Signed-off-by: Dushan Tcholich <dusanc@xxxxxxxxx>
--- estimate.c.orig 2007-10-23 17:07:54.000000000 +0200
+++ estimate.c 2007-10-23 17:14:19.000000000 +0200
@@ -1,4 +1,5 @@
-/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ reiser4/README */
#include "debug.h"
#include "dformat.h"
@@ -8,14 +9,18 @@
#include "plugin/cluster.h"
#include "plugin/item/ctail.h"
-/* this returns how many nodes might get dirty and added nodes if @children nodes are dirtied
+/* This returns how many nodes might get dirty and added nodes if @children
+ nodes are dirtied
- Amount of internals which will get dirty or get allocated we estimate as 5% of the childs + 1 balancing. 1 balancing
- is 2 neighbours, 2 new blocks and the current block on the leaf level, 2 neighbour nodes + the current (or 1
- neighbour and 1 new and the current) on twig level, 2 neighbour nodes on upper levels and 1 for a new root. So 5 for
- leaf level, 3 for twig level, 2 on upper + 1 for root.
+ Amount of internals which will get dirty or get allocated we estimate as 5%
+ of the childs + 1 balancing. 1 balancing is 2 neighbours, 2 new blocks and
+ the current block on the leaf level, 2 neighbour nodes + the current (or 1
+ neighbour and 1 new and the current) on twig level, 2 neighbour nodes on
+ upper levels and 1 for a new root. So 5 for leaf level, 3 for twig level,
+ 2 on upper + 1 for root.
- Do not calculate the current node of the lowest level here - this is overhead only.
+ Do not calculate the current node of the lowest level here - this is overhead
+ only.
children is almost always 1 here. Exception is flow insertion
*/
@@ -26,13 +31,15 @@ max_balance_overhead(reiser4_block_nr ch
ten_percent = ((103 * childen) >> 10);
- /* If we have too many balancings at the time, tree height can raise on more
- then 1. Assume that if tree_height is 5, it can raise on 1 only. */
+ /* If we have too many balancings at the time, tree height can raise on
+ more then 1. Assume that if tree_height is 5, it can raise on 1 only.
+ */
return ((tree_height < 5 ? 5 : tree_height) * 2 + (4 + ten_percent));
}
-/* this returns maximal possible number of nodes which can be modified plus number of new nodes which can be required to
- perform insertion of one item into the tree */
+/* this returns maximal possible number of nodes which can be modified plus
+ number of new nodes which can be required to perform insertion of one item
+ into the tree */
/* it is only called when tree height changes, or gets initialized */
reiser4_block_nr calc_estimate_one_insert(tree_level height)
{
@@ -44,8 +51,9 @@ reiser4_block_nr estimate_one_insert_ite
return tree->estimate_one_insert;
}
-/* this returns maximal possible number of nodes which can be modified plus number of new nodes which can be required to
- perform insertion of one unit into an item in the tree */
+/* this returns maximal possible number of nodes which can be modified plus
+ number of new nodes which can be required to perform insertion of one unit
+ into an item in the tree */
reiser4_block_nr estimate_one_insert_into_item(reiser4_tree * tree)
{
/* estimate insert into item just like item insertion */
@@ -54,14 +62,15 @@ reiser4_block_nr estimate_one_insert_int
reiser4_block_nr estimate_one_item_removal(reiser4_tree * tree)
{
- /* on item removal reiser4 does not try to pack nodes more complact, so, only one node may be dirtied on leaf
- level */
+ /* on item removal reiser4 does not try to pack nodes more complact, so,
+ only one node may be dirtied on leaf level */
return tree->estimate_one_insert;
}
-/* on leaf level insert_flow may add CARRY_FLOW_NEW_NODES_LIMIT new nodes and dirty 3 existing nodes (insert point and
- both its neighbors). Max_balance_overhead should estimate number of blocks which may change/get added on internal
- levels */
+/* on leaf level insert_flow may add CARRY_FLOW_NEW_NODES_LIMIT new nodes and
+ dirty 3 existing nodes (insert point and both its neighbors).
+ Max_balance_overhead should estimate number of blocks which may change/get
+ added on internal levels */
reiser4_block_nr estimate_insert_flow(tree_level height)
{
return 3 + CARRY_FLOW_NEW_NODES_LIMIT + max_balance_overhead(3 +
@@ -70,7 +79,7 @@ reiser4_block_nr estimate_insert_flow(tr
}
/* returnes max number of nodes can be occupied by disk cluster */
-static reiser4_block_nr estimate_cluster(struct inode * inode, int unprepped)
+static reiser4_block_nr estimate_cluster(struct inode *inode, int unprepped)
{
int per_cluster;
per_cluster = (unprepped ? 1 : cluster_nrpages(inode));
@@ -81,14 +90,14 @@ static reiser4_block_nr estimate_cluster
/* how many nodes might get dirty and added
during insertion of a disk cluster */
-reiser4_block_nr estimate_insert_cluster(struct inode * inode)
+reiser4_block_nr estimate_insert_cluster(struct inode *inode)
{
return estimate_cluster(inode, 1); /* 24 */
}
/* how many nodes might get dirty and added
during update of a (prepped or unprepped) disk cluster */
-reiser4_block_nr estimate_update_cluster(struct inode * inode)
+reiser4_block_nr estimate_update_cluster(struct inode *inode)
{
return estimate_cluster(inode, 0); /* 44, for 64K-cluster */
}
@@ -98,12 +107,12 @@ reiser4_block_nr estimate_update_cluster
can occupy more nodes).
Q: Why we don't use precise estimation?
A: 1.Because precise estimation is fairly bad: 65536 nodes
- for 64K logical cluster, it means 256M of dead space on
+ for 64K logical cluster, it means 256M of dead space on
a partition
2.It is a very rare case when disk cluster occupies more
- nodes then this estimation returns.
+ nodes then this estimation returns.
*/
-reiser4_block_nr estimate_dirty_cluster(struct inode * inode)
+reiser4_block_nr estimate_dirty_cluster(struct inode *inode)
{
return cluster_nrpages(inode) + 4;
}
