maple_tree: Don't use mas_extend_null in _mas_store()

mas_extend_null() is too heavy when the nulls are contained within a single node.

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

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index ce4e13738b3a90904aa527bc3d4eff2e7f46ea8d..eb8f549b4537e0a4f9a9c1774d96e7cffb7c24f0 100644 (file)
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -3303,20 +3303,42 @@ static inline void *_mas_store(struct ma_state *mas, void *entry, bool overwrite
        }
 
        if (!entry) {
-               unsigned long rmin, rmax;
                enum maple_type mt = mte_node_type(mas->node);
                unsigned long *pivots = ma_pivots(mas_mn(mas),mt);
+               void **slots = ma_slots(mas_mn(mas), mt);
+               unsigned char offset_end = mas->offset;
+
+               if (!content) {
+                       if (mas->index > r_min)
+                               mas->index = r_min;
+                       if (mas->last < r_max)
+                               mas->last = r_max;
+                       // if this one is null the next and prev are not.
+               } else {
+                       // Check prev slot if we are overwriting the start.
+                       if (mas->index == r_min && mas->offset &&
+                           !slots[mas->offset - 1]) {
+                               mas->offset--;
+                               r_min = mas->index = mas_safe_min(mas, pivots,
+                                                                 mas->offset);
+                               r_max = pivots[mas->offset];
+                       }
 
-               MA_STATE(r_mas, mas->tree, mas->last, mas->last);
-
-               r_mas.offset = mas->offset;
-               r_mas.node = mas->node;
-               mas_node_walk(&r_mas, mte_node_type(r_mas.node), &rmin,
-                             &rmax);
-               mas_extend_null(mas, &r_mas);
-               mas->last = r_mas.last;
-               r_min = mas_safe_min(mas, pivots, mas->offset);
-               r_max = _mas_safe_pivot(mas, pivots, mas->offset, mt);
+                       // Check next slot if we are overwriting the end.
+                       if (mas->last == r_max && !slots[mas->offset + 1]) {
+                               mas->last = pivots[mas->offset + 1];
+                       }
+                       else if (mas->last > r_max) { // expand over this slot if necessary.
+                               unsigned long piv;
+                               do {
+                                       piv = _mas_safe_pivot(mas, pivots,
+                                                             ++offset_end, mt);
+                               } while (mas->last > piv);
+
+                               if (!slots[offset_end])
+                                       mas->last = piv;
+                       }
+               }
        }
 
        end = mas_data_end(mas);