4 * Userspace RCU library - Red-Black Tree
6 * Copyright (c) 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with this library; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 * Implementation of RCU-adapted data structures and operations based on the RB
23 * tree algorithms found in chapter 12 of:
25 * Thomas H. Cormen, Charles E. Leiserson, Ronald L. Rivest, and
26 * Clifford Stein. Introduction to Algorithms, Third Edition. The MIT
27 * Press, September 2009.
39 #include <urcu/rcurbtree.h>
40 #include <urcu-pointer.h>
41 #include <urcu-call-rcu.h>
42 #include <urcu/compiler.h>
45 #define dbg_printf(args...) printf(args)
46 #define dbg_usleep(usecs) usleep(usecs)
48 #define dbg_printf(args...)
49 #define dbg_usleep(usecs)
53 * Undefine this to enable the non-RCU rotate and transplant functions
56 #define RBTREE_RCU_SUPPORT_ROTATE_LEFT
57 #define RBTREE_RCU_SUPPORT_ROTATE_RIGHT
58 #define RBTREE_RCU_SUPPORT_TRANSPLANT
61 static pthread_mutex_t test_mutex
= PTHREAD_MUTEX_INITIALIZER
;
62 static pthread_mutex_t outer_mutex
= PTHREAD_MUTEX_INITIALIZER
;
65 void lock_outer_mutex(void)
67 pthread_mutex_lock(&outer_mutex
);
71 void unlock_outer_mutex(void)
73 pthread_mutex_unlock(&outer_mutex
);
77 void lock_test_mutex(void)
79 pthread_mutex_lock(&test_mutex
);
83 void unlock_test_mutex(void)
85 pthread_mutex_unlock(&test_mutex
);
90 void set_parent(struct rcu_rbtree_node
*node
,
91 struct rcu_rbtree_node
*parent
,
94 _CMM_STORE_SHARED(node
->parent
, ((unsigned long) parent
) | pos
);
98 struct rcu_rbtree_node
*get_parent(struct rcu_rbtree_node
*node
)
100 return (struct rcu_rbtree_node
*) (node
->parent
& ~1UL);
104 unsigned int get_pos(struct rcu_rbtree_node
*node
)
106 return (unsigned int) (node
->parent
& 1UL);
110 struct rcu_rbtree_node
*get_parent_and_pos(struct rcu_rbtree_node
*node
,
113 unsigned long parent_pos
= rcu_dereference(node
->parent
);
115 *pos
= (unsigned int) (parent_pos
& 1UL);
116 return (struct rcu_rbtree_node
*) (parent_pos
& ~1UL);
120 void set_decay(struct rcu_rbtree_node
*x
, struct rcu_rbtree_node
*xc
)
126 struct rcu_rbtree_node
*get_decay(struct rcu_rbtree_node
*x
)
130 while (x
->decay_next
)
136 struct rcu_rbtree_node
*is_decay(struct rcu_rbtree_node
*x
)
138 return x
->decay_next
;
142 struct rcu_rbtree_node
*dup_decay_node(struct rcu_rbtree
*rbtree
,
143 struct rcu_rbtree_node
*x
)
145 struct rcu_rbtree_node
*xc
;
147 if (rcu_rbtree_is_nil(rbtree
, x
))
150 xc
= rbtree
->rballoc();
151 memcpy(xc
, x
, sizeof(struct rcu_rbtree_node
));
152 xc
->decay_next
= NULL
;
154 call_rcu(&x
->head
, rbtree
->rbfree
);
159 * Info for range lookups:
160 * Range lookup information is only valid when used when searching for
161 * ranges. It should never be used in next/prev traversal because the
162 * pointers to parents are not in sync with the parent vision of the
166 void set_left(struct rcu_rbtree
*rbtree
, struct rcu_rbtree_node
*node
,
167 struct rcu_rbtree_node
*left
)
173 void set_right(struct rcu_rbtree
*rbtree
, struct rcu_rbtree_node
*node
,
174 struct rcu_rbtree_node
*right
)
176 node
->_right
= right
;
181 * Deal with memory allocation errors.
182 * Can be ensured by reserving a pool of memory entries before doing the
183 * insertion, which will have to be function of number of
184 * transplantations/rotations required for the operation.
