From: Mathieu Desnoyers Date: Thu, 2 Jun 2011 02:22:51 +0000 (-0400) Subject: rbtree: Add end recalculation for transplant X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=fcb4eea806d6bf54a7cc1374c734d99a2a0b4adf;p=userspace-rcu.git rbtree: Add end recalculation for transplant Use a "propagation stop" trick to stop propagation of end update within the branch we are working on. Signed-off-by: Mathieu Desnoyers --- diff --git a/urcu-rbtree.c b/urcu-rbtree.c index 459bf70..d225729 100644 --- a/urcu-rbtree.c +++ b/urcu-rbtree.c @@ -193,13 +193,12 @@ void show_tree(struct rcu_rbtree *rbtree) node = rcu_rbtree_min(rbtree, rbtree->root); while (!rcu_rbtree_is_nil(rbtree, node)) { assert(!is_decay(node)); - printf("{ b:%lX e:%lX pb: %lX pe: %lX r:%lX l:%lX %s %s %s} ", + printf("{ b:%lX e:%lX pb: %lX r:%lX l:%lX %s %s %s} ", (unsigned long) node->begin, (unsigned long) node->end, (unsigned long) get_parent(node)->begin, - (unsigned long) get_parent(node)->end, - (unsigned long) node->_right->key, - (unsigned long) node->_left->key, + (unsigned long) node->_right->begin, + (unsigned long) node->_left->begin, node->color ? "red" : "black", get_pos(node) ? "right" : "left", rcu_rbtree_is_nil(rbtree, node) ? "nil" : ""); @@ -372,13 +371,14 @@ struct rcu_rbtree_node *rcu_rbtree_prev(struct rcu_rbtree *rbtree, */ static void populate_node_end(struct rcu_rbtree *rbtree, struct rcu_rbtree_node *node, - unsigned int copy) + unsigned int copy_parents, struct rcu_rbtree_node *stop) { struct rcu_rbtree_node *prev = NULL, *orig_node = node, *top; do { void *max_end; + assert(node); assert(!rcu_rbtree_is_nil(rbtree, node)); max_end = node->end; if (!rcu_rbtree_is_nil(rbtree, node->_right)) @@ -387,7 +387,7 @@ void populate_node_end(struct rcu_rbtree *rbtree, struct rcu_rbtree_node *node, max_end = max(max_end, node->_left->max_end); if (max_end != node->max_end) { - if (prev && copy) { + if (prev && copy_parents) { node = dup_decay_node(rbtree, node); if (get_pos(prev) == IS_RIGHT) node->_right = prev; @@ -417,8 +417,14 @@ void populate_node_end(struct rcu_rbtree *rbtree, struct rcu_rbtree_node *node, _CMM_STORE_SHARED(top->_right, node); goto end; } + + /* Check for propagation stop */ + if (node == stop) + return; + prev = node; - } while (!rcu_rbtree_is_nil(rbtree, node = get_parent(node))); + node = get_parent(node); + } while (!rcu_rbtree_is_nil(rbtree, node)); top = node; /* nil */ cmm_smp_wmb(); /* write into node before publish */ @@ -426,6 +432,8 @@ void populate_node_end(struct rcu_rbtree *rbtree, struct rcu_rbtree_node *node, _CMM_STORE_SHARED(rbtree->root, prev); end: + if (!copy_parents) + return; /* update children */ node = orig_node; do { @@ -747,7 +755,7 @@ int rcu_rbtree_insert(struct rcu_rbtree *rbtree, _CMM_STORE_SHARED(y->_left, z); else _CMM_STORE_SHARED(y->_right, z); - populate_node_end(rbtree, y, 1); + populate_node_end(rbtree, y, 1, NULL); } else { y = dup_decay_node(rbtree, y); set_parent(z, y, IS_RIGHT); @@ -755,7 +763,7 @@ int rcu_rbtree_insert(struct rcu_rbtree *rbtree, _CMM_STORE_SHARED(y->_left, z); else _CMM_STORE_SHARED(y->_right, z); - populate_node_end(rbtree, y, 