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=-4.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_2 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 AFC86C433EF for ; Mon, 13 Sep 2021 12:23:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9257160FC0 for ; Mon, 13 Sep 2021 12:23:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239960AbhIMMYg (ORCPT ); Mon, 13 Sep 2021 08:24:36 -0400 Received: from m12-14.163.com ([220.181.12.14]:57964 "EHLO m12-14.163.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236140AbhIMMYf (ORCPT ); Mon, 13 Sep 2021 08:24:35 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=Date:From:Subject:Message-ID:MIME-Version; bh=MlRAV ypdW7YrpBs8Eft4bSn/YCqHOQ7MShrKcxpxoek=; b=Fr/zqI1BmennualLNGtZS X8e8GeeEgMosg7cBqU5ei9pYjRz1P6dUGVR+mElVZzrdnstBTiGJv4iAhwQUuX/E CQEFqvvcG7521nwQ9bX1o+kbMyUQfCzipJl/A+Q4VMIQSriBSQxbS3j/32mbEpjX qNLq3YZTgFmDkmUKFQvrfo= Received: from rockpi4b (unknown [112.20.66.82]) by smtp10 (Coremail) with SMTP id DsCowABnSLakQj9hV8tMHg--.7297S2; Mon, 13 Sep 2021 20:23:01 +0800 (CST) Date: Mon, 13 Sep 2021 20:22:58 +0800 From: Yue Hu To: Gao Xiang Cc: Yue Hu , xiang@kernel.org, chao@kernel.org, linux-erofs@lists.ozlabs.org, linux-kernel@vger.kernel.org, huyue2@yulong.com, zhangwen@yulong.com Subject: Re: [PATCH] erofs: fix compacted_{4b_initial, 2b} when compacted_4b_initial > totalidx Message-ID: <20210913202258.356ba284.zbestahu@163.com> In-Reply-To: References: <20210913072405.1128-1-zbestahu@gmail.com> <20210913170016.00007580.zbestahu@gmail.com> <20210913185836.088e7059.zbestahu@163.com> X-Mailer: Claws Mail 3.14.1 (GTK+ 2.24.31; aarch64-unknown-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-CM-TRANSID: DsCowABnSLakQj9hV8tMHg--.7297S2 X-Coremail-Antispam: 1Uf129KBjvJXoWxuF45tF1DCr4kCw4UXrW8JFb_yoW5Gw4Up3 9rKF48ta4vqF1Iyw1xtw18XFW0vw48Cr4UW34YqFyxKr90yFn5Gr18tFWru3ZrXw13Kr4F yr4UWFn3AFy7A3DanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07U-eOXUUUUU= X-Originating-IP: [112.20.66.82] X-CM-SenderInfo: p2eh23xdkxqiywtou0bp/1tbitAQNEVSIm3vUmwAAsf Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 13 Sep 2021 19:19:16 +0800 Gao Xiang wrote: > Hi Yue, > > On Mon, Sep 13, 2021 at 06:58:36PM +0800, Yue Hu wrote: > > Hi Xiang, > > > > On Mon, 13 Sep 2021 17:11:24 +0800 > > Gao Xiang wrote: > > > > > On Mon, Sep 13, 2021 at 05:00:16PM +0800, Yue Hu wrote: > > > > On Mon, 13 Sep 2021 16:48:45 +0800 > > > > Gao Xiang wrote: > > > > > > > > > Hi Yue, > > > > > > > > > > On Mon, Sep 13, 2021 at 03:24:05PM +0800, Yue Hu wrote: > > > > > > From: Yue Hu > > > > > > > > > > > > mkfs.erofs will treat compacted_4b_initial & compacted_2b as 0 if > > > > > > compacted_4b_initial > totalidx, kernel should be aligned with it > > > > > > accordingly. > > > > > > > > > > There is no difference between compacted_4b_initial or compacted_4b_end > > > > > for compacted 4B. Since in this way totalidx for compact 2B won't larger > > > > > than 16 (number of lclusters in a compacted 2B pack.) > > > > > > > > However, we can see compacted_2b is a big number for this case. It should > > > > be pointless. > > > > > > Does it has some real impact? > > > > No real impact to correct result. > > > > > > > > compacted_4b_initial is only used for the alignment use for the > > > first compacted_2b so that each compacted_2b pack won't cross > > > the block (page) boundary. And compacted_4b_end