[PATCH 0/2] Fix va_high_addr_switch.sh test failure

[PATCH 0/2] Fix va_high_addr_switch.sh test failure

[Chunyu Hu]

The two patches fix the va_high_addr_switch.sh test failure on x86_64.
Patch 1 fixes the hugepages setup issue that nr_hugepages is reset too
early in run_vmtests.sh and break the later va_high_addr_switch testing.
Patch 2 fixes the test failure caused by the hint addr align method change
in hugetlb_get_unmapped_area().

Chunyu Hu (2):
  selftests/mm: fix hugepages cleanup too early
  selftests/mm: fix va_high_addr_switch.sh failure on x86_64

 tools/testing/selftests/mm/run_vmtests.sh        | 9 +++++++--
 tools/testing/selftests/mm/va_high_addr_switch.c | 4 ++--
 2 files changed, 9 insertions(+), 4 deletions(-)

-- 
2.49.0

[PATCH 1/2] selftests/mm: fix hugepages cleanup too early

[Chunyu Hu]

The nr_hugepgs variable is used to keep the original nr_hugepages at the
hugepage setup step at test beginning. After userfaultfd test, a cleaup is
executed, both /sys/kernel/mm/hugepages/hugepages-*/nr_hugepages and
/proc/sys//vm/nr_hugepages are reset to 'original' value before userfaultfd
test starts.

Issue here is the value used to restore /proc/sys/vm/nr_hugepages is
nr_hugepgs which is the initial value before the vm_runtests.sh runs, not
the value before userfaultfd test starts. 'va_high_addr_swith.sh' tests
runs after that will possibly see no hugepages available for test, and got
EINVAL when mmap(HUGETLB), making the result invalid.

And before pkey tests, nr_hugepgs is changed to be used as a temp variable
to save nr_hugepages before pkey test, and restore it after pkey tests
finish. The original nr_hugepages value is not tracked anymore, so no way
to restore it after all tests finish.

Add a new variable nr_hugepgs_origin to save the original nr_hugepages, and
and restore it to nr_hugepages after all tests finish. And change to use
the nr_hugepgs variable to save the /proc/sys/vm/nr_hugeages after hugepage
setup, it's also the value before userfaultfd test starts, and the correct
value to be restored after userfaultfd finishes. The va_high_addr_switch.sh
broken will be resolved.

Signed-off-by: Chunyu Hu <chuhu@redhat.com>
---
 tools/testing/selftests/mm/run_vmtests.sh | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh
index 471e539d82b8..f1a7ad3ec6a7 100755
--- a/tools/testing/selftests/mm/run_vmtests.sh
+++ b/tools/testing/selftests/mm/run_vmtests.sh
@@ -172,13 +172,13 @@ fi
 
 # set proper nr_hugepages
 if [ -n "$freepgs" ] && [ -n "$hpgsize_KB" ]; then
-	nr_hugepgs=$(cat /proc/sys/vm/nr_hugepages)
+	nr_hugepgs_origin=$(cat /proc/sys/vm/nr_hugepages)
 	needpgs=$((needmem_KB / hpgsize_KB))
 	tries=2
 	while [ "$tries" -gt 0 ] && [ "$freepgs" -lt "$needpgs" ]; do
 		lackpgs=$((needpgs - freepgs))
 		echo 3 > /proc/sys/vm/drop_caches
-		if ! echo $((lackpgs + nr_hugepgs)) > /proc/sys/vm/nr_hugepages; then
+		if ! echo $((lackpgs + nr_hugepgs_origin)) > /proc/sys/vm/nr_hugepages; then
 			echo "Please run this test as root"
 			exit $ksft_skip
 		fi
@@ -189,6 +189,7 @@ if [ -n "$freepgs" ] && [ -n "$hpgsize_KB" ]; then
 		done < /proc/meminfo
 		tries=$((tries - 1))
 	done
+	nr_hugepgs=$(cat /proc/sys/vm/nr_hugepages)
 	if [ "$freepgs" -lt "$needpgs" ]; then
 		printf "Not enough huge pages available (%d < %d)\n" \
 		       "$freepgs" "$needpgs"
@@ -532,6 +533,10 @@ CATEGORY="page_frag" run_test ./test_page_frag.sh aligned
 
