On 9/29/26 12:01, Yeoreum Yun wrote: > On Tue, Sep 29, 2026 at 10:07:37AM +0200, David Hildenbrand (Arm) wrote: >> On 9/24/26 21:11, Yeoreum Yun wrote: >>> check_large_folios() only checks for large folios without distinguishing >>> between anonymous and file-backed huge pages. >>> >>> To add huge page type checking, integrate the huge page checks into >>> __check_huge(): >>> >>> 1. If hpage_size == pmd_pagesize, check PAGE_IS_HUGE instead of using >>> check_large_folios(), since only the mapping type matters. This >>> identifies PMD-mapped huge pages. >>> >>> 2. Otherwise, use check_large_folios() to detect large folios. This >>> covers mTHP cases. >>> >>> 3. Check the folio flags according to the huge page type. >>> >>> Suggested-by: David Hildenbrand (Arm) <[email protected]> >>> Suggested-by: Zi Yan <[email protected]> >>> Signed-off-by: Yeoreum Yun <[email protected]> >>> --- >> >> Instead of merging both things (detecting mapping vs. detecting anon vs. >> file), >> could we simply perform the anon vs. file change separately? >> >> Doing another pagemap walk that focuses on that should end up with something >> that is easier to read. > > Okay. I'll change like below in next-spin: > > -------&<------- > > @@ -411,57 +400,78 @@ static bool check_huge_type(uint64_t categories, enum > check_huge_type type) > return false; > } > > -static bool __check_pmd_huge(void *addr, size_t len, int nr_hpages, > - uint64_t hpage_size, enum check_huge_type type) > +static bool __check_huge(void *addr, size_t len, int nr_hpages, > + uint64_t hpage_size, enum check_huge_type type) > { > { > - int pagemap_fd; > + bool ret = false; > + int pagemap_fd, kpageflags_fd; > int nr_pmd_mappings = 0; > + uint64_t pmd_pagesize, scan_mapping_size; > uint64_t categories; > + unsigned long pfn; > + bool check_pmd_mapping, allow_nonpresent; > char *start = addr; > char *end = start + len; > > + pmd_pagesize = read_pmd_pagesize(); > + if (!pmd_pagesize) > + ksft_exit_fail_msg("reading PMD pagesize failed\n"); > + > + check_pmd_mapping = hpage_size == pmd_pagesize; > + scan_mapping_size = (nr_hpages > 0) ? hpage_size : psize(); > + /* Some mTHP tests check a partially populated PMD-sized range. */ > + allow_nonpresent = (uint64_t)nr_hpages * hpage_size < len; > + > pagemap_fd = open(PAGEMAP_PATH, O_RDONLY); > if (pagemap_fd < 0) > ksft_exit_fail_perror("open pagemap"); > > - for (; start < end; start += hpage_size) { > + kpageflags_fd = open(KPAGEFLAGS_PATH, O_RDONLY); > + if (kpageflags_fd < 0) > + ksft_exit_fail_perror("open kpageflags"); > + > + for (; start < end; start += scan_mapping_size) { > categories = pagemap_scan_get_categories(pagemap_fd, start); > - if (!(categories & PAGE_IS_HUGE)) > + pfn = pagemap_get_pfn(pagemap_fd, start); > + if (pfn == -1UL) { > + if (!allow_nonpresent) > + goto out; > continue; > - if (check_huge_type(categories, type)) > + } > + if (!check_huge_type(categories, type)) > + goto out; > + } > + > + if (!check_pmd_mapping) { > + ret = check_large_folios(pagemap_fd, kpageflags_fd, > + addr, len, nr_hpages, hpage_size); > + goto out; > + } > + > + for (start = addr; start < end; start += scan_mapping_size) { > + categories = pagemap_scan_get_categories(pagemap_fd, start); > + if (categories & PAGE_IS_HUGE) > nr_pmd_mappings++; > } > - close(pagemap_fd); > > - return nr_hpages == nr_pmd_mappings; > + if (nr_pmd_mappings != nr_hpages) > + goto out; > + ret = true; > + > +out: > + close(pagemap_fd); > + close(kpageflags_fd); > + return ret; > } >
I'd leave existing __check_huge() mostly alone, and instead have an additional function that checks the type. Essentially a __check_type() or sth that we run after the large folio / pmd check. -- Cheers, David
