Commit 0c7fa0a8 authored by Matthew Wilcox's avatar Matthew Wilcox Committed by Linus Torvalds
Browse files

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: default avatarMatthew Wilcox <willy@linux.intel.com>
Reviewed-by: default avatarRoss 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 2fcd9005

include/linux/radix-tree.h

+2 −5
Original line number Diff line number Diff line
@@ -84,16 +84,13 @@ static inline int radix_tree_is_indirect_ptr(void *ptr) 
#define RADIX_TREE_MAX_PATH (DIV_ROUND_UP(RADIX_TREE_INDEX_BITS, \

					  RADIX_TREE_MAP_SHIFT))



/* Height component in node->path */

#define RADIX_TREE_HEIGHT_SHIFT	(RADIX_TREE_MAX_PATH + 1)

#define RADIX_TREE_HEIGHT_MASK	((1UL << RADIX_TREE_HEIGHT_SHIFT) - 1)



/* Internally used bits of node->count */

#define RADIX_TREE_COUNT_SHIFT	(RADIX_TREE_MAP_SHIFT + 1)

#define RADIX_TREE_COUNT_MASK	((1UL << RADIX_TREE_COUNT_SHIFT) - 1)



struct radix_tree_node {

	unsigned int	path;	/* Offset in parent & height from the bottom */

	unsigned char	height;	/* From the bottom */

	unsigned char	offset;	/* Slot offset in parent */

	unsigned int	count;

	union {

		struct {

lib/radix-tree.c

+17 −21
Original line number Diff line number Diff line
@@ -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;
@@ -477,8 +476,9 @@ 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;

		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);

CRA Git | Maintained and supported by SUSTech CRA and CCSE