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 81E77C7618F for ; Mon, 22 Jul 2019 16:27:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5A5812190F for ; Mon, 22 Jul 2019 16:27:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=aol.com header.i=@aol.com header.b="PDoIL05i" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730951AbfGVQ1i (ORCPT ); Mon, 22 Jul 2019 12:27:38 -0400 Received: from sonic313-20.consmr.mail.ir2.yahoo.com ([77.238.179.187]:40750 "EHLO sonic313-20.consmr.mail.ir2.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730077AbfGVQ1h (ORCPT ); Mon, 22 Jul 2019 12:27:37 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=aol.com; s=a2048; t=1563812854; bh=4tmyXeIY4oqFIVBQrFKdjj4C+ZBVcIroyn01PfQ/hHM=; h=Subject:To:References:Cc:From:Date:In-Reply-To:From:Subject; b=PDoIL05iiWF7UEY97RncX2mn5BEWGfVbh0EBTCk+45qefwCsQpBR2hdpoCu8ra+Rq7LpAqFFBDtGTpQLo755H+QAUR0z4wVOqck/uIIUQx3QFItccWtsyWCbwVWSnKGLnQ3VxEFLUhnPvJcdusnTGubs3PL/fpwTP+xwPYxU4KMA7vffNm7EPA0T0qPt3Fc+J2nhWqoaJ6c6Y1IY6vOGomAMTJen3YQZ43yHk5s3co8rnEUS/YfU4F7l+dpVsvoN8n25j8u2x8yOgBWwm5o2kDH/6E3BJ2hjuMPDUQDAPcCtPuj2lfJ/GsQy9QiFjdrR/NoXXYWmYF0aQhQumIn1vQ== X-YMail-OSG: kJzK8G0VM1nKSd0411aaQcR1cgN1N9H0NE1Il2FHTI9KnNHDofM4LaONFl1lApv Vyh8jk3edFw5qprRvl.92gaApjmfttnN6y6CGP4kx9ocxQZaKSqZhXvwaPQNMlXNucX3wwKllt4w ODZNWYmjZ3Fa7uqIkti4UqNl2Sn91EqI1VvpI.ikwSGpZZu1MhspOgtBFXeXaZJkZ5gHctBAHwit mR2dN2bgXHnJrPar5iqNYwTKPZL01Npgc6.UXOHl8wE7zcCTBfiMXVeVGbYqXsq3XmPYXlsQV_rA oXQ2bGuGeMmN5sxLIMim7NEf3Q86k7WiMy4ffi8wE2sxBzRoovZQadl7Tj9U0iRTgx4QHHA4w99S KQuBrfrz64khcZHTHb_sphzRQRUhwxefMk7hnc2PQkIqZsKPMKnkH7OMr3sR_8SrZq5CF4lbmELu 587MFziqA8Ug9HW4B1zxBAJOPhtEyj947WCxnh928ne3N_2KUd5MM3shSC34PdMLfF1RLFbW_vFt AQK9V_6DepeByE_YTaVKrf9dlBrhGojuoYGcTwWd5zOL_K68f1woziDex_YkysKi_cIXOibYqa7f CHVlk.8BCFkQx0yMVfg.jQfyCoH0eYlmKJfhBx.A00Lv5LFf.0A5Tij_BMmx8C4uaiVOWielMJUg rF6BvW3eIWef2ANZCPqDq0SxfR00jWyf3g1Bj95Vg3mB1N1mo9rrrAeRFqTWFssZk_aDLuozfhP6 wIT9sroPknqhOUale6sVeiGF6AvrOJE48TVytuKrJId0nuO9rzH9DgTIWOYCrS_2zTfg4wx0JJES eWpnGNG7zMPhfp2nVTqchZ0EpsWiLlITLbmW482a3NNarNeXIlZlmniBMarD6ogDqVA9qhrbWeBF CGkMFZUucrpZbUY.gBPxxdJjiCnrmdAyIL5h5XV9TyWvZjt4QodE9g8iv0NBnS_Auej3beTB7L06 RA9M8eaKOrqGb96ad_um_DaY43jI08vs8MOrpIJrKms2MDOJGJBtOhWB8LZ4TFZ_oGz2DI6XcFID qF_4caa_d3B5OUL9LK4ovobNaOEH4js3T9nOIx92H4yJxzxYbiytPbr9T8dzgi_PBdD43zDA5GDL 95qStHVJx7L.Mhqt31dJX.hnzthMVcuBOg3ekPH4ogu4uBh0Ux_F0xYTkTs6ESPA1vqkYyeIB0eg GGo3CZH2oGWdDwcfjbxNpINjZWASZbLgkk5ViHqc5k3821Ds0hZ8X77Q- Received: from sonic.gate.mail.ne1.yahoo.com by sonic313.consmr.mail.ir2.yahoo.com with HTTP; Mon, 22 Jul 2019 16:27:34 +0000 Received: by smtp420.mail.ir2.yahoo.com (Oath Hermes SMTP Server) with ESMTPA ID 0f3571226556d2a71ae3b00089e7ff33; Mon, 22 Jul 2019 16:27:30 +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> <20190722151226.GC5172@mit.edu> 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 From: Gao Xiang Message-ID: Date: Tue, 23 Jul 2019 00:27:16 +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: <20190722151226.GC5172@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 On 2019/7/22 ????11:12, Theodore Y. Ts'o wrote: > On Mon, Jul 22, 2019 at 10:16:44PM +0800, Gao Xiang wrote: >> 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. > > Yes; possible solutions include ignoring the issue (assuming that > cached data structures that "shouldn't" be in the cache given the new > cache strategy will fall out of the cache over time), forcibly > flushing the cache when the caching strategy has changed, and of > course, forbidding caching strategy change at remount time. Okay, thanks for your kindly suggestion :) will do, hopefully resend this week (I agree less bugs with less kernel configs.). Thanks, Gao Xiang > > Cheers, > > - Ted >