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To reduce the size of an rb_node, drop the color field. Set the least

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significant bit in the pointer to the node from its parent to indicate
that the node is red. Have the tree rotation macros leave the
old-parent/new-child node red and the new-parent/old-child node black.

This change makes RB_LEFT and RB_RIGHT no longer assignable, and
RB_COLOR no longer defined. Any code that modifies the tree or
examines a node color would have to be modified after this change.

Reviewed by:	markj
Tested by:	pho
Differential Revision:	https://reviews.freebsd.org/D25105
This commit is contained in:
dougm 2020-06-09 20:19:11 +00:00
parent ab2d1ba4b8
commit 16c1ffb4ff
2 changed files with 149 additions and 149 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
sys/compat/linuxkpi/common/include/linux/rbtree.h
View File

@ -57,11 +57,7 @@ RB_HEAD(linux_root, rb_node);
RB_PROTOTYPE(linux_root, rb_node, __entry, panic_cmp); RB_PROTOTYPE(linux_root, rb_node, __entry, panic_cmp);
#define rb_parent(r) RB_PARENT(r, __entry) #define rb_parent(r) RB_PARENT(r, __entry)
#define rb_color(r) RB_COLOR(r, __entry)
#define rb_is_red(r) (rb_color(r) == RB_RED)
#define rb_is_black(r) (rb_color(r) == RB_BLACK)
#define rb_set_parent(r, p) rb_parent((r)) = (p) #define rb_set_parent(r, p) rb_parent((r)) = (p)
#define rb_set_color(r, c) rb_color((r)) = (c)
#define rb_entry(ptr, type, member) container_of(ptr, type, member) #define rb_entry(ptr, type, member) container_of(ptr, type, member)
#define RB_EMPTY_ROOT(root) RB_EMPTY((struct linux_root *)root) #define RB_EMPTY_ROOT(root) RB_EMPTY((struct linux_root *)root)
@ -82,7 +78,6 @@ rb_link_node(struct rb_node *node, struct rb_node *parent,
struct rb_node **rb_link) struct rb_node **rb_link)
{ {
rb_set_parent(node, parent); rb_set_parent(node, parent);
rb_set_color(node, RB_RED);
node->__entry.rbe_left = node->__entry.rbe_right = NULL; node->__entry.rbe_left = node->__entry.rbe_right = NULL;
*rb_link = node; *rb_link = node;
} }

293
sys/sys/tree.h
View File

@ -307,34 +307,31 @@ struct name { \
(root)->rbh_root = NULL; \ (root)->rbh_root = NULL; \
} while (/*CONSTCOND*/ 0) } while (/*CONSTCOND*/ 0)
#define RB_BLACK 0
#define RB_RED 1
#define RB_ENTRY(type) \ #define RB_ENTRY(type) \
struct { \ struct { \
struct type *rbe_left; /* left element */ \ struct type *rbe_left; /* left element */ \
struct type *rbe_right; /* right element */ \ struct type *rbe_right; /* right element */ \
struct type *rbe_parent; /* parent element */ \ struct type *rbe_parent; /* parent element */ \
int rbe_color; /* node color */ \
} }
#define RB_LEFT(elm, field) (elm)->field.rbe_left #define RB_LF(elm, field) (elm)->field.rbe_left
#define RB_RIGHT(elm, field) (elm)->field.rbe_right #define RB_RT(elm, field) (elm)->field.rbe_right
#define RB_FLIP(elm) (*(__uintptr_t *)&(elm) ^= 1)
#define RB_FLIP_LF(elm, field) RB_FLIP(RB_LF(elm, field))
#define RB_FLIP_RT(elm, field) RB_FLIP(RB_RT(elm, field))
#define RB_ISRED(elm) ((*(__uintptr_t *)&(elm) & 1) != 0)
#define RB_RED_LF(elm, field) RB_ISRED(RB_LF(elm, field))
#define RB_RED_RT(elm, field) RB_ISRED(RB_RT(elm, field))
#define RB_PTR(elm, field) ((__typeof(elm->field.rbe_parent)) \
((__uintptr_t)(elm) & ~(__uintptr_t)1))
#define RB_LEFT(elm, field) RB_PTR(RB_LF(elm, field), field)
#define RB_RIGHT(elm, field) RB_PTR(RB_RT(elm, field), field)
#define RB_PARENT(elm, field) (elm)->field.rbe_parent #define RB_PARENT(elm, field) (elm)->field.rbe_parent
#define RB_COLOR(elm, field) (elm)->field.rbe_color
#define RB_ISRED(elm, field) ((elm) != NULL && RB_COLOR(elm, field) == RB_RED)
#define RB_ROOT(head) (head)->rbh_root #define RB_ROOT(head) (head)->rbh_root
#define RB_EMPTY(head) (RB_ROOT(head) == NULL) #define RB_EMPTY(head) (RB_ROOT(head) == NULL)
#define RB_BOOL int
#define RB_SET(elm, parent, field) do { \ #define RB_TRUE 1
RB_PARENT(elm, field) = parent; \ #define RB_FALSE 0
RB_LEFT(elm, field) = RB_RIGHT(elm, field) = NULL; \
RB_COLOR(elm, field) = RB_RED; \
} while (/*CONSTCOND*/ 0)
#define RB_SET_BLACKRED(black, red, field) do { \
RB_COLOR(black, field) = RB_BLACK; \
RB_COLOR(red, field) = RB_RED; \
} while (/*CONSTCOND*/ 0)
/* /*
* Something to be invoked in a loop at the root of every modified subtree, * Something to be invoked in a loop at the root of every modified subtree,
@ -344,37 +341,42 @@ struct { \
#define RB_AUGMENT(x) break #define RB_AUGMENT(x) break
#endif #endif
/*
* Fix pointers to a parent, and from a parent, as part of rotation.
