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authorMichel Lespinasse <walken@google.com>2012-10-08 16:31:25 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-10-09 16:22:39 +0900
commit6b2dbba8b6ac4df26f72eda1e5ea7bab9f950e08 (patch)
tree422ed8d7ac2fe45069f20cfba84a9a097bf444af /include
parentfff3fd8a1210a165252cd7cd01206da7a90d3a06 (diff)
mm: replace vma prio_tree with an interval tree
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>
Diffstat (limited to 'include')
-rw-r--r--include/linux/fs.h6
-rw-r--r--include/linux/interval_tree_tmpl.h215
-rw-r--r--include/linux/mm.h30
-rw-r--r--include/linux/mm_types.h14
4 files changed, 240 insertions, 25 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 5a8a273d5b2f..c617ed024df8 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -401,7 +401,7 @@ struct inodes_stat_t {
#include <linux/cache.h>
#include <linux/list.h>
#include <linux/radix-tree.h>
-#include <linux/prio_tree.h>
+#include <linux/rbtree.h>
#include <linux/init.h>
#include <linux/pid.h>
#include <linux/bug.h>
@@ -669,7 +669,7 @@ struct address_space {
struct radix_tree_root page_tree; /* radix tree of all pages */
spinlock_t tree_lock; /* and lock protecting it */
unsigned int i_mmap_writable;/* count VM_SHARED mappings */
- struct prio_tree_root i_mmap; /* tree of private and shared mappings */
+ struct rb_root i_mmap; /* tree of private and shared mappings */
struct list_head i_mmap_nonlinear;/*list VM_NONLINEAR mappings */
struct mutex i_mmap_mutex; /* protect tree, count, list */
/* Protected by tree_lock together with the radix tree */
@@ -741,7 +741,7 @@ int mapping_tagged(struct address_space *mapping, int tag);
*/
static inline int mapping_mapped(struct address_space *mapping)
{
- return !prio_tree_empty(&mapping->i_mmap) ||
+ return !RB_EMPTY_ROOT(&mapping->i_mmap) ||
!list_empty(&mapping->i_mmap_nonlinear);
}
diff --git a/include/linux/interval_tree_tmpl.h b/include/linux/interval_tree_tmpl.h
new file mode 100644
index 000000000000..c65deda31413
--- /dev/null
+++ b/include/linux/interval_tree_tmpl.h
@@ -0,0 +1,215 @@
+/*
+ Interval Trees
+ (C) 2012 Michel Lespinasse <walken@google.com>
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+ include/linux/interval_tree_tmpl.h
+*/
+
+/*
+ * Template for implementing interval trees
+ *
+ * ITSTRUCT: struct type of the interval tree nodes
+ * ITRB: name of struct rb_node field within ITSTRUCT
+ * ITTYPE: type of the interval endpoints
+ * ITSUBTREE: name of ITTYPE field within ITSTRUCT holding last-in-subtree
+ * ITSTART(n): start endpoint of ITSTRUCT node n
+ * ITLAST(n): last endpoing of ITSTRUCT node n
+ * ITSTATIC: 'static' or empty
+ * ITPREFIX: prefix to use for the inline tree definitions
+ */
+
+/* IT(name) -> ITPREFIX_name */
+#define _ITNAME(prefix, name) prefix ## _ ## name
+#define ITNAME(prefix, name) _ITNAME(prefix, name)
+#define IT(name) ITNAME(ITPREFIX, name)
+
+/* Callbacks for augmented rbtree insert and remove */
+
+static inline ITTYPE IT(compute_subtree_last)(ITSTRUCT *node)
+{
+ ITTYPE max = ITLAST(node), subtree_last;
+ if (node->ITRB.rb_left) {
+ subtree_last = rb_entry(node->ITRB.rb_left,
+ ITSTRUCT, ITRB)->ITSUBTREE;
+ if (max < subtree_last)
+ max = subtree_last;
+ }
+ if (node->ITRB.rb_right) {
+ subtree_last = rb_entry(node->ITRB.rb_right,
+ ITSTRUCT, ITRB)->ITSUBTREE;
+ if (max < subtree_last)
+ max = subtree_last;
+ }
+ return max;
+}
+