189 void show_tree(struct rcu_rbtree
*rbtree
)
191 struct rcu_rbtree_node
*node
;
193 node
= rcu_rbtree_min(rbtree
, rbtree
->root
);
194 while (!rcu_rbtree_is_nil(rbtree
, node
)) {
195 assert(!is_decay(node
));
196 printf("{ b:%lX e:%lX pb: %lX r:%lX l:%lX %s %s %s} ",
197 (unsigned long) node
->begin
,
198 (unsigned long) node
->end
,
199 (unsigned long) get_parent(node
)->begin
,
200 (unsigned long) node
->_right
->begin
,
201 (unsigned long) node
->_left
->begin
,
202 node
->color
? "red" : "black",
203 get_pos(node
) ? "right" : "left",
204 rcu_rbtree_is_nil(rbtree
, node
) ? "nil" : "");
205 node
= rcu_rbtree_next(rbtree
, node
);
211 void show_tree(struct rcu_rbtree
*rbtree
)
217 struct rcu_rbtree_node
*make_nil(struct rcu_rbtree
*rbtree
)
219 return &rbtree
->nil_node
;
223 * Iterative rbtree search.
225 struct rcu_rbtree_node
*rcu_rbtree_search(struct rcu_rbtree
*rbtree
,
226 struct rcu_rbtree_node
*x
,
229 x
= rcu_dereference(x
);
232 while (!rcu_rbtree_is_nil(rbtree
, x
) && (comp
= rbtree
->comp(k
, x
->begin
)) != 0) {
235 x
= rcu_dereference(x
->_left
);
237 x
= rcu_dereference(x
->_right
);
243 struct rcu_rbtree_node
*rcu_rbtree_min_dup_decay(struct rcu_rbtree
*rbtree
,
244 struct rcu_rbtree_node
*x
,
245 struct rcu_rbtree_node
**zr
)
247 struct rcu_rbtree_node
*xl
;
249 x
= rcu_dereference(x
);
251 if (rcu_rbtree_is_nil(rbtree
, x
)) {
255 *zr
= x
= dup_decay_node(rbtree
, x
);
257 while (!rcu_rbtree_is_nil(rbtree
, xl
= rcu_dereference(x
->_left
))) {
258 x
= dup_decay_node(rbtree
, xl
);
259 set_parent(x
, get_decay(get_parent(x
)), get_pos(x
));
260 get_parent(x
)->_left
= get_decay(get_parent(x
)->_left
);
266 struct rcu_rbtree_node
*rcu_rbtree_min_update_decay(struct rcu_rbtree
*rbtree
,
267 struct rcu_rbtree_node
*x
)
269 struct rcu_rbtree_node
*xl
;
271 x
= rcu_dereference(x
);
273 if (rcu_rbtree_is_nil(rbtree
, x
))
276 set_parent(x
->_right
, get_decay(get_parent(x
->_right
)),
278 set_parent(x
->_left
, get_decay(get_parent(x
->_left
)),
282 while (!rcu_rbtree_is_nil(rbtree
, xl
= rcu_dereference(x
->_left
))) {
284 set_parent(x
->_right
, get_decay(get_parent(x
->_right
)),
286 set_parent(x
->_left
, get_decay(get_parent(x
->_left
)),
292 struct rcu_rbtree_node
*rcu_rbtree_min(struct rcu_rbtree
*rbtree
,
293 struct rcu_rbtree_node
*x
)
295 struct rcu_rbtree_node
*xl
;
297 x
= rcu_dereference(x
);
299 if (rcu_rbtree_is_nil(rbtree
, x
))
302 while (!rcu_rbtree_is_nil(rbtree
, xl
= rcu_dereference(x
->_left
)))
307 struct rcu_rbtree_node
*rcu_rbtree_max(struct rcu_rbtree
*rbtree
,
308 struct rcu_rbtree_node
*x
)
310 struct rcu_rbtree_node
*xr
;
312 x
= rcu_dereference(x
);
314 if (rcu_rbtree_is_nil(rbtree
, x
))
317 while (!rcu_rbtree_is_nil(rbtree
, xr
= rcu_dereference(x
->_right
)))
324 * Updates should wait for a grace period between update of the
325 * redirect pointer and update of the parent child pointer. This is to make sure
326 * that no reference to the old entry exist.
