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authorDavid Chinner <dgc@sgi.com>2006-04-11 15:11:12 +1000
committerNathan Scott <nathans@sgi.com>2006-04-11 15:11:12 +1000
commit1fc5d959d88a5f77aa7e4435f6c9d0e2d2236704 (patch)
tree0a2d3fce6b4e296f2d2dfbfdd5a58c19624d754b
parent8272145c05c6d01a34f5114357c5e8093fb66472 (diff)
downloadop-kernel-dev-1fc5d959d88a5f77aa7e4435f6c9d0e2d2236704.zip
op-kernel-dev-1fc5d959d88a5f77aa7e4435f6c9d0e2d2236704.tar.gz
[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 <dgc@sgi.com> Signed-off-by: Nathan Scott <nathans@sgi.com>
-rw-r--r--fs/xfs/xfs_iget.c29
-rw-r--r--fs/xfs/xfs_inode.h1
2 files changed, 13 insertions, 17 deletions
diff --git a/fs/xfs/xfs_iget.c b/fs/xfs/xfs_iget.c
index bb33113..b538543 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;
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index 39ef9c3..3b544db 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 */
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