Re: [PATCH v5 3/4] selftest/mm: test enable_soft_offline behaviors

[Jiaqi Yan <jiaqiyan@google.com>]

On Tue, Jun 25, 2024 at 12:05 AM Miaohe Lin <linmiaohe@huawei.com> wrote:
>
> On 2024/6/25 0:33, Jiaqi Yan wrote:
> > Add regression and new tests when hugepage has correctable memory
> ...
> > 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..16fe52f972e2
> > --- /dev/null
> > +++ b/tools/testing/selftests/mm/hugetlb-soft-offline.c
> > @@ -0,0 +1,227 @@
> > +// 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.
>
> s/failed with EINVAL/failed with EOPNOTSUPP/g

To be fixed in v6.

>
> > + * - 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
> > + */
> > +
> ...
> > +static void test_soft_offline_common(int enable_soft_offline)
> > +{
> > +     int fd;
> > +     int expect_errno = enable_soft_offline ? 0 : EOPNOTSUPP;
> > +     struct statfs file_stat;
> > +     unsigned long hugepagesize_kb = 0;
> > +     unsigned long nr_hugepages_before = 0;
> > +     unsigned long nr_hugepages_after = 0;
> > +     int ret;
> > +
> > +     ksft_print_msg("Test soft-offline when enabled_soft_offline=%d\n",
> > +                    enable_soft_offline);
> > +
> > +     fd = create_hugetlbfs_file(&file_stat);
> > +     if (fd < 0) {
> > +             ksft_exit_fail_msg("Failed to create hugetlbfs file\n");
> > +             return;
> > +     }
> > +
> > +     hugepagesize_kb = file_stat.f_bsize / 1024;
> > +     ksft_print_msg("Hugepagesize is %ldkB\n", hugepagesize_kb);
> > +
> > +     if (set_enable_soft_offline(enable_soft_offline)) {
> > +             ksft_exit_fail_msg("Failed to set enable_soft_offline\n");
>
> Call destroy_hugetlbfs_file() in error path?

As the counterpart of destroy_hugetlbfs_file, I think the test only
needs to close(fd). Will add it in v6.

>
> > +             return;
> > +     }
> > +
> > +     if (read_nr_hugepages(hugepagesize_kb, &nr_hugepages_before) != 0) {
> > +             ksft_exit_fail_msg("Failed to read nr_hugepages\n");
> > +             return;
> > +     }
> > +
> > +     ksft_print_msg("Before MADV_SOFT_OFFLINE nr_hugepages=%ld\n",
> > +                    nr_hugepages_before);
> > +
> > +     ret = do_soft_offline(fd, 2 * file_stat.f_bsize, expect_errno);
> > +
> > +     if (read_nr_hugepages(hugepagesize_kb, &nr_hugepages_after) != 0) {
> > +             ksft_exit_fail_msg("Failed to read nr_hugepages\n");
> > +             return;
> > +     }
> > +
> > +     ksft_print_msg("After MADV_SOFT_OFFLINE nr_hugepages=%ld\n",
> > +             nr_hugepages_after);
> > +
> > +     if (enable_soft_offline) {
> > +             if (nr_hugepages_before != nr_hugepages_after + 1) {
> > +                     ksft_test_result_fail("MADV_SOFT_OFFLINE should reduced 1 hugepage\n");
> > +                     return;
> > +             }
> > +     } else {
> > +             if (nr_hugepages_before != nr_hugepages_after) {
> > +                     ksft_test_result_fail("MADV_SOFT_OFFLINE reduced %lu hugepages\n",
> > +                             nr_hugepages_before - nr_hugepages_after);
> > +                     return;
> > +             }
> > +     }
> > +
> > +     ksft_test_result(ret == 0,
> > +                      "Test soft-offline when enabled_soft_offline=%d\n",
> > +                      enable_soft_offline);
>
> Call destroy_hugetlbfs_file() when test finished ?

Test can just close(fd) once nr_hugepages_after is read.

>
> Thanks.
> .
>
>
>