maple_tree: add end of node tracking to the maple state

Analysis of the mas_for_each() iteration showed that there is a
significant time spent finding the end of a node.  This time can be
greatly reduced if the end of the node is cached in the maple state.  Care
must be taken to update & invalidate as necessary.

Link: https://lkml.kernel.org/r/20231101171629.3612299-5-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

include/linux/maple_tree.h

@@ -393,6 +393,7 @@ struct ma_state {
 	unsigned char depth;		/* depth of tree descent during write */
 	unsigned char offset;
 	unsigned char mas_flags;
+	unsigned char end;		/* The end of the node */
 };
 
 struct ma_wr_state {

lib/maple_tree.c

@@ -2841,6 +2841,7 @@ static inline void *mtree_range_walk(struct ma_state *mas)
 			goto dead_node;
 	} while (!ma_is_leaf(type));
 
+	mas->end = end;
 	mas->offset = offset;
 	mas->index = min;
 	mas->last = max;
@@ -3507,6 +3508,7 @@ static noinline_for_kasan int mas_commit_b_node(struct ma_wr_state *wr_mas,
 	mas_replace_node(wr_mas->mas, old_enode);
 reuse_node:
 	mas_update_gap(wr_mas->mas);
+	wr_mas->mas->end = b_end;
 	return 1;
 }
 
@@ -4010,6 +4012,7 @@ static inline bool mas_wr_node_store(struct ma_wr_state *wr_mas,
 	}
 	trace_ma_write(__func__, mas, 0, wr_mas->entry);
 	mas_update_gap(mas);
+	mas->end = new_end;
 	return true;
 }
 
@@ -4190,6 +4193,7 @@ static inline bool mas_wr_append(struct ma_wr_state *wr_mas,
 	if (!wr_mas->content || !wr_mas->entry)
 		mas_update_gap(mas);
 
+	mas->end = new_end;
 	trace_ma_write(__func__, mas, new_end, wr_mas->entry);
 	return  true;
 }
@@ -4428,6 +4432,7 @@ static inline int mas_prev_node(struct ma_state *mas, unsigned long min)
 	if (unlikely(mte_dead_node(mas->node)))
 		return 1;
 
+	mas->end = mas->offset;
 	return 0;
 
 no_entry:
@@ -5074,6 +5079,7 @@ int mas_empty_area(struct ma_state *mas, unsigned long min,
 	if (mas->index < min)
 		mas->index = min;
 	mas->last = mas->index + size - 1;
+	mas->end = mas_data_end(mas);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(mas_empty_area);
@@ -5134,6 +5140,7 @@ int mas_empty_area_rev(struct ma_state *mas, unsigned long min,
 		mas->last = max;
 
 	mas->index = mas->last - size + 1;
+	mas->end = mas_data_end(mas);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(mas_empty_area_rev);

tools/testing/radix-tree/maple.c

@@ -945,6 +945,7 @@ static inline bool mas_tree_walk(struct ma_state *mas, unsigned long *range_min,
 		goto retry;
 	}
 
+	mas->end = mas_data_end(mas);
 	return ret;
 
 not_found: