From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>

Hi,

There's a lot of dancing around HugeTLB settings in run_vmtests.sh.
Some test need just a few default huge pages, some require at least 256 MB, and
some just skip lots of tests if huge pages of all supported sizes are not
available.

The goal of this set is to make tests deal with HugeTLB setup and teardown.

There are already convenient helpers that allow easy reading and writing of
/proc and /sysfs, so adding a few APIs that will detect and update HugeTLB
settings shouldn't be a big deal. But these nice helpers use kselftest
framework, and many of HugeTLB (and even THP) test don't, so as a result this
patchset also includes a lot of churn for conversion of those tests to
kselftest framework (patches 7-19).

And there were a few small things I fixed on the way.

I don't mean for this set to land in 7.1-rc1, except perhaps the small fixes in
the beginning of the series (patches 1-4).

But after staring at this code for some time I realized that I won't spot any
new issues in these patches and an extra pair(s) of eyes would be helpful.

The extension of thp_settings to hugepage_settings that also include HugeTLB
helpers is implemented by patches 20-26.

Patches 27-28 are there to allow setting up SHM limits in hugetlb-shm and
thuge-gen tests.

Patches 29-51 integrate the new APIs in all the tests that use HugeTLB.

And at last patches 52-53 drop HugeTLB setup from run_vmtests.sh

Happy Easter to those who celebrate!

Mike Rapoport (Microsoft) (53):
  selftests/mm: hugetlb-read-hwpoison: add SIGBUS handler
  selftests/mm: khugepaged: enable collapse_single_pte_entry_compound for shmem
  selftests/mm: migration: don't assume hupe page is TWOMEG
  selftests/mm: run_vmtests.sh: don't gate THP and KSM tests on HAVE_HUGEPAGES
  selftests/mm: merge map_hugetlb into hugepage-mmap
  selftests/mm: rename hugepage-* tests to hugetlb-*
  selftests/mm: hugetlb-shm: use kselftest framework
  selftests/mm: hugetlb-vmemmap: use kselftest framework
  selftests/mm: hugetlb-madvise: use kselftest framework
  selftests/mm: hugetlb_madv_vs_map: use kselftest framework
  selftests/mm: hugetlb-read-hwpoison: use kselftest framework
  selftests/mm: khugepaged: group tests in an array
  selftests/mm: khugepaged: use ksefltest framework
  selftests/mm: ksm_tests: use kselftest framework
  selftests/mm: protection_keys: use descriptive test names in TAP output
  selftests/mm: protection_keys: use kselftest framework
  selftests/mm: uffd-stress: use kselftest framework
  selftests/mm: uffd-unit-tests: use kselftest framework
  selftests/mm: va_high_addr_switch: use kselftest framework
  selftests/mm: add atexit() and signal handlers to thp_settings
  selftests/mm: rename thp_settings.[ch] to  hugepage_settings.[ch]
  selftests/mm: move HugeTLB helpers to hugepage_settings
  selftests/mm: hugepage_settings: use unsigned long in detect_hugetlb_page_size
  selftests/mm: hugepage_settings: add APIs to get and set nr_hugepages
  selftests/mm: hugepage_settings: rename get_free_hugepages()
  selftests/mm: hugepage_settings: add APIs for HugeTLB setup and teardown
  selftests/mm: move read_file(), read_num() and write_num() to vm_util
  selftests/mm: vm_util: add helpers to set and restore shm limits
  selftests/mm: compaction_test: use HugeTLB helpers ...
  selftests/mm: cow: add setup of HugeTLB pages
  selftests/mm: gup_longterm: add setup of HugeTLB pages
  selftests/mm: gup_test: add setup of HugeTLB pages
  selftests/mm: hmm-tests: add setup of HugeTLB pages
  selftests/mm: hugepage_dio: add setup of HugeTLB pages
  selftests/mm: hugetlb_fault_after_madv: add setup of HugeTLB pages
  selftests/mm: hugetlb-madvise: add setup of HugeTLB pages
  selftests/mm: hugetlb_madv_vs_map: add setup of HugeTLB pages
  selftests/mm: hugetlb-mmap: add setup of HugeTLB pages
  selftests/mm: hugetlb-mremap: add setup of HugeTLB pages
  selftests/mm: hugetlb-shm: add setup of HugeTLB pages
  selftests/mm: hugetlb-soft-online: add setup of HugeTLB pages
  selftests/mm: hugetlb-vmemmap: add setup of HugeTLB pages
  selftests/mm: migration: add setup of HugeTLB pages
  selftests/mm: pagemap_ioctl: add setup of HugeTLB pages
  selftests/mm: protection_keys: use library code for HugeTLB setup
  selftests/mm: thuge-gen: add setup of HugeTLB pages
  selftests/mm: uffd-stress: use hugetlb_save and alloc huge pages
  selftests/mm: uffd-unit-tests: add setup of HugeTLB pages
  selftests/mm: uffd-wp-mremap: add setup of HugeTLB pages
  selftests/mm: va_high_addr_switch: add setup of HugeTLB pages
  selftests/mm: va_high_addr_switch.sh: drop huge pages setup
  selftests/mm: run_vmtests.sh: free memory if available memory is low
  selftests/mm: run_vmtests.sh: drop detection and setup of HugeTLB

