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nilfs2: apply read-ahead for nilfs_btree_lookup_contig

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This applies read-ahead to nilfs_btree_do_lookup and
nilfs_btree_lookup_contig functions and extends them to read ahead
siblings of level 1 btree nodes that hold data blocks.

At present, the read-ahead is not applied to most btree operations;
only get_block() callback function, which is used during read of
regular files or directories, receives the benefit.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
This commit is contained in:
Ryusuke Konishi 2010-07-18 10:42:26 +09:00
parent 4e13e66bee
commit 03bdb5ac58
1 changed files with 33 additions and 17 deletions
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50
fs/nilfs2/btree.c
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@ -504,9 +504,11 @@ static int nilfs_btree_get_block(const struct nilfs_bmap *btree, __u64 ptr,
static int nilfs_btree_do_lookup(const struct nilfs_bmap *btree,
struct nilfs_btree_path *path,
__u64 key, __u64 *ptrp, int minlevel)
__u64 key, __u64 *ptrp, int minlevel,
int readahead)
{
struct nilfs_btree_node *node;
struct nilfs_btree_readahead_info p, *ra;
__u64 ptr;
int level, index, found, ncmax, ret;
@ -523,10 +525,20 @@ static int nilfs_btree_do_lookup(const struct nilfs_bmap *btree,
ncmax = nilfs_btree_nchildren_per_block(btree);
for (level--; level >= minlevel; level--) {
ret = nilfs_btree_get_block(btree, ptr, &path[level].bp_bh);
while (--level >= minlevel) {
ra = NULL;
if (level == NILFS_BTREE_LEVEL_NODE_MIN && readahead) {
p.node = nilfs_btree_get_node(btree, path, level + 1,
&p.ncmax);
p.index = index;
p.max_ra_blocks = 7;
ra = &p;
}
ret = __nilfs_btree_get_block(btree, ptr, &path[level].bp_bh,
ra);
if (ret < 0)
return ret;
node = nilfs_btree_get_nonroot_node(path, level);
if (nilfs_btree_bad_node(node, level))
return -EINVAL;
@ -601,7 +613,7 @@ static int nilfs_btree_lookup(const struct nilfs_bmap *btree,
if (path == NULL)
return -ENOMEM;
ret = nilfs_btree_do_lookup(btree, path, key, ptrp, level);
ret = nilfs_btree_do_lookup(btree, path, key, ptrp, level, 0);
nilfs_btree_free_path(path);
@ -618,12 +630,13 @@ static int nilfs_btree_lookup_contig(const struct nilfs_bmap *btree,
sector_t blocknr;
int level = NILFS_BTREE_LEVEL_NODE_MIN;
int ret, cnt, index, maxlevel, ncmax;
struct nilfs_btree_readahead_info p;
path = nilfs_btree_alloc_path();
if (path == NULL)
return -ENOMEM;
ret = nilfs_btree_do_lookup(btree, path, key, &ptr, level);
ret = nilfs_btree_do_lookup(btree, path, key, &ptr, level, 1);
if (ret < 0)
goto out;
@ -662,17 +675,20 @@ static int nilfs_btree_lookup_contig(const struct nilfs_bmap *btree,
break;
/* look-up right sibling node */
node = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
index = path[level + 1].bp_index + 1;
if (index >= nilfs_btree_node_get_nchildren(node) ||
nilfs_btree_node_get_key(node, index) != key + cnt)
p.node = nilfs_btree_get_node(btree, path, level + 1, &p.ncmax);
p.index = path[level + 1].bp_index + 1;
p.max_ra_blocks = 7;
if (p.index >= nilfs_btree_node_get_nchildren(p.node) ||
nilfs_btree_node_get_key(p.node, p.index) != key + cnt)
break;
ptr2 = nilfs_btree_node_get_ptr(node, index, ncmax);
path[level + 1].bp_index = index;
ptr2 = nilfs_btree_node_get_ptr(p.node, p.index, p.ncmax);
path[level + 1].bp_index = p.index;
brelse(path[level].bp_bh);
path[level].bp_bh = NULL;
ret = nilfs_btree_get_block(btree, ptr2, &path[level].bp_bh);
ret = __nilfs_btree_get_block(btree, ptr2, &path[level].bp_bh,
&p);
if (ret < 0)
goto out;
node = nilfs_btree_get_nonroot_node(path, level);
@ -1147,7 +1163,7 @@ static int nilfs_btree_insert(struct nilfs_bmap *btree, __u64 key, __u64 ptr)
return -ENOMEM;
ret = nilfs_btree_do_lookup(btree, path, key, NULL,
NILFS_BTREE_LEVEL_NODE_MIN);
NILFS_BTREE_LEVEL_NODE_MIN, 0);
if (ret != -ENOENT) {
if (ret == 0)
ret = -EEXIST;
@ -1484,7 +1500,7 @@ static int nilfs_btree_delete(struct nilfs_bmap *btree, __u64 key)
return -ENOMEM;
ret = nilfs_btree_do_lookup(btree, path, key, NULL,
NILFS_BTREE_LEVEL_NODE_MIN);
NILFS_BTREE_LEVEL_NODE_MIN, 0);
if (ret < 0)
goto out;
@ -1955,7 +1971,7 @@ static int nilfs_btree_propagate(struct nilfs_bmap *btree,
level = NILFS_BTREE_LEVEL_DATA;
}
ret = nilfs_btree_do_lookup(btree, path, key, NULL, level + 1);
ret = nilfs_btree_do_lookup(btree, path, key, NULL, level + 1, 0);
if (ret < 0) {
if (unlikely(ret == -ENOENT))
printk(KERN_CRIT "%s: key = %llu, level == %d\n",
@ -2147,7 +2163,7 @@ static int nilfs_btree_assign(struct nilfs_bmap *btree,
level = NILFS_BTREE_LEVEL_DATA;
}
ret = nilfs_btree_do_lookup(btree, path, key, NULL, level + 1);
ret = nilfs_btree_do_lookup(btree, path, key, NULL, level + 1, 0);
if (ret < 0) {
WARN_ON(ret == -ENOENT);
goto out;
@ -2201,7 +2217,7 @@ static int nilfs_btree_mark(struct nilfs_bmap *btree, __u64 key, int level)
if (path == NULL)
return -ENOMEM;
ret = nilfs_btree_do_lookup(btree, path, key, &ptr, level + 1);
ret = nilfs_btree_do_lookup(btree, path, key, &ptr, level + 1, 0);
if (ret < 0) {
WARN_ON(ret == -ENOENT);
goto out;