330 * RCU read lock must be held across the next/prev calls to ensure validity of
333 struct rcu_rbtree_node
*rcu_rbtree_next(struct rcu_rbtree
*rbtree
,
334 struct rcu_rbtree_node
*x
)
336 struct rcu_rbtree_node
*xr
, *y
;
339 x
= rcu_dereference(x
);
341 if (!rcu_rbtree_is_nil(rbtree
, xr
= rcu_dereference(x
->_right
)))
342 return rcu_rbtree_min(rbtree
, xr
);
343 y
= get_parent_and_pos(x
, &x_pos
);
344 while (!rcu_rbtree_is_nil(rbtree
, y
) && x_pos
== IS_RIGHT
) {
346 y
= get_parent_and_pos(y
, &x_pos
);
351 struct rcu_rbtree_node
*rcu_rbtree_prev(struct rcu_rbtree
*rbtree
,
352 struct rcu_rbtree_node
*x
)
354 struct rcu_rbtree_node
*xl
, *y
;
357 x
= rcu_dereference(x
);
359 if (!rcu_rbtree_is_nil(rbtree
, xl
= rcu_dereference(x
->_left
)))
360 return rcu_rbtree_max(rbtree
, xl
);
361 y
= get_parent_and_pos(x
, &x_pos
);
362 while (!rcu_rbtree_is_nil(rbtree
, y
) && x_pos
== IS_LEFT
) {
364 y
= get_parent_and_pos(y
, &x_pos
);
370 * "node" needs to be non-visible by readers.
373 void populate_node_end(struct rcu_rbtree
*rbtree
, struct rcu_rbtree_node
*node
,
374 unsigned int copy_parents
, struct rcu_rbtree_node
*stop
)
376 struct rcu_rbtree_node
*prev
= NULL
, *orig_node
= node
, *top
;
382 assert(!rcu_rbtree_is_nil(rbtree
, node
));
384 if (!rcu_rbtree_is_nil(rbtree
, node
->_right
))
385 max_end
= max(max_end
, node
->_right
->max_end
);
386 if (!rcu_rbtree_is_nil(rbtree
, node
->_left
))
387 max_end
= max(max_end
, node
->_left
->max_end
);
389 if (max_end
!= node
->max_end
) {
390 if (prev
&& copy_parents
) {
391 node
= dup_decay_node(rbtree
, node
);
392 if (get_pos(prev
) == IS_RIGHT
)
396 set_parent(prev
, node
, get_pos(prev
));
398 node
->max_end
= max_end
;
401 * We did not have to change the current node,
402 * so set the pointer to the prev node. If prev
403 * was null, this means we are coming in the
404 * first loop, and must update the parent of the
405 * node received as parameter (node).
409 top
= get_parent(node
);
410 cmm_smp_wmb(); /* write into node before publish */
411 /* make new branch visible to readers */
412 if (rcu_rbtree_is_nil(rbtree
, top
))
413 _CMM_STORE_SHARED(rbtree
->root
, node
);
414 if (get_pos(node
) == IS_LEFT
)
415 _CMM_STORE_SHARED(top
->_left
, node
);
417 _CMM_STORE_SHARED(top
->_right
, node
);
421 /* Check for propagation stop */
426 node
= get_parent(node
);
427 } while (!rcu_rbtree_is_nil(rbtree
, node
));
429 top
= node
; /* nil */
430 cmm_smp_wmb(); /* write into node before publish */
431 /* make new branch visible to readers */
432 _CMM_STORE_SHARED(rbtree
->root
, prev
);
437 /* update children */
440 assert(!rcu_rbtree_is_nil(rbtree
, node
));
441 set_parent(node
->_left
, get_decay(get_parent(node
->_left
)), IS_LEFT
);
442 set_parent(node
->_right
, get_decay(get_parent(node
->_right
)), IS_RIGHT
);
443 } while ((node
= get_parent(node
)) != top
);
447 * We have to ensure these assumptions are correct for prev/next
450 * with x being a right child, the assumption that:
451 * get_parent(x)->_right == x
452 * or if x is a left child, the assumption that:
453 * get_parent(x)->_left == x
455 * This explains why we have to allocate a vc copy of the node for left_rotate,
456 * right_rotate and transplant operations.
