Add member functions to get and set btree internal node child refs that will

use relaxed memory order instead of acquire and release.

5 files changed, 24 insertions, 22 deletions

diff --git a/vespalib/src/vespa/vespalib/btree/btreebuilder.hpp b/vespalib/src/vespa/vespalib/btree/btreebuilder.hpp
index 5abe2b2cebd..3162dfb4820 100644
--- a/vespalib/src/vespa/vespalib/btree/btreebuilder.hpp
+++ b/vespalib/src/vespa/vespalib/btree/btreebuilder.hpp
@@ -106,10 +106,10 @@ normalize()
     /* Adjust validLeaves for rightmost nodes */
     for (level = 0; level < _inodes.size(); level++) {
         InternalNodeType *inode = _inodes[level].data;
-        NodeRef lcRef(inode->getLastChild());
+        NodeRef lcRef(inode->get_last_child_relaxed());
         assert(NodeAllocatorType::isValidRef(lcRef));
         assert((level == 0) == _allocator.isLeafRef(lcRef));
-        inode->incValidLeaves(_allocator.validLeaves(inode->getLastChild()));
+        inode->incValidLeaves(_allocator.validLeaves(inode->get_last_child_relaxed()));
         inode->update(inode->validSlots() - 1,
                       level == 0 ?
                       _allocator.mapLeafRef(lcRef)->getLastKey() :
@@ -134,10 +134,10 @@ normalize()
             inode = _allocator.mapInternalRef(iRef);
             assert(inode != nullptr);
             assert(inode->validSlots() >= 1);
-            child = inode->getLastChild();
+            child = inode->get_last_child_relaxed();
         } else {
             /* Use next to last child of rightmost node on level */
-            child = inode->getChild(inode->validSlots() - 2);
+            child = inode->get_child_relaxed(inode->validSlots() - 2);
         }
         if (level == 0)
             break;
@@ -190,11 +190,11 @@ normalize()
         }
         if (pnode->validSlots() > 0) {
             uint32_t s = pnode->validSlots() - 1;
-            LeafNodeType *l = _allocator.mapLeafRef(pnode->getChild(s));
+            LeafNodeType *l = _allocator.mapLeafRef(pnode->get_child_relaxed(s));
             pnode->writeKey(s, l->getLastKey());
             if (s > 0) {
                 --s;
-                l = _allocator.mapLeafRef(pnode->getChild(s));
+                l = _allocator.mapLeafRef(pnode->get_child_relaxed(s));
                 pnode->writeKey(s, l->getLastKey());
             }
         }
@@ -202,7 +202,7 @@ normalize()
             InternalNodeType *lpnode =
                 _allocator.mapInternalRef(leftInodes[0]);
             uint32_t s = lpnode->validSlots() - 1;
-            LeafNodeType *l = _allocator.mapLeafRef(lpnode->getChild(s));
+            LeafNodeType *l = _allocator.mapLeafRef(lpnode->get_child_relaxed(s));
             lpnode->writeKey(s, l->getLastKey());
         }
     }
@@ -256,11 +256,11 @@ normalize()
         if (pnode->validSlots() > 0) {
             uint32_t s = pnode->validSlots() - 1;
             InternalNodeType *n =
-                _allocator.mapInternalRef(pnode->getChild(s));
+                _allocator.mapInternalRef(pnode->get_child_relaxed(s));
             pnode->writeKey(s, n->getLastKey());
             if (s > 0) {
                 --s;
-                n = _allocator.mapInternalRef(pnode->getChild(s));
+                n = _allocator.mapInternalRef(pnode->get_child_relaxed(s));
                 pnode->writeKey(s, n->getLastKey());
             }
         }
@@ -270,7 +270,7 @@ normalize()
                 _allocator.mapInternalRef(leftInodes[level + 1]);
             uint32_t s = lpnode->validSlots() - 1;
             InternalNodeType *n =
-                _allocator.mapInternalRef(lpnode->getChild(s));
+                _allocator.mapInternalRef(lpnode->get_child_relaxed(s));
             lpnode->writeKey(s, n->getLastKey());
         }
     }
@@ -333,7 +333,7 @@ allocNewLeafNode()
         }
         inode = _inodes[level].data;
         assert(inode->validSlots() > 0);
-        NodeRef lcRef(inode->getLastChild());
+        NodeRef lcRef(inode->get_last_child_relaxed());
         inode->incValidLeaves(_allocator.validLeaves(lcRef));
         inode->update(inode->validSlots() - 1,
                       level == 0 ?
@@ -358,7 +358,7 @@ allocNewLeafNode()
     }
     while (level > 0) {
         assert(inode->validSlots() > 0);
-        child = inode->getLastChild();
+        child = inode->get_last_child_relaxed();
         assert(!_allocator.isLeafRef(child));
         inode = _allocator.mapInternalRef(child);
         level--;
diff --git a/vespalib/src/vespa/vespalib/btree/btreeinserter.hpp b/vespalib/src/vespa/vespalib/btree/btreeinserter.hpp
index b5980e53f93..de6454f8bae 100644
--- a/vespalib/src/vespa/vespalib/btree/btreeinserter.hpp
+++ b/vespalib/src/vespa/vespalib/btree/btreeinserter.hpp
@@ -34,17 +34,17 @@ BTreeInserter<KeyT, DataT, AggrT, CompareT, TraitsT, AggrCalcT>::rebalanceLeafEn
     auto &pathElem = itr.getPath(0);
     InternalNodeType *parentNode = pathElem.getWNode();
     uint32_t parentIdx = pathElem.getIdx();
-    BTreeNode::Ref leafRef = parentNode->getChild(parentIdx);
+    BTreeNode::Ref leafRef = parentNode->get_child_relaxed(parentIdx);
     BTreeNode::Ref leftRef = BTreeNode::Ref();
     LeafNodeType *leftNode = nullptr;
     BTreeNode::Ref rightRef = BTreeNode::Ref();
     LeafNodeType *rightNode = nullptr;
     if (parentIdx > 0) {
-        leftRef = parentNode->getChild(parentIdx - 1);
+        leftRef = parentNode->get_child_relaxed(parentIdx - 1);
         leftNode = allocator.mapLeafRef(leftRef);
     }
     if (parentIdx + 1 < parentNode->validSlots()) {
-        rightRef = parentNode->getChild(parentIdx + 1);
+        rightRef = parentNode->get_child_relaxed(parentIdx + 1);
         rightNode = allocator.mapLeafRef(rightRef);
     }
     if (leftNode != nullptr && leftNode->validSlots() < LeafNodeType::maxSlots() &&
@@ -138,7 +138,7 @@ insert(BTreeNode::Ref &root,
         idx = pe.getIdx();
         AggrT olda(AggrCalcT::hasAggregated() ?
                    node->getAggregated() : AggrT());
-        BTreeNode::Ref subNode = node->getChild(idx);
+        BTreeNode::Ref subNode = node->get_child_relaxed(idx);
         node->update(idx, *lastKey, subNode);
         node->incValidLeaves(1);
         if (NodeAllocatorType::isValidRef(splitNodeRef)) {
diff --git a/vespalib/src/vespa/vespalib/btree/btreeiterator.hpp b/vespalib/src/vespa/vespalib/btree/btreeiterator.hpp
index 042779f1b1b..8ecd26835c4 100644
--- a/vespalib/src/vespa/vespalib/btree/btreeiterator.hpp
+++ b/vespalib/src/vespa/vespalib/btree/btreeiterator.hpp
@@ -1163,13 +1163,13 @@ thaw(BTreeNode::Ref rootRef)
                                  rootRef;
         assert(node == allocator.mapInternalRef(nodeRef));
         if (!node->getFrozen()) {
-            node->setChild(pe.getIdx(), childRef);
+            node->set_child_relaxed(pe.getIdx(), childRef);
             return rootRef;
         }
         InternalNodeTypeRefPair thawed = allocator.thawNode(nodeRef, node);
         node = thawed.data;
         pe.setNode(node);
-        node->setChild(pe.getIdx(), childRef);
+        node->set_child_relaxed(pe.getIdx(), childRef);
         childRef = thawed.ref;
         ++level;
     }
diff --git a/vespalib/src/vespa/vespalib/btree/btreenode.h b/vespalib/src/vespa/vespalib/btree/btreenode.h
index 468f17fcd1a..deeaad40ae6 100644
--- a/vespalib/src/vespa/vespalib/btree/btreenode.h
+++ b/vespalib/src/vespa/vespalib/btree/btreenode.h
@@ -336,8 +336,10 @@ private:
 
