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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 DDFF8C43387 for ; Fri, 4 Jan 2019 20:49:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AFF5C21872 for ; Fri, 4 Jan 2019 20:49:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726009AbfADUti (ORCPT ); Fri, 4 Jan 2019 15:49:38 -0500 Received: from mail-pf1-f196.google.com ([209.85.210.196]:45932 "EHLO mail-pf1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725958AbfADUth (ORCPT ); Fri, 4 Jan 2019 15:49:37 -0500 Received: by mail-pf1-f196.google.com with SMTP id g62so18803556pfd.12 for ; Fri, 04 Jan 2019 12:49:36 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:subject:from:to:cc:date:in-reply-to :references:mime-version:content-transfer-encoding; bh=W4rIQVa1H38RC7FpdD+1oCJA+IqU948lfFpZwXiwtE0=; b=P4l9pdSU6cAhb/YKTYra077Allg666j/tavoq31OGvZPbvp8tUfwi/7obJn7VIMj3Y OXnqGbdJwlHgsfSdTH6Z8GEBAlDTMVWU8UzbhrSal7KGaRu5hUBETDND2crlhKs79nd7 wChQnF0nutEOeZhO4bJon4JjmLhIy9TvlQujh0eFaVoxq8at0XVCztFc+moetJ+0POfD /otIj/5iI9wR/Hp/9IRu+L3UyknToxY3fAzA2X3wdqBHilEQZAbZa7DugfE3n/riwxmt XwSb1oBylM5h/e8bn/XYKE000PGGsLs/9DNclOvHEpLaUbyHuiTeM13aiXonyFX0/yFc X/2A== X-Gm-Message-State: AJcUukctREpwM2IqkNjlFTVe0xV4pJx8mAPa3XLK4nTFpv8yR08liWCs fyuseuJ1HAgItRfdCvtjeISrpZcqbdc39g== X-Google-Smtp-Source: ALg8bN60Vec0ZN5zlxfhsrb2k0/LvDjkO523E/5woONrsTxQQyGaNmgJglM9qotO3oCuFMpAq+6wmg== X-Received: by 2002:a63:c051:: with SMTP id z17mr2835262pgi.20.1546634975691; Fri, 04 Jan 2019 12:49:35 -0800 (PST) Received: from ?IPv6:2620:15c:2cd:203:5cdc:422c:7b28:ebb5? ([2620:15c:2cd:203:5cdc:422c:7b28:ebb5]) by smtp.gmail.com with ESMTPSA id g3sm127148968pfe.37.2019.01.04.12.49.34 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 04 Jan 2019 12:49:34 -0800 (PST) Message-ID: <1546634973.83374.4.camel@acm.org> Subject: Re: [PATCH] null_blk: add zoned config support information From: Bart Van Assche To: John Pittman Cc: Jens Axboe , linux-block@vger.kernel.org Date: Fri, 04 Jan 2019 12:49:33 -0800 In-Reply-To: References: <20190104154243.3538-1-jpittman@redhat.com> <1546620417.163063.45.camel@acm.org> Content-Type: text/plain; charset="UTF-7" X-Mailer: Evolution 3.26.2-1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Fri, 2019-01-04 at 15:37 -0500, John Pittman wrote: +AD4 Thanks Bart+ADs I made the changes and sent them in as a v2, I'm sure you +AD4 already saw. I have a quick, unrelated question if you have a moment. +AD4 In testing the null+AF8-blk driver, I found that trim commands sent by fio +AD4 were rejected due to lack of support. Tracking down Shaohua's commit +AD4 306eb6b4a (+ACI-nullb: support discard+ACI), he mentions that +ACI-discard makes +AD4 sense for memory backed disk+ACI. Just to see what would happen, I +AD4 edited the source to make discard a configurable parameter at +AD4 modprobe, and after the edit +ACY build, the trim commands submitted +AD4 fine. Does this sort of change make sense? I mean the ability to do +AD4 discard to null+AF8-blk without it being memory backed+ADs solely for +AD4 testing/benchmarking purposes. I haven't found any good instructions +AD4 on creating a memory backed or discard enabled null+AF8-blk device from +AD4 the command line, so I assume a higher level driver would have to hook +AD4 in and enable these features manually. Thanks for your time and any +AD4 information. Hi John, Jens as the block layer maintainer has the last word about this. Personally I would welcome that functionality. Before discard functionality was removed from the brd driver I used the brd driver to test the discard functionality in storage target stacks. If discard functionality would be added to the null+AF8-blk driver then that would make it possible to use that driver for testing the discard functionality in e.g. LIO. See also commit f09a06a193d9 (+ACI-brd: remove discard support+ACI). I'm not sure that we need a modprobe parameter to enable or disable trim functionality in the null+AF8-blk driver. I'm fine with always enabling trim functionality in that driver. Bart.