From: Liam R. Howlett <Liam.Howlett@oracle.com>
Date: Fri, 25 Apr 2025 15:50:07 +0000 (-0400)
Subject: rebalance wip
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=a48b10364816de622898271ae0ce566c3be91f86;p=users%2Fjedix%2Flinux-maple.git

rebalance wip

Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
---

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 14666ff92a4a..d91cd5bfe5b3 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -3801,8 +3801,8 @@ struct split_data {
 	unsigned char split;	/* Proposed split of data */
 	unsigned char insert;	/* Insert location of destination */
 	unsigned char new_end;	/* Total data  */
-	unsigned char src_ins_end;
-	unsigned char len;
+	unsigned char src_ins_end; /* Offset into source data where the write ends */
+	unsigned char len;	/* Number of ma_node_states in the states array */
 	struct ma_node_state states[5];
 };
 
@@ -4072,7 +4072,7 @@ bool mas_wr_try_rebalance(struct ma_state *mas, struct ma_node_info *src,
 	return true;
 }
 
-#if 0
+#if 1
 static void mas_wr_rebalance(struct ma_wr_state *wr_mas)
 {
 	struct ma_state *mas;
@@ -4094,6 +4094,8 @@ static void mas_wr_rebalance(struct ma_wr_state *wr_mas)
 	 * compact to the left side.
 	 */
 	mt_dump(mas->tree, mt_dump_dec);
+	printk("Rebalance %p offset %u\n", mas->node, mas->offset);
+	printk("Store %lu - %lu\n", mas->index, mas->last);
 
 	height = mas_mt_height(mas);
 	mas->depth = height;
@@ -4101,21 +4103,103 @@ static void mas_wr_rebalance(struct ma_wr_state *wr_mas)
 	mni_mas_init(&src, mas);
 	src.end = mas->end;
 
+	mns_node_part_leaf_init(&part, wr_mas, &src);
+	sd.new_end = mas->end + part.size; /* - skip + 1 */
+	sd.src_ins_end = wr_mas->offset_end;
+	sd.len = 0;
+
 	mni_node_init(&left, mas_pop_node(mas), wr_mas->type);
 	if (mt_is_alloc(mas->tree))
 		left.is_alloc = true;
 
 	tmp_mas = *mas;
 	mas_wr_ascend_init(&tmp_mas, &parent);
-	if (mas_wr_try_right(&tmp_mas, &parent, &src2)) {
+	if (can_rebalance_right(&tmp_mas, &parent, &src2, &sd)) {
+		printk("rebalance right, split is %u\n", sd.split);
+		printk("rebalance with %p\n", src2.node);
+		/* Left will be src, right will be src2 */
 		sd.insert = mas->offset;
+		left_store = true;
 	} else {
 		/* Won't fail here */
-		MAS_BUG_ON(try_rebalance_left(&tmp_mas, &parent, &src2));
+		MAS_BUG_ON(mas, can_rebalance_left(&tmp_mas, &parent, &src2, &sd));
+		printk("rebalance left, split is %u\n", sd.split);
+		printk("rebalance with %p\n", src2.node);
+		/* Left will be src2, right will be src */
 		sd.insert = mas->offset + src2.end + 1;
 	}
 
+	sd.new_end += src2.end + 1;
+	if (sd.new_end < mt_min_slots[left.type]) {
+		printk("Not enough tdata\n");
+		exit(0);
+	}
+	if (sd.split < mt_min_slots[left.type]) {
+		printk("Too small split\n");
+		exit(0);
+	}
+	if (sd.new_end - sd.split < mt_min_slots[left.type]) {
+		printk("Too big split\n");
+		exit(0);
+	}
+	printk("Total data is %u\n", sd.new_end);
+	printk("sd insert is %u\n", sd.insert);
+	if (sd.new_end < mt_slots[left.type]) {
+		printk("Shrinking parent\n");
+		//mt_wr_split_data(&src, &left, /* right = */ NULL, &part, &sd);
+		if (parent.end <= mt_min_slots[parent.type])
+			printk("Have to go again\n");
+
+		exit(0);
+		/* Single entry replacing two, may need to rebalance again */
+	}
+
+	mni_node_init(&right, mas_pop_node(mas), wr_mas->type);
+	if (!left_store) {
+		printk("store right\n");
+		left.min = src2.min;
+		right.max = src.max;
+		sd.offset = src2.end + 1;
+		sd.space = sd.split - src2.end;
+		sd.states[sd.len].info = &src2;
+		/* The first state to copy is the left node */
+		mns_mni_init(&sd.states[sd.len], &left, 0, src2.end + 1);
+		sd.len++;
+	} else {
+		printk("store left\n");
+		sd.space = sd.split;
+		sd.offset = 0;
+		left.min = src.min;
+		right.max = src2.max;
+	}
+
+	mt_wr_split_data(&src, &left, &right, &part, &sd);
+	if (left_store) {
+		/* Stored to the left, copy the last of the right in src2 */
+		sd.states[sd.len].info = &src2;
+		mns_mni_init(&sd.states[sd.len], &right, 0, src2.end + 1);
+		sd.len++;
+	}
+
+	mns_assemble(sd.states, sd.len);
+	mni_finalise(&left);
+	mni_finalise(&right);
+	mni_node_part_init(&part, &left, &right);
+	mas_ascend(mas);
+	mas->end = parent.end;
+	mas->offset = parent.insert_off;
+	part.skip = 2;
+	mas_wr_converged(&parent, &new_parent, &part, mas, &sd);
+	src.enode = parent.enode;
+	printk("Replace %p\n", parent.node);
+	mas->node = new_parent.enode;
+	mas_wmb_replace(mas, src.enode);
+	mtree_range_walk(mas);
+	mt_dump(mas->tree, mt_dump_dec);
+	mt_validate(mas->tree);
+	return;
 
+	exit(0);
 	/*
 	 * allocate left
 	 * set alloc in left
@@ -4272,6 +4356,7 @@ replace_node:
 	mas_wmb_replace(mas, src.enode);
 	mtree_range_walk(mas);
 	mt_dump(mas->tree, mt_dump_dec);
+	mt_validate(mas->tree);
 }
 #endif
 
@@ -5232,8 +5317,8 @@ static inline void mas_wr_store_entry(struct ma_wr_state *wr_mas)
 		mas_wr_split(wr_mas);
 		break;
 	case wr_rebalance:
-		mas_wr_bnode(wr_mas);
-		//mas_wr_rebalance(wr_mas);
+		//mas_wr_bnode(wr_mas);
+		mas_wr_rebalance(wr_mas);
 		break;
 	case wr_exact_fit:
 		rcu_assign_pointer(wr_mas->slots[mas->offset], wr_mas->entry);