 tools/testing/selftests/mm/.gitignore         |   4 +
 tools/testing/selftests/mm/Makefile           |  13 +-
 tools/testing/selftests/mm/compaction_test.c  | 113 +----
 tools/testing/selftests/mm/cow.c              |  29 +-
 .../selftests/mm/folio_split_race_test.c      |   2 +-
 tools/testing/selftests/mm/guard-regions.c    |   2 +-
 tools/testing/selftests/mm/gup_longterm.c     |   3 +-
 tools/testing/selftests/mm/gup_test.c         |  12 +
 tools/testing/selftests/mm/hmm-tests.c        |  24 +-
 tools/testing/selftests/mm/hugepage-mmap.c    |  78 ----
 .../{thp_settings.c => hugepage_settings.c}   | 284 +++++++++++--
 .../{thp_settings.h => hugepage_settings.h}   |  75 +++-
 tools/testing/selftests/mm/hugetlb-madvise.c  | 209 ++++------
 tools/testing/selftests/mm/hugetlb-mmap.c     | 141 +++++++
 .../{hugepage-mremap.c => hugetlb-mremap.c}   |  13 +-
 .../selftests/mm/hugetlb-read-hwpoison.c      | 123 +++---
 .../mm/{hugepage-shm.c => hugetlb-shm.c}      |  65 ++-
 .../selftests/mm/hugetlb-soft-offline.c       |  45 +-
 .../{hugepage-vmemmap.c => hugetlb-vmemmap.c} |  46 +-
 tools/testing/selftests/mm/hugetlb_dio.c      |  15 +-
 .../selftests/mm/hugetlb_fault_after_madv.c   |   7 +-
 .../selftests/mm/hugetlb_madv_vs_map.c        |  22 +-
 tools/testing/selftests/mm/khugepaged.c       | 394 ++++++++----------
 tools/testing/selftests/mm/ksm_tests.c        | 182 ++++----
 tools/testing/selftests/mm/map_hugetlb.c      |  88 ----
 tools/testing/selftests/mm/migration.c        |  54 ++-
 tools/testing/selftests/mm/pagemap_ioctl.c    |  13 +-
 tools/testing/selftests/mm/pkey-helpers.h     |   6 +-
 .../testing/selftests/mm/prctl_thp_disable.c  |   2 +-
 tools/testing/selftests/mm/protection_keys.c  | 131 +++---
 tools/testing/selftests/mm/run_vmtests.sh     | 177 ++------
 tools/testing/selftests/mm/soft-dirty.c       |   2 +-
 .../selftests/mm/split_huge_page_test.c       |   2 +-
 tools/testing/selftests/mm/thuge-gen.c        |  80 +---
 tools/testing/selftests/mm/transhuge-stress.c |   2 +-
 tools/testing/selftests/mm/uffd-common.h      |   1 +
 tools/testing/selftests/mm/uffd-stress.c      |  44 +-
 tools/testing/selftests/mm/uffd-unit-tests.c  | 110 +++--
 tools/testing/selftests/mm/uffd-wp-mremap.c   |  12 +-
 .../selftests/mm/va_high_addr_switch.c        |  40 +-
 .../selftests/mm/va_high_addr_switch.sh       |  39 +-
 tools/testing/selftests/mm/vm_util.c          | 133 +++---
 tools/testing/selftests/mm/vm_util.h          |  15 +-
 43 files changed, 1377 insertions(+), 1475 deletions(-)
 delete mode 100644 tools/testing/selftests/mm/hugepage-mmap.c
 rename tools/testing/selftests/mm/{thp_settings.c => hugepage_settings.c} (60%)
 rename tools/testing/selftests/mm/{thp_settings.h => hugepage_settings.h} (55%)
 create mode 100644 tools/testing/selftests/mm/hugetlb-mmap.c
 rename tools/testing/selftests/mm/{hugepage-mremap.c => hugetlb-mremap.c} (94%)
 rename tools/testing/selftests/mm/{hugepage-shm.c => hugetlb-shm.c} (56%)
 rename tools/testing/selftests/mm/{hugepage-vmemmap.c => hugetlb-vmemmap.c} (76%)
 delete mode 100644 tools/testing/selftests/mm/map_hugetlb.c