*/
#define RB_ROTATE_PARENT(head, elm, tmp, field) do { \
if ((RB_PARENT(tmp, field) = RB_PARENT(elm, field)) == NULL) \
RB_ROOT(head) = (tmp); \
else if ((elm) == RB_LEFT(RB_PARENT(elm, field), field)) \
RB_LF(RB_PARENT(elm, field), field) = (tmp); \
else \
RB_RT(RB_PARENT(elm, field), field) = (tmp); \
RB_PARENT(elm, field) = (tmp); \
} while (/*CONSTCOND*/ 0)
/*
* Rotation makes the descending node red, and the ascending
* node not-red.
*/
#define RB_ROTATE_LEFT(head, elm, tmp, field) do { \ #define RB_ROTATE_LEFT(head, elm, tmp, field) do { \
(tmp) = RB_RIGHT(elm, field); \ (tmp) = RB_RIGHT(elm, field); \
if ((RB_RIGHT(elm, field) = RB_LEFT(tmp, field)) != NULL) { \ if ((RB_RT(elm, field) = RB_LF(tmp, field)) != NULL) { \
RB_PARENT(RB_LEFT(tmp, field), field) = (elm); \ RB_PARENT(RB_LEFT(tmp, field), field) = (elm); \
} \ } \
if ((RB_PARENT(tmp, field) = RB_PARENT(elm, field)) != NULL) { \ RB_ROTATE_PARENT(head, elm, tmp, field); \
if ((elm) == RB_LEFT(RB_PARENT(elm, field), field)) \ RB_LF(tmp, field) = (elm); \
RB_LEFT(RB_PARENT(elm, field), field) = (tmp); \ RB_FLIP_LF(tmp, field); \
else \
RB_RIGHT(RB_PARENT(elm, field), field) = (tmp); \
} else \
(head)->rbh_root = (tmp); \
RB_LEFT(tmp, field) = (elm); \
RB_PARENT(elm, field) = (tmp); \
RB_AUGMENT(elm); \ RB_AUGMENT(elm); \
} while (/*CONSTCOND*/ 0) } while (/*CONSTCOND*/ 0)
#define RB_ROTATE_RIGHT(head, elm, tmp, field) do { \ #define RB_ROTATE_RIGHT(head, elm, tmp, field) do { \
(tmp) = RB_LEFT(elm, field); \ (tmp) = RB_LEFT(elm, field); \
if ((RB_LEFT(elm, field) = RB_RIGHT(tmp, field)) != NULL) { \ if ((RB_LF(elm, field) = RB_RT(tmp, field)) != NULL) { \
RB_PARENT(RB_RIGHT(tmp, field), field) = (elm); \ RB_PARENT(RB_RIGHT(tmp, field), field) = (elm); \
} \ } \
if ((RB_PARENT(tmp, field) = RB_PARENT(elm, field)) != NULL) { \ RB_ROTATE_PARENT(head, elm, tmp, field); \
if ((elm) == RB_LEFT(RB_PARENT(elm, field), field)) \ RB_RT(tmp, field) = (elm); \
RB_LEFT(RB_PARENT(elm, field), field) = (tmp); \ RB_FLIP_RT(tmp, field); \
else \
RB_RIGHT(RB_PARENT(elm, field), field) = (tmp); \
} else \
(head)->rbh_root = (tmp); \
RB_RIGHT(tmp, field) = (elm); \
RB_PARENT(elm, field) = (tmp); \
RB_AUGMENT(elm); \ RB_AUGMENT(elm); \
} while (/*CONSTCOND*/ 0) } while (/*CONSTCOND*/ 0)
@ -439,110 +441,105 @@ struct { \
attr void \ attr void \
name##_RB_INSERT_COLOR(struct name *head, struct type *elm) \ name##_RB_INSERT_COLOR(struct name *head, struct type *elm) \
{ \ { \
struct type *parent, *gparent, *tmp; \ struct type *gparent, *parent; \
while (RB_ISRED((parent = RB_PARENT(elm, field)), field)) { \ while ((parent = RB_PARENT(elm, field)) != NULL) { \
gparent = RB_PARENT(parent, field); \ if (RB_LEFT(parent, field) == elm) \
if (parent == RB_LEFT(gparent, field)) { \ RB_FLIP_LF(parent, field); \
tmp = RB_RIGHT(gparent, field); \ else \
if (RB_ISRED(tmp, field)) { \ RB_FLIP_RT(parent, field); \
