Re: [LTP] [PATCH v2 5/5] memcontrol03: Copy from kselftest

[Cyril Hrubis <chrubis@suse.cz>]

Hi!
> Note that the tolerances had to be increased slightly otherwise the
> test only passed on ext4 in upstream 5.16 on x86_64. In all cases it
> seems more memory is evicted from C than expected and not enough from
> D. This may indicate some tuning is possible, but does not look like a
> serious regression.
> 
> Signed-off-by: Richard Palethorpe <rpalethorpe@suse.com>
> ---
>  runtest/controllers                           |   1 +
>  testcases/kernel/controllers/memcg/.gitignore |   1 +
>  .../kernel/controllers/memcg/memcontrol03.c   | 255 ++++++++++++++++++
>  3 files changed, 257 insertions(+)
>  create mode 100644 testcases/kernel/controllers/memcg/memcontrol03.c
> 
> diff --git a/runtest/controllers b/runtest/controllers
> index 09e0107e4..4a6f919af 100644
> --- a/runtest/controllers
> +++ b/runtest/controllers
> @@ -19,6 +19,7 @@ memcg_control		memcg_control_test.sh
>  # kselftest ports
>  memcontrol01 memcontrol01
>  memcontrol02 memcontrol02
> +memcontrol03 memcontrol03
>  
>  cgroup_fj_function_debug cgroup_fj_function.sh debug
>  cgroup_fj_function_cpuset cgroup_fj_function.sh cpuset
> diff --git a/testcases/kernel/controllers/memcg/.gitignore b/testcases/kernel/controllers/memcg/.gitignore
> index f7de40d53..49df1582c 100644
> --- a/testcases/kernel/controllers/memcg/.gitignore
> +++ b/testcases/kernel/controllers/memcg/.gitignore
> @@ -7,3 +7,4 @@
>  /stress/memcg_process_stress
>  memcontrol01
>  memcontrol02
> +memcontrol03
> diff --git a/testcases/kernel/controllers/memcg/memcontrol03.c b/testcases/kernel/controllers/memcg/memcontrol03.c
> new file mode 100644
> index 000000000..8f1d7f8c1
> --- /dev/null
> +++ b/testcases/kernel/controllers/memcg/memcontrol03.c
> @@ -0,0 +1,255 @@
> +// 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 struct tst_cgroup_group *trunk_cg[3];
> +static struct tst_cgroup_group *leaf_cg[4];
> +static int fd = -1;
> +
> +enum checkpoints {
> +	CHILD_IDLE,
> +	TEST_DONE,
> +};
> +
> +enum trunk_cg {
> +	A,
> +	B,
> +	G
> +};
> +
> +enum leaf_cg {
> +	C,
> +	D,
> +	E,
> +	F
> +};
> +
> +static void cleanup_sub_groups(void)
> +{
> +	size_t i;
> +
> +	for (i = ARRAY_SIZE(leaf_cg); i > 0; i--) {
> +		if (!leaf_cg[i - 1])
> +			continue;
> +
> +		TST_CHECKPOINT_WAKE2(TEST_DONE,
> +				     ARRAY_SIZE(leaf_cg) - 1);
> +		tst_reap_children();
> +		break;
> +	}
> +
> +	for (i = ARRAY_SIZE(leaf_cg); i > 0; i--) {
> +		if (!leaf_cg[i - 1])
> +			continue;
> +
> +		leaf_cg[i - 1] = tst_cgroup_group_rm(leaf_cg[i - 1]);
> +	}
> +
> +	for (i = ARRAY_SIZE(trunk_cg); i > 0; i--) {
> +		if (!trunk_cg[i - 1])
> +			continue;
> +
> +		trunk_cg[i - 1] = tst_cgroup_group_rm(trunk_cg[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);
> +	}
> +
> +	SAFE_WAITPID(pid, &status, 0);
> +
> +	if (!expect_oom) {
> +		if (WIFEXITED(status) && WEXITSTATUS(status) == 0)
> +			return;
> +	} else {
> +		if (WIFSIGNALED(status) && WTERMSIG(status) == SIGKILL)
> +			return;
> +	}

Maybe we should print TPASS in these as well to complement the TFAIL
below. Also the negation in !expect_oom is kind of useless since we
handle both cases anyways.

