[LTP] [PATCH 6/6] memcontrol03: Copy from kselftest
Cyril Hrubis
chrubis@suse.cz
Fri Jan 28 11:57:22 CET 2022
Hi!
> +// SPDX-License-Identifier: GPL-2.0
> +/*\
> + *
> + * [Description]
> + *
> + * Conversion of the third kself test in cgroup/test_memcontrol.c.
> + *
> + * Original description:
> + * "First, this test creates the following hierarchy:
> + * A memory.min = 50M, memory.max = 200M
> + * A/B memory.min = 50M, memory.current = 50M
> + * A/B/C memory.min = 75M, memory.current = 50M
> + * A/B/D memory.min = 25M, memory.current = 50M
> + * A/B/E memory.min = 500M, memory.current = 0
> + * A/B/F memory.min = 0, memory.current = 50M
> + *
> + * Usages are pagecache, but the test keeps a running
> + * process in every leaf cgroup.
> + * Then it creates A/G and creates a significant
> + * memory pressure in it.
> + *
> + * A/B memory.current ~= 50M
> + * A/B/C memory.current ~= 33M
> + * A/B/D memory.current ~= 17M
> + * A/B/E memory.current ~= 0
> + *
> + * After that it tries to allocate more than there is unprotected
> + * memory in A available, and checks that memory.min protects
> + * pagecache even in this case."
> + *
> + * memory.min doesn't appear to exist on V1 so we only test on V2 like
> + * the selftest. We do test on more file systems, but not tempfs
> + * becaue it can't evict the page cache without swap. Also we avoid
> + * filesystems which allocate extra memory for buffer heads.
> + *
> + * The tolerances have been increased from the self tests.
> + *
> + */
> +
> +#define _GNU_SOURCE
> +
> +#include <inttypes.h>
> +
> +#include "memcontrol_common.h"
> +
> +#define TMPDIR "mntdir"
> +
> +static const struct tst_cgroup_group *cg_test;
> +static struct tst_cgroup_group *parent[3];
> +static struct tst_cgroup_group *children[4];
> +static int fd;
> +
> +enum checkpoints {
> + CHILD_IDLE,
> + TEST_DONE,
> +};
> +
> +static void cleanup_sub_groups(void)
> +{
> + size_t i;
> +
> + for (i = ARRAY_SIZE(children); i > 0; i--) {
> + if (!children[i - 1])
> + continue;
> +
> + TST_CHECKPOINT_WAKE2(TEST_DONE,
> + ARRAY_SIZE(children) - 1);
> + tst_reap_children();
> + break;
> + }
> +
> + for (i = ARRAY_SIZE(children); i > 0; i--) {
> + if (!children[i - 1])
> + continue;
> +
> + children[i - 1] = tst_cgroup_group_rm(children[i - 1]);
> + }
> +
> + for (i = ARRAY_SIZE(parent); i > 0; i--) {
> + if (!parent[i - 1])
> + continue;
> +
> + parent[i - 1] = tst_cgroup_group_rm(parent[i - 1]);
> + }
> +}
> +
> +static void alloc_anon_in_child(const struct tst_cgroup_group *const cg,
> + const size_t size, const int expect_oom)
> +{
> + int status;
> + const pid_t pid = SAFE_FORK();
> +
> + if (!pid) {
> + SAFE_CGROUP_PRINTF(cg, "cgroup.procs", "%d", getpid());
> +
> + tst_res(TINFO, "%d in %s: Allocating anon: %"PRIdPTR,
> + getpid(), tst_cgroup_group_name(cg), size);
> + alloc_anon(size);
> + exit(0);
> + }
> +
> + if (expect_oom)
> + SAFE_WAITPID(pid, &status, 0);
> + else
> + tst_reap_child(pid);
I guess that we can do the SAFE_WAITPID() here in both cases but just
adjust expectations:
SAFE_WAITPID(pid, &status, 0);
if (WIFEXITTED(status) && WEXITSTATUS(status) == 0)
return;
if (expect_oom && WIFSIGNALED(status) && WTERMSIG(status) == SIGKILL)
return;
tst_res(TFAIL, "Child %s", tst_strstatus(status);
> +}
> +
> +static void alloc_pagecache_in_child(const struct tst_cgroup_group *const cg,
> + const size_t size)
> +{
> + const pid_t pid = SAFE_FORK();
> +
> + if (pid) {
> + TST_CHECKPOINT_WAIT(CHILD_IDLE);
> + return;
> + }
> +
> + SAFE_CGROUP_PRINTF(cg, "cgroup.procs", "%d", getpid());
> +
> + tst_res(TINFO, "%d in %s: Allocating pagecache: %"PRIdPTR,
> + getpid(), tst_cgroup_group_name(cg), size);
> + alloc_pagecache(fd, size);
> +
> + TST_CHECKPOINT_WAKE(CHILD_IDLE);
> + TST_CHECKPOINT_WAIT(TEST_DONE);
> + exit(0);
> +}
> +
> +/*
> + */
Empty comment.