RB_COLOR(tmp, field) = RB_BLACK; \ if ((gparent = RB_PARENT(parent, field)) == NULL) \
RB_SET_BLACKRED(parent, gparent, field);\ break; \
elm = gparent; \ if (RB_RED_LF(gparent, field) && \
continue; \ RB_RED_RT(gparent, field)) { \
} \ RB_FLIP_LF(gparent, field); \
if (RB_RIGHT(parent, field) == elm) { \ RB_FLIP_RT(gparent, field); \
RB_ROTATE_LEFT(head, parent, tmp, field);\ elm = gparent; \
tmp = parent; \ continue; \
parent = elm; \
elm = tmp; \
} \
RB_SET_BLACKRED(parent, gparent, field); \
RB_ROTATE_RIGHT(head, gparent, tmp, field); \
} else { \
tmp = RB_LEFT(gparent, field); \
if (RB_ISRED(tmp, field)) { \
RB_COLOR(tmp, field) = RB_BLACK; \
RB_SET_BLACKRED(parent, gparent, field);\
elm = gparent; \
continue; \
} \
if (RB_LEFT(parent, field) == elm) { \
RB_ROTATE_RIGHT(head, parent, tmp, field);\
tmp = parent; \
parent = elm; \
elm = tmp; \
} \
RB_SET_BLACKRED(parent, gparent, field); \
RB_ROTATE_LEFT(head, gparent, tmp, field); \
} \ } \
if (RB_RED_LF(gparent, field) && \
parent == RB_LEFT(gparent, field)) { \
if (RB_RIGHT(parent, field) == elm) { \
RB_ROTATE_LEFT(head, parent, elm, field);\
parent = elm; \
} \
RB_ROTATE_RIGHT(head, gparent, parent, field); \
} else if (RB_RED_RT(gparent, field) && \
parent == RB_RIGHT(gparent, field)) { \
if (RB_LEFT(parent, field) == elm) { \
RB_ROTATE_RIGHT(head, parent, elm, field);\
parent = elm; \
} \
RB_ROTATE_LEFT(head, gparent, parent, field); \
} \
break; \
} \ } \
RB_COLOR(head->rbh_root, field) = RB_BLACK; \
} }
#define RB_GENERATE_REMOVE_COLOR(name, type, field, attr) \ #define RB_GENERATE_REMOVE_COLOR(name, type, field, attr) \
attr void \ attr void \
name##_RB_REMOVE_COLOR(struct name *head, struct type *parent) \ name##_RB_REMOVE_COLOR(struct name *head, struct type *elm) \
{ \ { \
struct type *elm, *tmp; \ struct type *par, *sib, *tmp; \
elm = NULL; \ RB_BOOL go_left, left_child, red_par; \
left_child = (RB_LEFT(elm, field) == NULL); \
do { \ do { \
if (RB_LEFT(parent, field) == elm) { \ go_left = left_child; \
tmp = RB_RIGHT(parent, field); \ if (go_left ? \
if (RB_COLOR(tmp, field) == RB_RED) { \ !RB_RED_RT(elm, field) : \
RB_SET_BLACKRED(tmp, parent, field); \ !RB_RED_LF(elm, field)) { \
RB_ROTATE_LEFT(head, parent, tmp, field);\ par = RB_PARENT(elm, field); \
tmp = RB_RIGHT(parent, field); \ left_child = par != NULL && \
RB_LEFT(par, field) == elm; \
red_par = left_child ? RB_RED_LF(par, field) : \
par == NULL ? RB_TRUE : \
RB_RED_RT(par, field); \
} \
if (go_left) { \
if (RB_RED_RT(elm, field)) { \
red_par = RB_TRUE; \
RB_ROTATE_LEFT(head, elm, par, field); \
} \ } \
if (RB_ISRED(RB_LEFT(tmp, field), field)) { \ sib = RB_RIGHT(elm, field); \
struct type *oleft; \ if (RB_RED_LF(sib, field)) { \
oleft = RB_LEFT(tmp, field); \ RB_ROTATE_RIGHT(head, sib, tmp, field); \
RB_COLOR(oleft, field) = RB_BLACK; \ sib = tmp; \
RB_COLOR(tmp, field) = RB_RED; \ } else if (!RB_RED_RT(sib, field)) { \
RB_ROTATE_RIGHT(head, tmp, oleft, field); \ RB_FLIP_RT(elm, field); \
