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=-0.7 required=3.0 tests=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 82111C352A4 for ; Fri, 7 Feb 2020 08:03:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 63989214AF for ; Fri, 7 Feb 2020 08:03:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727009AbgBGIDD (ORCPT ); Fri, 7 Feb 2020 03:03:03 -0500 Received: from luna.lichtvoll.de ([194.150.191.11]:56173 "EHLO mail.lichtvoll.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726417AbgBGIDD (ORCPT ); Fri, 7 Feb 2020 03:03:03 -0500 Received: from 127.0.0.1 (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.lichtvoll.de (Postfix) with ESMTPSA id CBE58AC879; Fri, 7 Feb 2020 09:03:00 +0100 (CET) From: Martin Steigerwald To: Naohiro Aota Cc: linux-btrfs@vger.kernel.org, David Sterba , Chris Mason , Josef Bacik , Nikolay Borisov , Damien Le Moal , Johannes Thumshirn , Hannes Reinecke , Anand Jain , linux-fsdevel@vger.kernel.org, Zhi Yong Wu Subject: Re: [PATCH 00/20] btrfs: refactor and generalize chunk/dev_extent/extent allocation Date: Fri, 07 Feb 2020 09:02:59 +0100 Message-ID: <1977483.1kS9YxoVVV@merkaba> In-Reply-To: <20200207060600.bxcot22i3tpemrn5@naota.dhcp.fujisawa.hgst.com> References: <20200206104214.400857-1-naohiro.aota@wdc.com> <5861600.kR87CiLkK2@merkaba> <20200207060600.bxcot22i3tpemrn5@naota.dhcp.fujisawa.hgst.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Authentication-Results: mail.lichtvoll.de; auth=pass smtp.auth=martin smtp.mailfrom=martin@lichtvoll.de Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Naohiro Aota - 07.02.20, 07:06:00 CET: > On Thu, Feb 06, 2020 at 12:43:30PM +0100, Martin Steigerwald wrote: > >Hi Naohiro. > > > >Naohiro Aota - 06.02.20, 11:41:54 CET: > >> This series refactors chunk allocation, device_extent allocation > >> and > >> extent allocation functions and make them generalized to be able to > >> implement other allocation policy easily. > >> > >> On top of this series, we can simplify some part of the "btrfs: > >> zoned > >> block device support" series as adding a new type of chunk > >> allocator > >> and extent allocator for zoned block devices. Furthermore, we will > >> be > >> able to implement and test some other allocator in the idea page of > >> the wiki e.g. SSD caching, dedicated metadata drive, chunk > >> allocation > >> groups, and so on. > > > >Regarding SSD caching, are you aware that there has been previous > >work with even involved handling part of it in the Virtual > >Filesystem Switch (VFS)? > > > >VFS hot-data tracking, LWN article: > > > >https://lwn.net/Articles/525651/ > > > >Patchset, not sure whether it is the most recent one: > > > >[PATCH v2 00/12] VFS hot tracking > > > >https://lore.kernel.org/linux-btrfs/1368493184-5939-1-git-send-email-> >zwu.kernel@gmail.com/ > Yes, I once saw the patchset. Not sure about the detail, though. > > >So for SSD caching you may be able to re-use or pick up some of this > >work, unless it would be unsuitable to be used with this new > >approach. > Currently, I have no plan to implement the SSD caching feature by > myself. I think some patches of the series like this [1] can be > reworked on my series as adding an "SSD caching chunk allocator." So, > it's welcome to hear suggestions about the hook interface. Thank you. Adding Zhi Yong Wu to Cc. I don't know details about this patch set either. @Zhi Yong Wu: Are you interested interested in rebasing your SSD caching patch above this refactoring work? Ciao, Martin > [1] > https://lore.kernel.org/linux-btrfs/1371817260-8615-3-git-send-email-> zwu.kernel@gmail.com/ > >Thanks, -- Martin