458 * We always ensure that the right/left child and correct parent is set in the
459 * node copies *before* we reparent the children and make the upper-level point
463 /* RCU: copy x and y, atomically point to new versions. GC old. */
464 /* Should be eventually followed by a cmm_smp_wmc() */
466 #ifdef RBTREE_RCU_SUPPORT_ROTATE_LEFT
469 void left_rotate(struct rcu_rbtree
*rbtree
,
470 struct rcu_rbtree_node
*x
)
472 struct rcu_rbtree_node
*y
, *y_left
;
477 /* Now operate on new copy, decay old versions */
478 x
= dup_decay_node(rbtree
, x
);
479 y
= dup_decay_node(rbtree
, y
);
480 y_left
= dup_decay_node(rbtree
, y_left
);
482 /* Internal node modifications */
483 set_parent(y
, get_parent(x
), get_pos(x
));
484 set_parent(x
, y
, IS_LEFT
);
485 set_left(rbtree
, y
, x
);
486 set_right(rbtree
, x
, y_left
);
488 if (!rcu_rbtree_is_nil(rbtree
, y_left
))
489 set_parent(y_left
, x
, IS_RIGHT
);
491 cmm_smp_wmb(); /* write into node before publish */
493 /* External references update (visible by readers) */
494 if (rcu_rbtree_is_nil(rbtree
, get_parent(y
)))
495 _CMM_STORE_SHARED(rbtree
->root
, y
);
496 else if (get_pos(y
) == IS_LEFT
)
497 _CMM_STORE_SHARED(get_parent(y
)->_left
, y
);
499 _CMM_STORE_SHARED(get_parent(y
)->_right
, y
);
501 /* Point children to new copy (parent only used by updates/next/prev) */
502 set_parent(x
->_left
, get_decay(get_parent(x
->_left
)),
504 set_parent(y
->_right
, get_decay(get_parent(y
->_right
)),
506 if (!rcu_rbtree_is_nil(rbtree
, y_left
)) {
507 set_parent(y_left
->_right
,
508 get_decay(get_parent(y_left
->_right
)),
509 get_pos(y_left
->_right
));
510 set_parent(y_left
->_left
,
511 get_decay(get_parent(y_left
->_left
)),
512 get_pos(y_left
->_left
));
516 assert(y
== rbtree
->root
|| get_parent(y
)->_left
== y
517 || get_parent(y
)->_right
== y
);
518 assert(x
== rbtree
->root
|| get_parent(x
)->_left
== x
519 || get_parent(x
)->_right
== x
);
520 assert(rcu_rbtree_is_nil(rbtree
, x
->_right
) || get_parent(x
->_right
) == x
);
521 assert(rcu_rbtree_is_nil(rbtree
, x
->_left
) || get_parent(x
->_left
) == x
);
522 assert(rcu_rbtree_is_nil(rbtree
, y
->_right
) || get_parent(y
->_right
) == y
);
523 assert(rcu_rbtree_is_nil(rbtree
, y
->_left
) || get_parent(y
->_left
) == y
);
524 assert(!is_decay(rbtree
->root
));
525 assert(!is_decay(x
));
526 assert(!is_decay(y
));
527 assert(!is_decay(x
->_right
));
528 assert(!is_decay(x
->_left
));
529 assert(!is_decay(y
->_right
));
530 assert(!is_decay(y
->_left
));
535 /* non-rcu version */
537 void left_rotate(struct rcu_rbtree
*rbtree
,
538 struct rcu_rbtree_node
*x
)
540 struct rcu_rbtree_node
*y
;
544 x
->_right
= y
->_left
;
545 if (!rcu_rbtree_is_nil(rbtree
, y
->_left
))
546 set_parent(y
->_left
, x
, IS_RIGHT
);
547 set_parent(y
, get_parent(x
), get_pos(x
));
548 if (rcu_rbtree_is_nil(rbtree
, get_parent(x
)))
550 else if (x
== get_parent(x
)->_left
) {
551 get_parent(x
)->_left
= y
;
553 get_parent(x
)->_right
= y
;
556 set_parent(x
, y
, IS_LEFT
);
562 #ifdef RBTREE_RCU_SUPPORT_ROTATE_RIGHT
564 void right_rotate(struct rcu_rbtree
*rbtree
,
565 struct rcu_rbtree_node
*x
)
567 struct rcu_rbtree_node
*y
, *y_right
;
572 /* Now operate on new copy, decay old versions */
573 x
= dup_decay_node(rbtree
, x
);
574 y
= dup_decay_node(rbtree
, y
);
575 y_right
= dup_decay_node(rbtree
, y_right
);
577 /* Internal node modifications */
578 set_parent(y
, get_parent(x
), get_pos(x
));
579 set_parent(x
, y
, IS_RIGHT
);
580 set_right(rbtree
, y
, x
);
581 set_left(rbtree
, x
, y_right
);
583 if (!rcu_rbtree_is_nil(rbtree
, y_right
))
584 set_parent(y_right
, x
, IS_LEFT
);
586 cmm_smp_wmb(); /* write into node before publish */
588 /* External references update (visible by readers) */
589 if (rcu_rbtree_is_nil(rbtree
, get_parent(y
)))
590 _CMM_STORE_SHARED(rbtree
->root
, y
);
591 else if (get_pos(y
) == IS_RIGHT
)
592 _CMM_STORE_SHARED(get_parent(y
)->_right
, y
);
594 _CMM_STORE_SHARED(get_parent(y
)->_left
, y
);
596 /* Point children to new copy (parent only used by updates/next/prev) */
597 set_parent(x
->_right
, get_decay(get_parent(x
->_right
)),
599 set_parent(y
->_left
, get_decay(get_parent(y
->_left
)),
601 if (!rcu_rbtree_is_nil(rbtree
, y_right
)) {
602 set_parent(y_right
->_left
,
603 get_decay(get_parent(y_right
->_left
)),
604 get_pos(y_right
->_left
));
605 set_parent(y_right
->_right
,
606 get_decay(get_parent(y_right
->_right
)),
607 get_pos(y_right
->_right
));
611 assert(y
== rbtree
->root
|| get_parent(y
)->_right
== y
612 || get_parent(y
)->_left
== y
);
613 assert(x
== rbtree
->root
|| get_parent(x
)->_right
== x
614 || get_parent(x
)->_left
== x
);
615 assert(rcu_rbtree_is_nil(rbtree
, x
->_left
) || get_parent(x
->_left
) == x
);
616 assert(rcu_rbtree_is_nil(rbtree
, x
->_right
) || get_parent(x
->_right
) == x
);
617 assert(rcu_rbtree_is_nil(rbtree
, y
->_left
) || get_parent(y
->_left
) == y
);
618 assert(rcu_rbtree_is_nil(rbtree
, y
->_right
) || get_parent(y
->_right
) == y
);
619 assert(!is_decay(rbtree
->root
));
620 assert(!is_decay(x
));
621 assert(!is_decay(y
));
622 assert(!is_decay(x
->_left
));
623 assert(!is_decay(x
->_right
));
624 assert(!is_decay(y
->_left
));
625 assert(!is_decay(y
->_right
));
630 /* non-rcu version */
632 void right_rotate(struct rcu_rbtree
*rbtree
,
633 struct rcu_rbtree_node
*x
)
635 struct rcu_rbtree_node
*y
;
639 x
->_left
= y
->_right
;
640 if (!rcu_rbtree_is_nil(rbtree
, y
->_right
))
641 set_parent(y
->_right
, x
, IS_LEFT
);
642 set_parent(y
, get_parent(x
), get_pos(x
));
643 if (rcu_rbtree_is_nil(rbtree
, get_parent(x
)))
645 else if (x
== get_parent(x
)->_right
) {
646 get_parent(x
)->_right
= y
;
648 get_parent(x
)->_left
= y
;
651 set_parent(x
, y
, IS_RIGHT
);
657 static void rcu_rbtree_insert_fixup(struct rcu_rbtree
*rbtree
,
658 struct rcu_rbtree_node
*z
)
660 struct rcu_rbtree_node
*y
;
662 dbg_printf("insert fixup %p\n", z
->begin
);
663 assert(!is_decay(rbtree
->root
));
665 while (get_parent(z
)->color
== COLOR_RED
) {
666 if (get_parent(z
) == get_parent(get_parent(z
))->_left
) {
667 y
= get_parent(get_parent(z
))->_right
;
668 if (y
->color
== COLOR_RED
) {
669 get_parent(z
)->color
= COLOR_BLACK
;
670 y
->color
= COLOR_BLACK
;
671 get_parent(get_parent(z
))->color
= COLOR_RED
;
672 z
= get_parent(get_parent(z
));
674 if (z
== get_parent(z
)->_right
) {
676 left_rotate(rbtree
, z
);
678 assert(!is_decay(rbtree
->root
));
680 get_parent(z
)->color
= COLOR_BLACK
;
681 get_parent(get_parent(z
))->color
= COLOR_RED
;
682 assert(!is_decay(z
));
683 assert(!is_decay(get_parent(z
)));
684 assert(!is_decay(get_parent(get_parent(z
))));
685 right_rotate(rbtree
, get_parent(get_parent(z
)));
686 assert(!is_decay(z
));
687 assert(!is_decay(rbtree
->root
));
690 y
= get_parent(get_parent(z
))->_left
;
691 if (y
->color
== COLOR_RED
) {
692 get_parent(z
)->color
= COLOR_BLACK
;
693 y
->color
= COLOR_BLACK
;
694 get_parent(get_parent(z
))->color
= COLOR_RED
;
695 z
= get_parent(get_parent(z
));
697 if (z
== get_parent(z
)->_left
) {
699 right_rotate(rbtree
, z
);
701 assert(!is_decay(rbtree
->root
));
703 get_parent(z
)->color
= COLOR_BLACK
;
704 get_parent(get_parent(z
))->color
= COLOR_RED
;
705 left_rotate(rbtree
, get_parent(get_parent(z
)));
706 assert(!is_decay(z
));
707 assert(!is_decay(rbtree
->root
));
711 rbtree
->root
->color
= COLOR_BLACK
;
715 * rcu_rbtree_insert - Insert a node in the RCU rbtree
717 * Returns 0 on success, or < 0 on error.
719 int rcu_rbtree_insert(struct rcu_rbtree
*rbtree
,
720 struct rcu_rbtree_node
*z
)
722 struct rcu_rbtree_node
*x
, *y
;
724 dbg_printf("insert %p\n", z
->begin
);
725 assert(!is_decay(rbtree
->root
));
727 y
= make_nil(rbtree
);
729 while (!rcu_rbtree_is_nil(rbtree
, x
)) {
731 if (rbtree
->comp(z
->begin
, x
->begin
) < 0)
737 z
->_left
= make_nil(rbtree
);
738 z
->_right
= make_nil(rbtree
);
739 z
->color
= COLOR_RED
;
740 z
->decay_next
= NULL
;
743 if (rcu_rbtree_is_nil(rbtree
, y
)) {
744 set_parent(z
, y
, IS_RIGHT
); /* pos arbitrary for root node */
746 * Order stores to z (children/parents) before stores
747 * that will make it visible to the rest of the tree.
750 _CMM_STORE_SHARED(rbtree
->root
, z
);
751 } else if (rbtree
->comp(z
->begin
, y
->begin
) < 0) {
752 y
= dup_decay_node(rbtree
, y
);
753 set_parent(z
, y
, IS_LEFT
);
754 if (get_pos(z
) == IS_LEFT
)
755 _CMM_STORE_SHARED(y
->_left
, z
);
757 _CMM_STORE_SHARED(y
->_right
, z
);
758 populate_node_end(rbtree
, y
, 1, NULL
);
760 y
= dup_decay_node(rbtree
, y
);
761 set_parent(z
, y
, IS_RIGHT
);
762 if (get_pos(z
) == IS_LEFT
)
763 _CMM_STORE_SHARED(y
->_left
, z
);
765 _CMM_STORE_SHARED(y
->_right
, z
);
766 populate_node_end(rbtree
, y
, 1, NULL
);
768 rcu_rbtree_insert_fixup(rbtree
, z
);
770 * Make sure to commit all _CMM_STORE_SHARED() for non-coherent caches.
779 * Transplant v into u position.
