GitHub-Mirror/Star64_linux
2
0
Fork 0
mirror of https://github.com/Fishwaldo/Star64_linux.git synced 2025-06-19 21:21:09 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

mm: replace vma prio_tree with an interval tree

Browse source 
Implement an interval tree as a replacement for the VMA prio_tree.  The
algorithms are similar to lib/interval_tree.c; however that code can't be
directly reused as the interval endpoints are not explicitly stored in the
VMA.  So instead, the common algorithm is moved into a template and the
details (node type, how to get interval endpoints from the node, etc) are
filled in using the C preprocessor.

Once the interval tree functions are available, using them as a
replacement to the VMA prio tree is a relatively simple, mechanical job.

Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Michel Lespinasse 2012-10-08 16:31:25 -07:00 • committed by Linus Torvalds
parent fff3fd8a12
commit 6b2dbba8b6
25 changed files with 355 additions and 464 deletions
Download patch file Download diff file Expand all files Collapse all files

164
lib/interval_tree.c
View file

@ -1,159 +1,13 @@
#include <linux/init.h>
#include <linux/interval_tree.h>
/* Callbacks for augmented rbtree insert and remove */
#define ITSTRUCT struct interval_tree_node
#define ITRB rb
#define ITTYPE unsigned long
#define ITSUBTREE __subtree_last
#define ITSTART(n) ((n)->start)
#define ITLAST(n) ((n)->last)
#define ITSTATIC
#define ITPREFIX interval_tree
static inline unsigned long
compute_subtree_last(struct interval_tree_node *node)
{
unsigned long max = node->last, subtree_last;
if (node->rb.rb_left) {
subtree_last = rb_entry(node->rb.rb_left,
struct interval_tree_node, rb)->__subtree_last;
if (max < subtree_last)
max = subtree_last;
}
if (node->rb.rb_right) {
subtree_last = rb_entry(node->rb.rb_right,
struct interval_tree_node, rb)->__subtree_last;
if (max < subtree_last)
max = subtree_last;
}
return max;
}
RB_DECLARE_CALLBACKS(static, augment_callbacks, struct interval_tree_node, rb,
unsigned long, __subtree_last, compute_subtree_last)
/* Insert / remove interval nodes from the tree */
void interval_tree_insert(struct interval_tree_node *node,
struct rb_root *root)
{
struct rb_node **link = &root->rb_node, *rb_parent = NULL;
unsigned long start = node->start, last = node->last;
struct interval_tree_node *parent;
while (*link) {
rb_parent = *link;
parent = rb_entry(rb_parent, struct interval_tree_node, rb);
if (parent->__subtree_last < last)
parent->__subtree_last = last;
if (start < parent->start)
link = &parent->rb.rb_left;
else
link = &parent->rb.rb_right;
}
node->__subtree_last = last;
rb_link_node(&node->rb, rb_parent, link);
rb_insert_augmented(&node->rb, root, &augment_callbacks);
}
void interval_tree_remove(struct interval_tree_node *node,
struct rb_root *root)
{
rb_erase_augmented(&node->rb, root, &augment_callbacks);
}
/*
* Iterate over intervals intersecting [start;last]
*
* Note that a node's interval intersects [start;last] iff:
* Cond1: node->start <= last
* and
* Cond2: start <= node->last
*/
static struct interval_tree_node *
subtree_search(struct interval_tree_node *node,
unsigned long start, unsigned long last)
{
while (true) {
/*
* Loop invariant: start <= node->__subtree_last
* (Cond2 is satisfied by one of the subtree nodes)
*/
if (node->rb.rb_left) {
struct interval_tree_node *left =
rb_entry(node->rb.rb_left,
struct interval_tree_node, rb);
if (start <= left->__subtree_last) {
/*
* Some nodes in left subtree satisfy Cond2.
* Iterate to find the leftmost such node N.
* If it also satisfies Cond1, that's the match
* we are looking for. Otherwise, there is no
* matching interval as nodes to the right of N
* can't satisfy Cond1 either.
*/
node = left;
continue;
}
}
if (node->start <= last) { /* Cond1 */
if (start <= node->last) /* Cond2 */
return node; /* node is leftmost match */
if (node->rb.rb_right) {
node = rb_entry(node->rb.rb_right,
struct interval_tree_node, rb);
if (start <= node->__subtree_last)
continue;
}
}
return NULL; /* No match */
}
}
struct interval_tree_node *
interval_tree_iter_first(struct rb_root *root,
unsigned long start, unsigned long last)
{
struct interval_tree_node *node;
if (!root->rb_node)
return NULL;
node = rb_entry(root->rb_node, struct interval_tree_node, rb);
if (node->__subtree_last < start)
return NULL;
return subtree_search(node, start, last);
}
struct interval_tree_node *
interval_tree_iter_next(struct interval_tree_node *node,
unsigned long start, unsigned long last)
{
struct rb_node *rb = node->rb.rb_right, *prev;
while (true) {
/*
* Loop invariants:
* Cond1: node->start <= last
* rb == node->rb.rb_right
*
* First, search right subtree if suitable
*/
if (rb) {
struct interval_tree_node *right =
rb_entry(rb, struct interval_tree_node, rb);
if (start <= right->__subtree_last)
return subtree_search(right, start, last);
}
/* Move up the tree until we come from a node's left child */
do {
rb = rb_parent(&node->rb);
if (!rb)
return NULL;
prev = &node->rb;
node = rb_entry(rb, struct interval_tree_node, rb);
rb = node->rb.rb_right;
} while (prev == rb);
/* Check if the node intersects [start;last] */
if (last < node->start) /* !Cond1 */
return NULL;
else if (start <= node->last) /* Cond2 */
return node;
}
}
#include <linux/interval_tree_tmpl.h>