Re: [PATCH v1 2/3] selftests/mm: allocate 6 hugepages in va_high_addr_switch.sh

[Luiz Capitulino <luizcap@redhat.com>]

On 2025-12-07 07:22, Chunyu Hu wrote:
> The va_high_addr_switch test requires 6 hugepages, not 5. If running the
> test directly by: ./va_high_addr_switch.sh, the test will hit a mmap 'FAIL'
> caused by not enough hugepages:
>    ```
>    mmap(addr_switch_hint - hugepagesize, 2*hugepagesize, MAP_HUGETLB): 0x7f330f800000 - OK
>    mmap(addr_switch_hint , 2*hugepagesize, MAP_FIXED | MAP_HUGETLB): 0xffffffffffffffff - FAILED
>    ```
> The failure can't be hit if run the tests by running 'run_vmtests.sh -t
> hugevm' because the nr_hugepages is set to 128 at the beginning of
> run_vmtests.sh and va_high_addr_switch.sh skip the setup of nr_hugepages
> because already enough.
> 
> CC: Luiz Capitulino <luizcap@redhat.com>
> Fixes: d9d957bd7b61 ("selftests/mm: alloc hugepages in va_high_addr_switch test")
> Signed-off-by: Chunyu Hu <chuhu@redhat.com>
> ---
>   tools/testing/selftests/mm/va_high_addr_switch.sh | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/testing/selftests/mm/va_high_addr_switch.sh b/tools/testing/selftests/mm/va_high_addr_switch.sh
> index f89fe078a8e6..98f3dfab62c5 100755
> --- a/tools/testing/selftests/mm/va_high_addr_switch.sh
> +++ b/tools/testing/selftests/mm/va_high_addr_switch.sh
> @@ -111,8 +111,10 @@ setup_nr_hugepages()
>   
>   check_test_requirements
>   save_nr_hugepages
> -# 4 keep_mapped pages, and one for tmp usage
> -setup_nr_hugepages 5
> +# 5 keep_mapped hugepages are reserved in the first testings, and the last test
> +# requires two hugepages, with one verlaped with the last second test, so one
> +# extra, totally 6 hugepages

IMHO, I'd just say "The HugeTLB tests require 6 pages", otherwise the
fix look good to me.

> +setup_nr_hugepages 6
>   ./va_high_addr_switch --run-hugetlb
>   retcode=$?
>   restore_nr_hugepages