 CATEGORY="page_frag" run_test ./test_page_frag.sh nonaligned
 
+if [ "${HAVE_HUGEPAGES}" = 1 ]; then
+	echo "$nr_hugepgs_origin" > /proc/sys/vm/nr_hugepages
+fi
+
 echo "SUMMARY: PASS=${count_pass} SKIP=${count_skip} FAIL=${count_fail}" | tap_prefix
 echo "1..${count_total}" | tap_output
 
-- 
2.49.0

[PATCH 2/2] selftests/mm: fix va_high_addr_switch.sh failure on x86_64

[Chunyu Hu]

The test will fail as below on x86_64 with cpu la57 support (will skip if
no la57 support). Note, the test requries nr_hugepages to be set first.

  # running bash ./va_high_addr_switch.sh
  # -------------------------------------
  # mmap(addr_switch_hint - pagesize, pagesize): 0x7f55b60fa000 - OK
  # mmap(addr_switch_hint - pagesize, (2 * pagesize)): 0x7f55b60f9000 - OK
  # mmap(addr_switch_hint, pagesize): 0x800000000000 - OK
  # mmap(addr_switch_hint, 2 * pagesize, MAP_FIXED): 0x800000000000 - OK
  # mmap(NULL): 0x7f55b60f9000 - OK
  # mmap(low_addr): 0x40000000 - OK
  # mmap(high_addr): 0x1000000000000 - OK
  # mmap(high_addr) again: 0xffff55b6136000 - OK
  # mmap(high_addr, MAP_FIXED): 0x1000000000000 - OK
  # mmap(-1): 0xffff55b6134000 - OK
  # mmap(-1) again: 0xffff55b6132000 - OK
  # mmap(addr_switch_hint - pagesize, pagesize): 0x7f55b60fa000 - OK
  # mmap(addr_switch_hint - pagesize, 2 * pagesize): 0x7f55b60f9000 - OK
  # mmap(addr_switch_hint - pagesize/2 , 2 * pagesize): 0x7f55b60f7000 - OK
  # mmap(addr_switch_hint, pagesize): 0x800000000000 - OK
  # mmap(addr_switch_hint, 2 * pagesize, MAP_FIXED): 0x800000000000 - OK
  # mmap(NULL, MAP_HUGETLB): 0x7f55b5c00000 - OK
  # mmap(low_addr, MAP_HUGETLB): 0x40000000 - OK
  # mmap(high_addr, MAP_HUGETLB): 0x1000000000000 - OK
  # mmap(high_addr, MAP_HUGETLB) again: 0xffff55b5e00000 - OK
  # mmap(high_addr, MAP_FIXED | MAP_HUGETLB): 0x1000000000000 - OK
  # mmap(-1, MAP_HUGETLB): 0x7f55b5c00000 - OK
  # mmap(-1, MAP_HUGETLB) again: 0x7f55b5a00000 - OK
  # mmap(addr_switch_hint - pagesize, 2*hugepagesize, MAP_HUGETLB): 0x800000000000 - FAILED
  # mmap(addr_switch_hint , 2*hugepagesize, MAP_FIXED | MAP_HUGETLB): 0x800000000000 - OK
  # [FAIL]

addr_switch_hint is defined as DFEFAULT_MAP_WINDOW in the failed test (for
x86_64, DFEFAULT_MAP_WINDOW is defined as (1UL<<47) - pagesize) in 64 bit.

Before commit cc92882ee218 ("mm: drop hugetlb_get_unmapped_area{_*}
functions"), for x86_64 hugetlb_get_unmapped_area() is handled in arch code
arch/x86/mm/hugetlbpage.c and addr is checked with map_address_hint_valid()
after align with 'addr &= huge_page_mask(h)' which is a round down way, and
it will fail the check because the addr is within the DEFAULT_MAP_WINDOW but
(addr + len) is above the DFEFAULT_MAP_WINDOW. So it wil go through the
hugetlb_get_unmmaped_area_top_down() to find an area within the
DFEFAULT_MAP_WINDOW.

After commit cc92882ee218 ("mm: drop hugetlb_get_unmapped_area{_*}
functions").  The addr hint for hugetlb_get_unmmaped_area() will be rounded
up and aligned to hugepage size with ALIGN() for all arches.  And after the
align, the addr will be above the default MAP_DEFAULT_WINDOW, and the
map_addresshint_valid() check will pass because both aligned addr (addr0)
and (addr + len) are above the DEFAULT_MAP_WINDOW, and the aligned hint
address (0x800000000000) is returned as an suitable gap is found there,
in arch_get_unmapped_area_topdown().