base-commit: 9a5c21a0791faf7967feea87f8f345419330bd2f
--
2.53.0

On Mon, Apr 06, 2026 at 05:16:42PM +0300, Mike Rapoport wrote:

> I don't mean for this set to land in 7.1-rc1, except perhaps the small fixes in
> the beginning of the series (patches 1-4).

It might be useful to get some of the conversion to kselftest stuff in
earlier as well, if only to make things a bit more digestable.

On 06/04/2026 15:16, Mike Rapoport wrote:
> From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
> 
> Hi,
> 
> There's a lot of dancing around HugeTLB settings in run_vmtests.sh.
> Some test need just a few default huge pages, some require at least 256 MB, and
> some just skip lots of tests if huge pages of all supported sizes are not
> available.
> 
> The goal of this set is to make tests deal with HugeTLB setup and teardown.

Hi Mike,

I haven't had a chance to review this series properly, but the intent certainly
seems extremely valuable!

I thought I'd share some configuration magic that I always use when running on
arm64. Appologies if I'm teaching you to suck eggs...

arm64 supports multiple hugetlb sizes and (at least in the past) the magic in
run_vmtests.sh only reserves for the default size. As a consequence, whenever I
run these tests on arm64, I always boot with:

hugepagesz=1G hugepages=0:2,1:2
hugepagesz=32M hugepages=0:2,1:2
default_hugepagesz=2M hugepages=0:64,1:64
hugepagesz=64K hugepages=0:2,1:2

Which reserves 2 pages of each supported non-default size in each of 2 NUMA
nodes, and 64 of the default size in each NUMA node. (This would need adjusting
if using a different base page size).

My recollection is that this effectively overrides what the script was doing and
is sufficient to make all hugetlb tests run for all hugepage sizes.

If it's possible to get this non-default hugepage size reservation logic into
the tests themselves, this will make the mm selftests much easier to run on
arm64 with full coverage.

Another observation is that "secretmem.enable" is currently needed on the
cmdline to enable secretmem so that the associated tests run. Not sure what can
be done to make that simpler?

And there are tests that depend on having more than 1 NUMA node; I always run
under QEMU with 2 emulated NUMA nodes. I guess that's really just a property of
the HW, so nothing to be done from the test harness.

