1bp vGFdZXyMfG0zzTIBRcYl8SFjy7JZOqUka8IP5rHmUK/UqT1j7WPkk3hpiLU2f3nMIQBq tpnrCR8Y2midwlrbwJx8I/3G1CJVvwmRkaJx6d88LwHlRF5zH2jbUBr2lisOSHhW10hE ZCdzSzrB77RoZEDa6anJH7lt9PNCSXESjyzSnqfSZdblccMBPGTBlz7LP36lxBNkXYe5 oPlw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=qGTdmZTNycuSsZdYyd+aOzaPH9cISwBzNXZdZyFF4OI=; b=W7rteyHSLQBbgXLPirUrUWhvgyMXW9E0VFxG535wfStdldcEzk7eXGQN3FGjGdDcj3 zZ8cii9MfzvBo4R+LHnk2U2PAnvRDZaQME7u5BG4wmjdtXCEK/R5uARDqQYE42DN+823 /C5hDGlhK0+k3QjQ0gdTxgC02JaMIJI/nBPujQwAXSPcSXl6VBPH2b9CBgQTd/98GqY/ ngWRB/Nicj4uJ2vWXcnJNw5MRLp2JxSvhs1YW8UrXNguffY4/Nf1QjXeT4Lz1TKh2917 xLQs/KQXRuGJXDxN/vvFFpDd+6pqPsLGTGZRY7ywGAvb7h0AFLGJ+Y96EVCCuJb6UCzH wp1A== X-Gm-Message-State: AOAM531k3Vtj6CzVpSfIq5G9LTgUAJ0E3mrUW/8eetG2GKfLmz38NVKJ SzaTg2pbzThErpHmHEtsESdI6xaOucV7ee4XDRc= X-Google-Smtp-Source: ABdhPJxAXPyq+TgGM1KIrPXsNrVp0LsQhJw7n+KMql5in4TTsc5AAhvy36mPobH51Ew8wqP3H+CbX4J2nUXnh92VB5A= X-Received: by 2002:adf:f0ce:: with SMTP id x14mr65348995wro.137.1594389485356; Fri, 10 Jul 2020 06:58:05 -0700 (PDT) MIME-Version: 1.0 References: <1593974870-18919-1-git-send-email-joshi.k@samsung.com> <1593974870-18919-5-git-send-email-joshi.k@samsung.com> <20200709085501.GA64935@infradead.org> <20200709140053.GA7528@infradead.org> <2270907f-670c-5182-f4ec-9756dc645376@kernel.dk> <20200710130912.GA7491@infradead.org> In-Reply-To: From: Kanchan Joshi Date: Fri, 10 Jul 2020 19:27:38 +0530 Message-ID: Subject: Re: [PATCH v3 4/4] io_uring: add support for zone-append To: Christoph Hellwig Cc: Jens Axboe , Kanchan Joshi , viro@zeniv.linux.org.uk, bcrl@kvack.org, Damien.LeMoal@wdc.com, asml.silence@gmail.com, linux-fsdevel@vger.kernel.org, "Matias Bj??rling" , linux-kernel@vger.kernel.org, linux-aio@kvack.org, io-uring@vger.kernel.org, linux-block@vger.kernel.org, Selvakumar S , Nitesh Shetty , Javier Gonzalez Content-Type: text/plain; charset="UTF-8" Sender: io-uring-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On Fri, Jul 10, 2020 at 6:59 PM Kanchan Joshi wrote: > > On Fri, Jul 10, 2020 at 6:39 PM Christoph Hellwig wrote: > > > > On Thu, Jul 09, 2020 at 12:50:27PM -0600, Jens Axboe wrote: > > > It might, if you have IRQ context for the completion. task_work isn't > > > expensive, however. It's not like a thread offload. Not sure about polled-completion but we have IRQ context for regular completion. If I've got it right, I need to store task_struct during submission, and use that to register a task_work during completion. At some point when this task_work gets called it will update the user-space pointer with the result. It can be the case that we get N completions parallely, but they all would get serialized because all N task-works need to be executed in the context of single task/process? > > > > Using flags have not been liked here, but given the upheaval involved so > > > > far I have begun to feel - it was keeping things simple. Should it be > > > > reconsidered? > > > > > > It's definitely worth considering, especially since we can use cflags > > > like Pavel suggested upfront and not need any extra storage. But it > > > brings us back to the 32-bit vs 64-bit discussion, and then using blocks > > > instead of bytes. Which isn't exactly super pretty. > > > > block doesn't work for the case of writes to files that don't have > > to be aligned in any way. And that I think is the more broadly > > applicable use case than zone append on block devices. > > But when can it happen that we do zone-append on a file (zonefs I > asssume), and device returns a location (write-pointer essentially) > which is not in multiple of 512b? > > > -- > Joshi -- Joshi