On 9/25/26 12:41 AM, 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]>
> ---
Looks good to me, some nits below.
Reviewed-by: Sarthak Sharma <[email protected]>
[...]
> -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_msg("open pagemap fail\n");
>
> - for (; start < end; start += hpage_size) {
> + kpageflags_fd = open(KPAGEFLAGS_PATH, O_RDONLY);
> + if (kpageflags_fd < 0)
> + ksft_exit_fail_msg("open kpageflags fail\n");
Again, can we change it to ksft_exit_fail_perror()?
> +
> + if (!check_pmd_mapping &&
> + !check_large_folios(pagemap_fd, kpageflags_fd,
> + addr, len, nr_hpages, hpage_size))
> + goto out;
> +
> + for (; start < end; start += scan_mapping_size) {
> categories = pagemap_scan_get_categories(pagemap_fd, start);
> - if (!(categories & PAGE_IS_HUGE))
> - continue;
> - if (check_huge_type(categories, type))
> + pfn = pagemap_get_pfn(pagemap_fd, start);
> + if (pfn == -1UL) {
> + if (!allow_nonpresent)
> + goto out;
> + else
Nit: We can skip this else here.
> + continue;
> + }
> + if (check_pmd_mapping && (categories & PAGE_IS_HUGE))
> nr_pmd_mappings++;
> + if (!check_huge_type(categories, type))
> + goto out;
> }
> - close(pagemap_fd);
>
> - return nr_hpages == nr_pmd_mappings;
> + if (check_pmd_mapping && (nr_pmd_mappings != nr_hpages))
> + goto out;
> + ret = true;
> +
> +out:
> + close(pagemap_fd);
> + close(kpageflags_fd);
> + return ret;
> }
