On Mon, Sep 14, 2026 at 10:26:59PM -0400, Zi Yan wrote: > On Mon Sep 14, 2026 at 3:30 AM EDT, Yeoreum Yun wrote: > > HPAGE_SIZE and HPAGE_SHIFT macro is written based on the 4KB PAGE_SIZE. > > When this macro is used in some test, test result would be strange in > > the system where PAGE_SIZE is more then 4KB. > > > > Here is the example with transhuge-stress test with 16KB PAGE_SIZE: > > > > transhuge-stress: allocate 61073 transhuge pages, using 122146 MiB > > virtual memory and 1908 MiB of ram > > 3.292 s/loop, 0.054 ms/page, 37106.002 MiB/s 2566 succeed, 58507 > > failed, 2566 different pages > > 0.591 s/loop, 0.010 ms/page, 206850.792 MiB/s 0 succeed, 61073 > > failed, 0 different pages > > 0.527 s/loop, 0.009 ms/page, 231895.107 MiB/s 0 succeed, 61073 > > failed, 0 different pages > > 0.527 s/loop, 0.009 ms/page, 231839.704 MiB/s 0 succeed, 61073 > > failed, 0 different pages > > 0.528 s/loop, 0.009 ms/page, 231544.782 MiB/s 0 succeed, 61073 > > failed, 0 different pages > > 0.528 s/loop, 0.009 ms/page, 231462.074 MiB/s 0 succeed, 61073 > > failed, 0 different pages > > 0.527 s/loop, 0.009 ms/page, 231770.300 MiB/s 0 succeed, 61073 > > failed, 0 different pages > > ... > > ok 1 Completed > > > > Remove the HPAGE_SIZE and HPAGE_SHIFT macro and introduce pmd_pshift() > > helper to get the HPAGE_SHIFT properly. For HPAGE_SIZE, use pre-existing > > helper, pmd_psize(). > > > > Also, run the KSM_MERGE_TIME_HUGE_PAGES test with a size of 512 MiB, > > which is the least common multiple of the PMD sizes for 4 KiB, 16 KiB, > > and 64 KiB base pages. Since allocate_transhuge() allocates mappings in > > PMD-sized units, the test may fail with the previous size of 100 MiB, > > which is not a multiple of the PMD size when the base page size is > > 16 KiB or 64 KiB. > > > > After this patch, output of transhuge-stress: > > > > transhuge-stress: allocate 3817 transhuge pages, using 122146 MiB virtual > > memory and 119 MiB of ram > > 2.558 s/loop, 0.670 ms/page, 47755.759 MiB/s 2585 succeed, 1232 > > failed, 2585 different pages > > 2.640 s/loop, 0.692 ms/page, 46268.432 MiB/s 2585 succeed, 1232 > > failed, 2585 different pages > > 2.635 s/loop, 0.690 ms/page, 46360.298 MiB/s 2585 succeed, 1232 > > failed, 2585 different pages > > 2.782 s/loop, 0.729 ms/page, 43899.795 MiB/s 2616 succeed, 1201 > > failed, 2616 different pages > > 2.692 s/loop, 0.705 ms/page, 45380.876 MiB/s 2627 succeed, 1190 > > failed, 2627 different pages > > 2.612 s/loop, 0.684 ms/page, 46765.812 MiB/s 2628 succeed, 1189 > > failed, 2628 different pages > > 2.683 s/loop, 0.703 ms/page, 45520.990 MiB/s 2630 succeed, 1187 > > failed, 2630 different pages > > 2.727 s/loop, 0.714 ms/page, 44789.321 MiB/s 2631 succeed, 1186 > > failed, 2631 different pages > > ... > > ok 1 Completed > > > > Suggested-by: Lorenzo Stoakes (ARM) <[email protected]> > > Signed-off-by: Yeoreum Yun <[email protected]> > > --- > > tools/testing/selftests/mm/guard-regions.c | 11 ++++++-- > > tools/testing/selftests/mm/ksm_tests.c | 16 +++++++----- > > tools/testing/selftests/mm/run_vmtests.sh | 4 +-- > > tools/testing/selftests/mm/transhuge-stress.c | 25 +++++++++++-------- > > tools/testing/selftests/mm/vm_util.c | 36 > > ++++++++++++++++++++++++--- > > tools/testing/selftests/mm/vm_util.h | 9 +++---- > > 6 files changed, 71 insertions(+), 30 deletions(-) > > > > diff --git a/tools/testing/selftests/mm/guard-regions.c > > b/tools/testing/selftests/mm/guard-regions.c > > index b724d62d2b75..eee29ef88cb2 100644 > > --- a/tools/testing/selftests/mm/guard-regions.c > > +++ b/tools/testing/selftests/mm/guard-regions.c > > @@ -2195,14 +2195,21 @@ TEST_F(guard_regions, pagemap_scan) > > TEST_F(guard_regions, collapse) > > { > > const unsigned long page_size = self->page_size; > > - const unsigned long size = 2 * HPAGE_SIZE; > > - const unsigned long num_pages = size / page_size; > > + const uint64_t hpage_size = pmd_psize(); > > Is it better to use pmd_page_size/pmd_page_shift instead of > hpage_size/hpage_shift for clarification? Maybe in a follow-up patch if > you think it is reasonable.
He, I don’t have a strong opinion on this, but personally, I think explicitly naming the huge-page size used by the tests pmd_page_size makes it clearer. Still, if you think the suggested approach is better, I’m happy to change it accordingly. ;) > > Otherwise, with David's concern addressed, feel free to add > > Reviewed-by: Zi Yan <[email protected]> Thanks! > > -- > Best Regards, > Yan, Zi > -- Sincerely, Yeoreum Yun
