[XFS] Remove the xfs_icluster structure

Remove the xfs_icluster structure and replace with a radix tree lookup.

We don't need to keep a list of inodes in each cluster around anymore as
we can look them up quickly when we need to. The only time we need to do
this now is during inode writeback.

Factor the inode cluster writeback code out of xfs_iflush and convert it
to use radix_tree_gang_lookup() instead of walking a list of inodes built
when we first read in the inodes.

This remove 3 pointers from each xfs_inode structure and the xfs_icluster
structure per inode cluster. Hence we reduce the cache footprint of the
xfs_inodes by between 5-10% depending on cluster sparseness.

To be truly efficient we need a radix_tree_gang_lookup_range() call to
stop searching once we are past the end of the cluster instead of trying
to find a full cluster's worth of inodes.

Before (ia64):

$ cat /sys/slab/xfs_inode/object_size 536

After:

$ cat /sys/slab/xfs_inode/object_size 512

SGI-PV: 977460
SGI-Modid: xfs-linux-melb:xfs-kern:30502a

Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>

1 files changed, 0 insertions, 16 deletions

diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index c3bfffca9214..93c37697a72c 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -133,19 +133,6 @@ typedef struct dm_attrs_s {
 } dm_attrs_t;
 
 /*
- * This is the xfs inode cluster structure.  This structure is used by
- * xfs_iflush to find inodes that share a cluster and can be flushed to disk at
- * the same time.
- */
-typedef struct xfs_icluster {
-        struct hlist_head       icl_inodes;     /* list of inodes on cluster */
-        xfs_daddr_t             icl_blkno;      /* starting block number of
-                                                 * the cluster */
-        struct xfs_buf          *icl_buf;       /* the inode buffer */
-        spinlock_t              icl_lock;       /* inode list lock */
-} xfs_icluster_t;
-
-/*
  * This is the xfs in-core inode structure.
  * Most of the on-disk inode is embedded in the i_d field.
  *
@@ -248,8 +235,6 @@ typedef struct xfs_inode {
         unsigned int            i_delayed_blks; /* count of delay alloc blks */
 
         xfs_icdinode_t          i_d;            /* most of ondisk inode */
-        xfs_icluster_t          *i_cluster;     /* cluster list header */
-        struct hlist_node       i_cnode;        /* cluster link node */
 
         xfs_fsize_t             i_size;         /* in-memory size */
         xfs_fsize_t             i_new_size;     /* size when write completes */
@@ -594,7 +579,6 @@ void		xfs_inobp_check(struct xfs_mount *, struct xfs_buf *);
 #define xfs_inobp_check(mp, bp)
 #endif /* DEBUG */
 
-extern struct kmem_zone *xfs_icluster_zone;
 extern struct kmem_zone *xfs_ifork_zone;
 extern struct kmem_zone *xfs_inode_zone;
 extern struct kmem_zone *xfs_ili_zone;