From patchwork Tue Jun 1 22:40:29 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dave Chinner X-Patchwork-Id: 12292349 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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 AD0DDC47080 for ; Tue, 1 Jun 2021 22:40:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 88AAB613BD for ; Tue, 1 Jun 2021 22:40:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234934AbhFAWmQ (ORCPT ); Tue, 1 Jun 2021 18:42:16 -0400 Received: from mail105.syd.optusnet.com.au ([211.29.132.249]:49900 "EHLO mail105.syd.optusnet.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234714AbhFAWmP (ORCPT ); Tue, 1 Jun 2021 18:42:15 -0400 Received: from dread.disaster.area (pa49-179-138-183.pa.nsw.optusnet.com.au [49.179.138.183]) by mail105.syd.optusnet.com.au (Postfix) with ESMTPS id 7056B1043BED; Wed, 2 Jun 2021 08:40:31 +1000 (AEST) Received: from dave by dread.disaster.area with local (Exim 4.92.3) (envelope-from ) id 1loD3l-007sY3-Su; Wed, 02 Jun 2021 08:40:29 +1000 Date: Wed, 2 Jun 2021 08:40:29 +1000 From: Dave Chinner To: Brian Foster Cc: linux-xfs@vger.kernel.org Subject: [PATCH 18/23 V2] xfs: collapse AG selection for inode allocation Message-ID: <20210601224029.GF664593@dread.disaster.area> References: <20210519012102.450926-1-david@fromorbit.com> <20210519012102.450926-19-david@fromorbit.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.3 cv=YKPhNiOx c=1 sm=1 tr=0 a=MnllW2CieawZLw/OcHE/Ng==:117 a=MnllW2CieawZLw/OcHE/Ng==:17 a=kj9zAlcOel0A:10 a=r6YtysWOX24A:10 a=20KFwNOVAAAA:8 a=Ea7z_8LkaGOMw6jD5OgA:9 a=0Zjp8BJ-D7talOb3:21 a=MG-52QA8c4HFTcSE:21 a=CjuIK1q_8ugA:10 Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org From: Dave Chinner xfs_dialloc_select_ag() does a lot of repetitive work. It first calls xfs_ialloc_ag_select() to select the AG to start allocation attempts in, which can do up to two entire loops across the perags that inodes can be allocated in. This is simply checking if there is spce available to allocate inodes in an AG, and it returns when it finds the first candidate AG. xfs_dialloc_select_ag() then does it's own iterative walk across all the perags locking the AGIs and trying to allocate inodes from the locked AG. It also doesn't limit the search to mp->m_maxagi, so it will walk all AGs whether they can allocate inodes or not. Hence if we are really low on inodes, we could do almost 3 entire walks across the whole perag range before we find an allocation group we can allocate inodes in or report ENOSPC. Because xfs_ialloc_ag_select() returns on the first candidate AG it finds, we can simply do these checks directly in xfs_dialloc_select_ag() before we lock and try to allocate inodes. This reduces the inode allocation pass down to 2 perag sweeps at most - one for aligned inode cluster allocation and if we can't allocate full, aligned inode clusters anywhere we'll do another pass trying to do sparse inode cluster allocation. This also removes a big chunk of duplicate code. Signed-off-by: Dave Chinner Reviewed-by: Darrick J. Wong --- V2: fix space calculation in xfs_dialloc_select_ag() fs/xfs/libxfs/xfs_ialloc.c | 225 ++++++++++++++++----------------------------- 1 file changed, 78 insertions(+), 147 deletions(-) diff --git a/fs/xfs/libxfs/xfs_ialloc.c b/fs/xfs/libxfs/xfs_ialloc.c index 872591e8f5cb..79119af36d12 100644 --- a/fs/xfs/libxfs/xfs_ialloc.c +++ b/fs/xfs/libxfs/xfs_ialloc.c @@ -899,139 +899,6 @@ xfs_ialloc_ag_alloc( return 0; } -STATIC xfs_agnumber_t -xfs_ialloc_next_ag( - xfs_mount_t *mp) -{ - xfs_agnumber_t agno; - - spin_lock(&mp->m_agirotor_lock); - agno = mp->m_agirotor; - if (++mp->m_agirotor >= mp->m_maxagi) - mp->m_agirotor = 0; - spin_unlock(&mp->m_agirotor_lock); - - return agno; -} - -/* - * Select an allocation group to look for a free inode in, based on the parent - * inode and the mode. Return the allocation group buffer. - */ -STATIC xfs_agnumber_t -xfs_ialloc_ag_select( - xfs_trans_t *tp, /* transaction pointer */ - xfs_ino_t parent, /* parent directory inode number */ - umode_t mode) /* bits set to indicate file type */ -{ - xfs_agnumber_t agcount; /* number of ag's in the filesystem */ - xfs_agnumber_t agno; /* current ag number */ - int flags; /* alloc buffer locking flags */ - xfs_extlen_t ineed; /* blocks needed for inode allocation */ - xfs_extlen_t longest = 0; /* longest extent available */ - xfs_mount_t *mp; /* mount point structure */ - int needspace; /* file mode implies space allocated */ - xfs_perag_t *pag; /* per allocation group data */ - xfs_agnumber_t pagno; /* parent (starting) ag number */ - int error; - - /* - * Files of these types need at least one block if length > 0 - * (and they won't fit in the inode, but that's hard to figure out). - */ - needspace = S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode); - mp = tp->t_mountp; - agcount = mp->m_maxagi; - if (S_ISDIR(mode)) - pagno = xfs_ialloc_next_ag(mp); - else { - pagno = XFS_INO_TO_AGNO(mp, parent); - if (pagno >= agcount) - pagno = 0; - } - - ASSERT(pagno < agcount); - - /* - * Loop through allocation groups, looking for one with a little - * free space in it. Note we don't look for free inodes, exactly. - * Instead, we include whether there is a need to allocate inodes - * to mean that blocks must be allocated for them, - * if none are currently free. - */ - agno = pagno; - flags = XFS_ALLOC_FLAG_TRYLOCK; - for (;;) { - pag = xfs_perag_get(mp, agno); - if (!pag->pagi_inodeok) { - xfs_ialloc_next_ag(mp); - goto nextag; - } - - if (!pag->pagi_init) { - error = xfs_ialloc_pagi_init(mp, tp, agno); - if (error) - goto nextag; - } - - if (pag->pagi_freecount) { - xfs_perag_put(pag); - return agno; - } - - if (!pag->pagf_init) { - error = xfs_alloc_pagf_init(mp, tp, agno, flags); - if (error) - goto nextag; - } - - /* - * Check that there is enough free space for the file plus a - * chunk of inodes if we need to allocate some. If this is the - * first pass across the AGs, take into account the potential - * space needed for alignment of inode chunks when checking the - * longest contiguous free space in the AG - this prevents us - * from getting ENOSPC because we have free space larger than - * ialloc_blks but alignment constraints prevent us from using - * it. - * - * If we can't find an AG with space for full alignment slack to - * be taken into account, we must be near ENOSPC in all AGs. - * Hence we don't include alignment for the second pass and so - * if we fail allocation due to alignment issues then it is most - * likely a real ENOSPC condition. - */ - ineed = M_IGEO(mp)->ialloc_min_blks; - if (flags && ineed > 1) - ineed += M_IGEO(mp)->cluster_align; - longest = pag->pagf_longest; - if (!longest) - longest = pag->pagf_flcount > 0; - - if (pag->pagf_freeblks >= needspace + ineed && - longest >= ineed) { - xfs_perag_put(pag); - return agno; - } -nextag: - xfs_perag_put(pag); - /* - * No point in iterating over the rest, if we're shutting - * down. - */ - if (XFS_FORCED_SHUTDOWN(mp)) - return NULLAGNUMBER; - agno++; - if (agno >= agcount) - agno = 0; - if (agno == pagno) { - if (flags == 0) - return NULLAGNUMBER; - flags = 0; - } - } -} - /* * Try