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rbtree: move augmented rbtree functionality to rbtree_augmented.h

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Provide rb_insert_augmented() and rb_erase_augmented() through a new
rbtree_augmented.h include file.  rb_erase_augmented() is defined there as
an __always_inline function, in order to allow inlining of augmented
rbtree callbacks into it.  Since this generates a relatively large
function, each augmented rbtree user should make sure to have a single
call site.

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 16:31:33 -07:00 committed by Linus Torvalds
parent 147e615f83
commit 9c079add0d
7 changed files with 255 additions and 203 deletions
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13
Documentation/rbtree.txt
View File

@ -202,6 +202,14 @@ An rbtree user who wants this feature will have to call the augmentation
functions with the user provided augmentation callback when inserting
and erasing nodes.
C files implementing augmented rbtree manipulation must include
<linux/rbtree_augmented.h> instead of <linus/rbtree.h>. Note that
linux/rbtree_augmented.h exposes some rbtree implementations details
you are not expected to rely on; please stick to the documented APIs
there and do not include <linux/rbtree_augmented.h> from header files
either so as to minimize chances of your users accidentally relying on
such implementation details.
On insertion, the user must update the augmented information on the path
leading to the inserted node, then call rb_link_node() as usual and
rb_augment_inserted() instead of the usual rb_insert_color() call.
@ -227,6 +235,11 @@ In both cases, the callbacks are provided through struct rb_augment_callbacks.
subtree to a newly assigned subtree root AND recomputes the augmented
information for the former subtree root.
The compiled code for rb_erase_augmented() may inline the propagation and
copy callbacks, which results in a large function, so each augmented rbtree
user should have a single rb_erase_augmented() call site in order to limit
compiled code size.
Sample usage:

2
arch/x86/mm/pat_rbtree.c
View File

@ -12,7 +12,7 @@
#include <linux/debugfs.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/rbtree.h>
#include <linux/rbtree_augmented.h>
#include <linux/sched.h>
#include <linux/gfp.h>

8
include/linux/interval_tree_tmpl.h
View File

@ -19,6 +19,8 @@
include/linux/interval_tree_tmpl.h
*/
#include <linux/rbtree_augmented.h>
/*
* Template for implementing interval trees
*
@ -57,7 +59,8 @@ static inline ITTYPE IT(compute_subtree_last)(ITSTRUCT *node)
return max;
}
static void IT(augment_propagate)(struct rb_node *rb, struct rb_node *stop)
static inline void
IT(augment_propagate)(struct rb_node *rb, struct rb_node *stop)
{
while (rb != stop) {
ITSTRUCT *node = rb_entry(rb, ITSTRUCT, ITRB);
@ -69,7 +72,8 @@ static void IT(augment_propagate)(struct rb_node *rb, struct rb_node *stop)
}
}
static void IT(augment_copy)(struct rb_node *rb_old, struct rb_node *rb_new)
static inline 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);

