On 9/24/24 9:04 PM, Wei Yang wrote:
On Wed, Aug 14, 2024 at 12:19:31PM -0400, Sidhartha Kumar wrote:
Sorry for a late reply, I just see this change.
+
+/*
+ * mas_wr_store_type() - Set the store type for a given
+ * store operation.
+ * @wr_mas: The maple write state
+ */
+static inline void mas_wr_store_type(struct ma_wr_state *wr_mas)
+{
+ struct ma_state *mas = wr_mas->mas;
+ unsigned char new_end;
+
+ if (unlikely(mas_is_none(mas) || mas_is_ptr(mas))) {
+ mas->store_type = wr_store_root;
+ return;
+ }
+
+ if (unlikely(!mas_wr_walk(wr_mas))) {
+ mas->store_type = wr_spanning_store;
+ return;
+ }
+
+ /* At this point, we are at the leaf node that needs to be altered. */
+ mas_wr_end_piv(wr_mas);
+ if (!wr_mas->entry)
+ mas_wr_extend_null(wr_mas);
+
+ new_end = mas_wr_new_end(wr_mas);
+ if ((wr_mas->r_min == mas->index) && (wr_mas->r_max == mas->last)) {
+ mas->store_type = wr_exact_fit;
+ return;
+ }
+
+ if (unlikely(!mas->index && mas->last == ULONG_MAX)) {
+ mas->store_type = wr_new_root;
+ return;
+ }
+
+ /* Potential spanning rebalance collapsing a node */
+ if (new_end < mt_min_slots[wr_mas->type]) {
+ if (!mte_is_root(mas->node)) {
+ mas->store_type = wr_rebalance;
+ return;
+ }
+ mas->store_type = wr_node_store;
+ return;
+ }
After this check, we are sure new_end >= mt_min_slots[wr_mas->type].
+
+ if (new_end >= mt_slots[wr_mas->type]) {
+ mas->store_type = wr_split_store;
+ return;
+ }
+
+ if (!mt_in_rcu(mas->tree) && (mas->offset == mas->end)) {
+ mas->store_type = wr_append;
+ return;
+ }
+
+ if ((new_end == mas->end) && (!mt_in_rcu(mas->tree) ||
+ (wr_mas->offset_end - mas->offset == 1))) {
+ mas->store_type = wr_slot_store;
+ return;
+ }
+
+ if (mte_is_root(mas->node) || (new_end >= mt_min_slots[wr_mas->type]) ||
+ (mas->mas_flags & MA_STATE_BULK)) {
The check (new_end >= mt_min_slots[wr_mas->type]) here seems always be true.
So the if here seems not necessary. Do I miss something?
It is true that at this point new_end >= mt_min_slots[wr_mas->type] must
be true but if we remove that check we won't catch this wr_node_store
case if !mte_is_root() and !(mas->mas_flags & MA_STATE_BULK).
We could change the default store type to be wr_node_store and get rid
of that whole if statement entirely.
This diff passes the tests:
diff --git a/lib/maple_tree.c b/lib/maple_tree.c index
4f34e50c92b5..2ae0c4da9d74 100644 --- a/lib/maple_tree.c +++
b/lib/maple_tree.c @@ -4242,14 +4242,7 @@ static inline void
mas_wr_store_type(struct ma_wr_state *wr_mas) return; } - if
(mte_is_root(mas->node) || (new_end >= mt_min_slots[wr_mas->type]) || -
(mas->mas_flags & MA_STATE_BULK)) { - mas->store_type = wr_node_store; -
return; - } - - mas->store_type = wr_invalid; - MAS_WARN_ON(mas, 1); +
mas->store_type = wr_node_store; }
do you think this makes sense?
Thanks,
Sid
+ mas->store_type = wr_node_store;
+ return;
+ }
+
+ mas->store_type = wr_invalid;
+ MAS_WARN_ON(mas, 1);
+}
+