 public:
     BTreeNode::Ref getChild(uint32_t idx) const { return getData(idx); }
+    BTreeNode::Ref get_child_relaxed(uint32_t idx) const { return getData(idx); }
     void setChild(uint32_t idx, BTreeNode::Ref child) { setData(idx, child); }
-    BTreeNode::Ref getLastChild() const { return getChild(validSlots() - 1); }
+    void set_child_relaxed(uint32_t idx, BTreeNode::Ref child) { setData(idx, child); }
+    BTreeNode::Ref get_last_child_relaxed() const { return get_child_relaxed(validSlots() - 1); }
     uint32_t validLeaves() const { return _validLeaves; }
     void setValidLeaves(uint32_t newValidLeaves) { _validLeaves = newValidLeaves; }
     void incValidLeaves(uint32_t delta) { _validLeaves += delta; }
diff --git a/vespalib/src/vespa/vespalib/btree/btreeremover.hpp b/vespalib/src/vespa/vespalib/btree/btreeremover.hpp
index e0e41c1dd2d..24155abcff9 100644
--- a/vespalib/src/vespa/vespalib/btree/btreeremover.hpp
+++ b/vespalib/src/vespa/vespalib/btree/btreeremover.hpp
@@ -25,11 +25,11 @@ steal(InternalNodeType *pNode,
     BTreeNode::Ref rightVictimRef = BTreeNode::Ref();
     NodeType * rightVictim = nullptr;
     if (idx > 0) {
-        leftVictimRef = pNode->getChild(idx - 1);
+        leftVictimRef = pNode->get_child_relaxed(idx - 1);
         leftVictim = allocator.template mapRef<NodeType>(leftVictimRef);
     }
     if (idx + 1 < pNode->validSlots()) {
-        rightVictimRef = pNode->getChild(idx + 1);
+        rightVictimRef = pNode->get_child_relaxed(idx + 1);
         rightVictim = allocator.template mapRef<NodeType>(rightVictimRef);
     }
     if (leftVictim != nullptr &&
@@ -141,7 +141,7 @@ remove(BTreeNode::Ref &root,
         idx = pe.getIdx();
         AggrT olda(AggrCalcT::hasAggregated() ?
                    node->getAggregated() : AggrT());
-        BTreeNode::Ref subNode = node->getChild(idx);
+        BTreeNode::Ref subNode = node->get_child_relaxed(idx);
         node->update(idx, allocator.getLastKey(subNode), subNode);
         node->decValidLeaves(1);
         if (level == 0) {