maple_tree: add test for mas_wr_modify() fast path

Patch series "Optimize the fast path of mas_store()", v4.

Add fast paths for mas_wr_append() and mas_wr_slot_store() respectively.
The newly added fast path of mas_wr_append() is used in fork() and how
much it benefits fork() depends on how many VMAs are duplicated.

Thanks Liam for the review.

This patch (of 4):

Add tests for all cases of mas_wr_append() and mas_wr_slot_store().

Link: https://lkml.kernel.org/r/20230628073657.75314-1-zhangpeng.00@bytedance.com
Link: https://lkml.kernel.org/r/20230628073657.75314-2-zhangpeng.00@bytedance.com
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/lib/test_maple_tree.c b/lib/test_maple_tree.c
index 8d4c92cbdd0cfa670e81964383c1511801c47338..3207c21079184a5bca6506752b03322641fecc9d 100644 (file)
--- a/lib/test_maple_tree.c
+++ b/lib/test_maple_tree.c
@@ -1157,6 +1157,71 @@ static noinline void __init check_ranges(struct maple_tree *mt)
        MT_BUG_ON(mt, !mt_height(mt));
        mtree_destroy(mt);
 
+       /* Check in-place modifications */
+       mt_init_flags(mt, MT_FLAGS_ALLOC_RANGE);
+       /* Append to the start of last range */
+       mt_set_non_kernel(50);
+       for (i = 0; i <= 500; i++) {
+               val = i * 5 + 1;
+               val2 = val + 4;
+               check_store_range(mt, val, val2, xa_mk_value(val), 0);
+       }
+
+       /* Append to the last range without touching any boundaries */
+       for (i = 0; i < 10; i++) {
+               val = val2 + 5;
+               val2 = val + 4;
+               check_store_range(mt, val, val2, xa_mk_value(val), 0);
+       }
+
+       /* Append to the end of last range */
+       val = val2;
+       for (i = 0; i < 10; i++) {
+               val += 5;
+               MT_BUG_ON(mt, mtree_test_store_range(mt, val, ULONG_MAX,
+                                                    xa_mk_value(val)) != 0);
+       }
+
+       /* Overwriting the range and over a part of the next range */
+       for (i = 10; i < 30; i += 2) {
+               val = i * 5 + 1;
+               val2 = val + 5;
+               check_store_range(mt, val, val2, xa_mk_value(val), 0);
+       }
+
+       /* Overwriting a part of the range and over the next range */
+       for (i = 50; i < 70; i += 2) {
+               val2 = i * 5;
+               val = val2 - 5;
+               check_store_range(mt, val, val2, xa_mk_value(val), 0);
+       }
+
+       /*
+        * Expand the range, only partially overwriting the previous and
+        * next ranges
+        */
+       for (i = 100; i < 130; i += 3) {
+               val = i * 5 - 5;
+               val2 = i * 5 + 1;
+               check_store_range(mt, val, val2, xa_mk_value(val), 0);
+       }
+
+       /*
+        * Expand the range, only partially overwriting the previous and
+        * next ranges, in RCU mode
+        */
+       mt_set_in_rcu(mt);
+       for (i = 150; i < 180; i += 3) {
+               val = i * 5 - 5;
+               val2 = i * 5 + 1;
+               check_store_range(mt, val, val2, xa_mk_value(val), 0);
+       }
+
+       MT_BUG_ON(mt, !mt_height(mt));
+       mt_validate(mt);
+       mt_set_non_kernel(0);
+       mtree_destroy(mt);
+
        /* Test rebalance gaps */
        mt_init_flags(mt, MT_FLAGS_ALLOC_RANGE);
        mt_set_non_kernel(50);