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Removed free node / leaf pools in index_tree
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@josephg
josephg committed Aug 7, 2024
1 parent 7b74fb7 commit 2fddbf4
Showing 1 changed file with 83 additions and 91 deletions.
174 changes: 83 additions & 91 deletions src/ost/index_tree.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -17,14 +17,14 @@ use crate::ost::{LEAF_CHILDREN, LeafIdx, NODE_CHILDREN, NodeIdx, remove_from_arr
pub(crate) struct IndexTree<V: Copy> {
leaves: Vec<IndexLeaf<V>>,
nodes: Vec<IndexNode>,
// upper_bound: LV,

height: usize,
root: usize,
cursor: Cell<(LV, IndexCursor)>,

// Linked lists.
free_leaf_pool_head: LeafIdx,
free_node_pool_head: NodeIdx,
// free_leaf_pool_head: LeafIdx,
// free_node_pool_head: NodeIdx,
}

#[derive(Debug, Clone, Copy)]
Expand Down Expand Up @@ -191,12 +191,11 @@ impl<V: Default + IndexContent> IndexTree<V> {
Self {
leaves: vec![initial_root_leaf()],
nodes: vec![],
// upper_bound: 0,
height: 0,
root: 0,
cursor: Default::default(),
free_leaf_pool_head: LeafIdx(usize::MAX),
free_node_pool_head: NodeIdx(usize::MAX),
// free_leaf_pool_head: LeafIdx(usize::MAX),
// free_node_pool_head: NodeIdx(usize::MAX),
}
}

Expand All @@ -206,8 +205,8 @@ impl<V: Default + IndexContent> IndexTree<V> {
self.height = 0;
self.root = 0;
self.cursor = Default::default();
self.free_leaf_pool_head = LeafIdx(usize::MAX);
self.free_node_pool_head = NodeIdx(usize::MAX);
// self.free_leaf_pool_head = LeafIdx(usize::MAX);
// self.free_node_pool_head = NodeIdx(usize::MAX);

self.leaves.push(initial_root_leaf());
}
Expand Down Expand Up @@ -761,54 +760,55 @@ impl<V: Default + IndexContent> IndexTree<V> {
// *leaf_pool_head = leaf_idx;
// }

fn discard_leaf(&mut self, leaf_idx: LeafIdx) {
// println!("Discard leaf {:?}", leaf_idx);

// Self::discard_leaf_internal(&mut self.leaves, &mut self.free_leaf_pool_head, leaf_idx);
let leaf = &mut self.leaves[leaf_idx.0];
leaf.next_leaf = self.free_leaf_pool_head;
self.free_leaf_pool_head = leaf_idx;

if cfg!(debug_assertions) {
// Make sure discarded leaves aren't added multiple times to the discard queue.
assert_ne!(leaf.parent, NodeIdx(0xfefe));
leaf.parent = NodeIdx(0xfefe);
}
}

fn discard_node(&mut self, idx: usize, height: usize) {
if height == 0 {
self.discard_leaf(LeafIdx(idx));
} else {
// println!("DISCARD NODE {idx}");
// Move it to the free list.
let node = &mut self.nodes[idx];
node.parent = self.free_node_pool_head;
self.free_node_pool_head = NodeIdx(idx);

let old_children = mem::replace(&mut node.children, [EMPTY_NODE_CHILD; NODE_CHILDREN]);

for (_, child_idx) in old_children {
if child_idx == usize::MAX { break; }
self.discard_node(child_idx, height - 1);
}
}
}

fn remove_and_queue_node_children(&mut self, node_idx: NodeIdx, child_range: Range<usize>, height: usize) {
// This is horrible.
for i in child_range.clone() {
// TODO: Benchmark this against just copying out the children we care about.
let child_idx = self.nodes[node_idx.0].children[i].1; // boooo.
self.discard_node(child_idx, height - 1);
}
// Bleh. I want to do this but the borrowck suuucks.
// for (_, idx) in &node.children[..keep_child_idx] {
// self.discard_node(*idx, height - 1);
// }
// fn discard_leaf(&mut self, leaf_idx: LeafIdx) {
// // println!("Discard leaf {:?}", leaf_idx);
//
// // Self::discard_leaf_internal(&mut self.leaves, &mut self.free_leaf_pool_head, leaf_idx);
// let leaf = &mut self.leaves[leaf_idx.0];
// leaf.next_leaf = self.free_leaf_pool_head;
// self.free_leaf_pool_head = leaf_idx;
//
// if cfg!(debug_assertions) {
// // Make sure discarded leaves aren't added multiple times to the discard queue.
// assert_ne!(leaf.parent, NodeIdx(0xfefe));
// leaf.parent = NodeIdx(0xfefe);
// }
// }