48
include/linux/rbtree.h
View File

@ -62,54 +62,6 @@ extern void rb_insert_color(struct rb_node *, struct rb_root *);
extern void rb_erase(struct rb_node *, struct rb_root *);
struct rb_augment_callbacks {
void (*propagate)(struct rb_node *node, struct rb_node *stop);
void (*copy)(struct rb_node *old, struct rb_node *new);
void (*rotate)(struct rb_node *old, struct rb_node *new);
};
extern void __rb_insert_augmented(struct rb_node *node, struct rb_root *root,
void (*augment_rotate)(struct rb_node *old, struct rb_node *new));
extern void rb_erase_augmented(struct rb_node *node, struct rb_root *root,
const struct rb_augment_callbacks *augment);
static inline void
rb_insert_augmented(struct rb_node *node, struct rb_root *root,
const struct rb_augment_callbacks *augment)
{
__rb_insert_augmented(node, root, augment->rotate);
}
#define RB_DECLARE_CALLBACKS(rbstatic, rbname, rbstruct, rbfield, \
rbtype, rbaugmented, rbcompute) \
static void rbname ## _propagate(struct rb_node *rb, struct rb_node *stop) \
{ \
while (rb != stop) { \
rbstruct *node = rb_entry(rb, rbstruct, rbfield); \
rbtype augmented = rbcompute(node); \
if (node->rbaugmented == augmented) \
break; \
node->rbaugmented = augmented; \
rb = rb_parent(&node->rbfield); \
} \
} \
static void rbname ## _copy(struct rb_node *rb_old, struct rb_node *rb_new) \
{ \
rbstruct *old = rb_entry(rb_old, rbstruct, rbfield); \
rbstruct *new = rb_entry(rb_new, rbstruct, rbfield); \
new->rbaugmented = old->rbaugmented; \
} \
static void rbname ## _rotate(struct rb_node *rb_old, struct rb_node *rb_new) \
{ \
rbstruct *old = rb_entry(rb_old, rbstruct, rbfield); \
rbstruct *new = rb_entry(rb_new, rbstruct, rbfield); \
new->rbaugmented = old->rbaugmented; \
old->rbaugmented = rbcompute(old); \
} \
rbstatic const struct rb_augment_callbacks rbname = { \
rbname ## _propagate, rbname ## _copy, rbname ## _rotate \
};
/* Find logical next and previous nodes in a tree */
extern struct rb_node *rb_next(const struct rb_node *);
extern struct rb_node *rb_prev(const struct rb_node *);

