[LTP] [PATCH v1 2/3] Add process_madvise02 test

[Andrea Cervesato]

Hi!

On 10/18/22 14:24, Richard Palethorpe wrote:
> Hello,
>
> Looks like largely the same problems as with the previous test. Let's
> get that one merged then lessons learned from that can be applied to
> this.
Besides the "memory.high" change I see a big difference from MADV_COLD 
test. That is MADV_PAGEOUT will swap pages when advice is applied and so 
it's easier to check if advice worked properly or not.
> Andrea Cervesato via ltp <ltp@lists.linux.it> writes:
>
>> Test for checking MADV_PAGEOUT functionality over anonymous memory in
>> process_madvise syscall.
>>
>> Signed-off-by: Andrea Cervesato <andrea.cervesato@suse.com>
>> ---
>>   testcases/kernel/syscalls/cma/.gitignore      |   1 +
>>   .../kernel/syscalls/cma/process_madvise02.c   | 128 ++++++++++++++++++
>>   2 files changed, 129 insertions(+)
>>   create mode 100644 testcases/kernel/syscalls/cma/process_madvise02.c
>>
>> diff --git a/testcases/kernel/syscalls/cma/.gitignore b/testcases/kernel/syscalls/cma/.gitignore
>> index 846704294..47ae3e445 100644
>> --- a/testcases/kernel/syscalls/cma/.gitignore
>> +++ b/testcases/kernel/syscalls/cma/.gitignore
>> @@ -3,3 +3,4 @@
>>   /process_vm_readv03
>>   /process_vm_writev02
>>   /process_madvise01
>> +/process_madvise02
>> diff --git a/testcases/kernel/syscalls/cma/process_madvise02.c b/testcases/kernel/syscalls/cma/process_madvise02.c
>> new file mode 100644
>> index 000000000..9f42dd48a
>> --- /dev/null
>> +++ b/testcases/kernel/syscalls/cma/process_madvise02.c
>> @@ -0,0 +1,128 @@
>> +// SPDX-License-Identifier: GPL-2.0-or-later
>> +/*
>> + * Copyright (C) 2022 SUSE LLC Andrea Cervesato <andrea.cervesato@suse.com>
>> + */
>> +
>> +/*\
>> + * [Description]
>> + *
>> + * Spawn child inside cgroup and set max memory. Allocate anonymous memory
>> + * pages inside child and reclaim it with MADV_PAGEOUT. Then check if memory
>> + * pages have been swapped out.
>> + *
>> + * The advice might be ignored for some pages in the range when it is
>> + * not applicable, so test passes if swap memory increases after
>> + * reclaiming memory with MADV_PAGEOUT.
>> + */
>> +
>> +#define _GNU_SOURCE
>> +
>> +#include <sys/mman.h>
>> +#include "tst_test.h"
>> +#include "lapi/mmap.h"
>> +#include "lapi/syscalls.h"
>> +#include "cma.h"
>> +
>> +#define MEM_CHILD	(10 * 1024 * 1024)
>> +
>> +static void **data_ptr;
>> +
>> +static void child_alloc(void)
>> +{
>> +	char *ptr;
>> +	int freed = 1;
>> +	struct addr_mapping map_before;
>> +	struct addr_mapping map_after;
>> +
>> +	tst_res(TINFO, "Allocate memory");
>> +
>> +	*data_ptr = SAFE_MMAP(NULL, MEM_CHILD,
>> +			PROT_READ | PROT_WRITE,
>> +			MAP_SHARED | MAP_ANONYMOUS, -1, 0);
>> +	memset(*data_ptr, 'a', MEM_CHILD);
>> +
>> +	read_address_mapping((unsigned long)*data_ptr, &map_before);
>> +
>> +	TST_CHECKPOINT_WAKE_AND_WAIT(0);
>> +
>> +	for (ptr = *data_ptr; *ptr != '\0'; ptr++) {
>> +		if (*ptr == 'a') {
>> +			freed = 0;
>> +			break;
>> +		}
>> +	}
>> +
>> +	if (freed) {
>> +		tst_res(TFAIL, "Memory has been freed");
>> +		return;
>> +	}
>> +
>> +	read_address_mapping((unsigned long)*data_ptr, &map_after);
>> +
>> +	SAFE_MUNMAP(*data_ptr, MEM_CHILD);
>> +	*data_ptr = NULL;
>> +
>> +	if (map_before.swap < map_after.swap)
>> +		tst_res(TPASS, "Memory has been swapped out");
>> +	else
>> +		tst_res(TFAIL, "Swap memory has decreased");
>> +}
>> +
>> +static void setup(void)
>> +{
>> +	data_ptr = SAFE_MMAP(NULL, sizeof(void *),
>> +			PROT_READ | PROT_WRITE,
>> +			MAP_SHARED | MAP_ANONYMOUS, -1, 0);
>> +}
>> +
>> +static void cleanup(void)
>> +{
>> +	if (*data_ptr)
>> +		SAFE_MUNMAP(*data_ptr, MEM_CHILD);
>> +
>> +	if (data_ptr)
>> +		SAFE_MUNMAP(data_ptr, sizeof(void *));
>> +}
>> +
>> +static void run(void)
>> +{
>> +	int ret;
>> +	int pidfd;
>> +	pid_t pid_alloc;
>> +	struct iovec vec;
>> +
>> +	pid_alloc = SAFE_FORK();
>> +	if (!pid_alloc) {
>> +		child_alloc();
>> +		return;
>> +	}
>> +
>> +	TST_CHECKPOINT_WAIT(0);
>> +
>> +	tst_res(TINFO, "Apply MADV_PAGEOUT advise rule");
>> +
>> +	pidfd = SAFE_PIDFD_OPEN(pid_alloc, 0);
>> +
>> +	vec.iov_base = *data_ptr;
>> +	vec.iov_len = MEM_CHILD;
>> +
>> +	ret = tst_syscall(__NR_process_madvise, pidfd, &vec, 1UL,
>> +			MADV_PAGEOUT, 0UL);
>> +
>> +	if (ret == -1)
>> +		tst_brk(TBROK | TERRNO, "process_madvise failed");
>> +
>> +	if (ret != MEM_CHILD)
>> +		tst_brk(TBROK, "process_madvise reclaimed only %d bytes", ret);
>> +
>> +	TST_CHECKPOINT_WAKE(0);
>> +}
>> +
>> +static struct tst_test test = {
>> +	.setup = setup,
>> +	.cleanup = cleanup,
>> +	.test_all = run,
>> +	.forks_child = 1,
>> +	.min_kver = "5.10",
>> +	.needs_checkpoints = 1,
>> +};
>> -- 
>> 2.35.3
>
Andrea