test_no_invasive_cgroup_shrink uses fixed zswap/memory limits and allocation sizes that are too small on systems with large PAGE_SIZE (e.g. 64K). In that case, the test may fail to build enough pressure to trigger zswap writeback reliably, leading to false failures.
Make the test size parameters PAGE_SIZE-aware and consistent: - set control_allocation_size to PAGE_SIZE * 1024, - set memory.zswap.max to PAGE_SIZE, - set memory.max of both cgroups to control_allocation_size / 2, - allocate control_allocation_size in wb_group (2x memory.max). This keeps the test behavior stable across 4K and 64K PAGE_SIZE configurations and avoids spurious failures in test_no_invasive_cgroup_shrink. === Error Log === # getconf PAGESIZE 65536 # ./test_zswap TAP version 13 ... ok 5 test_zswap_writeback_disabled ok 6 # SKIP test_no_kmem_bypass not ok 7 test_no_invasive_cgroup_shrink 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: v3: - Make PAGE_SIZE aware instead of using fixed sizing. - Set memory.max for wb_group/control_group to control_allocation_size/2. - Update wb_group pressure allocation to control_allocation_size. - Clarify commit message to focus on this test's sizing issue. v2: - No change. tools/testing/selftests/cgroup/test_zswap.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/cgroup/test_zswap.c b/tools/testing/selftests/cgroup/test_zswap.c index cf5b1531c827..f84e84c3e7c8 100644 --- a/tools/testing/selftests/cgroup/test_zswap.c +++ b/tools/testing/selftests/cgroup/test_zswap.c @@ -421,17 +421,26 @@ static int test_zswap_writeback_disabled(const char *root) static int test_no_invasive_cgroup_shrink(const char *root) { int ret = KSFT_FAIL; - size_t control_allocation_size = MB(10); + size_t control_allocation_size = pagesize * 1024; + char zswap_max_buf[32], mem_max_buf[32]; char *control_allocation = NULL, *wb_group = NULL, *control_group = NULL; + snprintf(zswap_max_buf, sizeof(zswap_max_buf), "%ld", pagesize); + snprintf(mem_max_buf, sizeof(mem_max_buf), "%zu", control_allocation_size / 2); + wb_group = setup_test_group_1M(root, "per_memcg_wb_test1"); if (!wb_group) return KSFT_FAIL; - if (cg_write(wb_group, "memory.zswap.max", "10K")) + if (cg_write(wb_group, "memory.zswap.max", zswap_max_buf)) + goto out; + if (cg_write(wb_group, "memory.max", mem_max_buf)) goto out; + control_group = setup_test_group_1M(root, "per_memcg_wb_test2"); if (!control_group) goto out; + if (cg_write(control_group, "memory.max", mem_max_buf)) + goto out; /* Push some test_group2 memory into zswap */ if (cg_enter_current(control_group)) @@ -442,8 +451,8 @@ static int test_no_invasive_cgroup_shrink(const char *root) if (cg_read_key_long(control_group, "memory.stat", "zswapped") < 1) goto out; - /* Allocate 10x memory.max to push wb_group memory into zswap and trigger wb */ - if (cg_run(wb_group, allocate_bytes, (void *)MB(10))) + /* Allocate 2x memory.max to push wb_group memory into zswap and trigger wb */ + if (cg_run(wb_group, allocate_bytes, (void *)control_allocation_size)) goto out; /* Verify that only zswapped memory from gwb_group has been written back */ -- 2.53.0
