selftest/vm: fix ksm selftest to run with different NUMA topologies

Platforms can have non-contiguous NUMA nodes like below

   #numactl  -H
  available: 2 nodes (0,8)
  .....
  node distances:
  node   0   8
    0:  10  40
    8:  40  10

   #numactl  -H
  available: 1 nodes (1)
  ....
  node distances:
  node   1
    1:  10

Hence update the test to not assume the presence of Node 0 and 1 and
also use numa_num_configured_nodes() instead of numa_max_node for
finding whether to skip the test.

Link: https://lkml.kernel.org/r/20210914141414.350759-1-aneesh.kumar@linux.ibm.com
Fixes: 82e717ad3501 ("selftests: vm: add KSM merging across nodes test")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Zhansaya Bagdauletkyzy <zhansayabagdaulet@gmail.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Tyler Hicks <tyhicks@linux.microsoft.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/tools/testing/selftests/vm/ksm_tests.c b/tools/testing/selftests/vm/ksm_tests.c
index b61dcdb44c5beca53c91b5fafe68d8e894a06f9a..0e142d25b0316f210b806c1672f3b7650329fc52 100644 (file)
--- a/tools/testing/selftests/vm/ksm_tests.c
+++ b/tools/testing/selftests/vm/ksm_tests.c
@@ -354,12 +354,34 @@ err_out:
        return KSFT_FAIL;
 }
 
+static int get_next_mem_node(int node)
+{
+
+       long node_size;
+       int mem_node = 0;
+       int i, max_node = numa_max_node();
+
+       for (i = node + 1; i <= max_node + node; i++) {
+               mem_node = i % (max_node + 1);
+               node_size = numa_node_size(mem_node, NULL);
+               if (node_size > 0)
+                       break;
+       }
+       return mem_node;
+}
+
+static int get_first_mem_node(void)
+{
+       return get_next_mem_node(numa_max_node());
+}
+
 static int check_ksm_numa_merge(int mapping, int prot, int timeout, bool merge_across_nodes,
                                size_t page_size)
 {
        void *numa1_map_ptr, *numa2_map_ptr;
        struct timespec start_time;
        int page_count = 2;
+       int first_node;
 
        if (clock_gettime(CLOCK_MONOTONIC_RAW, &start_time)) {
                perror("clock_gettime");
@@ -370,7 +392,7 @@ static int check_ksm_numa_merge(int mapping, int prot, int timeout, bool merge_a
                perror("NUMA support not enabled");
                return KSFT_SKIP;
        }
-       if (numa_max_node() < 1) {
+       if (numa_num_configured_nodes() <= 1) {
                printf("At least 2 NUMA nodes must be available\n");
                return KSFT_SKIP;
        }
@@ -378,8 +400,9 @@ static int check_ksm_numa_merge(int mapping, int prot, int timeout, bool merge_a
                return KSFT_FAIL;
 
        /* allocate 2 pages in 2 different NUMA nodes and fill them with the same data */
-       numa1_map_ptr = numa_alloc_onnode(page_size, 0);
-       numa2_map_ptr = numa_alloc_onnode(page_size, 1);
+       first_node = get_first_mem_node();
+       numa1_map_ptr = numa_alloc_onnode(page_size, first_node);
+       numa2_map_ptr = numa_alloc_onnode(page_size, get_next_mem_node(first_node));
        if (!numa1_map_ptr || !numa2_map_ptr) {
                perror("numa_alloc_onnode");
                return KSFT_FAIL;