On 8/9/25 12:31 AM, Zi Yan wrote:
The helper gathers an folio order statistics of folios within a virtual address range and checks it against a given order list. It aims to provide a more precise folio order check instead of just checking the existence of PMD folios.
Signed-off-by: Zi Yan ziy@nvidia.com
.../selftests/mm/split_huge_page_test.c | 4 +- tools/testing/selftests/mm/vm_util.c | 133 ++++++++++++++++++ tools/testing/selftests/mm/vm_util.h | 7 + 3 files changed, 141 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c index cb364c5670c6..5ab488fab1cd 100644 --- a/tools/testing/selftests/mm/split_huge_page_test.c +++ b/tools/testing/selftests/mm/split_huge_page_test.c @@ -34,8 +34,6 @@ uint64_t pmd_pagesize; #define PID_FMT_OFFSET "%d,0x%lx,0x%lx,%d,%d" #define PATH_FMT "%s,0x%lx,0x%lx,%d" -#define PFN_MASK ((1UL<<55)-1) -#define KPF_THP (1UL<<22) #define GET_ORDER(nr_pages) (31 - __builtin_clz(nr_pages)) int is_backed_by_thp(char *vaddr, int pagemap_file, int kpageflags_file) @@ -49,7 +47,7 @@ int is_backed_by_thp(char *vaddr, int pagemap_file, int kpageflags_file) if (kpageflags_file) { pread(kpageflags_file, &page_flags, sizeof(page_flags),
(paddr & PFN_MASK) * sizeof(page_flags));
PAGEMAP_PFN(paddr) * sizeof(page_flags));return !!(page_flags & KPF_THP); } diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c index 6a239aa413e2..41d50b74b2f6 100644 --- a/tools/testing/selftests/mm/vm_util.c +++ b/tools/testing/selftests/mm/vm_util.c @@ -338,6 +338,139 @@ int detect_hugetlb_page_sizes(size_t sizes[], int max) return count; } +static int get_page_flags(char *vaddr, int pagemap_file, int kpageflags_file,
uint64_t *flags)+{
- unsigned long pfn;
- size_t count;
- pfn = pagemap_get_pfn(pagemap_file, vaddr);
- /*
* Treat non-present page as a page without any flag, so that* gather_folio_orders() just record the current folio order.*/- if (pfn == -1UL) {
*flags = 0;return 0;- }
- count = pread(kpageflags_file, flags, sizeof(*flags),
pfn * sizeof(*flags));- if (count != sizeof(*flags))
return -1;- return 0;
+}
+static int gather_folio_orders(char *vaddr_start, size_t len,
int pagemap_file, int kpageflags_file,int orders[], int nr_orders)+{
- uint64_t page_flags = 0;
- int cur_order = -1;
- char *vaddr;
- if (!pagemap_file || !kpageflags_file)
return -1;- if (nr_orders <= 0)
return -1;- for (vaddr = vaddr_start; vaddr < vaddr_start + len; ) {
char *next_folio_vaddr;int status;if (get_page_flags(vaddr, pagemap_file, kpageflags_file, &page_flags))return -1;/* all order-0 pages with possible false postive (non folio) */if (!(page_flags & (KPF_COMPOUND_HEAD | KPF_COMPOUND_TAIL))) {orders[0]++;vaddr += psize();continue;}/* skip non thp compound pages */if (!(page_flags & KPF_THP)) {vaddr += psize();continue;}/* vpn points to part of a THP at this point */if (page_flags & KPF_COMPOUND_HEAD)cur_order = 1;else {/* not a head nor a tail in a THP? */if (!(page_flags & KPF_COMPOUND_TAIL))return -1;continue;
If KPF_COMPOUND_TAIL is set, do we use the same vaddr, or should we advance to the next vaddr before continuing?
}next_folio_vaddr = vaddr + (1UL << (cur_order + pshift()));if (next_folio_vaddr >= vaddr_start + len)break;while (!(status = get_page_flags(next_folio_vaddr, pagemap_file,kpageflags_file,&page_flags))) {/* next compound head page or order-0 page */if ((page_flags & KPF_COMPOUND_HEAD) ||!(page_flags & (KPF_COMPOUND_HEAD |KPF_COMPOUND_TAIL))) {if (cur_order < nr_orders) {orders[cur_order]++;cur_order = -1;vaddr = next_folio_vaddr;}break;}/* not a head nor a tail in a THP? */if (!(page_flags & KPF_COMPOUND_TAIL))return -1;cur_order++;next_folio_vaddr = vaddr + (1UL << (cur_order + pshift()));}if (status)return status;- }
- if (cur_order > 0 && cur_order < nr_orders)
orders[cur_order]++;- return 0;
+}
+int check_folio_orders(char *vaddr_start, size_t len, int pagemap_file,
int kpageflags_file, int orders[], int nr_orders)+{
- int *vaddr_orders;
- int status;
- int i;
- vaddr_orders = (int *)malloc(sizeof(int) * nr_orders);
- if (!vaddr_orders)
ksft_exit_fail_msg("Cannot allocate memory for vaddr_orders");- memset(vaddr_orders, 0, sizeof(int) * nr_orders);
- status = gather_folio_orders(vaddr_start, len, pagemap_file,
kpageflags_file, vaddr_orders, nr_orders);- if (status)
return status;- status = 0;
- for (i = 0; i < nr_orders; i++)
if (vaddr_orders[i] != orders[i]) {ksft_print_msg("order %d: expected: %d got %d\n", i,orders[i], vaddr_orders[i]);status = -1;}- return status;
+}
- /* If `ioctls' non-NULL, the allowed ioctls will be returned into the var */ int uffd_register_with_ioctls(int uffd, void *addr, uint64_t len, bool miss, bool wp, bool minor, uint64_t *ioctls)
diff --git a/tools/testing/selftests/mm/vm_util.h b/tools/testing/selftests/mm/vm_util.h index 1843ad48d32b..02e3f1e7065b 100644 --- a/tools/testing/selftests/mm/vm_util.h +++ b/tools/testing/selftests/mm/vm_util.h @@ -18,6 +18,11 @@ #define PM_SWAP BIT_ULL(62) #define PM_PRESENT BIT_ULL(63) +#define KPF_COMPOUND_HEAD BIT_ULL(15) +#define KPF_COMPOUND_TAIL BIT_ULL(16) +#define KPF_THP BIT_ULL(22)
- /*
- Ignore the checkpatch warning, we must read from x but don't want to do
- anything with it in order to trigger a read page fault. We therefore must use
@@ -85,6 +90,8 @@ bool check_huge_shmem(void *addr, int nr_hpages, uint64_t hpage_size); int64_t allocate_transhuge(void *ptr, int pagemap_fd); unsigned long default_huge_page_size(void); int detect_hugetlb_page_sizes(size_t sizes[], int max); +int check_folio_orders(char *vaddr_start, size_t len, int pagemap_file,
int kpageflags_file, int orders[], int nr_orders);int uffd_register(int uffd, void *addr, uint64_t len, bool miss, bool wp, bool minor);