tmp = RB_RIGHT(parent, field); \ elm = par; \
} else if (!RB_ISRED(RB_RIGHT(tmp, field), field)) { \
RB_COLOR(tmp, field) = RB_RED; \
elm = parent; \
parent = RB_PARENT(elm, field); \
continue; \ continue; \
} \ } \
if (RB_ISRED(RB_RIGHT(tmp, field), field)) \ if (RB_RED_RT(sib, field)) \
RB_COLOR(RB_RIGHT(tmp, field), field) = RB_BLACK; \ RB_FLIP_RT(sib, field); \
RB_COLOR(tmp, field) = RB_COLOR(parent, field); \ RB_ROTATE_LEFT(head, elm, sib, field); \
RB_COLOR(parent, field) = RB_BLACK; \ RB_FLIP_LF(sib, field); \
RB_ROTATE_LEFT(head, parent, tmp, field); \
elm = RB_ROOT(head); \
break; \ break; \
} else { \ } else { \
tmp = RB_LEFT(parent, field); \ if (RB_RED_LF(elm, field)) { \
if (RB_COLOR(tmp, field) == RB_RED) { \ red_par = RB_TRUE; \
RB_SET_BLACKRED(tmp, parent, field); \ RB_ROTATE_RIGHT(head, elm, par, field); \
RB_ROTATE_RIGHT(head, parent, tmp, field);\
tmp = RB_LEFT(parent, field); \
} \ } \
if (RB_ISRED(RB_RIGHT(tmp, field), field)) { \ sib = RB_LEFT(elm, field); \
struct type *oright; \ if (RB_RED_RT(sib, field)) { \
oright = RB_RIGHT(tmp, field); \ RB_ROTATE_LEFT(head, sib, tmp, field); \
RB_COLOR(oright, field) = RB_BLACK; \ sib = tmp; \
RB_COLOR(tmp, field) = RB_RED; \ } else if (!RB_RED_LF(sib, field)) { \
RB_ROTATE_LEFT(head, tmp, oright, field); \ RB_FLIP_LF(elm, field); \
tmp = RB_LEFT(parent, field); \ elm = par; \
} else if (!RB_ISRED(RB_LEFT(tmp, field), field)) { \
RB_COLOR(tmp, field) = RB_RED; \
elm = parent; \
parent = RB_PARENT(elm, field); \
continue; \ continue; \
} \ } \
if (RB_ISRED(RB_LEFT(tmp, field), field)) \ if (RB_RED_LF(sib, field)) \
RB_COLOR(RB_LEFT(tmp, field), field) = RB_BLACK; \ RB_FLIP_LF(sib, field); \
RB_COLOR(tmp, field) = RB_COLOR(parent, field); \ RB_ROTATE_RIGHT(head, elm, sib, field); \
RB_COLOR(parent, field) = RB_BLACK; \ RB_FLIP_RT(sib, field); \
RB_ROTATE_RIGHT(head, parent, tmp, field); \
elm = RB_ROOT(head); \
break; \ break; \
} \ } \
} while (!RB_ISRED(elm, field) && parent != NULL); \ } while (!red_par); \
RB_COLOR(elm, field) = RB_BLACK; \ if (par != NULL && red_par) { \
if (left_child) \
RB_FLIP_LF(par, field); \
else \
RB_FLIP_RT(par, field); \
} \
} }
#define RB_GENERATE_REMOVE(name, type, field, attr) \ #define RB_GENERATE_REMOVE(name, type, field, attr) \
@ -550,12 +547,11 @@ attr struct type * \
name##_RB_REMOVE(struct name *head, struct type *elm) \ name##_RB_REMOVE(struct name *head, struct type *elm) \
{ \ { \
struct type *child, *old, *parent, *parent_old, *right; \ struct type *child, *old, *parent, *parent_old, *right; \
int color; \ RB_BOOL old_red, red; \
\ \
old = elm; \ old = elm; \
parent_old = parent = RB_PARENT(elm, field); \ parent_old = parent = RB_PARENT(elm, field); \
right = RB_RIGHT(elm, field); \ right = RB_RIGHT(elm, field); \
color = RB_COLOR(elm, field); \
if (RB_LEFT(elm, field) == NULL) \ if (RB_LEFT(elm, field) == NULL) \
elm = child = right; \ elm = child = right; \