To still cover the case that addr is within the DEFAULT_MAP_WINDOW, and
addr + len is above the DFEFAULT_MAP_WINDOW, make the addr hint one
hugepage lower, so that after the align it's still within DEFAULT_MAP_WINDOW,
and the addr + len (2 hugepages) will be above DEFAULT_MAP_WINDOW.

Fixes: cc92882ee218 ("mm: drop hugetlb_get_unmapped_area{_*} functions")
Signed-off-by: Chunyu Hu <chuhu@redhat.com>
---
 tools/testing/selftests/mm/va_high_addr_switch.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/mm/va_high_addr_switch.c b/tools/testing/selftests/mm/va_high_addr_switch.c
index 896b3f73fc53..bd96dc3b5931 100644
--- a/tools/testing/selftests/mm/va_high_addr_switch.c
+++ b/tools/testing/selftests/mm/va_high_addr_switch.c
@@ -230,10 +230,10 @@ void testcases_init(void)
 			.msg = "mmap(-1, MAP_HUGETLB) again",
 		},
 		{
-			.addr = (void *)(addr_switch_hint - pagesize),
+			.addr = (void *)(addr_switch_hint - pagesize - hugepagesize),
 			.size = 2 * hugepagesize,
 			.flags = MAP_HUGETLB | MAP_PRIVATE | MAP_ANONYMOUS,
-			.msg = "mmap(addr_switch_hint - pagesize, 2*hugepagesize, MAP_HUGETLB)",
+			.msg = "mmap(addr_switch_hint - pagesize - hugepagesize, 2*hugepagesize, MAP_HUGETLB)",
 			.low_addr_required = 1,
 			.keep_mapped = 1,
 		},
-- 
2.49.0

Re: [PATCH 1/2] selftests/mm: fix hugepages cleanup too early

[David Hildenbrand]

On 27.08.25 09:52, Chunyu Hu wrote:
> The nr_hugepgs variable is used to keep the original nr_hugepages at the
> hugepage setup step at test beginning. After userfaultfd test, a cleaup is
> executed, both /sys/kernel/mm/hugepages/hugepages-*/nr_hugepages and
> /proc/sys//vm/nr_hugepages are reset to 'original' value before userfaultfd
> test starts.
> 
> Issue here is the value used to restore /proc/sys/vm/nr_hugepages is
> nr_hugepgs which is the initial value before the vm_runtests.sh runs, not
> the value before userfaultfd test starts. 'va_high_addr_swith.sh' tests
> runs after that will possibly see no hugepages available for test, and got
> EINVAL when mmap(HUGETLB), making the result invalid.
> 
> And before pkey tests, nr_hugepgs is changed to be used as a temp variable
> to save nr_hugepages before pkey test, and restore it after pkey tests
> finish. The original nr_hugepages value is not tracked anymore, so no way
> to restore it after all tests finish.
> 
> Add a new variable nr_hugepgs_origin to save the original nr_hugepages, and
> and restore it to nr_hugepages after all tests finish. And change to use
> the nr_hugepgs variable to save the /proc/sys/vm/nr_hugeages after hugepage
> setup, it's also the value before userfaultfd test starts, and the correct
> value to be restored after userfaultfd finishes. The va_high_addr_switch.sh
> broken will be resolved.
> 
> Signed-off-by: Chunyu Hu <chuhu@redhat.com>
> ---
>   tools/testing/selftests/mm/run_vmtests.sh | 9 +++++++--
>   1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh
> index 471e539d82b8..f1a7ad3ec6a7 100755
> --- a/tools/testing/selftests/mm/run_vmtests.sh
> +++ b/tools/testing/selftests/mm/run_vmtests.sh
> @@ -172,13 +172,13 @@ fi
>   
>   # set proper nr_hugepages
>   if [ -n "$freepgs" ] && [ -n "$hpgsize_KB" ]; then
> -	nr_hugepgs=$(cat /proc/sys/vm/nr_hugepages)
> +	nr_hugepgs_origin=$(cat /proc/sys/vm/nr_hugepages)

I'd call this "orig_nr_hugepgs".

