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

[Richard Palethorpe]

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.

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


-- 
Thank you,
Richard.