223
include/linux/rbtree_augmented.h Normal file
View File

@ -0,0 +1,223 @@
/*
Red Black Trees
(C) 1999 Andrea Arcangeli <andrea@suse.de>
(C) 2002 David Woodhouse <dwmw2@infradead.org>
(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
linux/include/linux/rbtree_augmented.h
*/
#ifndef _LINUX_RBTREE_AUGMENTED_H
#define _LINUX_RBTREE_AUGMENTED_H
#include <linux/rbtree.h>
/*
* Please note - only struct rb_augment_callbacks and the prototypes for
* rb_insert_augmented() and rb_erase_augmented() are intended to be public.
* The rest are implementation details you are not expected to depend on.
*
* See Documentation/rbtree.txt for documentation and samples.
*/
struct rb_augment_callbacks {
void (*propagate)(struct rb_node *node, struct rb_node *stop);
void (*copy)(struct rb_node *old, struct rb_node *new);
void (*rotate)(struct rb_node *old, struct rb_node *new);
};
extern void __rb_insert_augmented(struct rb_node *node, struct rb_root *root,
void (*augment_rotate)(struct rb_node *old, struct rb_node *new));
static inline void
rb_insert_augmented(struct rb_node *node, struct rb_root *root,
const struct rb_augment_callbacks *augment)
{
__rb_insert_augmented(node, root, augment->rotate);
}
#define RB_DECLARE_CALLBACKS(rbstatic, rbname, rbstruct, rbfield, \
rbtype, rbaugmented, rbcompute) \
static inline void \
rbname ## _propagate(struct rb_node *rb, struct rb_node *stop) \
{ \
while (rb != stop) { \
rbstruct *node = rb_entry(rb, rbstruct, rbfield); \
rbtype augmented = rbcompute(node); \
if (node->rbaugmented == augmented) \
break; \
node->rbaugmented = augmented; \
rb = rb_parent(&node->rbfield); \
} \
} \
static inline void \
rbname ## _copy(struct rb_node *rb_old, struct rb_node *rb_new) \
{ \
rbstruct *old = rb_entry(rb_old, rbstruct, rbfield); \
rbstruct *new = rb_entry(rb_new, rbstruct, rbfield); \
new->rbaugmented = old->rbaugmented; \
} \
static void \
rbname ## _rotate(struct rb_node *rb_old, struct rb_node *rb_new) \
{ \
rbstruct *old = rb_entry(rb_old, rbstruct, rbfield); \
rbstruct *new = rb_entry(rb_new, rbstruct, rbfield); \
new->rbaugmented = old->rbaugmented; \
old->rbaugmented = rbcompute(old); \
} \
rbstatic const struct rb_augment_callbacks rbname = { \
rbname ## _propagate, rbname ## _copy, rbname ## _rotate \
};
#define RB_RED 0
#define RB_BLACK 1
#define __rb_parent(pc) ((struct rb_node *)(pc & ~3))
#define __rb_color(pc) ((pc) & 1)
#define __rb_is_black(pc) __rb_color(pc)
#define __rb_is_red(pc) (!__rb_color(pc))
#define rb_color(rb) __rb_color((rb)->__rb_parent_color)
#define rb_is_red(rb) __rb_is_red((rb)->__rb_parent_color)
#define rb_is_black(rb) __rb_is_black((rb)->__rb_parent_color)
static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p)
{
rb->__rb_parent_color = rb_color(rb) | (unsigned long)p;
}
static inline void rb_set_parent_color(struct rb_node *rb,
struct rb_node *p, int color)
{
rb->__rb_parent_color = (unsigned long)p | color;
}
static inline void
__rb_change_child(struct rb_node *old, struct rb_node *new,
struct rb_node *parent, struct rb_root *root)
{
if (parent) {
if (parent->rb_left == old)
parent->rb_left = new;
else
parent->rb_right = new;
} else
root->rb_node = new;
}
extern void __rb_erase_color(struct rb_node *parent, struct rb_root *root,
void (*augment_rotate)(struct rb_node *old, struct rb_node *new));
static __always_inline void
rb_erase_augmented(struct rb_node *node, struct rb_root *root,
const struct rb_augment_callbacks *augment)
{
struct rb_node *child = node->rb_right, *tmp = node->rb_left;
struct rb_node *parent, *rebalance;
unsigned long pc;
if (!tmp) {
/*
* Case 1: node to erase has no more than 1 child (easy!)
*
* Note that if there is one child it must be red due to 5)
* and node must be black due to 4). We adjust colors locally
* so as to bypass __rb_erase_color() later on.
*/
pc = node->__rb_parent_color;
parent = __rb_parent(pc);
__rb_change_child(node, child, parent, root);
if (child) {
child->__rb_parent_color = pc;
rebalance = NULL;
} else
rebalance = __rb_is_black(pc) ? parent : NULL;
tmp = parent;
} else if (!child) {
/* Still case 1, but this time the child is node->rb_left */
tmp->__rb_parent_color = pc = node->__rb_parent_color;
parent = __rb_parent(pc);
__rb_change_child(node, tmp, parent, root);
rebalance = NULL;
tmp = parent;
} else {
struct rb_node *successor = child, *child2;
tmp = child->rb_left;
if (!tmp) {
/*
* Case 2: node's successor is its right child
*
* (n) (s)
* / \ / \
* (x) (s) -> (x) (c)
* \
* (c)
*/
parent = successor;
child2 = successor->rb_right;
augment->copy(node, successor);
} else {
/*
* Case 3: node's successor is leftmost under
* node's right child subtree
*
* (n) (s)
* / \ / \
* (x) (y) -> (x) (y)
* / /
* (p) (p)
* / /
* (s) (c)
* \
* (c)
*/
do {
parent = successor;
successor = tmp;
tmp = tmp->rb_left;
} while (tmp);
parent->rb_left = child2 = successor->rb_right;
successor->rb_right = child;
rb_set_parent(child, successor);
augment->copy(node, successor);
augment->propagate(parent, successor);
}
successor->rb_left = tmp = node->rb_left;
rb_set_parent(tmp, successor);
pc = node->__rb_parent_color;
tmp = __rb_parent(pc);
__rb_change_child(node, successor, tmp, root);
if (child2) {
successor->__rb_parent_color = pc;
rb_set_parent_color(child2, parent, RB_BLACK);
rebalance = NULL;
} else {
unsigned long pc2 = successor->__rb_parent_color;
successor->__rb_parent_color = pc;
rebalance = __rb_is_black(pc2) ? parent : NULL;
}
tmp = successor;
}
augment->propagate(tmp, NULL);
if (rebalance)
__rb_erase_color(rebalance, root, augment->rotate);
}
#endif /* _LINUX_RBTREE_AUGMENTED_H */

