The new test verifies that memory.swap.max and memory.swap.current behave as expected for simple allocation scenarios

Signed-off-by: Mike Rapoport rppt@linux.vnet.ibm.com ---

The patch is against kselftest/next branch

tools/testing/selftests/cgroup/cgroup_util.c | 16 +++++ tools/testing/selftests/cgroup/cgroup_util.h | 1 + tools/testing/selftests/cgroup/test_memcontrol.c | 91 ++++++++++++++++++++++++ 3 files changed, 108 insertions(+)

diff --git a/tools/testing/selftests/cgroup/cgroup_util.c b/tools/testing/selftests/cgroup/cgroup_util.c index a938b6c8b55a..41cc3b5e5be1 100644 --- a/tools/testing/selftests/cgroup/cgroup_util.c +++ b/tools/testing/selftests/cgroup/cgroup_util.c @@ -315,3 +315,19 @@ int alloc_anon(const char *cgroup, void *arg) free(buf); return 0; } + +int is_swap_enabled(void) +{ + char buf[PAGE_SIZE]; + const char delim[] = "\n"; + int cnt = 0; + char *line; + + if (read_text("/proc/swaps", buf, sizeof(buf)) <= 0) + return -1; + + for (line = strtok(buf, delim); line; line = strtok(NULL, delim)) + cnt++; + + return cnt > 1; +} diff --git a/tools/testing/selftests/cgroup/cgroup_util.h b/tools/testing/selftests/cgroup/cgroup_util.h index 000de075d3d8..fe82a297d4e0 100644 --- a/tools/testing/selftests/cgroup/cgroup_util.h +++ b/tools/testing/selftests/cgroup/cgroup_util.h @@ -38,3 +38,4 @@ extern int cg_run_nowait(const char *cgroup, extern int get_temp_fd(void); extern int alloc_pagecache(int fd, size_t size); extern int alloc_anon(const char *cgroup, void *arg); +extern int is_swap_enabled(void); diff --git a/tools/testing/selftests/cgroup/test_memcontrol.c b/tools/testing/selftests/cgroup/test_memcontrol.c index c92a21f3c806..beae06c9c899 100644 --- a/tools/testing/selftests/cgroup/test_memcontrol.c +++ b/tools/testing/selftests/cgroup/test_memcontrol.c @@ -638,6 +638,96 @@ static int test_memcg_max(const char *root) return ret; }

+static int alloc_anon_50M_check_swap(const char *cgroup, void *arg) +{ + long mem_max = (long)arg; + size_t size = MB(50); + char *buf, *ptr; + long mem_current, swap_current; + int ret = -1; + + buf = malloc(size); + for (ptr = buf; ptr < buf + size; ptr += PAGE_SIZE) + *ptr = 0; + + mem_current = cg_read_long(cgroup, "memory.current"); + if (!mem_current || !values_close(mem_current, mem_max, 3)) + goto cleanup; + + swap_current = cg_read_long(cgroup, "memory.swap.current"); + if (!swap_current || + !values_close(mem_current + swap_current, size, 3)) + goto cleanup; + + ret = 0; +cleanup: + free(buf); + return ret; +} + +/* + * This test checks that memory.swap.max limits the amount of + * anonymous memory which can be swapped out. + */ +static int test_memcg_swap_max(const char *root) +{ + int ret = KSFT_FAIL; + char *memcg; + long max; + + if (!is_swap_enabled()) + return KSFT_SKIP; + + memcg = cg_name(root, "memcg_test"); + if (!memcg) + goto cleanup; + + if (cg_create(memcg)) + goto cleanup; + + if (cg_read_long(memcg, "memory.swap.current")) { + ret = KSFT_SKIP; + goto cleanup; + } + + if (cg_read_strcmp(memcg, "memory.max", "max\n")) + goto cleanup; + + if (cg_read_strcmp(memcg, "memory.swap.max", "max\n")) + goto cleanup; + + if (cg_write(memcg, "memory.swap.max", "30M")) + goto cleanup; + + if (cg_write(memcg, "memory.max", "30M")) + goto cleanup; + + /* Should be killed by OOM killer */ + if (!cg_run(memcg, alloc_anon, (void *)MB(100))) + goto cleanup; + + if (cg_read_key_long(memcg, "memory.events", "oom ") != 1) + goto cleanup; + + if (cg_read_key_long(memcg, "memory.events", "oom_kill ") != 1) + goto cleanup; + + if (cg_run(memcg, alloc_anon_50M_check_swap, (void *)MB(30))) + goto cleanup; + + max = cg_read_key_long(memcg, "memory.events", "max "); + if (max <= 0) + goto cleanup; + + ret = KSFT_PASS; + +cleanup: + cg_destroy(memcg); + free(memcg); + + return ret; +} + /* * This test disables swapping and tries to allocate anonymous memory * up to OOM. Then it checks for oom and oom_kill events in @@ -694,6 +784,7 @@ struct memcg_test { T(test_memcg_high), T(test_memcg_max), T(test_memcg_oom_events), + T(test_memcg_swap_max), }; #undef T