But it's a shame that the naming is then out of sync with nr_size_hugepgs?


>   	needpgs=$((needmem_KB / hpgsize_KB))
>   	tries=2
>   	while [ "$tries" -gt 0 ] && [ "$freepgs" -lt "$needpgs" ]; do
>   		lackpgs=$((needpgs - freepgs))
>   		echo 3 > /proc/sys/vm/drop_caches
> -		if ! echo $((lackpgs + nr_hugepgs)) > /proc/sys/vm/nr_hugepages; then
> +		if ! echo $((lackpgs + nr_hugepgs_origin)) > /proc/sys/vm/nr_hugepages; then
>   			echo "Please run this test as root"
>   			exit $ksft_skip
>   		fi
> @@ -189,6 +189,7 @@ if [ -n "$freepgs" ] && [ -n "$hpgsize_KB" ]; then
>   		done < /proc/meminfo
>   		tries=$((tries - 1))
>   	done
> +	nr_hugepgs=$(cat /proc/sys/vm/nr_hugepages)
>   	if [ "$freepgs" -lt "$needpgs" ]; then
>   		printf "Not enough huge pages available (%d < %d)\n" \
>   		       "$freepgs" "$needpgs"
> @@ -532,6 +533,10 @@ CATEGORY="page_frag" run_test ./test_page_frag.sh aligned
>   
>   CATEGORY="page_frag" run_test ./test_page_frag.sh nonaligned
>   
> +if [ "${HAVE_HUGEPAGES}" = 1 ]; then
> +	echo "$nr_hugepgs_origin" > /proc/sys/vm/nr_hugepages
> +fi

FWIW, I think the tests should maybe be doing that 
(save+configure+restore) themselves, like we do with THP settings through.

thp_save_settings()
thp_write_settings()

and friends.

This is not really something run_vmtests.sh should bother with.

A bigger rework, though ...

-- 
Cheers

David / dhildenb

Re: [PATCH 1/2] selftests/mm: fix hugepages cleanup too early

[Chunyu Hu]

[-- Attachment #1: Type: text/plain, Size: 4646 bytes --]

On Wed, Aug 27, 2025 at 7:41 PM David Hildenbrand <david@redhat.com> wrote:

> On 27.08.25 09:52, Chunyu Hu wrote:
> > The nr_hugepgs variable is used to keep the original nr_hugepages at the
> > hugepage setup step at test beginning. After userfaultfd test, a cleaup
> is
> > executed, both /sys/kernel/mm/hugepages/hugepages-*/nr_hugepages and
> > /proc/sys//vm/nr_hugepages are reset to 'original' value before
> userfaultfd
> > test starts.
> >
> > Issue here is the value used to restore /proc/sys/vm/nr_hugepages is
> > nr_hugepgs which is the initial value before the vm_runtests.sh runs, not
> > the value before userfaultfd test starts. 'va_high_addr_swith.sh' tests
> > runs after that will possibly see no hugepages available for test, and
> got
> > EINVAL when mmap(HUGETLB), making the result invalid.
> >
> > And before pkey tests, nr_hugepgs is changed to be used as a temp
> variable
> > to save nr_hugepages before pkey test, and restore it after pkey tests
> > finish. The original nr_hugepages value is not tracked anymore, so no way
> > to restore it after all tests finish.
> >
> > Add a new variable nr_hugepgs_origin to save the original nr_hugepages,
> and
> > and restore it to nr_hugepages after all tests finish. And change to use
> > the nr_hugepgs variable to save the /proc/sys/vm/nr_hugeages after
> hugepage
> > setup, it's also the value before userfaultfd test starts, and the
> correct
> > value to be restored after userfaultfd finishes. The
> va_high_addr_switch.sh
> > broken will be resolved.
> >
> > Signed-off-by: Chunyu Hu <chuhu@redhat.com>
> > ---
> >   tools/testing/selftests/mm/run_vmtests.sh | 9 +++++++--
> >   1 file changed, 7 insertions(+), 2 deletions(-)
> >
> > diff --git a/tools/testing/selftests/mm/run_vmtests.sh
> b/tools/testing/selftests/mm/run_vmtests.sh
> > index 471e539d82b8..f1a7ad3ec6a7 100755
> > --- a/tools/testing/selftests/mm/run_vmtests.sh
> > +++ b/tools/testing/selftests/mm/run_vmtests.sh
> > @@ -172,13 +172,13 @@ fi
> >
> >   # set proper nr_hugepages
> >   if [ -n "$freepgs" ] && [ -n "$hpgsize_KB" ]; then
> > -     nr_hugepgs=$(cat /proc/sys/vm/nr_hugepages)
> > +     nr_hugepgs_origin=$(cat /proc/sys/vm/nr_hugepages)
>
> I'd call this "orig_nr_hugepgs".
>