Thanks,
Ryan


> 
> There are already convenient helpers that allow easy reading and writing of
> /proc and /sysfs, so adding a few APIs that will detect and update HugeTLB
> settings shouldn't be a big deal. But these nice helpers use kselftest
> framework, and many of HugeTLB (and even THP) test don't, so as a result this
> patchset also includes a lot of churn for conversion of those tests to
> kselftest framework (patches 7-19).
> 
> And there were a few small things I fixed on the way.
> 
> I don't mean for this set to land in 7.1-rc1, except perhaps the small fixes in
> the beginning of the series (patches 1-4).
> 
> But after staring at this code for some time I realized that I won't spot any
> new issues in these patches and an extra pair(s) of eyes would be helpful.
> 
> The extension of thp_settings to hugepage_settings that also include HugeTLB
> helpers is implemented by patches 20-26.
> 
> Patches 27-28 are there to allow setting up SHM limits in hugetlb-shm and
> thuge-gen tests.
> 
> Patches 29-51 integrate the new APIs in all the tests that use HugeTLB.
> 
> And at last patches 52-53 drop HugeTLB setup from run_vmtests.sh
> 
> Happy Easter to those who celebrate!
> 
> Mike Rapoport (Microsoft) (53):
>   selftests/mm: hugetlb-read-hwpoison: add SIGBUS handler
>   selftests/mm: khugepaged: enable collapse_single_pte_entry_compound for shmem
>   selftests/mm: migration: don't assume hupe page is TWOMEG
>   selftests/mm: run_vmtests.sh: don't gate THP and KSM tests on HAVE_HUGEPAGES
>   selftests/mm: merge map_hugetlb into hugepage-mmap
>   selftests/mm: rename hugepage-* tests to hugetlb-*
>   selftests/mm: hugetlb-shm: use kselftest framework
>   selftests/mm: hugetlb-vmemmap: use kselftest framework
>   selftests/mm: hugetlb-madvise: use kselftest framework
>   selftests/mm: hugetlb_madv_vs_map: use kselftest framework
>   selftests/mm: hugetlb-read-hwpoison: use kselftest framework
>   selftests/mm: khugepaged: group tests in an array
>   selftests/mm: khugepaged: use ksefltest framework
>   selftests/mm: ksm_tests: use kselftest framework
>   selftests/mm: protection_keys: use descriptive test names in TAP output
>   selftests/mm: protection_keys: use kselftest framework
>   selftests/mm: uffd-stress: use kselftest framework
>   selftests/mm: uffd-unit-tests: use kselftest framework
>   selftests/mm: va_high_addr_switch: use kselftest framework
>   selftests/mm: add atexit() and signal handlers to thp_settings
>   selftests/mm: rename thp_settings.[ch] to  hugepage_settings.[ch]
>   selftests/mm: move HugeTLB helpers to hugepage_settings
>   selftests/mm: hugepage_settings: use unsigned long in detect_hugetlb_page_size
>   selftests/mm: hugepage_settings: add APIs to get and set nr_hugepages
>   selftests/mm: hugepage_settings: rename get_free_hugepages()
>   selftests/mm: hugepage_settings: add APIs for HugeTLB setup and teardown
>   selftests/mm: move read_file(), read_num() and write_num() to vm_util
>   selftests/mm: vm_util: add helpers to set and restore shm limits
>   selftests/mm: compaction_test: use HugeTLB helpers ...
>   selftests/mm: cow: add setup of HugeTLB pages
>   selftests/mm: gup_longterm: add setup of HugeTLB pages
>   selftests/mm: gup_test: add setup of HugeTLB pages
>   selftests/mm: hmm-tests: add setup of HugeTLB pages
>   selftests/mm: hugepage_dio: add setup of HugeTLB pages
>   selftests/mm: hugetlb_fault_after_madv: add setup of HugeTLB pages
>   selftests/mm: hugetlb-madvise: add setup of HugeTLB pages
>   selftests/mm: hugetlb_madv_vs_map: add setup of HugeTLB pages
>   selftests/mm: hugetlb-mmap: add setup of HugeTLB pages
>   selftests/mm: hugetlb-mremap: add setup of HugeTLB pages
>   selftests/mm: hugetlb-shm: add setup of HugeTLB pages
>   selftests/mm: hugetlb-soft-online: add setup of HugeTLB pages
>   selftests/mm: hugetlb-vmemmap: add setup of HugeTLB pages
>   selftests/mm: migration: add setup of HugeTLB pages