> +	tst_res(TFAIL,
> +		"Expected child %d to %s, but instead %s",
> +		pid,
> +		expect_oom ? "be killed" : "exit(0)",
> +		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, "PID %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);
> +}
> +
> +static void test_memcg_min(void)
> +{
> +	long c[4];
> +	unsigned int i;
> +	size_t attempts;
> +
> +	fd = SAFE_OPEN(TMPDIR"/tmpfile", O_RDWR | O_CREAT, 0600);
> +	trunk_cg[A] = tst_cgroup_group_mk(tst_cgroup, "trunk_A");
> +
> +	SAFE_CGROUP_SCANF(trunk_cg[A], "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(trunk_cg[A], "memory")) {
> +		SAFE_CGROUP_PRINT(trunk_cg[A], "cgroup.subtree_control",
> +				  "+memory");
> +	}
> +	SAFE_CGROUP_PRINT(trunk_cg[A], "memory.max", "200M");
> +	SAFE_CGROUP_PRINT(trunk_cg[A], "memory.swap.max", "0");
> +
> +	trunk_cg[B] = tst_cgroup_group_mk(trunk_cg[A], "trunk_B");
> +	if (!TST_CGROUP_VER_IS_V1(trunk_cg[A], "memory")) {
> +		SAFE_CGROUP_PRINT(trunk_cg[B], "cgroup.subtree_control",
> +				  "+memory");
> +	}

Don't we require V2 for the whole test anyways?

Also I think I asked if this si really needed in v1, don't we enable the
required subgroups in group_mk() anyways?

> +	trunk_cg[G] = tst_cgroup_group_mk(trunk_cg[A], "trunk_G");
> +
> +	for (i = 0; i < ARRAY_SIZE(leaf_cg); i++) {
> +		leaf_cg[i] = tst_cgroup_group_mk(trunk_cg[B],
> +						 "leaf_%c", 'C' + i);
> +
> +		if (i == E)
> +			continue;
> +
> +		alloc_pagecache_in_child(leaf_cg[i], MB(50));
> +	}
> +
> +	SAFE_CGROUP_PRINT(trunk_cg[A], "memory.min", "50M");
> +	SAFE_CGROUP_PRINT(trunk_cg[B], "memory.min", "50M");
> +	SAFE_CGROUP_PRINT(leaf_cg[C], "memory.min", "75M");
> +	SAFE_CGROUP_PRINT(leaf_cg[D], "memory.min", "25M");
> +	SAFE_CGROUP_PRINT(leaf_cg[E], "memory.min", "500M");
> +	SAFE_CGROUP_PRINT(leaf_cg[F], "memory.min", "0");
> +
> +	for (attempts = 0; attempts < 5; attempts++) {
> +		SAFE_CGROUP_SCANF(trunk_cg[B], "memory.current", "%ld", c);
> +		if (values_close(c[0], MB(150), 3))
> +			break;
> +
> +		sleep(1);
> +	}
> +
> +	alloc_anon_in_child(trunk_cg[G], MB(148), 0);
> +
> +	SAFE_CGROUP_SCANF(trunk_cg[B], "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(leaf_cg); i++)
> +		SAFE_CGROUP_SCANF(leaf_cg[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(trunk_cg[G], MB(170), 1);
> +
> +	SAFE_CGROUP_SCANF(trunk_cg[B], "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);
> +	SAFE_UNLINK(TMPDIR"/tmpfile");
> +}
> +
> +static void cleanup(void)
> +{
> +	cleanup_sub_groups();
> +	if (fd > -1)
> +		SAFE_CLOSE(fd);
> +}
> +
> +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 },
> +};
> -- 
> 2.34.1
> 
> 
> -- 
> Mailing list info: https://lists.linux.it/listinfo/ltp

-- 
Cyril Hrubis
chrubis@suse.cz

-- 
Mailing list info: https://lists.linux.it/listinfo/ltp