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/* -*- mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*- */
// vim: ft=cpp:expandtab:ts=8:sw=4:softtabstop=4:
#ident "$Id$"
/*
COPYING CONDITIONS NOTICE:
This program is free software; you can redistribute it and/or modify
it under the terms of version 2 of the GNU General Public License as
published by the Free Software Foundation, and provided that the
following conditions are met:
* Redistributions of source code must retain this COPYING
CONDITIONS NOTICE, the COPYRIGHT NOTICE (below), the
DISCLAIMER (below), the UNIVERSITY PATENT NOTICE (below), the
PATENT MARKING NOTICE (below), and the PATENT RIGHTS
GRANT (below).
* Redistributions in binary form must reproduce this COPYING
CONDITIONS NOTICE, the COPYRIGHT NOTICE (below), the
DISCLAIMER (below), the UNIVERSITY PATENT NOTICE (below), the
PATENT MARKING NOTICE (below), and the PATENT RIGHTS
GRANT (below) in the documentation and/or other materials
provided with the distribution.
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., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301, USA.
COPYRIGHT NOTICE:
TokuFT, Tokutek Fractal Tree Indexing Library.
Copyright (C) 2007-2013 Tokutek, Inc.
DISCLAIMER:
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.
UNIVERSITY PATENT NOTICE:
The technology is licensed by the Massachusetts Institute of
Technology, Rutgers State University of New Jersey, and the Research
Foundation of State University of New York at Stony Brook under
United States of America Serial No. 11/760379 and to the patents
and/or patent applications resulting from it.
PATENT MARKING NOTICE:
This software is covered by US Patent No. 8,185,551.
This software is covered by US Patent No. 8,489,638.
PATENT RIGHTS GRANT:
"THIS IMPLEMENTATION" means the copyrightable works distributed by
Tokutek as part of the Fractal Tree project.
"PATENT CLAIMS" means the claims of patents that are owned or
licensable by Tokutek, both currently or in the future; and that in
the absence of this license would be infringed by THIS
IMPLEMENTATION or by using or running THIS IMPLEMENTATION.
"PATENT CHALLENGE" shall mean a challenge to the validity,
patentability, enforceability and/or non-infringement of any of the
PATENT CLAIMS or otherwise opposing any of the PATENT CLAIMS.
Tokutek hereby grants to you, for the term and geographical scope of
the PATENT CLAIMS, a non-exclusive, no-charge, royalty-free,
irrevocable (except as stated in this section) patent license to
make, have made, use, offer to sell, sell, import, transfer, and
otherwise run, modify, and propagate the contents of THIS
IMPLEMENTATION, where such license applies only to the PATENT
CLAIMS. This grant does not include claims that would be infringed
only as a consequence of further modifications of THIS
IMPLEMENTATION. If you or your agent or licensee institute or order
or agree to the institution of patent litigation against any entity
(including a cross-claim or counterclaim in a lawsuit) alleging that
THIS IMPLEMENTATION constitutes direct or contributory patent
infringement, or inducement of patent infringement, then any rights
granted to you under this License shall terminate as of the date
such litigation is filed. If you or your agent or exclusive
licensee institute or order or agree to the institution of a PATENT
CHALLENGE, then Tokutek may terminate any rights granted to you
under this License.
*/
#ident "Copyright (c) 2007-2013 Tokutek Inc. All rights reserved."
#ident "The technology is licensed by the Massachusetts Institute of Technology, Rutgers State University of New Jersey, and the Research Foundation of State University of New York at Stony Brook under United States of America Serial No. 11/760379 and to the patents and/or patent applications resulting from it."
#include <toku_race_tools.h>
void treenode::mutex_lock(void) {
toku_mutex_lock(&m_mutex);
}
void treenode::mutex_unlock(void) {
toku_mutex_unlock(&m_mutex);
}
void treenode::init(const comparator *cmp) {
m_txnid = TXNID_NONE;
m_is_root = false;
m_is_empty = true;
m_cmp = cmp;
// use an adaptive mutex at each node since we expect the time the
// lock is held to be relatively short compared to a context switch.
