From 1fc5d959d88a5f77aa7e4435f6c9d0e2d2236704 Mon Sep 17 00:00:00 2001 From: David Chinner Date: Tue, 11 Apr 2006 15:11:12 +1000 Subject: [PATCH] [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 ++++++++++++----------------- fs/xfs/xfs_inode.h | 1 + 2 files changed, 13 insertions(+), 17 deletions(-) diff --git a/fs/xfs/xfs_iget.c b/fs/xfs/xfs_iget.c index bb33113eef9f..b53854325266 100644 --- a/fs/xfs/xfs_iget.c +++ b/fs/xfs/xfs_iget.c @@ -421,7 +421,10 @@ xfs_iget_core( 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; diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h index 39ef9c36ea55..3b544db1790b 100644 --- a/fs/xfs/xfs_inode.h +++ b/fs/xfs/xfs_inode.h @@ -189,6 +189,7 @@ typedef struct xfs_ihash { */ typedef struct xfs_chashlist { struct xfs_chashlist *chl_next; + struct xfs_chashlist *chl_prev; struct xfs_inode *chl_ip; xfs_daddr_t chl_blkno; /* starting block number of * the cluster */