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=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 044DFC76194 for ; Mon, 22 Jul 2019 14:17:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D0D6B21955 for ; Mon, 22 Jul 2019 14:17:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=aol.com header.i=@aol.com header.b="qYB90E9n" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730822AbfGVORJ (ORCPT ); Mon, 22 Jul 2019 10:17:09 -0400 Received: from sonic317-20.consmr.mail.gq1.yahoo.com ([98.137.66.146]:42769 "EHLO sonic317-20.consmr.mail.gq1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730810AbfGVORI (ORCPT ); Mon, 22 Jul 2019 10:17:08 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=aol.com; s=a2048; t=1563805023; bh=xECj9m2xLSVUpudrwyR6+luhiAWEZ0tY/RvhMhV/bZQ=; h=Subject:To:References:From:Cc:Date:In-Reply-To:From:Subject; b=qYB90E9n9p2hxZA0lEfH/3+0P3CXOotPsRediTaJtnxRqX8rXbkm3N7rw6ACqGVj/xDOFFQO2lBfZKb/IYG8btDSRpHbuoEM1XkuXTGtFVHbmEW3w+fUsHaSZ6JlmvtoiY3qzILebk8kajRcTBlffJvyyEpNiRIhAIZo6B33VuXuvpr5XcvWbHCQzMl289vIkhLWBrRD4tnJ+18OKng5gGxcHrU0t6Yn3AaapcoWqDYyBULprIwuC2Xy5au5zcijJTZvsmYdc0tYoQcLagJxe43BLhArPD8T2jpVC4aF7S8nXOAPKmOGZev1nr6kHyCUhVctjAsxyukzYrmY+u+HaQ== X-YMail-OSG: H0aMGxQVM1mvOAgQM.BAOlrQE3d.1NSa3bvXBG0WEx9WjJxsItK445bMZKRUfVj 12opgBUymkaVs.u7jpTtxwwa_9GIYRGzyhxP6dFJwVGqa21crki_tZyomWJOspBHrkG9SPzOKRBm D7ufuipeZJ7UXSx_RvAPo1oddnINNrEZbgnso0SMh553gm4Xt3I2HWp8fvGcF6wC3PGdYKtMa9jb 578ArDg3h4v1MjhPDB6Yf2MNsqlnGKnShpZs.JY5Uv9ecp94VS.Xos8wHOoSC8S1EDaDh6IBNxvu uj7xNLnuYXObUN4PIY3VjFIDlpf_6R7gyqFs_MMqi4yvgBqOackLXCeycoj91kprPwdmyDJwqs.f qir7zoltA1FLl.Cj98THb5yimboDtcDxjbyuE.lCfxzOK4IYr2Vsv4uJbjBGzM7YKtqDwG6a1BFU 5vXXwcxGBSMoAOhO2E._UA.d4RMenZngT0tdB29RPSnv9XwU9TfnEJiPRL2LUnFhSc4FORGXT.2O cw69s15OhmZoJQ6f28ofqR521zU.v26Y4Iec1F9ToyPo_MGHv9TBwI02C7DES2z7rA6YAQ3Mgj8o oIjXLO3uZgny.L4lKW78IIxNLfaOgz_y67rH1D_M6H6M_O52G9R_M91TaCDFALRslgEEZDaglPFc ZKN5_BPt65jOgxl8gJjJxvb4XNdvsp6HqydGveyY.rPIDQrxpS1C2hQQSPEoiN1u1D8rfKmBF4jn J2ETvbcvpMU2zbc4y9tCM7LxVzANwro0rulZ3cyLrlQczLrV0cNkZ0mxaJggRaFnekjy.3Wo87wS .c.iEQfKP0Iy3QCR.ncEBd2t0meT1xzXtXPBSuCMzkntXiJhpB08vTX_vvdnZRd0PCDGU7lHiY0x D1oqCQA2kTK0XjqzjSs3QXiLWscRb6qoJUsNpRKzg70YDMsmpzUySjxHcKk4AxSE8Uzaxgsb6mV7 yD2xECQ56Ln6ogsx6pNFVewDSl3s.WnSrg.94IsYLIrKYwzUnELlNev9aaC_Ln6eaWFZfudS4Qsg swka882uKsWuYoaxWR1boPTytRoNqgmNKZ0UTHudEkDFBqvOOxamSY7ar5_FpTaW7Sp7AEzyhS0F pW6c_6jmAxUWcSiXK_t6sBXTwuAyBb7AI2DYphKjPe.j6jJUobyHkSPyAi.Vkve0W1fMbwwRkGof PUhAMEvlKm0rhLQsm_SnAx4sgaAMGCWQ.psCllwsv4F8tC2Bc3YOlLiNWdu.ncQ-- Received: from sonic.gate.mail.ne1.yahoo.com by sonic317.consmr.mail.gq1.yahoo.com with HTTP; Mon, 22 Jul 2019 14:17:03 +0000 Received: by smtp411.mail.gq1.yahoo.com (Oath Hermes SMTP Server) with ESMTPA ID 947e087edc5dc48dc717612cdbe533da; Mon, 22 Jul 2019 14:16:59 +0000 (UTC) Subject: Re: [PATCH v3 23/24] erofs: introduce cached decompression To: "Theodore Y. Ts'o" References: <20190722025043.166344-1-gaoxiang25@huawei.com> <20190722025043.166344-24-gaoxiang25@huawei.com> <20190722101818.GN20977@twin.jikos.cz> <41f1659a-0d16-4316-34fc-335b7d142d5c@aol.com> <20190722132513.GA5172@mit.edu> From: Gao Xiang Cc: dsterba@suse.cz, Gao Xiang , Alexander Viro , Greg Kroah-Hartman , Andrew Morton , Stephen Rothwell , Linus Torvalds , linux-fsdevel@vger.kernel.org, devel@driverdev.osuosl.org, LKML , linux-erofs@lists.ozlabs.org, Chao Yu , Miao Xie , Li Guifu , Fang Wei Message-ID: Date: Mon, 22 Jul 2019 22:16:44 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190722132513.GA5172@mit.edu> Content-Type: text/plain; charset=gbk Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Ted, On 2019/7/22 ????9:25, Theodore Y. Ts'o wrote, > On Mon, Jul 22, 2019 at 06:58:59PM +0800, Gao Xiang wrote: >>> The number of individual Kconfig options is quite high, are you sure you >>> need them to be split like that? >> >> You mean the above? these are 3 cache strategies, which impact the >> runtime memory consumption and performance. I tend to leave the above >> as it-is... > > Unless cache strategies involve a huge amount of kernel code, I'd > recommend always compiling all of the cache strategies, and then have > a way to change the cache strategy via a mount option (and possibly > remount, although that can get tricky if there is already cached > information). You could also specify a default in the erofs > superblock, you think that would be useful. OK, I will give a try. One point I think is how to deal with the case if there is already cached information when remounting as well as you said. As the first step, maybe the mount option can be defined as allowing/forbiding caching from now on, which can be refined later. Thanks, Gao Xiang > > - Ted >