On Mon, Sep 14, 2026 at 04:08:03PM +0200, David Hildenbrand (Arm) wrote: > On 9/14/26 09:30, 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]> > > --- > > [...] > > > index e712a980851c..fd1432dc6152 100644 > > --- a/tools/testing/selftests/mm/vm_util.c > > +++ b/tools/testing/selftests/mm/vm_util.c > > @@ -21,6 +21,8 @@ > > > > unsigned int __page_size; > > unsigned int __page_shift; > > +uint64_t __pmd_psize; > > +uint64_t __pmd_pshift; > > > > uint64_t pagemap_get_entry(int fd, char *start) > > { > > @@ -161,6 +163,9 @@ uint64_t pmd_psize(void) > > char buf[20]; > > ssize_t num_read; > > > > + if (__pmd_psize) > > + return __pmd_psize; > > The only suboptmial thing about these functions is that we keep querying > repeatedly in case of failure. > > If it failed once, it will fail always. > > You could either add a new variable for "queried" or encode it in the > variables like > > uint64_t __pmd_psize = -1ull; > uint64_t __pmd_pshift = -1ull; > > To then set them to 0 or the actual value after we queried.
Okay. I'll respin it with above. Thanks. -- Sincerely, Yeoreum Yun
