[LTP] [PATCH v2 02/13] thp: ensure THP/hugetlbfs is available

[Cyril Hrubis]

Hi!
> > I do not get what is the problem with this test on a machine without
> > hugepages or transparent hugepages. The test just tries to execute true
> > with excessively large array of command line arguments, if that fails
> > without hugepages it's a kernel bug.
> 
> The test passes even if THP is not enabled on the test kernel. This
> gives the false impression that THP is working as expected.
> 
> The explicit check is making sure the functionality under test is is
> enabled in the test kernel.

I see where that came from, but I do not think that the test name is a
reason to disable this stress test. However I'm not sure if there is a
better name for the test. I guess that we may possibly move it to the
cve directory.

> >> diff --git a/testcases/kernel/mem/thp/thp02.c b/testcases/kernel/mem/thp/thp02.c
> >> index acc70e215..6502210e5 100644
> >> --- a/testcases/kernel/mem/thp/thp02.c
> >> +++ b/testcases/kernel/mem/thp/thp02.c
> >> @@ -90,6 +90,8 @@ static void setup(void)
> >>  	if (access(PATH_THP, F_OK) == -1)
> >>  		tst_brk(TCONF, "THP not enabled in kernel?");
> >>  
> >> +	check_hugepage();
> >> +
> >>  	ps = sysconf(_SC_PAGESIZE);
> >>  	hps = SAFE_READ_MEMINFO("Hugepagesize:") * 1024;
> >>  	size = hps * 4;
> >> diff --git a/testcases/kernel/mem/thp/thp03.c b/testcases/kernel/mem/thp/thp03.c
> >> index 19db44944..c6062505f 100644
> >> --- a/testcases/kernel/mem/thp/thp03.c
> >> +++ b/testcases/kernel/mem/thp/thp03.c
> >> @@ -82,6 +82,8 @@ static void setup(void)
> >>  	if (access(PATH_THP, F_OK) == -1)
> >>  		tst_brk(TCONF, "THP not enabled in kernel?");
> >>  
> >> +	check_hugepage();
> >> +
> >>  	hugepage_size = SAFE_READ_MEMINFO("Hugepagesize:") * KB;
> >>  	unaligned_size = hugepage_size * 4 - 1;
> >>  	page_size = SAFE_SYSCONF(_SC_PAGESIZE);
> >
> > Does this two fail on an attempt to find "Hugepagesize:" in meminfo
> > file? Otherwise I do not see how they can fail.
> 
> Yes, "Hugepagesize:" goes missing in /proc/meminfo. When the kernel
> doesn't have hugepage support enabled, the tests fail with message like
> -
> 
> safe_file_ops.c:220: BROK: Expected 1 conversions got 0 at thp03.c:85
> 
> With the patch, the message helps identify the cause of the failure.

That's fine. Can you plese include this description in the commit
message as well?

-- 
Cyril Hrubis
chrubis@suse.cz