782 #ifdef RBTREE_RCU_SUPPORT_TRANSPLANT
785 void rcu_rbtree_transplant(struct rcu_rbtree
*rbtree
,
786 struct rcu_rbtree_node
*u
,
787 struct rcu_rbtree_node
*v
,
788 unsigned int copy_parents
,
789 struct rcu_rbtree_node
*stop
)
791 dbg_printf("transplant %p\n", v
->begin
);
793 if (!rcu_rbtree_is_nil(rbtree
, v
))
794 v
= dup_decay_node(rbtree
, v
);
796 if (rcu_rbtree_is_nil(rbtree
, get_parent(u
))) {
797 /* pos is arbitrary for root node */
798 set_parent(v
, get_parent(u
), IS_RIGHT
);
799 cmm_smp_wmb(); /* write into node before publish */
800 _CMM_STORE_SHARED(rbtree
->root
, v
);
802 struct rcu_rbtree_node
*vp
;
806 vp
= dup_decay_node(rbtree
, vp
);
807 set_parent(v
, vp
, get_pos(u
));
808 if (get_pos(v
) == IS_LEFT
)
809 _CMM_STORE_SHARED(vp
->_left
, v
);
811 _CMM_STORE_SHARED(vp
->_right
, v
);
812 populate_node_end(rbtree
, vp
, copy_parents
, stop
);
815 /* Point children to new copy (parent only used by updates/next/prev) */
816 if (!rcu_rbtree_is_nil(rbtree
, v
)) {
817 set_parent(v
->_right
, get_decay(get_parent(v
->_right
)),
819 set_parent(v
->_left
, get_decay(get_parent(v
->_left
)),
822 assert(!is_decay(rbtree
->root
));
827 /* Non-RCU version */
829 void rcu_rbtree_transplant(struct rcu_rbtree
*rbtree
,
830 struct rcu_rbtree_node
*u
,
831 struct rcu_rbtree_node
*v
,
832 unsigned int copy_parents
,
833 struct rcu_rbtree_node
*stop
)
835 dbg_printf("transplant %p\n", v
->begin
);
838 if (rcu_rbtree_is_nil(rbtree
, get_parent(u
)))
840 else if (u
== get_parent(u
)->_left
)
841 get_parent(u
)->_left
= v
;
843 get_parent(u
)->_right
= v
;
844 set_parent(v
, get_parent(u
), get_pos(u
));
850 static void rcu_rbtree_remove_fixup(struct rcu_rbtree
*rbtree
,
851 struct rcu_rbtree_node
*x
)
853 dbg_printf("remove fixup %p\n", x
->begin
);
855 while (x
!= rbtree
->root
&& x
->color
== COLOR_BLACK
) {
856 assert(!is_decay(get_parent(x
)));
857 assert(!is_decay(get_parent(x
)->_left
));
858 if (x
== get_parent(x
)->_left
) {
859 struct rcu_rbtree_node
*w
;
861 w
= get_parent(x
)->_right
;
863 if (w
->color
== COLOR_RED
) {
864 w
->color
= COLOR_BLACK
;
865 get_parent(x
)->color
= COLOR_RED
;
866 left_rotate(rbtree
, get_parent(x
));
868 assert(!is_decay(rbtree
->root
));
869 w
= get_parent(x
)->_right
;
871 if (w
->_left
->color
== COLOR_BLACK
872 && w
->_right
->color
== COLOR_BLACK
) {
873 w
->color
= COLOR_RED
;
875 assert(!is_decay(rbtree
->root
));
876 assert(!is_decay(x
));
878 if (w
->_right
->color
== COLOR_BLACK
) {
879 w
->_left
->color
= COLOR_BLACK
;
880 w
->color
= COLOR_RED
;
881 right_rotate(rbtree
, w
);
882 assert(!is_decay(rbtree
->root
));
884 w
= get_parent(x
)->_right
;
886 w
->color
= get_parent(x
)->color
;
887 get_parent(x
)->color
= COLOR_BLACK
;
888 w
->_right
->color
= COLOR_BLACK
;
889 left_rotate(rbtree
, get_parent(x
));
890 assert(!is_decay(rbtree
->root
));
894 struct rcu_rbtree_node
*w
;
896 w
= get_parent(x
)->_left
;
898 if (w
->color
== COLOR_RED
) {
899 w
->color
= COLOR_BLACK
;
900 get_parent(x
)->color
= COLOR_RED
;
901 right_rotate(rbtree
, get_parent(x
));
902 assert(!is_decay(rbtree
->root
));
904 w
= get_parent(x
)->_left
;
906 if (w
->_right
->color
== COLOR_BLACK
907 && w
->_left
->color
== COLOR_BLACK
) {
908 w
->color
= COLOR_RED
;
910 assert(!is_decay(rbtree
->root
));
911 assert(!is_decay(x
));
913 if (w
->_left
->color
== COLOR_BLACK
) {
914 w
->_right
->color
= COLOR_BLACK
;
915 w
->color
= COLOR_RED
;
916 left_rotate(rbtree
, w
);
917 assert(!is_decay(rbtree
->root
));
919 w
= get_parent(x
)->_left
;
921 w
->color
= get_parent(x
)->color
;
922 get_parent(x
)->color
= COLOR_BLACK
;
923 w
->_left
->color
= COLOR_BLACK
;
924 right_rotate(rbtree
, get_parent(x
));
925 assert(!is_decay(rbtree
->root
));
930 x
->color
= COLOR_BLACK
;
934 * Delete z. All non-copied children left/right positions are unchanged.