// indeed, this improves performance at high thread counts considerably.
memset(&m_mutex, 0, sizeof(toku_mutex_t));
toku_pthread_mutexattr_t attr;
toku_mutexattr_init(&attr);
toku_mutexattr_settype(&attr, TOKU_MUTEX_ADAPTIVE);
toku_mutex_init(&m_mutex, &attr);
toku_mutexattr_destroy(&attr);
m_left_child.set(nullptr);
m_right_child.set(nullptr);
}
void treenode::create_root(const comparator *cmp) {
init(cmp);
m_is_root = true;
}
void treenode::destroy_root(void) {
invariant(is_root());
invariant(is_empty());
toku_mutex_destroy(&m_mutex);
m_cmp = nullptr;
}
void treenode::set_range_and_txnid(const keyrange &range, TXNID txnid) {
// allocates a new copy of the range for this node
m_range.create_copy(range);
m_txnid = txnid;
m_is_empty = false;
}
bool treenode::is_root(void) {
return m_is_root;
}
bool treenode::is_empty(void) {
return m_is_empty;
}
bool treenode::range_overlaps(const keyrange &range) {
return m_range.overlaps(*m_cmp, range);
}
treenode *treenode::alloc(const comparator *cmp, const keyrange &range, TXNID txnid) {
treenode *XCALLOC(node);
node->init(cmp);
node->set_range_and_txnid(range, txnid);
return node;
}
void treenode::swap_in_place(treenode *node1, treenode *node2) {
keyrange tmp_range = node1->m_range;
TXNID tmp_txnid = node1->m_txnid;
node1->m_range = node2->m_range;
node1->m_txnid = node2->m_txnid;
node2->m_range = tmp_range;
node2->m_txnid = tmp_txnid;
}
void treenode::free(treenode *node) {
// destroy the range, freeing any copied keys
node->m_range.destroy();
// the root is simply marked as empty.
if (node->is_root()) {
toku_mutex_assert_locked(&node->m_mutex);
node->m_is_empty = true;
} else {
toku_mutex_assert_unlocked(&node->m_mutex);
toku_mutex_destroy(&node->m_mutex);
toku_free(node);
}
}
uint32_t treenode::get_depth_estimate(void) const {
const uint32_t left_est = m_left_child.depth_est;
const uint32_t right_est = m_right_child.depth_est;
return (left_est > right_est ? left_est : right_est) + 1;
}
treenode *treenode::find_node_with_overlapping_child(const keyrange &range,
const keyrange::comparison *cmp_hint) {
// determine which child to look at based on a comparison. if we were
// given a comparison hint, use that. otherwise, compare them now.
keyrange::comparison c = cmp_hint ? *cmp_hint : range.compare(*m_cmp, m_range);
treenode *child;
if (c == keyrange::comparison::LESS_THAN) {
child = lock_and_rebalance_left();
} else {
// The caller (locked_keyrange::acquire) handles the case where
// the root of the locked_keyrange is the node that overlaps.
// range is guaranteed not to overlap this node.
invariant(c == keyrange::comparison::GREATER_THAN);
child = lock_and_rebalance_right();
}
// if the search would lead us to an empty subtree (child == nullptr),
// or the child overlaps, then we know this node is the parent we want.
// otherwise we need to recur into that child.
if (child == nullptr) {
return this;
} else {
c = range.compare(*m_cmp, child->m_range);
if (c == keyrange::comparison::EQUALS || c == keyrange::comparison::OVERLAPS) {
child->mutex_unlock();
return this;
} else {
// unlock this node before recurring into the locked child,
// passing in a comparison hint since we just comapred range
// to the child's range.
mutex_unlock();
return child->find_node_with_overlapping_child(range, &c);
}
}
}
template <class F>
void treenode::traverse_overlaps(const keyrange &range, F *function) {
keyrange::comparison c = range.compare(*m_cmp, m_range);
if (c == keyrange::comparison::EQUALS) {
// Doesn't matter if fn wants to keep going, there
// is nothing left, so return.
function->fn(m_range, m_txnid);
return;
}
treenode *left = m_left_child.get_locked();
if (left) {
if (c != keyrange::comparison::GREATER_THAN) {
// Target range is less than this node, or it overlaps this
// node. There may be something on the left.