162
lib/rbtree.c
View File

@ -21,7 +21,7 @@
linux/lib/rbtree.c
*/
#include <linux/rbtree.h>
#include <linux/rbtree_augmented.h>
#include <linux/export.h>
/*
@ -44,52 +44,16 @@
* parentheses and have some accompanying text comment.
*/
#define RB_RED 0
#define RB_BLACK 1
#define __rb_parent(pc) ((struct rb_node *)(pc & ~3))
#define __rb_color(pc) ((pc) & 1)
#define __rb_is_black(pc) __rb_color(pc)
#define __rb_is_red(pc) (!__rb_color(pc))
#define rb_color(rb) __rb_color((rb)->__rb_parent_color)
#define rb_is_red(rb) __rb_is_red((rb)->__rb_parent_color)
#define rb_is_black(rb) __rb_is_black((rb)->__rb_parent_color)
static inline void rb_set_black(struct rb_node *rb)
{
rb->__rb_parent_color |= RB_BLACK;
}
static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p)
{
rb->__rb_parent_color = rb_color(rb) | (unsigned long)p;
}
static inline void rb_set_parent_color(struct rb_node *rb,
struct rb_node *p, int color)
{
rb->__rb_parent_color = (unsigned long)p | color;
}
static inline struct rb_node *rb_red_parent(struct rb_node *red)
{
return (struct rb_node *)red->__rb_parent_color;
}
static inline void
__rb_change_child(struct rb_node *old, struct rb_node *new,
struct rb_node *parent, struct rb_root *root)
{
if (parent) {
if (parent->rb_left == old)
parent->rb_left = new;
else
parent->rb_right = new;
} else
root->rb_node = new;
}
/*
* Helper function for rotations:
* - old's parent and color get assigned to new
@ -230,9 +194,9 @@ __rb_insert(struct rb_node *node, struct rb_root *root,
}
}
static __always_inline void
__always_inline void
__rb_erase_color(struct rb_node *parent, struct rb_root *root,
const struct rb_augment_callbacks *augment)
void (*augment_rotate)(struct rb_node *old, struct rb_node *new))
{
struct rb_node *node = NULL, *sibling, *tmp1, *tmp2;
@ -261,7 +225,7 @@ __rb_erase_color(struct rb_node *parent, struct rb_root *root,
rb_set_parent_color(tmp1, parent, RB_BLACK);
__rb_rotate_set_parents(parent, sibling, root,
RB_RED);
augment->rotate(parent, sibling);
augment_rotate(parent, sibling);
sibling = tmp1;
}
tmp1 = sibling->rb_right;
@ -313,7 +277,7 @@ __rb_erase_color(struct rb_node *parent, struct rb_root *root,
if (tmp1)
rb_set_parent_color(tmp1, sibling,
RB_BLACK);
augment->rotate(sibling, tmp2);
augment_rotate(sibling, tmp2);
tmp1 = sibling;
sibling = tmp2;
}
@ -336,7 +300,7 @@ __rb_erase_color(struct rb_node *parent, struct rb_root *root,
rb_set_parent(tmp2, parent);
__rb_rotate_set_parents(parent, sibling, root,
RB_BLACK);
augment->rotate(parent, sibling);
augment_rotate(parent, sibling);
break;
} else {
sibling = parent->rb_left;
@ -347,7 +311,7 @@ __rb_erase_color(struct rb_node *parent, struct rb_root *root,
rb_set_parent_color(tmp1, parent, RB_BLACK);
__rb_rotate_set_parents(parent, sibling, root,
RB_RED);
augment->rotate(parent, sibling);
augment_rotate(parent, sibling);
sibling = tmp1;
}
tmp1 = sibling->rb_left;
@ -374,7 +338,7 @@ __rb_erase_color(struct rb_node *parent, struct rb_root *root,
if (tmp1)
rb_set_parent_color(tmp1, sibling,
RB_BLACK);
augment->rotate(sibling, tmp2);
augment_rotate(sibling, tmp2);
tmp1 = sibling;
sibling = tmp2;
}
@ -386,109 +350,12 @@ __rb_erase_color(struct rb_node *parent, struct rb_root *root,
rb_set_parent(tmp2, parent);