>   selftests/mm: pagemap_ioctl: add setup of HugeTLB pages
>   selftests/mm: protection_keys: use library code for HugeTLB setup
>   selftests/mm: thuge-gen: add setup of HugeTLB pages
>   selftests/mm: uffd-stress: use hugetlb_save and alloc huge pages
>   selftests/mm: uffd-unit-tests: add setup of HugeTLB pages
>   selftests/mm: uffd-wp-mremap: add setup of HugeTLB pages
>   selftests/mm: va_high_addr_switch: add setup of HugeTLB pages
>   selftests/mm: va_high_addr_switch.sh: drop huge pages setup
>   selftests/mm: run_vmtests.sh: free memory if available memory is low
>   selftests/mm: run_vmtests.sh: drop detection and setup of HugeTLB
> 
>  tools/testing/selftests/mm/.gitignore         |   4 +
>  tools/testing/selftests/mm/Makefile           |  13 +-
>  tools/testing/selftests/mm/compaction_test.c  | 113 +----
>  tools/testing/selftests/mm/cow.c              |  29 +-
>  .../selftests/mm/folio_split_race_test.c      |   2 +-
>  tools/testing/selftests/mm/guard-regions.c    |   2 +-
>  tools/testing/selftests/mm/gup_longterm.c     |   3 +-
>  tools/testing/selftests/mm/gup_test.c         |  12 +
>  tools/testing/selftests/mm/hmm-tests.c        |  24 +-
>  tools/testing/selftests/mm/hugepage-mmap.c    |  78 ----
>  .../{thp_settings.c => hugepage_settings.c}   | 284 +++++++++++--
>  .../{thp_settings.h => hugepage_settings.h}   |  75 +++-
>  tools/testing/selftests/mm/hugetlb-madvise.c  | 209 ++++------
>  tools/testing/selftests/mm/hugetlb-mmap.c     | 141 +++++++
>  .../{hugepage-mremap.c => hugetlb-mremap.c}   |  13 +-
>  .../selftests/mm/hugetlb-read-hwpoison.c      | 123 +++---
>  .../mm/{hugepage-shm.c => hugetlb-shm.c}      |  65 ++-
>  .../selftests/mm/hugetlb-soft-offline.c       |  45 +-
>  .../{hugepage-vmemmap.c => hugetlb-vmemmap.c} |  46 +-
>  tools/testing/selftests/mm/hugetlb_dio.c      |  15 +-
>  .../selftests/mm/hugetlb_fault_after_madv.c   |   7 +-
>  .../selftests/mm/hugetlb_madv_vs_map.c        |  22 +-
>  tools/testing/selftests/mm/khugepaged.c       | 394 ++++++++----------
>  tools/testing/selftests/mm/ksm_tests.c        | 182 ++++----
>  tools/testing/selftests/mm/map_hugetlb.c      |  88 ----
>  tools/testing/selftests/mm/migration.c        |  54 ++-
>  tools/testing/selftests/mm/pagemap_ioctl.c    |  13 +-
>  tools/testing/selftests/mm/pkey-helpers.h     |   6 +-
>  .../testing/selftests/mm/prctl_thp_disable.c  |   2 +-
>  tools/testing/selftests/mm/protection_keys.c  | 131 +++---
>  tools/testing/selftests/mm/run_vmtests.sh     | 177 ++------
>  tools/testing/selftests/mm/soft-dirty.c       |   2 +-
>  .../selftests/mm/split_huge_page_test.c       |   2 +-
>  tools/testing/selftests/mm/thuge-gen.c        |  80 +---
>  tools/testing/selftests/mm/transhuge-stress.c |   2 +-
>  tools/testing/selftests/mm/uffd-common.h      |   1 +
>  tools/testing/selftests/mm/uffd-stress.c      |  44 +-
>  tools/testing/selftests/mm/uffd-unit-tests.c  | 110 +++--
>  tools/testing/selftests/mm/uffd-wp-mremap.c   |  12 +-
>  .../selftests/mm/va_high_addr_switch.c        |  40 +-
>  .../selftests/mm/va_high_addr_switch.sh       |  39 +-
>  tools/testing/selftests/mm/vm_util.c          | 133 +++---
>  tools/testing/selftests/mm/vm_util.h          |  15 +-
>  43 files changed, 1377 insertions(+), 1475 deletions(-)
>  delete mode 100644 tools/testing/selftests/mm/hugepage-mmap.c
>  rename tools/testing/selftests/mm/{thp_settings.c => hugepage_settings.c} (60%)
>  rename tools/testing/selftests/mm/{thp_settings.h => hugepage_settings.h} (55%)
>  create mode 100644 tools/testing/selftests/mm/hugetlb-mmap.c
>  rename tools/testing/selftests/mm/{hugepage-mremap.c => hugetlb-mremap.c} (94%)
>  rename tools/testing/selftests/mm/{hugepage-shm.c => hugetlb-shm.c} (56%)
>  rename tools/testing/selftests/mm/{hugepage-vmemmap.c => hugetlb-vmemmap.c} (76%)
>  delete mode 100644 tools/testing/selftests/mm/map_hugetlb.c
> 
> 
> base-commit: 9a5c21a0791faf7967feea87f8f345419330bd2f
> --
> 2.53.0

