On 6/30/26 11:32, Sayali Patil wrote:
> Some MM selftests attempt to configure the amount of
> HugeTLB pages of different sizes by writing to nr_hugepages.
>
> PowerPC hash MMU pSeries systems advertise gigantic hugepage sizes
> but do not support runtime allocation of such pages, writes
> to the corresponding nr_hugepages file fail with -EINVAL.
> This causes the test to bail out even though the failure is due
> to a platform limitation rather than the
> functionality being tested.
>
> Treat -EINVAL from the sysfs write as a skipped configuration request
> and continue running the test instead of failing.
>
> Before patch:
> -------------------------
> running ./hugetlb-madvise
> -------------------------
> TAP version 13
> 1..1
> [INFO] detected hugetlb page size: 16777216 KiB
> [INFO] detected hugetlb page size: 16384 KiB
> ok 1 MADV_DONTNEED and MADV_REMOVE on hugetlb
> Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0
> Bail out! /sys/kernel/mm/hugepages/hugepages-16777216kB/nr_hugepages
> write(0) failed: Invalid argument
> Totals: pass:0 fail:0 xfail:0 xpass:0 skip:0 error:0
> [FAIL]
>
> After patch:
> -------------------------
> running ./hugetlb-madvise
> -------------------------
> TAP version 13
> 1..1
> [INFO] detected hugetlb page size: 16777216 KiB
> [INFO] detected hugetlb page size: 16384 KiB
> ok 1 MADV_DONTNEED and MADV_REMOVE on hugetlb
> Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0
> /sys/kernel/mm/hugepages/hugepages-16777216kB/nr_hugepages
> write(0) failed: Invalid argument
> [PASS]
>
> Fixes: 27477b28b74f ("selftests/mm: hugepage_settings: add APIs to get and
> set nr_hugepages")
> Signed-off-by: Sayali Patil <[email protected]>
> ---
> .../testing/selftests/mm/hugepage_settings.c | 32 ++++++++++++++++++-
> .../testing/selftests/mm/hugepage_settings.h | 1 +
> 2 files changed, 32 insertions(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/mm/hugepage_settings.c
> b/tools/testing/selftests/mm/hugepage_settings.c
> index 2eab2110ac6a..ce38ae3da01a 100644
> --- a/tools/testing/selftests/mm/hugepage_settings.c
> +++ b/tools/testing/selftests/mm/hugepage_settings.c
> @@ -422,6 +422,36 @@ static void hugetlb_sysfs_path(char *buf, size_t buflen,
> size / 1024, attr);
> }
>
> +void hugetlb_write_num(const char *path, unsigned long num)
> +{
> + int fd, saved_errno;
> + ssize_t numwritten;
> + char buf[21];
> +
> + sprintf(buf, "%lu", num);
> +
> + fd = open(path, O_WRONLY);
> + if (fd == -1)
> + ksft_exit_fail_msg("%s open failed: %s\n", path,
> strerror(errno));
> +
> + numwritten = write(fd, buf, strlen(buf));
> + saved_errno = errno;
> + close(fd);
> + errno = saved_errno;
> +
> + /* Treat EINVAL as a skipped configuration (e.g., unsupported gigantic
> pages) */
> + if (numwritten < 0 && errno == EINVAL) {
> + ksft_print_msg("%s write(%s) failed: %s\n", path, buf,
> strerror(errno));
Should we even print anything here? Rather confusing. It's just like we cannot
allocate anything (no memory).
In general, you are copy-pasting a lot of write_num()+write_file() content,
which is really suboptimal.
All you want is an option for write_num -> write_file to skip on -EINVAL,
correct?
There are not that many write_num / write_file users ...
--
Cheers,
David
