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 9BDD4C10F14 for ; Tue, 15 Oct 2019 13:27:29 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 671A8218DE for ; Tue, 15 Oct 2019 13:27:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 671A8218DE Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=mit.edu Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id E14368E0006; Tue, 15 Oct 2019 09:27:28 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id DC5508E0001; Tue, 15 Oct 2019 09:27:28 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CBB838E0006; Tue, 15 Oct 2019 09:27:28 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0193.hostedemail.com [216.40.44.193]) by kanga.kvack.org (Postfix) with ESMTP id A38C28E0001 for ; Tue, 15 Oct 2019 09:27:28 -0400 (EDT) Received: from smtpin18.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id 43C34181AEF23 for ; Tue, 15 Oct 2019 13:27:28 +0000 (UTC) X-FDA: 76046095776.18.lace34_6ef7c7f5592c X-HE-Tag: lace34_6ef7c7f5592c X-Filterd-Recvd-Size: 2224 Received: from outgoing.mit.edu (outgoing-auth-1.mit.edu [18.9.28.11]) by imf10.hostedemail.com (Postfix) with ESMTP for ; Tue, 15 Oct 2019 13:27:27 +0000 (UTC) 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) X-Bogosity: Ham, tests=bogofilter, spamicity=0.012287, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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?