Currently, test_zswap only checks for the presence of zswap via /sys/module/zswap, but it does not account for the global runtime state in /sys/module/zswap/parameters/enabled.
If zswap is configured in the kernel but globally disabled at runtime, the zswap cgroup tests will run in an invalid environment and fail spuriously. Fix this by reading the 'enabled' parameter and gracefully skipping the test when zswap is disabled. A helpful hint is also added to the skip message to show users how to enable it. Signed-off-by: Li Wang <[email protected]> Cc: Johannes Weiner <[email protected]> Cc: Michal Hocko <[email protected]> Cc: Michal Koutný <[email protected]> Cc: Muchun Song <[email protected]> Cc: Nhat Pham <[email protected]> Cc: Tejun Heo <[email protected]> Cc: Roman Gushchin <[email protected]> Cc: Shakeel Butt <[email protected]> Cc: Yosry Ahmed <[email protected]> --- Notes: v1 --> v2: * remove enable/disable_zswap functions * skip the test if zswap is not enabled * reporting fail when zswap_enabled return -1 tools/testing/selftests/cgroup/test_zswap.c | 28 +++++++++++++++++---- 1 file changed, 23 insertions(+), 5 deletions(-) diff --git a/tools/testing/selftests/cgroup/test_zswap.c b/tools/testing/selftests/cgroup/test_zswap.c index 64ebc3f3f203..ec64daaa2f5a 100644 --- a/tools/testing/selftests/cgroup/test_zswap.c +++ b/tools/testing/selftests/cgroup/test_zswap.c @@ -589,23 +589,41 @@ struct zswap_test { }; #undef T -static bool zswap_configured(void) +static int zswap_enabled(void) { - return access("/sys/module/zswap", F_OK) == 0; + char buf[16]; + ssize_t n; + + if (access("/sys/module/zswap", F_OK)) + ksft_exit_skip("zswap isn't configured\n"); + + n = read_text("/sys/module/zswap/parameters/enabled", buf, sizeof(buf)); + if (n <= 0) + return -1; + + if (buf[0] == 'Y') + return 1; + else if (buf[0] == 'N') + return 0; + + return -1; } int main(int argc, char **argv) { char root[PATH_MAX]; - int i; + int i, state; ksft_print_header(); ksft_set_plan(ARRAY_SIZE(tests)); if (cg_find_unified_root(root, sizeof(root), NULL)) ksft_exit_skip("cgroup v2 isn't mounted\n"); - if (!zswap_configured()) - ksft_exit_skip("zswap isn't configured\n"); + state = zswap_enabled(); + if (state == 0) + ksft_exit_skip("zswap is disabled (hint: echo 1 > /sys/module/zswap/parameters/enabled)\n"); + else if (state < 0) + ksft_exit_fail_msg("Failed to read zswap state\n"); /* * Check that memory controller is available: -- 2.53.0
