Re: [PATCH v4 3/4] selftest/mm: test enable_soft_offline behaviors

[Muhammad Usama Anjum <usama.anjum@collabora.com>]

On 6/20/24 11:48 PM, Jiaqi Yan wrote:
> Add regression and new tests when hugepage has correctable memory
> errors, and how userspace wants to deal with it:
> * if enable_soft_offline=1, mapped hugepage is soft offlined
> * if enable_soft_offline=0, mapped hugepage is intact
> 
> Free hugepages case is not explicitly covered by the tests.
> 
> Hugepage having corrected memory errors is emulated with
> MADV_SOFT_OFFLINE.
> 
> Signed-off-by: Jiaqi Yan <jiaqiyan@google.com>
> ---
>  tools/testing/selftests/mm/.gitignore         |   1 +
>  tools/testing/selftests/mm/Makefile           |   1 +
>  .../selftests/mm/hugetlb-soft-offline.c       | 229 ++++++++++++++++++
>  tools/testing/selftests/mm/run_vmtests.sh     |   4 +
>  4 files changed, 235 insertions(+)
>  create mode 100644 tools/testing/selftests/mm/hugetlb-soft-offline.c
> 
> diff --git a/tools/testing/selftests/mm/.gitignore b/tools/testing/selftests/mm/.gitignore
> index 0b9ab987601c..064e7b125643 100644
> --- a/tools/testing/selftests/mm/.gitignore
> +++ b/tools/testing/selftests/mm/.gitignore
> @@ -6,6 +6,7 @@ hugepage-shm
>  hugepage-vmemmap
>  hugetlb-madvise
>  hugetlb-read-hwpoison
> +hugetlb-soft-offline
>  khugepaged
>  map_hugetlb
>  map_populate
> diff --git a/tools/testing/selftests/mm/Makefile b/tools/testing/selftests/mm/Makefile
> index 3b49bc3d0a3b..d166067d75ef 100644
> --- a/tools/testing/selftests/mm/Makefile
> +++ b/tools/testing/selftests/mm/Makefile
> @@ -42,6 +42,7 @@ TEST_GEN_FILES += gup_test
>  TEST_GEN_FILES += hmm-tests
>  TEST_GEN_FILES += hugetlb-madvise
>  TEST_GEN_FILES += hugetlb-read-hwpoison
> +TEST_GEN_FILES += hugetlb-soft-offline
>  TEST_GEN_FILES += hugepage-mmap
>  TEST_GEN_FILES += hugepage-mremap
>  TEST_GEN_FILES += hugepage-shm
> diff --git a/tools/testing/selftests/mm/hugetlb-soft-offline.c b/tools/testing/selftests/mm/hugetlb-soft-offline.c
> new file mode 100644
> index 000000000000..5701eea4ee48
> --- /dev/null
> +++ b/tools/testing/selftests/mm/hugetlb-soft-offline.c
> @@ -0,0 +1,229 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Test soft offline behavior for HugeTLB pages:
> + * - if enable_soft_offline = 0, hugepages should stay intact and soft
> + *   offlining failed with EINVAL.
> + * - if enable_soft_offline = 1, a hugepage should be dissolved and
> + *   nr_hugepages/free_hugepages should be reduced by 1.
> + *
> + * Before running, make sure more than 2 hugepages of default_hugepagesz
> + * are allocated. For example, if /proc/meminfo/Hugepagesize is 2048kB:
> + *   echo 8 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
> + */
> +
> +#define _GNU_SOURCE
> +#include <errno.h>
> +#include <stdlib.h>
> +#include <stdio.h>
> +#include <string.h>
> +#include <unistd.h>
> +
> +#include <linux/magic.h>
> +#include <linux/memfd.h>
> +#include <sys/mman.h>
> +#include <sys/statfs.h>
> +#include <sys/types.h>
> +
> +#ifndef MADV_SOFT_OFFLINE
> +#define MADV_SOFT_OFFLINE 101
> +#endif
> +
> +#define PREFIX " ... "
> +#define EPREFIX " !!! "
> +
> +enum test_status {
> +	TEST_PASS = 0,
> +	TEST_FAILED = 1,
> +	// From ${ksft_skip} in run_vmtests.sh.
> +	TEST_SKIPPED = 4,
> +};
Include ../kselftest.h and use macros from there instead of redifining.
Also try to use helper functions from same header file to mark the test
pass/fail or exit the test entirely. You can look at soft-dirty.c how that
is written.

-- 
BR,
Muhammad Usama Anjum