On 10 Aug 2025, at 12:49, Donet Tom wrote:
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?
Yeah, I missed a vaddr += psize() here. Thank you for pointing this out.
Best Regards, Yan, Zi