is for the last > > > lclusters aren't fitted in any compacted_2b pack. > > > > > > If compacted_4b_initial > totalidx, I think the whole indexes > > > would be compacted 4B and handled in > > > > > > if (lcn < compacted_4b_initial) { > > > amortizedshift = 2; > > > goto out; > > > } > > > > Yes, it is. > > > > My point is why we need compacted_2b here for this case. If it's > > not helpful/used for next code logic, we should remove/avoid it. > > I think that may cause some misunderstanding and consume unneeded > > CPU resources. > > Okay, make sense. If the number of compacted_2b misleads, how about > just > > if ((vi->z_advise & Z_EROFS_ADVISE_COMPACTED_2B) && > compacted_4b_initial <= totalidx) { > compacted_2b = ...; > } else { > compacted_2b = 0; > } Looks good. So, the patch title may change a little. > > , and refine the commit message to point out the following facts for > other folks: > > - compacted_4b_initial is used contain the very first lclusters in order > to fulfill the alignment of the first compacted_2b pack; > > - compacted_4b_end is used for the last lclusters which aren't fitted in > the previous compacted_2b packs; > > - if compacted_4b_initial > totalidx, the whole indexes will be compacted > 4B and handled with compacted_4b_initial. Ok, will add these facts above in v2. Thanks. > > Thanks, > Gao Xiang > > > > > Thanks. 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=-4.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_2 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 5C9A5C433F5 for ; Mon, 13 Sep 2021 12:23:24 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id C4F1460FBF for ; Mon, 13 Sep 2021 12:23:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org C4F1460FBF Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=163.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.ozlabs.org Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4H7QcV2R3xz2yKQ for ; Mon, 13 Sep 2021 22:23:22 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=163.com header.i=@163.com header.a=rsa-sha256 header.s=s110527 header.b=Fr/zqI1B; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=163.com (client-ip=220.181.12.14; helo=m12-14.163.com; envelope-from=zbestahu@163.com; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=163.com header.i=@163.com header.a=rsa-sha256 header.s=s110527 header.b=Fr/zqI1B; dkim-atps=neutral Received: from m12-14.163.com (m12-14.163.com [220.181.12.14]) by lists.ozlabs.org (Postfix) with ESMTP id 4H7QcM2JV2z2xtT for ; Mon, 13 Sep 2021 22:23:14 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=Date:From:Subject:Message-ID:MIME-Version; bh=MlRAV ypdW7YrpBs8Eft4bSn/YCqHOQ7MShrKcxpxoek=; b=Fr/zqI1BmennualLNGtZS X8e8GeeEgMosg7cBqU5ei9pYjRz1P6dUGVR+mElVZzrdnstBTiGJv4iAhwQUuX/E CQEFqvvcG7521nwQ9bX1o+kbMyUQfCzipJl/A+Q4VMIQSriBSQxbS3j/32mbEpjX qNLq3YZTgFmDkmUKFQvrfo= Received: from rockpi4b (unknown [112.20.66.82]) by smtp10 (Coremail) with SMTP id DsCowABnSLakQj9hV8tMHg--.7297S2; Mon, 13 Sep 2021 20:23:01 +0800 (CST) Date: Mon, 13 Sep 2021 20:22:58 +0800 From: Yue Hu To: Gao Xiang Subject: Re: [PATCH] erofs: fix compacted_{4b_initial, 2b} when compacted_4b_initial > totalidx Message-ID: <20210913202258.356ba284.zbestahu@163.com> In-Reply-To: References: <20210913072405.1128-1-zbestahu@gmail.com> <20210913170016.00007580.zbestahu@gmail.com> <20210913185836.088e7059.zbestahu@163.com> X-Mailer: Claws Mail 3.14.1 (GTK+ 2.24.31; aarch64-unknown-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-CM-TRANSID: DsCowABnSLakQj9hV8tMHg--.7297S2 X-Coremail-Antispam: 1Uf129KBjvJXoWxuF45tF1DCr4kCw4UXrW8JFb_yoW5Gw4Up3 9rKF48ta4vqF1Iyw1xtw18XFW0vw48Cr4UW34YqFyxKr90yFn5Gr18tFWru3ZrXw13Kr4F yr4UWFn3AFy7A3DanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07U-eOXUUUUU= X-Originating-IP: [112.20.66.82] X-CM-SenderInfo: p2eh23xdkxqiywtou0bp/1tbitAQNEVSIm3vUmwAAsf 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-kernel@vger.kernel.org, huyue2@yulong.com, linux-erofs@lists.ozlabs.org, zhangwen@yulong.com Errors-To: linux-erofs-bounces+linux-erofs=archiver.kernel.org@lists.ozlabs.org Sender: "Linux-erofs" On Mon, 13 Sep 2021 19:19:16 +0800 Gao Xiang wrote: > Hi Yue, > > On Mon, Sep 13, 2021 at 06:58:36PM +0800, Yue Hu wrote: > > Hi Xiang, > > > > On Mon, 13 Sep 2021 17:11:24 +0800 > > Gao Xiang wrote: > > > > > On Mon, Sep 13, 2021 at 05:00:16PM +0800, Yue Hu wrote: > > > > On Mon, 13 Sep 2021 16:48:45 +0800 > > > > Gao Xiang wrote: > > > > > > > > > Hi Yue, > > > > > > > > > > On Mon, Sep 13, 2021 at 03:24:05PM +0800, Yue Hu wrote: > > > > > > From: Yue Hu > > > > > > > > > > > > mkfs.erofs will treat compacted_4b_initial & compacted_2b as 0 if > > > > > > compacted_4b_initial > totalidx, kernel should be aligned with it > > > > > > accordingly. > > > > > > > > > > There is no difference between compacted_4b_initial or compacted_4b_end > > > > > for compacted 4B. Since in this way totalidx for compact 2B won't larger > > > > > than 16 (number of lclusters in a compacted 2B pack.) > > > > > > > > However, we can see compacted_2b is a big number for this case. It should > > > > be pointless. > > > > > > Does it has some real impact? > > > > No real impact to correct result. > > > > > > > > compacted_4b_initial is only used for the alignment use for the > > > first compacted_2b so that each compacted_2b pack won't cross > > > the block (page) boundary. And compacted_4b_end is for the last > > > lclusters aren't fitted in any compacted_2b pack. > > > > > > If compacted_4b_initial > totalidx, I think the whole indexes > > > would be compacted 4B and handled in > > > > > > if (lcn < compacted_4b_initial) { > > > amortizedshift = 2; > > > goto out; > > > } > > > > Yes, it is. > > > > My point is why we need compacted_2b here for this case. If it's > > not helpful/used for next code logic, we should remove/avoid it. > > I think that may cause some misunderstanding and consume unneeded > > CPU resources. > > Okay, make sense. If the number of compacted_2b misleads, how about > just > > if ((vi->z_advise & Z_EROFS_ADVISE_COMPACTED_2B) && > compacted_4b_initial <= totalidx) { > compacted_2b = ...; > } else { > compacted_2b = 0; > } Looks good. So, the patch title may change a little. > > , and refine the commit message to point out the following facts for > other folks: > > - compacted_4b_initial is used contain the very first lclusters in order > to fulfill the alignment of the first compacted_2b pack; > > - compacted_4b_end is used for the last lclusters which aren't fitted in > the previous compacted_2b packs; > > - if compacted_4b_initial > totalidx, the whole indexes will be compacted > 4B and handled with compacted_4b_initial. Ok, will add these facts above in v2. Thanks. > > Thanks, > Gao Xiang > > > > > Thanks.