1); + populate_node_end(rbtree, y, 1, NULL); } rcu_rbtree_insert_fixup(rbtree, z); /* @@ -777,7 +785,8 @@ static void rcu_rbtree_transplant(struct rcu_rbtree *rbtree, struct rcu_rbtree_node *u, struct rcu_rbtree_node *v, - unsigned int copy_parents) + unsigned int copy_parents, + struct rcu_rbtree_node *stop) { dbg_printf("transplant %p\n", v->begin); @@ -790,15 +799,17 @@ void rcu_rbtree_transplant(struct rcu_rbtree *rbtree, cmm_smp_wmb(); /* write into node before publish */ _CMM_STORE_SHARED(rbtree->root, v); } else { - set_parent(v, get_parent(u), get_pos(u)); - cmm_smp_wmb(); /* write into node before publish */ - - if (rcu_rbtree_is_nil(rbtree, get_parent(u))) - _CMM_STORE_SHARED(rbtree->root, v); - else if (get_pos(u) == IS_LEFT) - _CMM_STORE_SHARED(get_parent(u)->_left, v); + struct rcu_rbtree_node *vp; + + vp = get_parent(u); + if (copy_parents) + vp = dup_decay_node(rbtree, vp); + set_parent(v, vp, get_pos(u)); + if (get_pos(v) == IS_LEFT) + _CMM_STORE_SHARED(vp->_left, v); else - _CMM_STORE_SHARED(get_parent(u)->_right, v); + _CMM_STORE_SHARED(vp->_right, v); + populate_node_end(rbtree, vp, copy_parents, stop); } /* Point children to new copy (parent only used by updates/next/prev) */ @@ -818,7 +829,8 @@ static void rcu_rbtree_transplant(struct rcu_rbtree *rbtree, struct rcu_rbtree_node *u, struct rcu_rbtree_node *v, - unsigned int copy_parents) + unsigned int copy_parents, + struct rcu_rbtree_node *stop) { dbg_printf("transplant %p\n", v->begin); @@ -942,7 +954,7 @@ void rcu_rbtree_remove_nonil(struct rcu_rbtree *rbtree, set_parent(x, y, get_pos(x)); /* parent for nil */ /* y is z's right node: set left will just update y */ set_left(rbtree, y, z->_left); - rcu_rbtree_transplant(rbtree, z, y, 1); + rcu_rbtree_transplant(rbtree, z, y, 1, NULL); } else { struct rcu_rbtree_node *oy_right, *z_right; @@ -965,14 +977,14 @@ void rcu_rbtree_remove_nonil(struct rcu_rbtree *rbtree, assert(!is_decay(oy_right)); /* * Transplant of oy_right to old y's location will only - * trigger a min/max update of the already copied branch + * trigger a "end" value update of the already copied branch * (which is not visible yet). We are transplanting * oy_right as a left child of old y's parent, so the * min values update propagated upward necessarily stops * at z_right. */ - rcu_rbtree_transplant(rbtree, y, oy_right, 0); - rcu_rbtree_transplant(rbtree, z, y, 1); + rcu_rbtree_transplant(rbtree, y, oy_right, 0, y); + rcu_rbtree_transplant(rbtree, z, y, 1, NULL); /* Update children */ (void) rcu_rbtree_min_update_decay(rbtree, y->_right); } @@ -1001,12 +1013,12 @@ int rcu_rbtree_remove(struct rcu_rbtree *rbtree, y_original_color = y->color; if (rcu_rbtree_is_nil(rbtree, z->_left)) { - rcu_rbtree_transplant(rbtree, z, z->_right, 1); + rcu_rbtree_transplant(rbtree, z, z->_right, 1, NULL); assert(!is_decay(z)); x = get_decay(z->_right); show_tree(rbtree); } else if (rcu_rbtree_is_nil(rbtree, z->_right)) { - rcu_rbtree_transplant(rbtree, z, z->_left, 1); + rcu_rbtree_transplant(rbtree, z, z->_left, 1, NULL); assert(!is_decay(z)); x = get_decay(z->_left); show_tree(rbtree);