Re: [RESEND PATCH 3/4] selftests/mm: split_huge_page_test: skip the test when thp is not available

[Chunyu Hu <chuhu@redhat.com>]

On Fri, Mar 13, 2026 at 05:15:57PM +0200, Mike Rapoport wrote:
> On Thu, Mar 12, 2026 at 10:11:12AM -0400, Zi Yan wrote:
> > On 12 Mar 2026, at 7:40, Chunyu Hu wrote:
> > 
> > > When thp is not enabled on some kernel config such as realtime kernel, the
> > > test will report failure. Fix the false positive by skipping the test
> > > directly when thp is not enabled.
> > >
> > > There's a naming conflict on write_file() function, both thp_settings.h and
> > > split_huge_page_test.c define it. To make use of thp_is_enabled() helper in
> > > the thp_settings.h, rename this local write_file to safe_write_file to
> > > avoid the conflict. The reason to use 'safe_' is it does some error check.
> > 
> > Both write_file() do safe checks. Actually the code of both functions looks
> > almost identical except that the thp_settings one does exit() instead of
> > ksft_exit_fail_msg().
> > 
> > Can you rename the split_huge_page_test’s write_file() to write_file_local()
> > and add a comment above the function like
> > /* add _local to avoid a function conflict with thp_settings.h */?
> 
> Looks like we can move the version that uses ksft_exit_fail_msg() to
> vm_util and drop the other one.

Good point. I'll try this in the v2. And I think we can keep return
value.

>  
> > With that, feel free to add:
> > 
> > Reviewed-by: Zi Yan <ziy@nvidia.com>
> > 
> > Thanks.
> > 
> > >
> > > Tested with thp disabled kernel:
> > > Before The fix:
> > >   # --------------------------------------------------
> > >   # running ./split_huge_page_test /tmp/xfs_dir_Ywup9p
> > >   # --------------------------------------------------
> > >   # TAP version 13
> > >   # Bail out! Reading PMD pagesize failed
> > >   # # Totals: pass:0 fail:0 xfail:0 xpass:0 skip:0 error:0
> > >   # [FAIL]
> > >   not ok 61 split_huge_page_test /tmp/xfs_dir_Ywup9p # exit=1
> > >
> > > After the fix:
> > >   # --------------------------------------------------
> > >   # running ./split_huge_page_test /tmp/xfs_dir_YHPUPl
> > >   # --------------------------------------------------
> > >   # TAP version 13
> > >   # 1..0 # SKIP Transparent Hugepages not available
> > >   # [SKIP]
> > >   ok 6 split_huge_page_test /tmp/xfs_dir_YHPUPl # SKIP
> > >
> > > CC: Li Wang <liwang@redhat.com>
> > > Signed-off-by: Chunyu Hu <chuhu@redhat.com>
> > > ---
> > >  tools/testing/selftests/mm/split_huge_page_test.c | 9 +++++++--
> > >  1 file changed, 7 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c
> > > index e0167111bdd1..615b75ca62cc 100644
> > > --- a/tools/testing/selftests/mm/split_huge_page_test.c
> > > +++ b/tools/testing/selftests/mm/split_huge_page_test.c
> > > @@ -21,6 +21,7 @@
> > >  #include <time.h>
> > >  #include "vm_util.h"
> > >  #include "kselftest.h"
> > > +#include "thp_settings.h"
> > >
> > >  uint64_t pagesize;
> > >  unsigned int pageshift;
> > > @@ -255,7 +256,7 @@ static int check_after_split_folio_orders(char *vaddr_start, size_t len,
> > >  	return status;
> > >  }
> > >
> > > -static void write_file(const char *path, const char *buf, size_t buflen)
> > > +static void safe_write_file(const char *path, const char *buf, size_t buflen)
> > >  {
> > >  	int fd;
> > >  	ssize_t numwritten;
> > > @@ -283,7 +284,7 @@ static void write_debugfs(const char *fmt, ...)
> > >  	if (ret >= INPUT_MAX)
> > >  		ksft_exit_fail_msg("%s: Debugfs input is too long\n", __func__);
> > >
> > > -	write_file(SPLIT_DEBUGFS, input, ret + 1);
> > > +	safe_write_file(SPLIT_DEBUGFS, input, ret + 1);
> > >  }
> > >
> > >  static char *allocate_zero_filled_hugepage(size_t len)
> > > @@ -772,6 +773,10 @@ int main(int argc, char **argv)
> > >  		ksft_finished();
> > >  	}
> > >
> > > +	if (!thp_is_enabled()) {
> > > +		ksft_exit_skip("Transparent Hugepages not available\n");
> > > +	}
> > > +
> > >  	if (argc > 1)
> > >  		optional_xfs_path = argv[1];
> > >
> > > -- 
> > > 2.53.0
> > 
> > 
> > Best Regards,
> > Yan, Zi
> 
> -- 
> Sincerely yours,
> Mike.
>