aboutsummaryrefslogtreecommitdiffstats
path: root/lib/radix-tree.c
diff options
context:
space:
mode:
authorNick Piggin <nickpiggin@yahoo.com.au>2006-01-08 01:01:41 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-01-08 20:13:41 -0800
commitd5274261ea46f0aae93820fe36628249120d2f75 (patch)
treee95c41295270c55ef27a3534894f066f31719ecc /lib/radix-tree.c
parent6e954b9e90c3a7157c0c1457dd3919e2a1345d23 (diff)
[PATCH] radix tree: early termination of tag clearing
Correctly determine the tags to be cleared in radix_tree_delete() so we don't keep moving up the tree clearing tags that we don't need to. For example, if a tag is simply not set in the deleted item, nor anywhere up the tree, radix_tree_delete() would attempt to clear it up the entire height of the tree. Also, tag_set() was made conditional so as not to dirty too many cachelines high up in the radix tree. Instead, put this logic into radix_tree_tag_set(). Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'lib/radix-tree.c')
-rw-r--r--lib/radix-tree.c40
1 files changed, 23 insertions, 17 deletions
diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index 1403e2c8bb3e..336852f23592 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -137,18 +137,17 @@ out:
static inline void tag_set(struct radix_tree_node *node, int tag, int offset)
{
- if (!test_bit(offset, &node->tags[tag][0]))
- __set_bit(offset, &node->tags[tag][0]);
+ __set_bit(offset, node->tags[tag]);
}
static inline void tag_clear(struct radix_tree_node *node, int tag, int offset)
{
- __clear_bit(offset, &node->tags[tag][0]);
+ __clear_bit(offset, node->tags[tag]);
}
static inline int tag_get(struct radix_tree_node *node, int tag, int offset)
{
- return test_bit(offset, &node->tags[tag][0]);
+ return test_bit(offset, node->tags[tag]);
}
/*
@@ -375,7 +374,8 @@ void *radix_tree_tag_set(struct radix_tree_root *root,
int offset;
offset = (index >> shift) & RADIX_TREE_MAP_MASK;
- tag_set(slot, tag, offset);
+ if (!tag_get(slot, tag, offset))
+ tag_set(slot, tag, offset);
slot = slot->slots[offset];
BUG_ON(slot == NULL);
shift -= RADIX_TREE_MAP_SHIFT;
@@ -435,6 +435,8 @@ void *radix_tree_tag_clear(struct radix_tree_root *root,
goto out;
do {
+ if (!tag_get(pathp->node, tag, pathp->offset))
+ goto out;
tag_clear(pathp->node, tag, pathp->offset);
if (any_tag_set(pathp->node, tag))
goto out;
@@ -695,6 +697,8 @@ void *radix_tree_delete(struct radix_tree_root *root, unsigned long index)
void *ret = NULL;
char tags[RADIX_TREE_TAGS];
int nr_cleared_tags;
+ int tag;
+ int offset;
height = root->height;
if (index > radix_tree_maxindex(height))
@@ -705,16 +709,14 @@ void *radix_tree_delete(struct radix_tree_root *root, unsigned long index)
slot = root->rnode;
for ( ; height > 0; height--) {
- int offset;
-
if (slot == NULL)
goto out;
+ pathp++;
offset = (index >> shift) & RADIX_TREE_MAP_MASK;
- pathp[1].offset = offset;
- pathp[1].node = slot;
+ pathp->offset = offset;
+ pathp->node = slot;
slot = slot->slots[offset];
- pathp++;
shift -= RADIX_TREE_MAP_SHIFT;
}
@@ -727,24 +729,28 @@ void *radix_tree_delete(struct radix_tree_root *root, unsigned long index)
/*
* Clear all tags associated with the just-deleted item
*/
- memset(tags, 0, sizeof(tags));
- do {
- int tag;
+ nr_cleared_tags = 0;
+ for (tag = 0; tag < RADIX_TREE_TAGS; tag++) {
+ if (tag_get(pathp->node, tag, pathp->offset)) {
+ tag_clear(pathp->node, tag, pathp->offset);
+ tags[tag] = 0;
+ nr_cleared_tags++;
+ } else
+ tags[tag] = 1;
+ }
- nr_cleared_tags = RADIX_TREE_TAGS;
+ for (pathp--; nr_cleared_tags && pathp->node; pathp--) {
for (tag = 0; tag < RADIX_TREE_TAGS; tag++) {
if (tags[tag])
continue;
tag_clear(pathp->node, tag, pathp->offset);
-
if (any_tag_set(pathp->node, tag)) {
tags[tag] = 1;
nr_cleared_tags--;
}
}
- pathp--;
- } while (pathp->node && nr_cleared_tags);
+ }
/* Now free the nodes we do not need anymore */
for (pathp = orig_pathp; pathp->node; pathp--) {

Privacy Policy