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=-2.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, 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 E9DCAC3F2C6 for ; Wed, 4 Mar 2020 01:00:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B66C820728 for ; Wed, 4 Mar 2020 01:00:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=gmx.net header.i=@gmx.net header.b="MrHbH0BV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387396AbgCDBAn (ORCPT ); Tue, 3 Mar 2020 20:00:43 -0500 Received: from mout.gmx.net ([212.227.15.18]:54685 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727854AbgCDBAm (ORCPT ); Tue, 3 Mar 2020 20:00:42 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1583283635; bh=nU7ndp1PZLwXq/7frlnp1PAB04fTmtwHtfBAjHKUbHI=; h=X-UI-Sender-Class:Subject:To:References:From:Date:In-Reply-To; b=MrHbH0BVSHJlvoFwprEo2HUKbwdMuYn46zv0OTmjnS3hEWwFm/a7uln2hJ4l4u0iX kLX4FCWbPvd76ht/0YkWBhOMt/DogZ8tz/EUuTkd+6IZv1FWDd4H1QEE5WY+FnjZdv nZAJD0zlWnIXHJpARi+abo+07FMVrkoI0fI/wBFE= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [0.0.0.0] ([149.28.201.231]) by mail.gmx.com (mrgmx005 [212.227.17.184]) with ESMTPSA (Nemesis) id 1MWASe-1itDi41sB0-00XbxY; Wed, 04 Mar 2020 02:00:35 +0100 Subject: Re: [PATCH v2 05/10] btrfs: relocation: Refactor tree backref processing into its own function To: dsterba@suse.cz, Qu Wenruo , linux-btrfs@vger.kernel.org References: <20200302094553.58827-1-wqu@suse.com> <20200302094553.58827-6-wqu@suse.com> <20200303172917.GK2902@twin.jikos.cz> From: Qu Wenruo Autocrypt: addr=quwenruo.btrfs@gmx.com; prefer-encrypt=mutual; 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Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <20200303172917.GK2902@twin.jikos.cz> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="UZUqh3wxv7F7FRGa2z9Ug9AGLIsQiwGzc" X-Provags-ID: V03:K1:U6VbwBUz5WnI06PbBQjk1JtH0hQ+G42ypWd+qXrvvT4gz9ZBIl9 QYPsODj5I+PuXXz/e3ancSkC255pqfxgF/PrBSpGvagkkaEx5Y3kBgohwCVJcruxKMngXyH ot9aVSDG8htI4pWJ3KAlltrkF40cfHezx6HgWx48IZuG2H65e/FZKRdPdMoL9Lkm6TKx67Q X04VDkT9j81X2PHj39rEA== X-UI-Out-Filterresults: notjunk:1;V03:K0:4oWlCswgg/I=:09EioO3y/29ENmC27iTEGi wpY3veg0xFIoGMFdmJNX0nDO6sM9+jDiDfTwYPPu9xh760YDvmjKtrbOolwuBtOGXP1093bfC wBYHp87Vs6Y7cjqMpwjAufrcp4/LcKCP1dSPCljgX1YcKBePE98n1Vb+6RNrLaaTIXVIObrl6 G2G/K+Fp+0s4is59ZZ0l7IzGzSkn/WzLJIzMT5Dz90ah5zsot9kWRkqT8lrSCmxcoWpInRJqs /ER3Cn4Mj3I/R7G+vqaestm+xD91bj/bnR87WyjGKo5qp49hgZeuCMvpgqdSqd8/zET9VLaCQ oghytCmBRH4AJt2WFd/oRIfIrZAIWFuSr2GxL5C5FqnvNxOzFjgEAUZXUqqGfsAQERF7DMrbA FPJumZnI6cuWheqeDNs8jUe+8dzbX1bjS4q8n31XEkYcbftG9Zl/LTL/MdwdNLDZFNaPE1uVG PUbWoEDTOEwKPizFtpGFAhZJ4DeID+VeK8vpjo6aQNJ4VjyIc3Wu4kz7W7T/ibPpq6Ar4zbD1 3qTPdcByWqnwlPpYsoHR6NRljtcWuAsNq7It8Vi7ze7Jt8Yra6LYxrTs8wB17mO9tbAoRGJ/Q