[LTP] [PATCH v2] controllers/memcg: Add testcase for kmem_limit_in_bytes of memory cgroup

[zhaogongyi]

Hi Richard,

Yes, I will pay attention on your patchs about cgroup API.

> > +static void run(void)
> > +{
> > +	pid_t pid;
> > +	int st;
> > +
> > +	pid = SAFE_FORK();
> > +	if (!pid) {
> > +		SAFE_SETPGID(0, 0);
> > +
> > +		SAFE_FILE_PRINTF(KMEM_LIMIT_IN_BYTES, "%d", 0);
> > +
> > +		SAFE_FILE_PRINTF(CGROUP_PROCS, "%d", getpgid(getpid()));
> 
> After setting this we should avoid doing any work in this process except
> calling fork. AFAIK there is no guarantee that some other syscall or tasklet
> etc. Won't try to allocate memory and also fail.
>

It seems that we would not be afraid since there is no asynchronous operation in the test process.


> > +		TEST(fork());
> > +		if (TST_RET == -1) {
> > +			if (TST_ERR == ENOMEM)
> > +				tst_res(TPASS, "fork fail as expected");
> > +			else
> > +				tst_brk(TFAIL | TTERRNO,
> > +					"fork fail as unexpected");
> 
> This should be "fork failed with unexpected error".

It's right. Thanks for your review.