937 void rcu_rbtree_remove_nonil(struct rcu_rbtree
*rbtree
,
938 struct rcu_rbtree_node
*z
,
939 struct rcu_rbtree_node
*y
)
941 struct rcu_rbtree_node
*x
;
943 dbg_printf("remove nonil %p\n", z
->begin
);
946 assert(!is_decay(z
));
947 assert(!is_decay(y
));
948 assert(!is_decay(y
->_right
));
949 assert(!is_decay(get_parent(y
)));
951 assert(!is_decay(x
));
952 if (get_parent(y
) == z
) {
953 y
= dup_decay_node(rbtree
, y
);
954 set_parent(x
, y
, get_pos(x
)); /* parent for nil */
955 /* y is z's right node: set left will just update y */
956 set_left(rbtree
, y
, z
->_left
);
957 rcu_rbtree_transplant(rbtree
, z
, y
, 1, NULL
);
959 struct rcu_rbtree_node
*oy_right
, *z_right
;
962 * Need to make sure y is always visible by readers.
964 y
= rcu_rbtree_min_dup_decay(rbtree
, z
->_right
, &z_right
);
965 assert(!is_decay(y
));
966 assert(!is_decay(z
));
967 oy_right
= y
->_right
;
970 * The max child begin of z_right does not change, because
971 * we're only changing its left children.
974 set_parent(y
->_right
, y
, IS_RIGHT
);
975 assert(!is_decay(z
->_left
));
977 assert(!is_decay(oy_right
));
979 * Transplant of oy_right to old y's location will only
980 * trigger a "end" value update of the already copied branch
981 * (which is not visible yet). We are transplanting
982 * oy_right as a left child of old y's parent, so the
983 * min values update propagated upward necessarily stops
986 rcu_rbtree_transplant(rbtree
, y
, oy_right
, 0, y
);
987 rcu_rbtree_transplant(rbtree
, z
, y
, 1, NULL
);
988 /* Update children */
989 (void) rcu_rbtree_min_update_decay(rbtree
, y
->_right
);
992 assert(!is_decay(z
));
993 assert(!is_decay(z
->_left
));
995 set_parent(y
->_left
, y
, IS_LEFT
);
996 set_parent(y
->_right
, get_decay(get_parent(y
->_right
)), IS_RIGHT
);
997 assert(!is_decay(y
->_left
));
998 assert(!is_decay(y
->_right
));
1001 int rcu_rbtree_remove(struct rcu_rbtree
*rbtree
,
1002 struct rcu_rbtree_node
*z
)
1004 struct rcu_rbtree_node
*x
, *y
;
1005 unsigned int y_original_color
;
1007 assert(!is_decay(rbtree
->root
));
1008 dbg_printf("remove %p\n", z
->begin
);
1011 assert(!is_decay(z
));
1013 y_original_color
= y
->color
;
1015 if (rcu_rbtree_is_nil(rbtree
, z
->_left
)) {
1016 rcu_rbtree_transplant(rbtree
, z
, z
->_right
, 1, NULL
);
1017 assert(!is_decay(z
));
1018 x
= get_decay(z
->_right
);
1020 } else if (rcu_rbtree_is_nil(rbtree
, z
->_right
)) {
1021 rcu_rbtree_transplant(rbtree
, z
, z
->_left
, 1, NULL
);
1022 assert(!is_decay(z
));
1023 x
= get_decay(z
->_left
);
1026 y
= rcu_rbtree_min(rbtree
, z
->_right
);
1027 assert(!is_decay(y
));
1028 y_original_color
= y
->color
;
1030 rcu_rbtree_remove_nonil(rbtree
, z
, y
);
1034 if (y_original_color
== COLOR_BLACK
)
1035 rcu_rbtree_remove_fixup(rbtree
, x
);
1038 * Commit all _CMM_STORE_SHARED().