UBjvGEk5gmMB20bgcaf4yUk2EUwnogtwiyGNtXMVfFgLAJTfzMmGxh5aUE6ls4S7QMWkbxCFe KR51jIxQCApPy+9a6JVJrw7LmDsb3U//wywO9oYR9NI1b79Xl4So+3pS781K6VTqIbsgKb4e4 cSTzkzVIpJjV5g3k6Rk9qNrA2jXqSTzIx+QD5PX8kBHwywBsI+b4keUFMS01l9NUxJAmmGMym N806O4as8SpEKjdiUHBRkZ5SxRi4irCHGCiuZ/yju+BDrsT7tztSLMxjO+ReuZUY+P8jxJLHg hA4CW1F2cFbd5HpWoJXBjQf4ew2IWzxySJWaGS7ucAMVhf6f5U9MZeKV6ty6LZqYgEnUyq5kA 2ngFb/B/iyQIbMpmvu7p1OwBHkfKN4w4Exz9zw6lzRRRuVyUZL+BJNhIeeXar1pV4Vvr95GyU oc85/t0rehatrYWfLUeHldYSScZiR1RCzCJdIkub/5dZZNs6J6VmrzSctj65/86KMgPQFoco1 S46HOxBteme8O4kP6/ohi4brg7/awC4RFKbOJgl9hBI8MDEpD14KPz2R7bhQrAKTSQGfNgbVD 5T43Ar9o2P1sfxQmPU9pxSTXGd3XkjV2tTIi8tvXwaNwExiHYGqppG+6s+SPxiVGzaGD+p2af WUL73znYfASyw9trC Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --UZUqh3wxv7F7FRGa2z9Ug9AGLIsQiwGzc Content-Type: multipart/mixed; boundary="yjhSzXiX84iPhGabxCUMRccg4qdzHKUaA" --yjhSzXiX84iPhGabxCUMRccg4qdzHKUaA Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 2020/3/4 =E4=B8=8A=E5=8D=881:29, David Sterba wrote: > On Mon, Mar 02, 2020 at 05:45:48PM +0800, Qu Wenruo wrote: >> build_backref_tree() function is painfully long, as it has 3 big parts= : >> - Tree backref handling >> - Weaving backref nodes >> - Useless nodes pruning >=20 > So this is the first patch that mentions the 'useless' nodes. This seem= s > like a misnomer or confusing at best but I haven't read enough code to > see if it's really the right name. The 'useless' is from the original code, there is a list called 'useless'= =2E It's not that useless, those nodes are just ignored, but still cached to prevent extra lookup. Hopes there would be a better name. >=20 > Also the term 'weaving', that seems to be added by you. Did you mean > splicing or merging? >=20 It's complex, but definitely not splicing or merge. The overall workflow looks like this: 1) Iteration works build a map like this: (start point is X) A B ^ ^ \ / C ^ | X At this stage, it's single directional, means we can only go X->C, C->A, C->B 2) Weaving part makes the map bi-directional A B ^ ^ \ / v v C ^ | v X That's the weaving part. Any better naming is welcomed. Thanks, Qu --yjhSzXiX84iPhGabxCUMRccg4qdzHKUaA-- --UZUqh3wxv7F7FRGa2z9Ug9AGLIsQiwGzc Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEELd9y5aWlW6idqkLhwj2R86El/qgFAl5e/a8ACgkQwj2R86El /qh4MAf+N2dKvkXsFvuL1HXCzSY0yGMsLPhN6+6GecL5LzNLdW0l9C3HtvFvvR52 qcJzPIW0fdQi7bsPbdAYLJyalK6aD0zbtQ+jV48aInJQSuELImrDoClu+FI8jZ2A 35Qs3wGveOO2cK6O1f6blFTI3arCzLJNrmXGiNTpq5mgDAsu0Rp3oJ0QxNbvvHRP kVkLvgE0yUJrtiWBoX5Rf0dyhvBWha9iHEcmEaj+awmhh5pCcMaZ3HFagdVHal/1 LKbm+OVKjQMaXWO/2KMadCfyfnXwpQxTv7GcQ5LrUJuWATo9J8yOv3ZYV5z/ggJE 6iSAXRqa4aeAJKvrwVMVZwSW2JZYpQ== =APRj -----END PGP SIGNATURE----- --UZUqh3wxv7F7FRGa2z9Ug9AGLIsQiwGzc--