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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 8AB67C2D0B1 for ; Thu, 6 Feb 2020 11:52:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5D7DB206CC for ; Thu, 6 Feb 2020 11:52:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727548AbgBFLwh (ORCPT ); Thu, 6 Feb 2020 06:52:37 -0500 Received: from luna.lichtvoll.de ([194.150.191.11]:39463 "EHLO mail.lichtvoll.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727111AbgBFLwh (ORCPT ); Thu, 6 Feb 2020 06:52:37 -0500 X-Greylist: delayed 544 seconds by postgrey-1.27 at vger.kernel.org; Thu, 06 Feb 2020 06:52:37 EST 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 04959AC2B6; Thu, 6 Feb 2020 12:43:30 +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 Subject: Re: [PATCH 00/20] btrfs: refactor and generalize chunk/dev_extent/extent allocation Date: Thu, 06 Feb 2020 12:43:30 +0100 Message-ID: <5861600.kR87CiLkK2@merkaba> In-Reply-To: <20200206104214.400857-1-naohiro.aota@wdc.com> References: <20200206104214.400857-1-naohiro.aota@wdc.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 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/ 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. Thanks, -- Martin