left->traverse_overlaps(range, function);
}
left->mutex_unlock();
}
if (c == keyrange::comparison::OVERLAPS) {
bool keep_going = function->fn(m_range, m_txnid);
if (!keep_going) {
return;
}
}
treenode *right = m_right_child.get_locked();
if (right) {
if (c != keyrange::comparison::LESS_THAN) {
// Target range is greater than this node, or it overlaps this
// node. There may be something on the right.
right->traverse_overlaps(range, function);
}
right->mutex_unlock();
}
}
void treenode::insert(const keyrange &range, TXNID txnid) {
// choose a child to check. if that child is null, then insert the new node there.
// otherwise recur down that child's subtree
keyrange::comparison c = range.compare(*m_cmp, m_range);
if (c == keyrange::comparison::LESS_THAN) {
treenode *left_child = lock_and_rebalance_left();
if (left_child == nullptr) {
left_child = treenode::alloc(m_cmp, range, txnid);
m_left_child.set(left_child);
} else {
left_child->insert(range, txnid);
left_child->mutex_unlock();
}
} else {
invariant(c == keyrange::comparison::GREATER_THAN);
treenode *right_child = lock_and_rebalance_right();
if (right_child == nullptr) {
right_child = treenode::alloc(m_cmp, range, txnid);
m_right_child.set(right_child);
} else {
right_child->insert(range, txnid);
right_child->mutex_unlock();
}
}
}
treenode *treenode::find_child_at_extreme(int direction, treenode **parent) {
treenode *child = direction > 0 ?
m_right_child.get_locked() : m_left_child.get_locked();
if (child) {
*parent = this;
treenode *child_extreme = child->find_child_at_extreme(direction, parent);
child->mutex_unlock();
return child_extreme;
} else {
return this;
}
}
treenode *treenode::find_leftmost_child(treenode **parent) {
return find_child_at_extreme(-1, parent);
}
treenode *treenode::find_rightmost_child(treenode **parent) {
return find_child_at_extreme(1, parent);
}
treenode *treenode::remove_root_of_subtree() {
// if this node has no children, just free it and return null
if (m_left_child.ptr == nullptr && m_right_child.ptr == nullptr) {
// treenode::free requires that non-root nodes are unlocked
if (!is_root()) {
mutex_unlock();
}
treenode::free(this);
return nullptr;
}
// we have a child, so get either the in-order successor or
// predecessor of this node to be our replacement.
// replacement_parent is updated by the find functions as
// they recur down the tree, so initialize it to this.
treenode *child, *replacement;
treenode *replacement_parent = this;
if (m_left_child.ptr != nullptr) {
child = m_left_child.get_locked();
replacement = child->find_rightmost_child(&replacement_parent);
invariant(replacement == child || replacement_parent != this);
// detach the replacement from its parent
if (replacement_parent == this) {
m_left_child = replacement->m_left_child;
} else {
replacement_parent->m_right_child = replacement->m_left_child;
}
} else {
child = m_right_child.get_locked();
replacement = child->find_leftmost_child(&replacement_parent);
invariant(replacement == child || replacement_parent != this);
// detach the replacement from its parent
if (replacement_parent == this) {
m_right_child = replacement->m_right_child;
} else {
replacement_parent->m_left_child = replacement->m_right_child;
}
}
child->mutex_unlock();
// swap in place with the detached replacement, then destroy it
treenode::swap_in_place(replacement, this);
treenode::free(replacement);
return this;
}
void treenode::recursive_remove(void) {
treenode *left = m_left_child.ptr;
if (left) {
left->recursive_remove();
}
m_left_child.set(nullptr);
treenode *right = m_right_child.ptr;
if (right) {
right->recursive_remove();
}
m_right_child.set(nullptr);
// we do not take locks on the way down, so we know non-root nodes
// are unlocked here and the caller is required to pass a locked
// root, so this free is correct.
treenode::free(this);
}
treenode *treenode::remove(const keyrange &range) {
treenode *child;
// if the range is equal to this node's range, then just remove
// the root of this subtree. otherwise search down the tree
// in either the left or right children.
keyrange::comparison c = range.compare(*m_cmp, m_range);
switch (c) {
case keyrange::comparison::EQUALS:
return remove_root_of_subtree();
case keyrange::comparison::LESS_THAN:
child = m_left_child.get_locked();
invariant_notnull(child);
child = child->remove(range);
// unlock the child if there still is one.