to retrieve the next record to the left/right from the current one. */ @@ -1708,6 +1575,21 @@ xfs_dialloc_roll( return 0; } +STATIC xfs_agnumber_t +xfs_ialloc_next_ag( + xfs_mount_t *mp) +{ + xfs_agnumber_t agno; + + spin_lock(&mp->m_agirotor_lock); + agno = mp->m_agirotor; + if (++mp->m_agirotor >= mp->m_maxagi) + mp->m_agirotor = 0; + spin_unlock(&mp->m_agirotor_lock); + + return agno; +} + /* * Select and prepare an AG for inode allocation. * @@ -1734,16 +1616,24 @@ xfs_dialloc_select_ag( struct xfs_perag *pag; struct xfs_ino_geometry *igeo = M_IGEO(mp); bool okalloc = true; + int needspace; + int flags; *IO_agbp = NULL; /* - * We do not have an agbp, so select an initial allocation - * group for inode allocation. + * Directories, symlinks, and regular files frequently allocate at least + * one block, so factor that potential expansion when we examine whether + * an AG has enough space for file creation. */ - start_agno = xfs_ialloc_ag_select(*tpp, parent, mode); - if (start_agno == NULLAGNUMBER) - return -ENOSPC; + needspace = S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode); + if (S_ISDIR(mode)) + start_agno = xfs_ialloc_next_ag(mp); + else { + start_agno = XFS_INO_TO_AGNO(mp, parent); + if (start_agno >= mp->m_maxagi) + start_agno = 0; + } /* * If we have already hit the ceiling of inode blocks then clear @@ -1765,12 +1655,14 @@ xfs_dialloc_select_ag( * allocation groups upward, wrapping at the end. */ agno = start_agno; + flags = XFS_ALLOC_FLAG_TRYLOCK; for (;;) { + xfs_extlen_t ineed; + xfs_extlen_t longest = 0; + pag = xfs_perag_get(mp, agno); - if (!pag->pagi_inodeok) { - xfs_ialloc_next_ag(mp); + if (!pag->pagi_inodeok) goto nextag; - } if (!pag->pagi_init) { error = xfs_ialloc_pagi_init(mp, *tpp, agno); @@ -1778,12 +1670,44 @@ xfs_dialloc_select_ag( break; } - /* - * Do a first racy fast path check if this AG is usable. - */ if (!pag->pagi_freecount && !okalloc) goto nextag; + if (!pag->pagf_init) { + error = xfs_alloc_pagf_init(mp, *tpp, agno, flags); + if (error) + goto nextag; + } + + /* + * Check that there is enough free space for the file plus a + * chunk of inodes if we need to allocate some. If this is the + * first pass across the AGs, take into account the potential + * space needed for alignment of inode chunks when checking the + * longest contiguous free space in the AG - this prevents us + * from getting ENOSPC because we have free space larger than + * ialloc_blks but alignment constraints prevent us from using + * it. + * + * If we can't find an AG with space for full alignment slack to + * be taken into account, we must be near ENOSPC in all AGs. + * Hence we don't include alignment for the second pass and so + * if we fail allocation due to alignment issues then it is most + * likely a real ENOSPC condition. + */ + if (!pag->pagi_freecount) { + ineed = M_IGEO(mp)->ialloc_min_blks; + if (flags && ineed > 1) + ineed += M_IGEO(mp)->cluster_align; + longest = pag->pagf_longest; + if (!longest) + longest = pag->pagf_flcount > 0; + + if (pag->pagf_freeblks < needspace + ineed || + longest < ineed) + goto nextag; + } + /* * Then read in the AGI buffer and recheck with the AGI buffer * lock held. @@ -1823,10 +1747,17 @@ xfs_dialloc_select_ag( nextag_relse_buffer: xfs_trans_brelse(*tpp, agbp); nextag: - if (++agno == mp->m_sb.sb_agcount) - agno = 0; - if (agno == start_agno) + if (XFS_FORCED_SHUTDOWN(mp)) { + error = -EFSCORRUPTED; break; + } + if (++agno == mp->m_maxagi) + agno = 0; + if (agno == start_agno) { + if (!flags) + break; + flags = 0; + } xfs_perag_put(pag); }