__rb_rotate_set_parents(parent, sibling, root,
RB_BLACK);
augment->rotate(parent, sibling);
augment_rotate(parent, sibling);
break;
}
}
}
static __always_inline void
__rb_erase(struct rb_node *node, struct rb_root *root,
const struct rb_augment_callbacks *augment)
{
struct rb_node *child = node->rb_right, *tmp = node->rb_left;
struct rb_node *parent, *rebalance;
unsigned long pc;
if (!tmp) {
/*
* Case 1: node to erase has no more than 1 child (easy!)
*
* Note that if there is one child it must be red due to 5)
* and node must be black due to 4). We adjust colors locally
* so as to bypass __rb_erase_color() later on.
*/
pc = node->__rb_parent_color;
parent = __rb_parent(pc);
__rb_change_child(node, child, parent, root);
if (child) {
child->__rb_parent_color = pc;
rebalance = NULL;
} else
rebalance = __rb_is_black(pc) ? parent : NULL;
tmp = parent;
} else if (!child) {
/* Still case 1, but this time the child is node->rb_left */
tmp->__rb_parent_color = pc = node->__rb_parent_color;
parent = __rb_parent(pc);
__rb_change_child(node, tmp, parent, root);
rebalance = NULL;
tmp = parent;
} else {
struct rb_node *successor = child, *child2;
tmp = child->rb_left;
if (!tmp) {
/*
* Case 2: node's successor is its right child
*
* (n) (s)
* / \ / \
* (x) (s) -> (x) (c)
* \
* (c)
*/
parent = successor;
child2 = successor->rb_right;
augment->copy(node, successor);
} else {
/*
* Case 3: node's successor is leftmost under
* node's right child subtree
*
* (n) (s)
* / \ / \
* (x) (y) -> (x) (y)
* / /
* (p) (p)
* / /
* (s) (c)
* \
* (c)
*/
do {
parent = successor;
successor = tmp;
tmp = tmp->rb_left;
} while (tmp);
parent->rb_left = child2 = successor->rb_right;
successor->rb_right = child;
rb_set_parent(child, successor);
augment->copy(node, successor);
augment->propagate(parent, successor);
}
successor->rb_left = tmp = node->rb_left;
rb_set_parent(tmp, successor);
pc = node->__rb_parent_color;
tmp = __rb_parent(pc);
__rb_change_child(node, successor, tmp, root);
if (child2) {
successor->__rb_parent_color = pc;
rb_set_parent_color(child2, parent, RB_BLACK);
rebalance = NULL;
} else {
unsigned long pc2 = successor->__rb_parent_color;
successor->__rb_parent_color = pc;
rebalance = __rb_is_black(pc2) ? parent : NULL;
}
tmp = successor;
}
augment->propagate(tmp, NULL);
if (rebalance)
__rb_erase_color(rebalance, root, augment);
}
EXPORT_SYMBOL(__rb_erase_color);
/*
* Non-augmented rbtree manipulation functions.
@ -513,7 +380,7 @@ EXPORT_SYMBOL(rb_insert_color);
void rb_erase(struct rb_node *node, struct rb_root *root)
{
__rb_erase(node, root, &dummy_callbacks);
rb_erase_augmented(node, root, &dummy_callbacks);
}
EXPORT_SYMBOL(rb_erase);
@ -531,13 +398,6 @@ void __rb_insert_augmented(struct rb_node *node, struct rb_root *root,
}
EXPORT_SYMBOL(__rb_insert_augmented);
void rb_erase_augmented(struct rb_node *node, struct rb_root *root,
const struct rb_augment_callbacks *augment)
{
__rb_erase(node, root, augment);
}
EXPORT_SYMBOL(rb_erase_augmented);
/*
* This function returns the first node (in sort order) of the tree.
*/

2
lib/rbtree_test.c
View File

@ -1,5 +1,5 @@
#include <linux/module.h>
#include <linux/rbtree.h>
#include <linux/rbtree_augmented.h>
#include <linux/random.h>
#include <asm/timex.h>