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 Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id EB61AC43334 for ; Thu, 21 Jul 2022 00:58:31 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4LpDhk1nLhz3c46 for ; Thu, 21 Jul 2022 10:58:30 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=ZrOE8fOC; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=2604:1380:4601:e00::1; helo=ams.source.kernel.org; envelope-from=xiang@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=ZrOE8fOC; dkim-atps=neutral Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4LpDhZ6mtTz2ynx for ; Thu, 21 Jul 2022 10:58:22 +1000 (AEST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 03243B82156; Thu, 21 Jul 2022 00:58:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A569DC3411E; Thu, 21 Jul 2022 00:58:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1658365095; bh=4JdUnCsdBHN0EjyTXiz3Hpq6NmilTbZ1NX9AlgddAY4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ZrOE8fOCEa33EOc+MrGdUHwW3fjksFG4cBop8yB7tFVDHo9BjzLias1jzWRyLH51v fAGwV7BFYoPzMrUVIufvB1s6c0S5HsFxnX3Mg1TmRrmdgLgOkovrj1VqRm+7FzilPq GPzGid3zbu8wzs3tWci8GhRx6trPw/+1VSqkNF7TUUIknp9qM/n03brI45qcwPJTph Vs/KsQGVjhvnVEL8obeie1jkjUuFr3UntAk8ZVz5yYaLdTiHIVnqBvC/ggsPtF316R 1ndpxPRulgVDszyAPwGH7iqjvCAd2DVB74IoCvU5WhXAJo3xFz8BwSwK7WbQ77V/V9 +56BE0d1w6kjw== Date: Thu, 21 Jul 2022 08:58:10 +0800 From: Gao Xiang To: Paul Spooren Subject: Re: Tail packing feature on 5.15 Kernel Message-ID: Mail-Followup-To: Paul Spooren , linux-erofs@lists.ozlabs.org References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-BeenThere: linux-erofs@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Development of Linux EROFS file system List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-erofs@lists.ozlabs.org Errors-To: linux-erofs-bounces+linux-erofs=archiver.kernel.org@lists.ozlabs.org Sender: "Linux-erofs" Hi Paul, On Wed, Jul 20, 2022 at 10:38:15PM +0200, Paul Spooren wrote: > Hi all, > > I’m currently in the process[1] to evaluate erofs as a replacement of squashfs on OpenWrt. > > Since 5.15 will be our next Kernel release but tail packing is only available starting from 5.17, did anyone already do the work of back porting the required patches? If not, could anyone please give me pointers which patches are required? > > Thank you very much for all further advice! Thanks for your interest. EROFS is now actively developing so you could see new features on each new Linux version (I believe many active in-kernel features behave like this, for example iouring.) The initial EROFS version was formed as an optimized solution to compress in 4KiB pcluster so it has minimized memory footprints and best random performance on Android smartphones, for now the optimized and recommended configuration is still this one (4KiB, lz4hc) even though things are quickly changing since recent features add more possibility but most of these are still quite new and need to go with the next LTS version (maybe 6.0?). Also if you'd like to maximize the compression ratio you probably need `fragments` features which is still under development by Yue Hu [1]. As I said to you before [2], I still suggest that Openwrt takes EROFS as an _alternative approach_ instead of a replacement of Squashfs at least this year since we still need time to optimize the maximum compression ratio scenarios in addition to 4KiB, lz4hc (we also need to wait the next stable XZ-utils version first.) [1] https://lore.kernel.org/r/YpXnhI8gBlSgHEBW@B-P7TQMD6M-0146.local [2] https://lore.kernel.org/r/cover.1657528899.git.huyue2@coolpad.com Thanks, Gao Xiang > > Best, > Paul > > [1]: https://github.com/openwrt/openwrt/pull/9968