From patchwork Thu Aug 29 10:47:10 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dave Chinner X-Patchwork-Id: 11120965 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 7D59318EC for ; Thu, 29 Aug 2019 10:47:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 674002189D for ; Thu, 29 Aug 2019 10:47:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726416AbfH2KrU (ORCPT ); Thu, 29 Aug 2019 06:47:20 -0400 Received: from mail105.syd.optusnet.com.au ([211.29.132.249]:34827 "EHLO mail105.syd.optusnet.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726973AbfH2KrT (ORCPT ); Thu, 29 Aug 2019 06:47:19 -0400 Received: from dread.disaster.area (pa49-181-255-194.pa.nsw.optusnet.com.au [49.181.255.194]) by mail105.syd.optusnet.com.au (Postfix) with ESMTPS id 26B3C361CB4 for ; Thu, 29 Aug 2019 20:47:14 +1000 (AEST) Received: from discord.disaster.area ([192.168.253.110]) by dread.disaster.area with esmtp (Exim 4.92) (envelope-from ) id 1i3HxQ-00032e-Ki for linux-xfs@vger.kernel.org; Thu, 29 Aug 2019 20:47:12 +1000 Received: from dave by discord.disaster.area with local (Exim 4.92) (envelope-from ) id 1i3HxQ-0007OE-J9 for linux-xfs@vger.kernel.org; Thu, 29 Aug 2019 20:47:12 +1000 From: Dave Chinner To: linux-xfs@vger.kernel.org Subject: [PATCH 5/5] xfs: reverse search directory freespace indexes Date: Thu, 29 Aug 2019 20:47:10 +1000 Message-Id: <20190829104710.28239-6-david@fromorbit.com> X-Mailer: git-send-email 2.23.0.rc1 In-Reply-To: <20190829104710.28239-1-david@fromorbit.com> References: <20190829104710.28239-1-david@fromorbit.com> MIME-Version: 1.0 X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.2 cv=FNpr/6gs c=1 sm=1 tr=0 a=YO9NNpcXwc8z/SaoS+iAiA==:117 a=YO9NNpcXwc8z/SaoS+iAiA==:17 a=jpOVt7BSZ2e4Z31A5e1TngXxSK0=:19 a=FmdZ9Uzk2mMA:10 a=20KFwNOVAAAA:8 a=SUicX0odFCYvpFH38aAA:9 a=p-Z9SOsmXBCEoUSk:21 a=tddZAhjlFDH3ISzV:21 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org From: Dave Chinner When a directory is growing rapidly, new blocks tend to get added at the end of the directory. These end up at the end of the freespace index, and when the directory gets large finding these new freespaces gets expensive. The code does a linear search across the frespace index from the first block in the directory to the last, hence meaning the newly added space is the last index searched. Instead, do a reverse order index search, starting from the last block and index in the freespace index. This makes most lookups for free space on rapidly growing directories O(1) instead of O(N), but should not have any impact on random insert workloads because the average search length is the same regardless of which end of the array we start at. The result is a major improvement in large directory grow rates: create time(sec) / rate (files/s) File count vanilla Prev commit Patched 10k 0.41 / 24.3k 0.42 / 23.8k 0.41 / 24.3k 20k 0.74 / 27.0k 0.76 / 26.3k 0.75 / 26.7k 100k 3.81 / 26.4k 3.47 / 28.8k 3.27 / 30.6k 200k 8.58 / 23.3k 7.19 / 27.8k 6.71 / 29.8k 1M 85.69 / 11.7k 48.53 / 20.6k 37.67 / 26.5k 2M 280.31 / 7.1k 130.14 / 15.3k 79.55 / 25.2k 10M 3913.26 / 2.5k 552.89 / 18.1k Signed-Off-By: Dave Chinner Reviewed-by: Darrick J. Wong Reviewed-by: Christoph Hellwig --- fs/xfs/libxfs/xfs_dir2_node.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) diff --git a/fs/xfs/libxfs/xfs_dir2_node.c b/fs/xfs/libxfs/xfs_dir2_node.c index a81f56d9e538..705c4f562758 100644 --- a/fs/xfs/libxfs/xfs_dir2_node.c +++ b/fs/xfs/libxfs/xfs_dir2_node.c @@ -1745,10 +1745,11 @@ xfs_dir2_node_find_freeblk( struct xfs_inode *dp = args->dp; struct xfs_trans *tp = args->trans; struct xfs_buf *fbp = NULL; + xfs_dir2_db_t firstfbno; xfs_dir2_db_t lastfbno; xfs_dir2_db_t ifbno = -1; xfs_dir2_db_t dbno = -1; - xfs_dir2_db_t fbno = -1; + xfs_dir2_db_t fbno; xfs_fileoff_t fo; __be16 *bests = NULL; int findex = 0; @@ -1780,7 +1781,6 @@ xfs_dir2_node_find_freeblk( * We'll start at the beginning of the freespace entries. */ ifbno = fblk->blkno; - fbno = ifbno; xfs_trans_brelse(tp, fbp); fbp = NULL; fblk->bp = NULL; @@ -1794,12 +1794,9 @@ xfs_dir2_node_find_freeblk( if (error) return error; lastfbno = xfs_dir2_da_to_db(args->geo, (xfs_dablk_t)fo); + firstfbno = xfs_dir2_byte_to_db(args->geo, XFS_DIR2_FREE_OFFSET); - /* If we haven't get a search start block, set it now */ - if (fbno == -1) - fbno = xfs_dir2_byte_to_db(args->geo, XFS_DIR2_FREE_OFFSET); - - for ( ; fbno < lastfbno; fbno++) { + for (fbno = lastfbno - 1; fbno >= firstfbno; fbno--) { /* If it's ifbno we already looked at it. */ if (fbno == ifbno) continue; @@ -1822,7 +1819,7 @@ xfs_dir2_node_find_freeblk( dp->d_ops->free_hdr_from_disk(&freehdr, free); /* Scan the free entry array for a large enough free space. */ - for (findex = 0; findex < freehdr.nvalid; findex++) { + for (findex = freehdr.nvalid - 1; findex >= 0; findex--) { if (be16_to_cpu(bests[findex]) != NULLDATAOFF && be16_to_cpu(bests[findex]) >= length) { dbno = freehdr.firstdb + findex;