Hi David,

Thank you for your review and valuable feedback. I will rename it with
a v2 and resend the two patches. Do you have suggestions on patch 2?



>
> But it's a shame that the naming is then out of sync with nr_size_hugepgs?
>

nr_size_hugepgs is for uffd-wp-mremap, the test need all sizes hugepages,
it's used to save and restore the nr_hugepagees of all sizes of hugepages,
it's a test case setup, not like nr_hugepgs which is a global/general
setup.
They are not the same kind, maybe they don't need to be aligned...



>
>
> >       needpgs=$((needmem_KB / hpgsize_KB))
> >       tries=2
> >       while [ "$tries" -gt 0 ] && [ "$freepgs" -lt "$needpgs" ]; do
> >               lackpgs=$((needpgs - freepgs))
> >               echo 3 > /proc/sys/vm/drop_caches
> > -             if ! echo $((lackpgs + nr_hugepgs)) >
> /proc/sys/vm/nr_hugepages; then
> > +             if ! echo $((lackpgs + nr_hugepgs_origin)) >
> /proc/sys/vm/nr_hugepages; then
> >                       echo "Please run this test as root"
> >                       exit $ksft_skip
> >               fi
> > @@ -189,6 +189,7 @@ if [ -n "$freepgs" ] && [ -n "$hpgsize_KB" ]; then
> >               done < /proc/meminfo
> >               tries=$((tries - 1))
> >       done
> > +     nr_hugepgs=$(cat /proc/sys/vm/nr_hugepages)
> >       if [ "$freepgs" -lt "$needpgs" ]; then
> >               printf "Not enough huge pages available (%d < %d)\n" \
> >                      "$freepgs" "$needpgs"
> > @@ -532,6 +533,10 @@ CATEGORY="page_frag" run_test ./test_page_frag.sh
> aligned
> >
> >   CATEGORY="page_frag" run_test ./test_page_frag.sh nonaligned
> >
> > +if [ "${HAVE_HUGEPAGES}" = 1 ]; then
> > +     echo "$nr_hugepgs_origin" > /proc/sys/vm/nr_hugepages
> > +fi
>
> FWIW, I think the tests should maybe be doing that
> (save+configure+restore) themselves, like we do with THP settings through.
>
> thp_save_settings()
> thp_write_settings()
>
> and friends.


> This is not really something run_vmtests.sh should bother with.
>
> A bigger rework, though ...
>

Totally agree, with the c interface to do that is better. then the
vm_runtest.sh would  be clean. It's a bigger rework outside of this topic...



>
> --
> Cheers
>
> David / dhildenb
>
>

-- 
----
Thanks,
Chunyu Hu

[-- Attachment #2: Type: text/html, Size: 7646 bytes --]

Re: [PATCH 1/2] selftests/mm: fix hugepages cleanup too early

[Chunyu Hu]