Hi Ryan,

On Mon, Apr 20, 2026 at 09:37:03AM +0100, Ryan Roberts wrote:
> On 06/04/2026 15:16, Mike Rapoport wrote:
> > From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
> > 
> > Hi,
> > 
> > There's a lot of dancing around HugeTLB settings in run_vmtests.sh.
> > Some test need just a few default huge pages, some require at least 256 MB, and
> > some just skip lots of tests if huge pages of all supported sizes are not
> > available.
> > 
> > The goal of this set is to make tests deal with HugeTLB setup and teardown.
> 
> Hi Mike,
> 
> I haven't had a chance to review this series properly, but the intent certainly
> seems extremely valuable!
> 
> I thought I'd share some configuration magic that I always use when running on
> arm64. Appologies if I'm teaching you to suck eggs...
> 
> arm64 supports multiple hugetlb sizes and (at least in the past) the magic in
> run_vmtests.sh only reserves for the default size. As a consequence, whenever I
> run these tests on arm64, I always boot with:
> 
> hugepagesz=1G hugepages=0:2,1:2
> hugepagesz=32M hugepages=0:2,1:2
> default_hugepagesz=2M hugepages=0:64,1:64
> hugepagesz=64K hugepages=0:2,1:2
> 
> Which reserves 2 pages of each supported non-default size in each of 2 NUMA
> nodes, and 64 of the default size in each NUMA node. (This would need adjusting
> if using a different base page size).
> 
> My recollection is that this effectively overrides what the script was doing and
> is sufficient to make all hugetlb tests run for all hugepage sizes.

My goal is to let the tests themself set up the right hugetlb configuration
without forcing it neither in command line nor in the wrapper scripts.

On x86 I can run all the tests in a virtio-ng VM with two nodes and no
kernel command line overrides. I suppose that should work on arm64 too.

There are some additional settings that such a VM would need to avoid
skipping tests that presume swap or a real filesystem, but that's more of
virtio-ng limitation.

> If it's possible to get this non-default hugepage size reservation logic into
> the tests themselves, this will make the mm selftests much easier to run on
> arm64 with full coverage.

That's what the second half of series do. E.g for cow tests:

https://lore.kernel.org/linux-mm/ee6bbac9-b375-4413-a771-6d32c7afda67@arm.com/T/#m62f23b835061449bc6249afacf993bb32ea11234
 
> Another observation is that "secretmem.enable" is currently needed on the
> cmdline to enable secretmem so that the associated tests run. Not sure what can
> be done to make that simpler?

