Re: [PATCH v3 44/54] selftests/mm: migration: add setup of HugeTLB pages

[Sarthak Sharma <sarthak.sharma@arm.com>]

On 4/29/26 2:12 AM, Mike Rapoport wrote:
> From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
> 
> migration skips HugeTLB tests if there are no free huge pages
> prepared by a wrapper script.
> 
> Add setup of HugeTLB pages to the test and make sure that the original
> settings are restored on the test exit.
> 
> Since kselftest_harness runs fixture setup and the tests in child
> processes, use HUGETLB_SETUP_DEFAULT_PAGES() that defines a constructor
> that runs in the main process and add verification that there are enough
> free huge pages to the tests that use them.
> 
> Reset signal handlers to defaults in FIXTURE_SETUP() so that sending
> SIGTERM and SIGHUP during the tests won't cause restoration of HugeTLB
> settings.
> 
> Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

I have run the test before and after applying the patch. Before the
patch, the hugetlb subtests failed with MAP_FAILED because hugepages
were not preallocated. After the patch, those subtests correctly
allocate the required hugepages and pass successfully, restoring the
original settings at exit.

Tested-by: Sarthak Sharma sarthak.sharma@arm.com

> ---
>  tools/testing/selftests/mm/migration.c | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
> 
> diff --git a/tools/testing/selftests/mm/migration.c b/tools/testing/selftests/mm/migration.c
> index 0212cd5bde6e..f212c1b06455 100644
> --- a/tools/testing/selftests/mm/migration.c
> +++ b/tools/testing/selftests/mm/migration.c
> @@ -23,6 +23,8 @@
>  #define MAX_RETRIES	100
>  #define ALIGN(x, a)	(((x) + (a - 1)) & (~((a) - 1)))
>  
> +HUGETLB_SETUP_DEFAULT_PAGES(1)
> +
>  FIXTURE(migration)
>  {
>  	pthread_t *threads;
> @@ -32,10 +34,21 @@ FIXTURE(migration)
>  	int n2;
>  };
>  
> +static void reset_signals(void)
> +{
> +	struct sigaction sa = { .sa_handler = SIG_DFL };
> +
> +	sigemptyset(&sa.sa_mask);
> +	sigaction(SIGTERM, &sa, NULL);
> +	sigaction(SIGHUP, &sa, NULL);
> +}
> +
>  FIXTURE_SETUP(migration)
>  {
>  	int n;
>  
> +	reset_signals();
> +
>  	if (numa_available() < 0)
>  		SKIP(return, "NUMA not available");
>  	self->nthreads = numa_num_task_cpus() - 2;
> @@ -271,6 +284,9 @@ TEST_F_TIMEOUT(migration, private_anon_htlb, 2*RUNTIME)
>  	if (!hugepage_size)
>  		SKIP(return, "Reading HugeTLB pagesize failed\n");
>  
> +	if (hugetlb_free_default_pages() < 1)
> +		SKIP(return, "Not enough huge pages\n");
> +
>  	ptr = mmap(NULL, hugepage_size, PROT_READ | PROT_WRITE,
>  		MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB, -1, 0);
>  	ASSERT_NE(ptr, MAP_FAILED);
> @@ -299,6 +315,9 @@ TEST_F_TIMEOUT(migration, shared_anon_htlb, 2*RUNTIME)
>  	if (!hugepage_size)
>  		SKIP(return, "Reading HugeTLB pagesize failed\n");
>  
> +	if (hugetlb_free_default_pages() < 1)
> +		SKIP(return, "Not enough huge pages\n");
> +
>  	ptr = mmap(NULL, hugepage_size, PROT_READ | PROT_WRITE,
>  		MAP_SHARED | MAP_ANONYMOUS | MAP_HUGETLB, -1, 0);
>  	ASSERT_NE(ptr, MAP_FAILED);