From da353b0d64e070ae7c5342a0d56ec20ae9ef5cfb Mon Sep 17 00:00:00 2001 From: David Chinner Date: Tue, 28 Aug 2007 14:00:13 +1000 Subject: [XFS] Radix tree based inode caching One of the perpetual scaling problems XFS has is indexing it's incore inodes. We currently uses hashes and the default hash sizes chosen can only ever be a tradeoff between memory consumption and the maximum realistic size of the cache. As a result, anyone who has millions of inodes cached on a filesystem needs to tunes the size of the cache via the ihashsize mount option to allow decent scalability with inode cache operations. A further problem is the separate inode cluster hash, whose size is based on the ihashsize but is smaller, and so under certain conditions (sparse cluster cache population) this can become a limitation long before the inode hash is causing issues. The following patchset removes the inode hash and cluster hash and replaces them with radix trees to avoid the scalability limitations of the hashes. It also reduces the size of the inodes by 3 pointers.... SGI-PV: 969561 SGI-Modid: xfs-linux-melb:xfs-kern:29481a Signed-off-by: David Chinner Signed-off-by: Christoph Hellwig Signed-off-by: Tim Shimmin --- fs/xfs/xfs_ag.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'fs/xfs/xfs_ag.h') diff --git a/fs/xfs/xfs_ag.h b/fs/xfs/xfs_ag.h index 51c09c114a2..9381b0360c4 100644 --- a/fs/xfs/xfs_ag.h +++ b/fs/xfs/xfs_ag.h @@ -197,6 +197,10 @@ typedef struct xfs_perag #endif xfs_perag_busy_t *pagb_list; /* unstable blocks */ atomic_t pagf_fstrms; /* # of filestreams active in this AG */ + + int pag_ici_init; /* incore inode cache initialised */ + rwlock_t pag_ici_lock; /* incore inode lock */ + struct radix_tree_root pag_ici_root; /* incore inode cache root */ } xfs_perag_t; #define XFS_AG_MAXLEVELS(mp) ((mp)->m_ag_maxlevels) -- cgit v1.2.3-70-g09d2