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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 49AE9ECE58F for ; Tue, 15 Oct 2019 13:27:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2A2DD218DE for ; Tue, 15 Oct 2019 13:27:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731974AbfJON1b (ORCPT ); Tue, 15 Oct 2019 09:27:31 -0400 Received: from outgoing-auth-1.mit.edu ([18.9.28.11]:36271 "EHLO outgoing.mit.edu" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727745AbfJON1b (ORCPT ); Tue, 15 Oct 2019 09:27:31 -0400 Received: from callcc.thunk.org (guestnat-104-133-0-98.corp.google.com [104.133.0.98] (may be forged)) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id x9FDRICi023055 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 15 Oct 2019 09:27:19 -0400 Received: by callcc.thunk.org (Postfix, from userid 15806) id 68F6D420287; Tue, 15 Oct 2019 09:27:18 -0400 (EDT) Date: Tue, 15 Oct 2019 09:27:18 -0400 From: "Theodore Y. Ts'o" To: Matthew Wilcox Cc: Naohiro Aota , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, Andrew Morton Subject: Re: Project idea: Swap to zoned block devices Message-ID: <20191015132718.GB7456@mit.edu> References: <20191015043827.160444-1-naohiro.aota@wdc.com> <20191015113548.GD32665@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191015113548.GD32665@bombadil.infradead.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Tue, Oct 15, 2019 at 04:35:48AM -0700, Matthew Wilcox wrote: > On Tue, Oct 15, 2019 at 01:38:27PM +0900, Naohiro Aota wrote: > > A zoned block device consists of a number of zones. Zones are > > eitherconventional and accepting random writes or sequential and > > requiringthat writes be issued in LBA order from each zone write > > pointerposition. For the write restriction, zoned block devices are > > notsuitable for a swap device. Disallow swapon on them. > > That's unfortunate. I wonder what it would take to make the swap code be > suitable for zoned devices. It might even perform better on conventional > drives since swapout would be a large linear write. Swapin would be a > fragmented, seeky set of reads, but this would seem like an excellent > university project. Also maybe a great Outreachy or GSOC project?