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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=unavailable 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 5AFC9C282CF for ; Mon, 28 Jan 2019 23:25:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 28940214DA for ; Mon, 28 Jan 2019 23:25:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727006AbfA1XZO (ORCPT ); Mon, 28 Jan 2019 18:25:14 -0500 Received: from mga17.intel.com ([192.55.52.151]:42433 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726750AbfA1XZO (ORCPT ); Mon, 28 Jan 2019 18:25:14 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 28 Jan 2019 15:25:13 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,535,1539673200"; d="scan'208";a="122080213" Received: from unknown (HELO localhost.localdomain) ([10.232.112.69]) by orsmga003.jf.intel.com with ESMTP; 28 Jan 2019 15:25:12 -0800 Date: Mon, 28 Jan 2019 16:24:24 -0700 From: Keith Busch To: Jan Kara Cc: Kanchan Joshi , "linux-fsdevel@vger.kernel.org" , "linux-block@vger.kernel.org" , "linux-ext4@vger.kernel.org" , "linux-nvme@lists.infradead.org" , "jack@suse.com" , "david@fromorbit.com" , "tytso@mit.edu" , "prakash.v@samsung.com" Subject: Re: [PATCH v2 0/4] Write-hint for FS journal Message-ID: <20190128232423.GD15302@localhost.localdomain> References: <1547047861-7271-1-git-send-email-joshi.k@samsung.com> <20190125162353.GA11210@localhost.localdomain> <20190128124709.GB27972@quack2.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190128124709.GB27972@quack2.suse.cz> User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Mon, Jan 28, 2019 at 04:47:09AM -0800, Jan Kara wrote: > On Fri 25-01-19 09:23:53, Keith Busch wrote: > > On Wed, Jan 09, 2019 at 09:00:57PM +0530, Kanchan Joshi wrote: > > > Towards supporing write-hints/streams for filesystem journal. > > > > > > Here is the v1 patch for background - > > > https://marc.info/?l=linux-fsdevel&m=154444637519020&w=2 > > > > > > Changes since v1: > > > - introduce four more hints for in-kernel use, as recommended by Dave chinner > > > & Jens axboe. This isolates kernel-mode hints from user-mode ones. > > > > The nvme driver disables streams if the controller doesn't support > > BLK_MAX_WRITE_HINT number of streams, so this series breaks the feature > > for controllers that only support up to 4. > > Right. Do you know if there are such controllers? Or are you just afraid > that there could be? I've asked around, and the concensus I received is all currently support at least 8, but they couldn't say if that would be true for potential lower budget products. Can we implement a reasonable fallback to use what's available?