On Wed, Aug 27, 2025 at 7:41 PM David Hildenbrand <david@redhat.com> wrote:
>
> On 27.08.25 09:52, Chunyu Hu wrote:
> > The nr_hugepgs variable is used to keep the original nr_hugepages at the
> > hugepage setup step at test beginning. After userfaultfd test, a cleaup is
> > executed, both /sys/kernel/mm/hugepages/hugepages-*/nr_hugepages and
> > /proc/sys//vm/nr_hugepages are reset to 'original' value before userfaultfd
> > test starts.
> >
> > Issue here is the value used to restore /proc/sys/vm/nr_hugepages is
> > nr_hugepgs which is the initial value before the vm_runtests.sh runs, not
> > the value before userfaultfd test starts. 'va_high_addr_swith.sh' tests
> > runs after that will possibly see no hugepages available for test, and got
> > EINVAL when mmap(HUGETLB), making the result invalid.
> >
> > And before pkey tests, nr_hugepgs is changed to be used as a temp variable
> > to save nr_hugepages before pkey test, and restore it after pkey tests
> > finish. The original nr_hugepages value is not tracked anymore, so no way
> > to restore it after all tests finish.
> >
> > Add a new variable nr_hugepgs_origin to save the original nr_hugepages, and
> > and restore it to nr_hugepages after all tests finish. And change to use
> > the nr_hugepgs variable to save the /proc/sys/vm/nr_hugeages after hugepage
> > setup, it's also the value before userfaultfd test starts, and the correct
> > value to be restored after userfaultfd finishes. The va_high_addr_switch.sh
> > broken will be resolved.
> >
> > Signed-off-by: Chunyu Hu <chuhu@redhat.com>
> > ---
> >   tools/testing/selftests/mm/run_vmtests.sh | 9 +++++++--
> >   1 file changed, 7 insertions(+), 2 deletions(-)
> >
> > diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh
> > index 471e539d82b8..f1a7ad3ec6a7 100755
> > --- a/tools/testing/selftests/mm/run_vmtests.sh
> > +++ b/tools/testing/selftests/mm/run_vmtests.sh
> > @@ -172,13 +172,13 @@ fi
> >
> >   # set proper nr_hugepages
> >   if [ -n "$freepgs" ] && [ -n "$hpgsize_KB" ]; then
> > -     nr_hugepgs=$(cat /proc/sys/vm/nr_hugepages)
> > +     nr_hugepgs_origin=$(cat /proc/sys/vm/nr_hugepages)
>
> I'd call this "orig_nr_hugepgs".

Hi David,

Thank you for your review and valuable feedback. I will rename it with
a v2 and resend the two patches. Do you have suggestions on patch 2?

>
> But it's a shame that the naming is then out of sync with nr_size_hugepgs?

nr_size_hugepgs is for uffd-wp-mremap, the test need all sizes hugepages,
it's used to save and restore the nr_hugepagees of all sizes of hugepages,
it's a test case setup, not like nr_hugepgs which is a global/general setup.
They are not the same kind, maybe they don't need to be aligned...

>
>
> >       needpgs=$((needmem_KB / hpgsize_KB))
> >       tries=2
> >       while [ "$tries" -gt 0 ] && [ "$freepgs" -lt "$needpgs" ]; do
> >               lackpgs=$((needpgs - freepgs))
> >               echo 3 > /proc/sys/vm/drop_caches
> > -             if ! echo $((lackpgs + nr_hugepgs)) > /proc/sys/vm/nr_hugepages; then
> > +             if ! echo $((lackpgs + nr_hugepgs_origin)) > /proc/sys/vm/nr_hugepages; then
> >                       echo "Please run this test as root"
> >                       exit $ksft_skip
> >               fi
> > @@ -189,6 +189,7 @@ if [ -n "$freepgs" ] && [ -n "$hpgsize_KB" ]; then
> >               done < /proc/meminfo
> >               tries=$((tries - 1))
> >       done
> > +     nr_hugepgs=$(cat /proc/sys/vm/nr_hugepages)
> >       if [ "$freepgs" -lt "$needpgs" ]; then
> >               printf "Not enough huge pages available (%d < %d)\n" \
> >                      "$freepgs" "$needpgs"
> > @@ -532,6 +533,10 @@ CATEGORY="page_frag" run_test ./test_page_frag.sh aligned
> >
> >   CATEGORY="page_frag" run_test ./test_page_frag.sh nonaligned
> >
> > +if [ "${HAVE_HUGEPAGES}" = 1 ]; then
> > +     echo "$nr_hugepgs_origin" > /proc/sys/vm/nr_hugepages
> > +fi
>
> FWIW, I think the tests should maybe be doing that
> (save+configure+restore) themselves, like we do with THP settings through.
>
> thp_save_settings()
> thp_write_settings()
>
> and friends.
>
> This is not really something run_vmtests.sh should bother with.
>
> A bigger rework, though ...

Totally agree, with the c interface to do that is better. then the
vm_runtest.sh would  be clean. It's a bigger rework outside of this topic...

>
> --
> Cheers
>
> David / dhildenb
>


--
----
Thanks,
Chunyu Hu