Looks like you're testing really old kernels :)
The secretmem default changed to "enabled" from 6.5 ;-)
 
> And there are tests that depend on having more than 1 NUMA node; I always run
> under QEMU with 2 emulated NUMA nodes. I guess that's really just a property of
> the HW, so nothing to be done from the test harness.

Right, test harness can't do much about it. It's either run in a virtual
machines with 2 (or more) nodes or enable NUMA emulation in the kernel
configuration and the kernel command line.

> Thanks,
> Ryan

-- 
Sincerely yours,
Mike.

On 20/04/2026 10:19, Mike Rapoport wrote:
> Hi Ryan,
> 
> On Mon, Apr 20, 2026 at 09:37:03AM +0100, Ryan Roberts wrote:
>> On 06/04/2026 15:16, Mike Rapoport wrote:
>>> From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
>>>
>>> Hi,
>>>
>>> There's a lot of dancing around HugeTLB settings in run_vmtests.sh.
>>> Some test need just a few default huge pages, some require at least 256 MB, and
>>> some just skip lots of tests if huge pages of all supported sizes are not
>>> available.
>>>
>>> The goal of this set is to make tests deal with HugeTLB setup and teardown.
>>
>> Hi Mike,
>>
>> I haven't had a chance to review this series properly, but the intent certainly
>> seems extremely valuable!
>>
>> I thought I'd share some configuration magic that I always use when running on
>> arm64. Appologies if I'm teaching you to suck eggs...
>>
>> arm64 supports multiple hugetlb sizes and (at least in the past) the magic in
>> run_vmtests.sh only reserves for the default size. As a consequence, whenever I
>> run these tests on arm64, I always boot with:
>>
>> hugepagesz=1G hugepages=0:2,1:2
>> hugepagesz=32M hugepages=0:2,1:2
>> default_hugepagesz=2M hugepages=0:64,1:64
>> hugepagesz=64K hugepages=0:2,1:2
>>
>> Which reserves 2 pages of each supported non-default size in each of 2 NUMA
>> nodes, and 64 of the default size in each NUMA node. (This would need adjusting
>> if using a different base page size).
>>
>> My recollection is that this effectively overrides what the script was doing and
>> is sufficient to make all hugetlb tests run for all hugepage sizes.
> 
> My goal is to let the tests themself set up the right hugetlb configuration
> without forcing it neither in command line nor in the wrapper scripts.
> 
> On x86 I can run all the tests in a virtio-ng VM with two nodes and no
> kernel command line overrides. I suppose that should work on arm64 too.
> 
> There are some additional settings that such a VM would need to avoid
> skipping tests that presume swap or a real filesystem, but that's more of
> virtio-ng limitation.
> 
>> If it's possible to get this non-default hugepage size reservation logic into
>> the tests themselves, this will make the mm selftests much easier to run on
>> arm64 with full coverage.
> 
> That's what the second half of series do. E.g for cow tests:
> 
> https://lore.kernel.org/linux-mm/ee6bbac9-b375-4413-a771-6d32c7afda67@arm.com/T/#m62f23b835061449bc6249afacf993bb32ea11234

Ahh, excellent; you're already considering the non-default sizes. I'll get back
in my box :)

>  
>> Another observation is that "secretmem.enable" is currently needed on the
>> cmdline to enable secretmem so that the associated tests run. Not sure what can
>> be done to make that simpler?
> 
> Looks like you're testing really old kernels :)
> The secretmem default changed to "enabled" from 6.5 ;-)

Good to know; I created my scripts/environment pre-6.5, so that's just
historical baggage on my part, I guess.

>  
>> And there are tests that depend on having more than 1 NUMA node; I always run
>> under QEMU with 2 emulated NUMA nodes. I guess that's really just a property of
>> the HW, so nothing to be done from the test harness.
> 
> Right, test harness can't do much about it. It's either run in a virtual
> machines with 2 (or more) nodes or enable NUMA emulation in the kernel
> configuration and the kernel command line.

ACK

Thanks again for this improvement!

> 
>> Thanks,
>> Ryan
>