// regardless, set the right child pointer
if (child) {
child->mutex_unlock();
}
m_left_child.set(child);
break;
case keyrange::comparison::GREATER_THAN:
child = m_right_child.get_locked();
invariant_notnull(child);
child = child->remove(range);
// unlock the child if there still is one.
// regardless, set the right child pointer
if (child) {
child->mutex_unlock();
}
m_right_child.set(child);
break;
case keyrange::comparison::OVERLAPS:
// shouldn't be overlapping, since the tree is
// non-overlapping and this range must exist
abort();
}
return this;
}
bool treenode::left_imbalanced(int threshold) const {
uint32_t left_depth = m_left_child.depth_est;
uint32_t right_depth = m_right_child.depth_est;
return m_left_child.ptr != nullptr && left_depth > threshold + right_depth;
}
bool treenode::right_imbalanced(int threshold) const {
uint32_t left_depth = m_left_child.depth_est;
uint32_t right_depth = m_right_child.depth_est;
return m_right_child.ptr != nullptr && right_depth > threshold + left_depth;
}
// effect: rebalances the subtree rooted at this node
// using AVL style O(1) rotations. unlocks this
// node if it is not the new root of the subtree.
// requires: node is locked by this thread, children are not
// returns: locked root node of the rebalanced tree
treenode *treenode::maybe_rebalance(void) {
// if we end up not rotating at all, the new root is this
treenode *new_root = this;
treenode *child = nullptr;
if (left_imbalanced(IMBALANCE_THRESHOLD)) {
child = m_left_child.get_locked();
if (child->right_imbalanced(0)) {
treenode *grandchild = child->m_right_child.get_locked();
child->m_right_child = grandchild->m_left_child;
grandchild->m_left_child.set(child);
m_left_child = grandchild->m_right_child;
grandchild->m_right_child.set(this);
new_root = grandchild;
} else {
m_left_child = child->m_right_child;
child->m_right_child.set(this);
new_root = child;
}
} else if (right_imbalanced(IMBALANCE_THRESHOLD)) {
child = m_right_child.get_locked();
if (child->left_imbalanced(0)) {
treenode *grandchild = child->m_left_child.get_locked();
child->m_left_child = grandchild->m_right_child;
grandchild->m_right_child.set(child);
m_right_child = grandchild->m_left_child;
grandchild->m_left_child.set(this);
new_root = grandchild;
} else {
m_right_child = child->m_left_child;
child->m_left_child.set(this);
new_root = child;
}
}
// up to three nodes may be locked.
// - this
// - child
// - grandchild (but if it is locked, its the new root)
//
// one of them is the new root. we unlock everything except the new root.
if (child && child != new_root) {
TOKU_VALGRIND_RESET_MUTEX_ORDERING_INFO(&child->m_mutex);
child->mutex_unlock();
}
if (this != new_root) {
TOKU_VALGRIND_RESET_MUTEX_ORDERING_INFO(&m_mutex);
mutex_unlock();
}
TOKU_VALGRIND_RESET_MUTEX_ORDERING_INFO(&new_root->m_mutex);
return new_root;
}
treenode *treenode::lock_and_rebalance_left(void) {
treenode *child = m_left_child.get_locked();
if (child) {
treenode *new_root = child->maybe_rebalance();
m_left_child.set(new_root);
child = new_root;
}
return child;
}
treenode *treenode::lock_and_rebalance_right(void) {
treenode *child = m_right_child.get_locked();
if (child) {
treenode *new_root = child->maybe_rebalance();
m_right_child.set(new_root);
child = new_root;
}
return child;
}
void treenode::child_ptr::set(treenode *node) {
ptr = node;
depth_est = ptr ? ptr->get_depth_estimate() : 0;
}
treenode *treenode::child_ptr::get_locked(void) {
if (ptr) {
ptr->mutex_lock();
depth_est = ptr->get_depth_estimate();
}
return ptr;
}
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