else if (right == NULL) \ else if (right == NULL) \
@ -563,7 +559,8 @@ name##_RB_REMOVE(struct name *head, struct type *elm) \
else { \ else { \
if ((child = RB_LEFT(right, field)) == NULL) { \ if ((child = RB_LEFT(right, field)) == NULL) { \
child = RB_RIGHT(right, field); \ child = RB_RIGHT(right, field); \
RB_RIGHT(old, field) = child; \ red = RB_RED_RT(old, field); \
RB_RT(old, field) = child; \
parent = elm = right; \ parent = elm = right; \
} else { \ } else { \
do \ do \
@ -571,23 +568,31 @@ name##_RB_REMOVE(struct name *head, struct type *elm) \
while ((child = RB_LEFT(elm, field)) != NULL); \ while ((child = RB_LEFT(elm, field)) != NULL); \
child = RB_RIGHT(elm, field); \ child = RB_RIGHT(elm, field); \
parent = RB_PARENT(elm, field); \ parent = RB_PARENT(elm, field); \
RB_LEFT(parent, field) = child; \ red = RB_RED_LF(parent, field); \
RB_LF(parent, field) = child; \
RB_PARENT(RB_RIGHT(old, field), field) = elm; \ RB_PARENT(RB_RIGHT(old, field), field) = elm; \
} \ } \
RB_PARENT(RB_LEFT(old, field), field) = elm; \ RB_PARENT(RB_LEFT(old, field), field) = elm; \
color = RB_COLOR(elm, field); \
elm->field = old->field; \ elm->field = old->field; \
} \ } \
if (parent_old == NULL) \ if (parent_old == NULL) { \
RB_ROOT(head) = elm; \ RB_ROOT(head) = elm; \
else if (RB_LEFT(parent_old, field) == old) \ old_red = RB_FALSE; \
RB_LEFT(parent_old, field) = elm; \ } else if (RB_LEFT(parent_old, field) == old) { \
else \ old_red = RB_RED_LF(parent_old, field); \
RB_RIGHT(parent_old, field) = elm; \ RB_LF(parent_old, field) = elm; \
if (child != NULL) { \ if (old_red && parent != parent_old) \
RB_FLIP_LF(parent_old, field); \
} else { \
old_red = RB_RED_RT(parent_old, field); \
RB_RT(parent_old, field) = elm; \
if (old_red && parent != parent_old) \
RB_FLIP_RT(parent_old, field); \
} \
if (child != NULL) \
RB_PARENT(child, field) = parent; \ RB_PARENT(child, field) = parent; \
RB_COLOR(child, field) = RB_BLACK; \ else if (parent != NULL && \
} else if (color != RB_RED && parent != NULL) \ (parent != parent_old ? !red : !old_red)) \
name##_RB_REMOVE_COLOR(head, parent); \ name##_RB_REMOVE_COLOR(head, parent); \
while (parent != NULL) { \ while (parent != NULL) { \
RB_AUGMENT(parent); \ RB_AUGMENT(parent); \
@ -615,14 +620,14 @@ name##_RB_INSERT(struct name *head, struct type *elm) \
else \ else \
return (tmp); \ return (tmp); \
} \ } \
RB_SET(elm, parent, field); \ RB_PARENT(elm, field) = parent; \
if (parent != NULL) { \ RB_LF(elm, field) = RB_RT(elm, field) = NULL; \
if (comp < 0) \ if (parent == NULL) \
RB_LEFT(parent, field) = elm; \
else \
RB_RIGHT(parent, field) = elm; \
} else \
RB_ROOT(head) = elm; \ RB_ROOT(head) = elm; \
else if (comp < 0) \
RB_LF(parent, field) = elm; \
else \
RB_RT(parent, field) = elm; \
name##_RB_INSERT_COLOR(head, elm); \ name##_RB_INSERT_COLOR(head, elm); \
while (elm != NULL) { \ while (elm != NULL) { \
RB_AUGMENT(elm); \ RB_AUGMENT(elm); \