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authorMatthew Wilcox <willy@linux.intel.com>2016-05-20 17:03:07 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-05-20 17:58:30 -0700
commit0c7fa0a8418cbe0e8963fe36db9575d03b8589f7 (patch)
tree847a7e84548372584bbea5a4c67f765d8e9cff36 /lib
parent2fcd9005cc03ab09ea2a940515ed728d43df66c4 (diff)
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radix-tree: split node->path into offset and height
Neither piece of information we're storing in node->path can be larger than 64, so store each in its own unsigned char instead of shifting and masking to store them both in an unsigned int. Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib')
-rw-r--r--lib/radix-tree.c38
1 files changed, 17 insertions, 21 deletions
diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index 75944e42e4a0..dd04b51e5fbb 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -218,15 +218,15 @@ radix_tree_find_next_bit(const unsigned long *addr,
}
#ifndef __KERNEL__
-static void dump_node(struct radix_tree_node *node, unsigned offset,
+static void dump_node(struct radix_tree_node *node,
unsigned shift, unsigned long index)
{
unsigned long i;
- pr_debug("radix node: %p offset %d tags %lx %lx %lx path %x count %d parent %p\n",
- node, offset,
+ pr_debug("radix node: %p offset %d tags %lx %lx %lx height %d count %d parent %p\n",
+ node, node->offset,
node->tags[0][0], node->tags[1][0], node->tags[2][0],
- node->path, node->count, node->parent);
+ node->height, node->count, node->parent);
for (i = 0; i < RADIX_TREE_MAP_SIZE; i++) {
unsigned long first = index | (i << shift);
@@ -243,7 +243,7 @@ static void dump_node(struct radix_tree_node *node, unsigned offset,
pr_debug("radix entry %p offset %ld indices %ld-%ld\n",
entry, i, first, last);
} else {
- dump_node(indirect_to_ptr(entry), i,
+ dump_node(indirect_to_ptr(entry),
shift - RADIX_TREE_MAP_SHIFT, first);
}
}
@@ -257,7 +257,7 @@ static void radix_tree_dump(struct radix_tree_root *root)
root->gfp_mask >> __GFP_BITS_SHIFT);
if (!radix_tree_is_indirect_ptr(root->rnode))
return;
- dump_node(indirect_to_ptr(root->rnode), 0,
+ dump_node(indirect_to_ptr(root->rnode),
(root->height - 1) * RADIX_TREE_MAP_SHIFT, 0);
}
#endif
@@ -421,7 +421,7 @@ static inline unsigned long radix_tree_maxindex(unsigned int height)
static inline unsigned long node_maxindex(struct radix_tree_node *node)
{
- return radix_tree_maxindex(node->path & RADIX_TREE_HEIGHT_MASK);
+ return radix_tree_maxindex(node->height);
}
static unsigned radix_tree_load_root(struct radix_tree_root *root,
@@ -434,8 +434,7 @@ static unsigned radix_tree_load_root(struct radix_tree_root *root,
if (likely(radix_tree_is_indirect_ptr(node))) {
node = indirect_to_ptr(node);
*maxindex = node_maxindex(node);
- return (node->path & RADIX_TREE_HEIGHT_MASK) *
- RADIX_TREE_MAP_SHIFT;
+ return node->height * RADIX_TREE_MAP_SHIFT;
}
*maxindex = 0;
@@ -476,9 +475,10 @@ static int radix_tree_extend(struct radix_tree_root *root,
}
/* Increase the height. */
- newheight = root->height+1;
- BUG_ON(newheight & ~RADIX_TREE_HEIGHT_MASK);
- node->path = newheight;
+ newheight = root->height + 1;
+ BUG_ON(newheight > BITS_PER_LONG);
+ node->height = newheight;
+ node->offset = 0;
node->count = 1;
node->parent = NULL;
slot = root->rnode;
@@ -546,13 +546,13 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index,
slot = radix_tree_node_alloc(root);
if (!slot)
return -ENOMEM;
- slot->path = height;
+ slot->height = height;
+ slot->offset = offset;
slot->parent = node;
if (node) {
rcu_assign_pointer(node->slots[offset],
ptr_to_indirect(slot));
node->count++;
- slot->path |= offset << RADIX_TREE_HEIGHT_SHIFT;
} else
rcu_assign_pointer(root->rnode,
ptr_to_indirect(slot));
@@ -1319,11 +1319,10 @@ struct locate_info {
static unsigned long __locate(struct radix_tree_node *slot, void *item,
unsigned long index, struct locate_info *info)
{
- unsigned int shift, height;
+ unsigned int shift;
unsigned long i;
- height = slot->path & RADIX_TREE_HEIGHT_MASK;
- shift = height * RADIX_TREE_MAP_SHIFT;
+ shift = slot->height * RADIX_TREE_MAP_SHIFT;
do {
shift -= RADIX_TREE_MAP_SHIFT;
@@ -1508,10 +1507,7 @@ bool __radix_tree_delete_node(struct radix_tree_root *root,
parent = node->parent;
if (parent) {
- unsigned int offset;
-
- offset = node->path >> RADIX_TREE_HEIGHT_SHIFT;
- parent->slots[offset] = NULL;
+ parent->slots[node->offset] = NULL;
parent->count--;
} else {
root_tag_clear_all(root);