On Fri, Aug 28, 2026 at 11:13:00AM -0400, Zi Yan wrote: > On Fri Aug 28, 2026 at 4:11 AM EDT, Yeoreum Yun wrote: > > Since glibc commit 321e1fc73f (“malloc: Enable 2MB THP by default on > > AArch64”), > > glibc may call madvise(MADV_HUGEPAGE) for sufficiently large allocations > > made by memalign(). > > > > The underlying VMA may start at a different address from the aligned > > address returned by memalign(). Furthermore, a subsequent > > madvise(MADV_HUGEPAGE) call does not split the VMA because the flag is > > already set. > > > > This causes split_huge_page_test to fail because the check_huge_xxx() > > helpers incorrectly require the address returned by memalign() to > > match the VMA start address reported in /proc/self/smaps. > > > > Fix this by using /proc/self/pagemap and /proc/kpageflags instead of > > /proc/self/smaps to detect huge pages. > > > > Reported-by: David Hildenbrand (Arm) <[email protected]> > > Suggested-by: Zi Yan <[email protected]> > > Signed-off-by: Yeoreum Yun <[email protected]> > > --- > > tools/testing/selftests/mm/vm_util.c | 145 > > ++++++++++++++++++++++------------- > > tools/testing/selftests/mm/vm_util.h | 1 + > > 2 files changed, 92 insertions(+), 54 deletions(-) > > > > diff --git a/tools/testing/selftests/mm/vm_util.c > > b/tools/testing/selftests/mm/vm_util.c > > index 4821a3563036..083b72d92b14 100644 > > --- a/tools/testing/selftests/mm/vm_util.c > > +++ b/tools/testing/selftests/mm/vm_util.c > > @@ -351,31 +351,13 @@ char *__get_smap_entry(void *addr, const char > > *pattern, char *buf, size_t len) > > return entry; > > } > > > > <snip> > > > + for (; start < end; start += scan_mapping_size) { > > + categories = pagemap_scan_get_categories(pagemap_fd, start); > > + pfn = pagemap_get_pfn(pagemap_fd, start); > > + if (pfn == -1UL) { > > + if (!allow_nonpresent) > > + goto out; > > + else > > + continue; > > + } > > + if (pageflags_get(pfn, kpageflags_fd, &kpf)) > > + ksft_exit_fail_msg("read kpageflags: %s\n", > > strerror(errno)); > > + if (check_pmd_mapping && (categories & PAGE_IS_HUGE)) > > + nr_pmd_mappings++; > > + if (kpf & KPF_COMPOUND_TAIL) > > + continue; > > + if (!check_huge_type(categories, kpf, type)) > > + goto out; > > + } > > + > > There is a trailing tab. > > > + if (check_pmd_mapping && (nr_pmd_mappings != nr_hpages)) > > + goto out; > > + ret = true; > > + > > +out: > > + close(pagemap_fd); > > + close(kpageflags_fd); > > + return ret; > > } > > > > Otherwise, LGTM. I assume the replacement of memalign(), from the > discussion between you and Lorenzo, will be added in a separate patch. > For this patch,
Yeap. I'll post with the separated one. > > Reviewed-by: Zi Yan <[email protected]> Thanks! -- Sincerely, Yeoreum Yun
