From 1fc5d959d88a5f77aa7e4435f6c9d0e2d2236704 Mon Sep 17 00:00:00 2001 From: David Chinner Date: Tue, 11 Apr 2006 15:11:12 +1000 Subject: [XFS] Fix inode reclaim scalability regression. When a filesystem has millions of inodes cached and has sparse cluster population, removing inodes from the cluster hash consumes excessive amounts of CPU time. Reduce the CPU cost by making removal O(1) via use of a double linked list for the hash chains. SGI-PV: 951551 SGI-Modid: xfs-linux-melb:xfs-kern:25683a Signed-off-by: David Chinner Signed-off-by: Nathan Scott --- fs/xfs/xfs_iget.c | 29 ++++++++++++----------------- 1 file changed, 12 insertions(+), 17 deletions(-) (limited to 'fs/xfs/xfs_iget.c') diff --git a/fs/xfs/xfs_iget.c b/fs/xfs/xfs_iget.c index bb33113eef9..b5385432526 100644 --- a/fs/xfs/xfs_iget.c +++ b/fs/xfs/xfs_iget.c @@ -421,7 +421,10 @@ finish_inode: ip->i_chash = chlnew; chlnew->chl_ip = ip; chlnew->chl_blkno = ip->i_blkno; + if (ch->ch_list) + ch->ch_list->chl_prev = chlnew; chlnew->chl_next = ch->ch_list; + chlnew->chl_prev = NULL; ch->ch_list = chlnew; chlnew = NULL; } @@ -723,23 +726,15 @@ xfs_iextract( ASSERT(ip->i_cnext == ip && ip->i_cprev == ip); ASSERT(ip->i_chash != NULL); chm=NULL; - for (chl = ch->ch_list; chl != NULL; chl = chl->chl_next) { - if (chl->chl_blkno == ip->i_blkno) { - if (chm == NULL) { - /* first item on the list */ - ch->ch_list = chl->chl_next; - } else { - chm->chl_next = chl->chl_next; - } - kmem_zone_free(xfs_chashlist_zone, chl); - break; - } else { - ASSERT(chl->chl_ip != ip); - chm = chl; - } - } - ASSERT_ALWAYS(chl != NULL); - } else { + chl = ip->i_chash; + if (chl->chl_prev) + chl->chl_prev->chl_next = chl->chl_next; + else + ch->ch_list = chl->chl_next; + if (chl->chl_next) + chl->chl_next->chl_prev = chl->chl_prev; + kmem_zone_free(xfs_chashlist_zone, chl); + } else { /* delete one inode from a non-empty list */ iq = ip->i_cnext; iq->i_cprev = ip->i_cprev; -- cgit v1.2.3