Best Regards,
Gongyi


> 
> Hello,
> 
> Zhao Gongyi <zhaogongyi@huawei.com> writes:
> 
> > Add memory cgroup testcase for checking that kmem overflow is
> > controlled by kmem.limit_in_bytes.
> 
> I am currently working on a new LTP CGroups API, please see:
> https://patchwork.ozlabs.org/project/ltp/list/?series=238773
> 
> If the new API is merged quickly, then this test will need to be converted
> to it. Also please see comments below.
> 
> >
> > Signed-off-by: Zhao Gongyi <zhaogongyi@huawei.com>
> > ---
> > v1->v2:
> > 	1) add testcase to runtest/controllers
> > 	2) add testcase to testcases/kernel/controllers/memcg/.gitignore
> > ---
> >  runtest/controllers                           |  1 +
> >  testcases/kernel/controllers/memcg/.gitignore |  1 +
> >  .../functional/memcg_kmem_limit_in_bytes.c    | 87
> +++++++++++++++++++
> >  3 files changed, 89 insertions(+)
> >  create mode 100644
> >
> testcases/kernel/controllers/memcg/functional/memcg_kmem_limit_in_b
> yte
> > s.c
> >
> > diff --git a/runtest/controllers b/runtest/controllers index
> > e3d0243f1..f13a112c7 100644
> > --- a/runtest/controllers
> > +++ b/runtest/controllers
> > @@ -15,6 +15,7 @@ memcg_use_hierarchy
> 	memcg_use_hierarchy_test.sh
> >  memcg_usage_in_bytes	memcg_usage_in_bytes_test.sh
> >  memcg_stress		memcg_stress_test.sh
> >  memcg_control		memcg_control_test.sh
> > +memcg_kmem_limit_in_bytes memcg_kmem_limit_in_bytes
> >
> >  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 c0b6d0714..dce8412de 100644
> > --- a/testcases/kernel/controllers/memcg/.gitignore
> > +++ b/testcases/kernel/controllers/memcg/.gitignore
> > @@ -1,5 +1,6 @@
> >  /control/mem_process
> >  /functional/memcg_process
> > +/functional/memcg_kmem_limit_in_bytes
> >  /regression/memcg_test_1
> >  /regression/memcg_test_2
> >  /regression/memcg_test_3
> > diff --git
> >
> a/testcases/kernel/controllers/memcg/functional/memcg_kmem_limit_in
> _by
> > tes.c
> >
> b/testcases/kernel/controllers/memcg/functional/memcg_kmem_limit_in
> _by
> > tes.c
> > new file mode 100644
> > index 000000000..61f3f6fd5
> > --- /dev/null
> > +++
> b/testcases/kernel/controllers/memcg/functional/memcg_kmem_limit_i
> > +++ n_bytes.c
> > @@ -0,0 +1,87 @@
> > +// SPDX-License-Identifier: GPL-2.0-or-later
> > +/*
> > + * Copyright (c) 2021 HUAWEI LIMITED
> > + * Author: Zhao Gongyi <zhaogongyi@huawei.com>  */
> > +
> > +/*\
> > + * [Description]
> > + * Check that kmem overflow is controlled by kmem.limit_in_bytes.
> > + *
> > + * [Algorithm]
> > + * 1) mount memory cgroup
> > + * 2) set 0 to memory.kmem.limit_in_bytes
> > + * 3) set test process group to cgroup.procs
> > + * 4) fork in test process group to trig kmem overflow  */
> > +
> > +#include <sys/wait.h>
> > +#include "tst_test.h"
> > +
> > +#define MNT_POINT "memcg"
> > +#define TESTDIR "memcg/ltpmemcg"
> > +#define CGROUP_PROCS "memcg/ltpmemcg/cgroup.procs"
> > +#define KMEM_LIMIT_IN_BYTES
> "memcg/ltpmemcg/memory.kmem.limit_in_bytes"
> > +
> > +static void cleanup(void)
> > +{
> > +	SAFE_RMDIR(TESTDIR);
> > +	SAFE_UMOUNT(MNT_POINT);
> > +	SAFE_RMDIR(MNT_POINT);
> > +}
> > +
> > +static void setup(void)
> > +{
> > +	SAFE_MKDIR(MNT_POINT, 0755);
> > +	SAFE_MOUNT("memcg", MNT_POINT, "cgroup", 0, "memory");
> > +	SAFE_MKDIR(TESTDIR, 0755);
> > +}
> > +
> > +static void run(void)
> > +{
> > +	pid_t pid;
> > +	int st;
> > +
> > +	pid = SAFE_FORK();
> > +	if (!pid) {
> > +		SAFE_SETPGID(0, 0);
> > +
> > +		SAFE_FILE_PRINTF(KMEM_LIMIT_IN_BYTES, "%d", 0);
> > +
> > +		SAFE_FILE_PRINTF(CGROUP_PROCS, "%d", getpgid(getpid()));
> 
> After setting this we should avoid doing any work in this process except
> calling fork. AFAIK there is no guarantee that some other syscall or tasklet
> etc. Won't try to allocate memory and also fail.
> 
> > +
> > +		TEST(fork());
> > +		if (TST_RET == -1) {
> > +			if (TST_ERR == ENOMEM)
> > +				tst_res(TPASS, "fork fail as expected");
> > +			else
> > +				tst_brk(TFAIL | TTERRNO,
> > +					"fork fail as unexpected");
> 
> This should be "fork failed with unexpected error".
> 
> > +		} else if (TST_RET == 0) {
> > +			tst_brk(TFAIL, "fork success as unexpected");
> > +		} else {
> > +			SAFE_WAIT(NULL);
> > +			tst_brk(TFAIL, "fork success as unexpected");
> > +		}
> > +	} else {
> > +		SAFE_WAIT(&st);
> > +		if (WIFEXITED(st))
> > +			if (!WEXITSTATUS(st)) {
> > +				tst_res(TPASS, "kmem alloc is controled "
> > +					"by memory.kmem.limit_in_bytes");
> > +				return;
> > +			}
> > +
> > +		tst_res(TFAIL,"kmem alloc is not controled "
> > +			"by memory.kmem.limit_in_bytes");
> > +	}
> > +}
> > +
> > +static struct tst_test test = {
> > +	.needs_root = 1,
> > +	.needs_tmpdir = 1,
> > +	.forks_child = 1,
> > +	.setup = setup,
> > +	.test_all = run,
> > +	.cleanup = cleanup,
> > +};
> > --
> > 2.17.1
> 
> 
> --
> Thank you,
> Richard.