> +static void test_memcg_min(void)
> +{
> + long c[4];
> + size_t i, attempts;
> + char child_name[64];
> +
> + fd = SAFE_OPEN(TMPDIR"/tmpfile", O_RDWR | O_CREAT, 0600);
> + parent[0] = tst_cgroup_group_mk(cg_test, "memcg_test_0");
> +
> + SAFE_CGROUP_SCANF(parent[0], "memory.min", "%ld", c);
> + if (c[0]) {
> + tst_brk(TCONF,
> + "memory.min already set to %ld on parent group", c[0]);
> + }
> +
> + if (!TST_CGROUP_VER_IS_V1(parent[0], "memory")) {
> + SAFE_CGROUP_PRINT(parent[0], "cgroup.subtree_control",
> + "+memory");
> + }
> + SAFE_CGROUP_PRINT(parent[0], "memory.max", "200M");
> + SAFE_CGROUP_PRINT(parent[0], "memory.swap.max", "0");
> +
> + parent[1] = tst_cgroup_group_mk(parent[0], "memcg_test_1");
> + if (!TST_CGROUP_VER_IS_V1(parent[0], "memory")) {
> + SAFE_CGROUP_PRINT(parent[1], "cgroup.subtree_control",
> + "+memory");
Don't we enable the memory controller automatically in the LTP library?
> + }
> +
> + parent[2] = tst_cgroup_group_mk(parent[0], "memcg_test_2");
> +
> + for (i = 0; i < ARRAY_SIZE(children); i++) {
> + sprintf(child_name, "child_memcg_%"PRIdPTR, i);
> +
> + children[i] = tst_cgroup_group_mk(parent[1], child_name);
I guess that it would be a bit more elegant if the tst_cgroup_group_mk()
would have been printf-like function.
> + if (i == 2)
> + continue;
> +
> + alloc_pagecache_in_child(children[i], MB(50));
> + }
> +
> + SAFE_CGROUP_PRINT(parent[0], "memory.min", "50M");
> + SAFE_CGROUP_PRINT(parent[1], "memory.min", "50M");
> + SAFE_CGROUP_PRINT(children[0], "memory.min", "75M");
> + SAFE_CGROUP_PRINT(children[1], "memory.min", "25M");
> + SAFE_CGROUP_PRINT(children[2], "memory.min", "500M");
> + SAFE_CGROUP_PRINT(children[3], "memory.min", "0");
> +
> + for (attempts = 0; attempts < 5; attempts++) {
> + SAFE_CGROUP_SCANF(parent[1], "memory.current", "%ld", c);
> + if (values_close(c[0], MB(150), 3))
> + break;
> +
> + sleep(1);
> + }
> +
> + alloc_anon_in_child(parent[2], MB(148), 0);
I find the usage of parent and child in the code a bit confusing, the
parent[2] is actually a child of parent[0].
Maybe we should call them "generation" such as gen1, gen2, etc.
So that we would have:
gen1 = tst_cgroup_group_mk(cg_test, "memcg_test_gen1");
gen2[0] = tst_cgroup_group_mk(gen1, "memcg_test_gen2_0");
gen2[1] = tst_cgroup_group_mk(gen2, "memcg_test_get2_1");
for (...)
gen3[i] = tst_cgroup_group_mk(gen2[0], "memcg_test_gen3_%i", i);
> + SAFE_CGROUP_SCANF(parent[1], "memory.current", "%ld", c);
> + TST_EXP_EXPR(values_close(c[0], MB(50), 5), "(A/B memory.current=%ld) ~= %d", c[0], MB(50));
> +
> + for (i = 0; i < ARRAY_SIZE(children); i++)
> + SAFE_CGROUP_SCANF(children[i], "memory.current", "%ld", c + i);
> +
> + TST_EXP_EXPR(values_close(c[0], MB(33), 20), "(A/B/C memory.current=%ld) ~= %d", c[0], MB(33));
> + TST_EXP_EXPR(values_close(c[1], MB(17), 20), "(A/B/D memory.current=%ld) ~= %d", c[1], MB(17));
> + TST_EXP_EXPR(values_close(c[2], 0, 1), "(A/B/E memory.current=%ld) ~= 0", c[2]);
> +
> + alloc_anon_in_child(parent[2], MB(170), 1);
> +
> + SAFE_CGROUP_SCANF(parent[1], "memory.current", "%ld", c);
> + TST_EXP_EXPR(values_close(c[0], MB(50), 5), "(A/B memory.current=%ld) ~= %d", c[0], MB(50));
> +
> + cleanup_sub_groups();
> + SAFE_CLOSE(fd);
> +}
> +
> +static void cleanup(void)
> +{
> + cleanup_sub_groups();
> + if (fd > -1)
> + SAFE_CLOSE(fd);
Technically this should either be fd > 0 or the global should be
initialized to -1.
> +}
> +
> +static struct tst_test test = {
> + .cleanup = cleanup,
> + .test_all = test_memcg_min,
> + .mount_device = 1,
> + .dev_min_size = 256,
> + .mntpoint = TMPDIR,
> + .all_filesystems = 1,
> + .skip_filesystems = (const char *const[]){
> + "exfat", "vfat", "fuse", "ntfs", "tmpfs", NULL
> + },
> + .forks_child = 1,
> + .needs_root = 1,
> + .needs_checkpoints = 1,
> + .needs_cgroup_ver = TST_CGROUP_V2,
> + .needs_cgroup_controllers = (const char *const[]){ "memory", NULL },
> + .test_cgroup = &cg_test,
> +};
> --
> 2.34.1
>
>
> --
> Mailing list info: https://lists.linux.it/listinfo/ltp
--
Cyril Hrubis
chrubis@suse.cz
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