self.nodes[node_idx.0].remove_children(child_range);
}
// fn discard_node(&mut self, idx: usize, height: usize) {
// if height == 0 {
// self.discard_leaf(LeafIdx(idx));
// } else {
// // println!("DISCARD NODE {idx}");
// // Move it to the free list.
// let node = &mut self.nodes[idx];
// node.parent = self.free_node_pool_head;
// self.free_node_pool_head = NodeIdx(idx);
//
// let old_children = mem::replace(&mut node.children, [EMPTY_NODE_CHILD; NODE_CHILDREN]);
//
// for (_, child_idx) in old_children {
// if child_idx == usize::MAX { break; }
// self.discard_node(child_idx, height - 1);
// }
// }
// }
//
// fn remove_and_queue_node_children(&mut self, node_idx: NodeIdx, child_range: Range<usize>, _height: usize) {
// // This is horrible.
// // for i in child_range.clone() {
// // // TODO: Benchmark this against just copying out the children we care about.
// // let child_idx = self.nodes[node_idx.0].children[i].1; // boooo.
// // self.discard_node(child_idx, height - 1);
// // }
//
// // Bleh. I want to do this but the borrowck suuucks.
// // for (_, idx) in &node.children[..keep_child_idx] {
// // self.discard_node(*idx, height - 1);
// // }
//
// self.nodes[node_idx.0].remove_children(child_range);
// }

fn trim_node_start(&mut self, mut idx: usize, end: LV, mut height: usize) -> LeafIdx {
while height > 0 {
Expand All @@ -824,16 +824,8 @@ impl<V: Default + IndexContent> IndexTree<V> {
}

if keep_child_idx >= 1 {
self.remove_and_queue_node_children(NodeIdx(idx), 0..keep_child_idx, height);
// for i in 0..keep_child_idx {
// // TODO: Benchmark this against just copying out the children we care about.
// let child_idx = self.nodes[idx].children[i].1; // boooo.
// self.discard_node(child_idx, height - 1);
// }
// node = &mut self.nodes[idx];
// node.remove_children(0..keep_child_idx);

node = &mut self.nodes[idx]; // borrowck.
// Remove children and move the rest to the start of the array.
node.remove_children(0..keep_child_idx);
}

node.children[0].0 = end;
Expand Down Expand Up @@ -927,7 +919,7 @@ impl<V: Default + IndexContent> IndexTree<V> {
return self.trim_node_start(child_idx, end, height - 1);
} else {
// Remove this child.
self.discard_node(child_idx, height - 1);
// self.discard_node(child_idx, height - 1);
}

// Borrowck.
Expand Down Expand Up @@ -1285,24 +1277,24 @@ impl<V: Default + IndexContent> IndexTree<V> {
count
}

/// returns number of internal nodes, leaves.
pub fn count_obj_pool(&self) -> (usize, usize) {
let mut nodes = 0;
let mut leaves = 0;

let mut idx = self.free_node_pool_head;
while idx.0 != usize::MAX {
nodes += 1;
idx = self.nodes[idx.0].parent;
}
let mut idx = self.free_leaf_pool_head;
while idx.0 != usize::MAX {
leaves += 1;
idx = self.leaves[idx.0].next_leaf;
}

(nodes, leaves)
}
// /// returns number of internal nodes, leaves.
// pub fn count_obj_pool(&self) -> (usize, usize) {
// let mut nodes = 0;
// let mut leaves = 0;
//
// let mut idx = self.free_node_pool_head;
// while idx.0 != usize::MAX {
// nodes += 1;
// idx = self.nodes[idx.0].parent;
// }
// let mut idx = self.free_leaf_pool_head;
// while idx.0 != usize::MAX {
// leaves += 1;
// idx = self.leaves[idx.0].next_leaf;
// }
//
// (nodes, leaves)
// }

/// Iterate over the contents of the index. Note the index tree may contain extra entries
/// for items within the range, with a value of V::default.
Expand Down Expand Up @@ -1422,13 +1414,13 @@ impl<V: Default + IndexContent> IndexTree<V> {
leaf_idx = leaf.next_leaf;
}

let mut leaf_pool_size = 0;
let mut i = self.free_leaf_pool_head;
while i.0 != usize::MAX {
leaf_pool_size += 1;
i = self.leaves[i.0].next_leaf;
}
assert_eq!(leaves_visited + leaf_pool_size, self.leaves.len());
// let mut leaf_pool_size = 0;
// let mut i = self.free_leaf_pool_head;
// while i.0 != usize::MAX {
// leaf_pool_size += 1;
// i = self.leaves[i.0].next_leaf;
// }
// assert_eq!(leaves_visited + leaf_pool_size, self.leaves.len());

if self.height == 0 {
assert!(self.root < self.leaves.len());
Expand Down

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