From: "Liam R. Howlett" <liam.howl...@oracle.com>

commit 24662decdd44645e8f027d7912be962dd461d1aa upstream.

Since the pivot being set is now reliable, the optimized loop no longer
needs to find the node end.  The redundant check for a dead node can also
be avoided as there is no danger of using the wrong pivot since the
results will be thrown out in the case of a dead node by the later check.

This patch also adds a benchmark test for the function to the maple tree
test framework.  The benchmark shows an average increase performance of
5.98% over 3 runs with this commit.

Link: 
https://lkml.kernel.org/r/20231101171629.3612299-12-liam.howl...@oracle.com
Signed-off-by: Liam R. Howlett <liam.howl...@oracle.com>
Cc: Peng Zhang <zhangpeng...@bytedance.com>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
Signed-off-by: Yu Kuai <yuku...@huawei.com>
---
 lib/maple_tree.c      | 12 +++---------
 lib/test_maple_tree.c | 21 +++++++++++++++++++++
 2 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 472aef7a3d5c..ad8bf3413889 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -3742,23 +3742,17 @@ static inline void *mtree_lookup_walk(struct ma_state 
*mas)
        enum maple_type type;
        void __rcu **slots;
        unsigned char end;
-       unsigned long max;
 
        next = mas->node;
-       max = ULONG_MAX;
        do {
-               offset = 0;
                node = mte_to_node(next);
                type = mte_node_type(next);
                pivots = ma_pivots(node, type);
-               end = ma_data_end(node, type, pivots, max);
-               if (unlikely(ma_dead_node(node)))
-                       goto dead_node;
+               end = mt_pivots[type];
+               offset = 0;
                do {
-                       if (pivots[offset] >= mas->index) {
-                               max = pivots[offset];
+                       if (pivots[offset] >= mas->index)
                                break;
-                       }
                } while (++offset < end);
 
                slots = ma_slots(node, type);
diff --git a/lib/test_maple_tree.c b/lib/test_maple_tree.c
index f9acc6ef0728..26991888da14 100644
--- a/lib/test_maple_tree.c
+++ b/lib/test_maple_tree.c
@@ -43,6 +43,7 @@ atomic_t maple_tree_tests_passed;
 /* #define BENCH_NODE_STORE */
 /* #define BENCH_AWALK */
 /* #define BENCH_WALK */
+/* #define BENCH_LOAD */
 /* #define BENCH_MT_FOR_EACH */
 /* #define BENCH_FORK */
 /* #define BENCH_MAS_FOR_EACH */
@@ -1754,6 +1755,19 @@ static noinline void __init bench_walk(struct maple_tree 
*mt)
 }
 #endif
 
+#if defined(BENCH_LOAD)
+static noinline void __init bench_load(struct maple_tree *mt)
+{
+       int i, max = 2500, count = 550000000;
+
+       for (i = 0; i < max; i += 10)
+               mtree_store_range(mt, i, i + 5, xa_mk_value(i), GFP_KERNEL);
+
+       for (i = 0; i < count; i++)
+               mtree_load(mt, 1470);
+}
+#endif
+
 #if defined(BENCH_MT_FOR_EACH)
 static noinline void __init bench_mt_for_each(struct maple_tree *mt)
 {
@@ -3620,6 +3634,13 @@ static int __init maple_tree_seed(void)
        mtree_destroy(&tree);
        goto skip;
 #endif
+#if defined(BENCH_LOAD)
+#define BENCH
+       mt_init_flags(&tree, MT_FLAGS_ALLOC_RANGE);
+       bench_load(&tree);
+       mtree_destroy(&tree);
+       goto skip;
+#endif
 #if defined(BENCH_FORK)
 #define BENCH
        mt_init_flags(&tree, MT_FLAGS_ALLOC_RANGE);
-- 
2.39.2

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