nilfs2: optimize calculation of min/max number of btree node children
nilfs_btree_node_nchildren_max() and nilfs_btree_node_nchildren_min()
functions switch return value depending on whether target node is the
root or a node block. In most uses of these functions, however, the
node type is fixed, and moreover the same calculation is repeatedly
performed in loop.
This unfold these functions depending on context and move them outside
loops wherever possible.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
diff --git a/fs/nilfs2/btree.c b/fs/nilfs2/btree.c
index 18bb965..c0266f7 100644
--- a/fs/nilfs2/btree.c
+++ b/fs/nilfs2/btree.c
@@ -473,7 +473,7 @@
{
struct nilfs_btree_node *node;
__u64 ptr;
- int level, index, found, ret;
+ int level, index, found, ncmax, ret;
node = nilfs_btree_get_root(btree);
level = nilfs_btree_node_get_level(node);
@@ -485,6 +485,8 @@
path[level].bp_bh = NULL;
path[level].bp_index = index;
+ ncmax = NILFS_BTREE_NODE_NCHILDREN_MAX(nilfs_btree_node_size(btree));
+
for (level--; level >= minlevel; level--) {
ret = nilfs_btree_get_block(btree, ptr, &path[level].bp_bh);
if (ret < 0)
@@ -496,9 +498,9 @@
found = nilfs_btree_node_lookup(node, key, &index);
else
index = 0;
- if (index < nilfs_btree_node_nchildren_max(node, btree))
+ if (index < ncmax) {
ptr = nilfs_btree_node_get_ptr(btree, node, index);
- else {
+ } else {
WARN_ON(found || level != NILFS_BTREE_LEVEL_NODE_MIN);
/* insert */
ptr = NILFS_BMAP_INVALID_PTR;
@@ -921,7 +923,7 @@
struct buffer_head *bh;
struct nilfs_btree_node *node, *parent, *sib;
__u64 sibptr;
- int pindex, level, ret;
+ int pindex, level, ncmax, ret;
struct inode *dat = NULL;
stats->bs_nblocks = 0;
@@ -938,12 +940,13 @@
if (ret < 0)
goto err_out_data;
+ ncmax = NILFS_BTREE_NODE_NCHILDREN_MAX(nilfs_btree_node_size(btree));
+
for (level = NILFS_BTREE_LEVEL_NODE_MIN;
level < nilfs_btree_height(btree) - 1;
level++) {
node = nilfs_btree_get_nonroot_node(path, level);
- if (nilfs_btree_node_get_nchildren(node) <
- nilfs_btree_node_nchildren_max(node, btree)) {
+ if (nilfs_btree_node_get_nchildren(node) < ncmax) {
path[level].bp_op = nilfs_btree_do_insert;
stats->bs_nblocks++;
goto out;
@@ -960,8 +963,7 @@
if (ret < 0)
goto err_out_child_node;
sib = (struct nilfs_btree_node *)bh->b_data;
- if (nilfs_btree_node_get_nchildren(sib) <
- nilfs_btree_node_nchildren_max(sib, btree)) {
+ if (nilfs_btree_node_get_nchildren(sib) < ncmax) {
path[level].bp_sib_bh = bh;
path[level].bp_op = nilfs_btree_carry_left;
stats->bs_nblocks++;
@@ -979,8 +981,7 @@
if (ret < 0)
goto err_out_child_node;
sib = (struct nilfs_btree_node *)bh->b_data;
- if (nilfs_btree_node_get_nchildren(sib) <
- nilfs_btree_node_nchildren_max(sib, btree)) {
+ if (nilfs_btree_node_get_nchildren(sib) < ncmax) {
path[level].bp_sib_bh = bh;
path[level].bp_op = nilfs_btree_carry_right;
stats->bs_nblocks++;
@@ -1014,7 +1015,7 @@
/* root */
node = nilfs_btree_get_root(btree);
if (nilfs_btree_node_get_nchildren(node) <
- nilfs_btree_node_nchildren_max(node, btree)) {
+ NILFS_BTREE_ROOT_NCHILDREN_MAX) {
path[level].bp_op = nilfs_btree_do_insert;
stats->bs_nblocks++;
goto out;
@@ -1281,10 +1282,12 @@
struct buffer_head *bh;
struct nilfs_btree_node *node, *parent, *sib;
__u64 sibptr;
- int pindex, level, ret;
+ int pindex, level, ncmin, ret;
ret = 0;
stats->bs_nblocks = 0;
+ ncmin = NILFS_BTREE_NODE_NCHILDREN_MIN(nilfs_btree_node_size(btree));
+
for (level = NILFS_BTREE_LEVEL_NODE_MIN;
level < nilfs_btree_height(btree) - 1;
level++) {
@@ -1297,8 +1300,7 @@
if (ret < 0)
goto err_out_child_node;
- if (nilfs_btree_node_get_nchildren(node) >
- nilfs_btree_node_nchildren_min(node, btree)) {
+ if (nilfs_btree_node_get_nchildren(node) > ncmin) {
path[level].bp_op = nilfs_btree_do_delete;
stats->bs_nblocks++;
goto out;
@@ -1315,8 +1317,7 @@
if (ret < 0)
goto err_out_curr_node;
sib = (struct nilfs_btree_node *)bh->b_data;
- if (nilfs_btree_node_get_nchildren(sib) >
- nilfs_btree_node_nchildren_min(sib, btree)) {
+ if (nilfs_btree_node_get_nchildren(sib) > ncmin) {
path[level].bp_sib_bh = bh;
path[level].bp_op = nilfs_btree_borrow_left;
stats->bs_nblocks++;
@@ -1336,8 +1337,7 @@
if (ret < 0)
goto err_out_curr_node;
sib = (struct nilfs_btree_node *)bh->b_data;
- if (nilfs_btree_node_get_nchildren(sib) >
- nilfs_btree_node_nchildren_min(sib, btree)) {
+ if (nilfs_btree_node_get_nchildren(sib) > ncmin) {
path[level].bp_sib_bh = bh;
path[level].bp_op = nilfs_btree_borrow_right;
stats->bs_nblocks++;