+static void IT(augment_propagate)(struct rb_node *rb, struct rb_node *stop)
+{
+ while (rb != stop) {
+ ITSTRUCT *node = rb_entry(rb, ITSTRUCT, ITRB);
+ ITTYPE subtree_last = IT(compute_subtree_last)(node);
+ if (node->ITSUBTREE == subtree_last)
+ break;
+ node->ITSUBTREE = subtree_last;
+ rb = rb_parent(&node->ITRB);
+ }
+}
+
+static void IT(augment_copy)(struct rb_node *rb_old, struct rb_node *rb_new)
+{
+ ITSTRUCT *old = rb_entry(rb_old, ITSTRUCT, ITRB);
+ ITSTRUCT *new = rb_entry(rb_new, ITSTRUCT, ITRB);
+
+ new->ITSUBTREE = old->ITSUBTREE;
+}
+
+static void IT(augment_rotate)(struct rb_node *rb_old, struct rb_node *rb_new)
+{
+ ITSTRUCT *old = rb_entry(rb_old, ITSTRUCT, ITRB);
+ ITSTRUCT *new = rb_entry(rb_new, ITSTRUCT, ITRB);
+
+ new->ITSUBTREE = old->ITSUBTREE;
+ old->ITSUBTREE = IT(compute_subtree_last)(old);
+}
+
+static const struct rb_augment_callbacks IT(augment_callbacks) = {
+ IT(augment_propagate), IT(augment_copy), IT(augment_rotate)
+};
+
+/* Insert / remove interval nodes from the tree */
+
+ITSTATIC void IT(insert)(ITSTRUCT *node, struct rb_root *root)
+{
+ struct rb_node **link = &root->rb_node, *rb_parent = NULL;
+ ITTYPE start = ITSTART(node), last = ITLAST(node);
+ ITSTRUCT *parent;
+
+ while (*link) {
+ rb_parent = *link;
+ parent = rb_entry(rb_parent, ITSTRUCT, ITRB);
+ if (parent->ITSUBTREE < last)
+ parent->ITSUBTREE = last;
+ if (start < ITSTART(parent))
+ link = &parent->ITRB.rb_left;
+ else
+ link = &parent->ITRB.rb_right;
+ }
+
+ node->ITSUBTREE = last;
+ rb_link_node(&node->ITRB, rb_parent, link);
+ rb_insert_augmented(&node->ITRB, root, &IT(augment_callbacks));
+}
+
+ITSTATIC void IT(remove)(ITSTRUCT *node, struct rb_root *root)
+{
+ rb_erase_augmented(&node->ITRB, root, &IT(augment_callbacks));
+}
+
+/*
+ * Iterate over intervals intersecting [start;last]
+ *
+ * Note that a node's interval intersects [start;last] iff:
+ * Cond1: ITSTART(node) <= last
+ * and
+ * Cond2: start <= ITLAST(node)
+ */
+
+static ITSTRUCT *IT(subtree_search)(ITSTRUCT *node, ITTYPE start, ITTYPE last)
+{
+ while (true) {
+ /*
+ * Loop invariant: start <= node->ITSUBTREE
+ * (Cond2 is satisfied by one of the subtree nodes)
+ */
+ if (node->ITRB.rb_left) {
+ ITSTRUCT *left = rb_entry(node->ITRB.rb_left,
+ ITSTRUCT, ITRB);
+ if (start <= left->ITSUBTREE) {
+ /*
+ * 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 (ITSTART(node) <= last) { /* Cond1 */
+ if (start <= ITLAST(node)) /* Cond2 */
+ return node; /* node is leftmost match */
+ if (node->ITRB.rb_right) {
+ node = rb_entry(node->ITRB.rb_right,
+ ITSTRUCT, ITRB);
+ if (start <= node->ITSUBTREE)
+ continue;
+ }
+ }
+ return NULL; /* No match */
+ }
+}
+
+ITSTATIC ITSTRUCT *IT(iter_first)(struct rb_root *root,
+ ITTYPE start, ITTYPE last)
+{
+ ITSTRUCT *node;
+
+ if (!root->rb_node)
+ return NULL;
+ node = rb_entry(root->rb_node, ITSTRUCT, ITRB);
+ if (node->ITSUBTREE < start)
+ return NULL;
+ return IT(subtree_search)(node, start, last);
+}
+
+ITSTATIC ITSTRUCT *IT(iter_next)(ITSTRUCT *node, ITTYPE start, ITTYPE last)
+{
+ struct rb_node *rb = node->ITRB.rb_right, *prev;
+
+ while (true) {
+ /*
+ * Loop invariants:
+ * Cond1: ITSTART(node) <= last
+ * rb == node->ITRB.rb_right
+ *
+ * First, search right subtree if suitable
+ */
+ if (rb) {
+ ITSTRUCT *right = rb_entry(rb, ITSTRUCT, ITRB);
+ if (start <= right->ITSUBTREE)
+ return IT(subtree_search)(right, start, last);
+ }
+
