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=-6.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 404FCC433E0 for ; Mon, 6 Jul 2020 06:13:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EAFB120724 for ; Mon, 6 Jul 2020 06:13:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=synology.com header.i=@synology.com header.b="HQ5Gjlj+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728861AbgGFGNs (ORCPT ); Mon, 6 Jul 2020 02:13:48 -0400 Received: from mail.synology.com ([211.23.38.101]:33326 "EHLO synology.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728828AbgGFGNs (ORCPT ); Mon, 6 Jul 2020 02:13:48 -0400 Subject: Re: [PATCH] btrfs: speedup mount time with force readahead chunk tree DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=synology.com; s=123; t=1594016025; bh=C0NEDavYnBj6fMGimUMhF+UC0dZgU1GeX3vtuGYaQa0=; h=Subject:To:References:From:Date:In-Reply-To; b=HQ5Gjlj+CLQAVRVNYoZn3LJ8QzjHdocXyMvu48qbFS/bRpCS9XPQk3xeS4fQcNvMt Cwg91/lsYqQf0AMmCrgpVy1gBcZzMp/QS7e4uVZRjsyF9VejduU+SHliuf6/SXDBZd anNdjxxB5MZ2O9xFeqeUhz/Lc8PdZbZ4Bwx0VVk8= To: linux-btrfs@vger.kernel.org References: <20200701092957.20870-1-robbieko@synology.com> From: Robbie Ko Message-ID: Date: Mon, 6 Jul 2020 14:13:45 +0800 MIME-Version: 1.0 In-Reply-To: <20200701092957.20870-1-robbieko@synology.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Synology-MCP-Status: no X-Synology-Spam-Flag: no X-Synology-Spam-Status: score=0, required 6, WHITELIST_FROM_ADDRESS 0 X-Synology-Virus-Status: no Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org Does anyone have any suggestions? robbieko 於 2020/7/1 下午5:29 寫道: > From: Robbie Ko > > When mounting, we always need to read the whole chunk tree, > when there are too many chunk items, most of the time is > spent on btrfs_read_chunk_tree, because we only read one > leaf at a time. > > We fix this by adding a new readahead mode READA_FORWARD_FORCE, > which reads all the leaves after the key in the node when > reading a level 1 node. > > Signed-off-by: Robbie Ko > --- > fs/btrfs/ctree.c | 7 +++++-- > fs/btrfs/ctree.h | 2 +- > fs/btrfs/volumes.c | 1 + > 3 files changed, 7 insertions(+), 3 deletions(-) > > diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c > index 3a7648bff42c..abb9108e2d7d 100644 > --- a/fs/btrfs/ctree.c > +++ b/fs/btrfs/ctree.c > @@ -2194,7 +2194,7 @@ static void reada_for_search(struct btrfs_fs_info *fs_info, > if (nr == 0) > break; > nr--; > - } else if (path->reada == READA_FORWARD) { > + } else if (path->reada == READA_FORWARD || path->reada == READA_FORWARD_FORCE) { > nr++; > if (nr >= nritems) > break; > @@ -2205,12 +2205,15 @@ static void reada_for_search(struct btrfs_fs_info *fs_info, > break; > } > search = btrfs_node_blockptr(node, nr); > - if ((search <= target && target - search <= 65536) || > + if ((path->reada == READA_FORWARD_FORCE) || > + (search <= target && target - search <= 65536) || > (search > target && search - target <= 65536)) { > readahead_tree_block(fs_info, search); > nread += blocksize; > } > nscan++; > + if (path->reada == READA_FORWARD_FORCE) > + continue; > if ((nread > 65536 || nscan > 32)) > break; > } > diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h > index d404cce8ae40..808bcbdc9530 100644 > --- a/fs/btrfs/ctree.h > +++ b/fs/btrfs/ctree.h > @@ -353,7 +353,7 @@ struct btrfs_node { > * The slots array records the index of the item or block pointer > * used while walking the tree. > */ > -enum { READA_NONE, READA_BACK, READA_FORWARD }; > +enum { READA_NONE, READA_BACK, READA_FORWARD, READA_FORWARD_FORCE }; > struct btrfs_path { > struct extent_buffer *nodes[BTRFS_MAX_LEVEL]; > int slots[BTRFS_MAX_LEVEL]; > diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c > index 0d6e785bcb98..78fd65abff69 100644 > --- a/fs/btrfs/volumes.c > +++ b/fs/btrfs/volumes.c > @@ -7043,6 +7043,7 @@ int btrfs_read_chunk_tree(struct btrfs_fs_info *fs_info) > path = btrfs_alloc_path(); > if (!path) > return -ENOMEM; > + path->reada = READA_FORWARD_FORCE; > > /* > * uuid_mutex is needed only if we are mounting a sprout FS