+ /* Move up the tree until we come from a node's left child */
+ do {
+ rb = rb_parent(&node->ITRB);
+ if (!rb)
+ return NULL;
+ prev = &node->ITRB;
+ node = rb_entry(rb, ITSTRUCT, ITRB);
+ rb = node->ITRB.rb_right;
+ } while (prev == rb);
+
+ /* Check if the node intersects [start;last] */
+ if (last < ITSTART(node)) /* !Cond1 */
+ return NULL;
+ else if (start <= ITLAST(node)) /* Cond2 */
+ return node;
+ }
+}
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 5ddb11b2b4bb..0f671ef09eba 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -10,7 +10,6 @@
#include <linux/list.h>
#include <linux/mmzone.h>
#include <linux/rbtree.h>
-#include <linux/prio_tree.h>
#include <linux/atomic.h>
#include <linux/debug_locks.h>
#include <linux/mm_types.h>
@@ -1355,22 +1354,27 @@ extern void zone_pcp_reset(struct zone *zone);
extern atomic_long_t mmap_pages_allocated;
extern int nommu_shrink_inode_mappings(struct inode *, size_t, size_t);
-/* prio_tree.c */
-void vma_prio_tree_add(struct vm_area_struct *, struct vm_area_struct *old);
-void vma_prio_tree_insert(struct vm_area_struct *, struct prio_tree_root *);
-void vma_prio_tree_remove(struct vm_area_struct *, struct prio_tree_root *);
-struct vm_area_struct *vma_prio_tree_next(struct vm_area_struct *vma,
- struct prio_tree_iter *iter);
-
-#define vma_prio_tree_foreach(vma, iter, root, begin, end) \
- for (prio_tree_iter_init(iter, root, begin, end), vma = NULL; \
- (vma = vma_prio_tree_next(vma, iter)); )
+/* interval_tree.c */
+void vma_interval_tree_add(struct vm_area_struct *vma,
+ struct vm_area_struct *old,
+ struct address_space *mapping);
+void vma_interval_tree_insert(struct vm_area_struct *node,
+ struct rb_root *root);
+void vma_interval_tree_remove(struct vm_area_struct *node,
+ struct rb_root *root);
+struct vm_area_struct *vma_interval_tree_iter_first(struct rb_root *root,
+ unsigned long start, unsigned long last);
+struct vm_area_struct *vma_interval_tree_iter_next(struct vm_area_struct *node,
+ unsigned long start, unsigned long last);
+
+#define vma_interval_tree_foreach(vma, root, start, last) \
+ for (vma = vma_interval_tree_iter_first(root, start, last); \
+ vma; vma = vma_interval_tree_iter_next(vma, start, last))
static inline void vma_nonlinear_insert(struct vm_area_struct *vma,
struct list_head *list)
{
- vma->shared.vm_set.parent = NULL;
- list_add_tail(&vma->shared.vm_set.list, list);
+ list_add_tail(&vma->shared.nonlinear, list);
}
/* mmap.c */
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index a57a43f5ca7c..31f8a3af7d94 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -6,7 +6,6 @@
#include <linux/threads.h>
#include <linux/list.h>
#include <linux/spinlock.h>
-#include <linux/prio_tree.h>
#include <linux/rbtree.h>
#include <linux/rwsem.h>
#include <linux/completion.h>
@@ -240,18 +239,15 @@ struct vm_area_struct {
/*
* For areas with an address space and backing store,
- * linkage into the address_space->i_mmap prio tree, or
- * linkage to the list of like vmas hanging off its node, or
+ * linkage into the address_space->i_mmap interval tree, or
* linkage of vma in the address_space->i_mmap_nonlinear list.
*/
union {
struct {
- struct list_head list;
- void *parent; /* aligns with prio_tree_node parent */
- struct vm_area_struct *head;
- } vm_set;
-
- struct raw_prio_tree_node prio_tree_node;
+ struct rb_node rb;
+ unsigned long rb_subtree_last;
+ } linear;
+ struct list_head nonlinear;
} shared;
/*