On Tue, Aug 12, 2025 at 11:55:11AM -0400, Zi Yan wrote:
and rename it to is_backed_by_folio().
is_backed_by_folio() checks if the given vaddr is backed a folio with a given order. It does so by:
- getting the pfn of the vaddr;
- checking kpageflags of the pfn;
if order is greater than 0: 3. checking kpageflags of the head pfn; 4. checking kpageflags of all tail pfns.
pmd_order is added to split_huge_page_test.c and replaces max_order.
Signed-off-by: Zi Yan ziy@nvidia.com
.../selftests/mm/split_huge_page_test.c | 67 +++++++++++++------ tools/testing/selftests/mm/vm_util.c | 2 +- tools/testing/selftests/mm/vm_util.h | 1 + 3 files changed, 48 insertions(+), 22 deletions(-)
diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c index 63ac82f0b9e0..3aaf783f339f 100644 --- a/tools/testing/selftests/mm/split_huge_page_test.c +++ b/tools/testing/selftests/mm/split_huge_page_test.c @@ -25,6 +25,7 @@ uint64_t pagesize; unsigned int pageshift; uint64_t pmd_pagesize; +unsigned int pmd_order;
#define SPLIT_DEBUGFS "/sys/kernel/debug/split_huge_pages" #define SMAP_PATH "/proc/self/smaps" @@ -36,23 +37,48 @@ uint64_t pmd_pagesize;
#define GET_ORDER(nr_pages) (31 - __builtin_clz(nr_pages))
-int is_backed_by_thp(char *vaddr, int pagemap_file, int kpageflags_file) +int is_backed_by_folio(char *vaddr, int order, int pagemap_fd, int kpageflags_fd) {
- uint64_t paddr;
- uint64_t page_flags;
- unsigned long pfn_head;
- uint64_t pfn_flags;
- unsigned long pfn;
- unsigned long i;
- if (pagemap_file) {
pread(pagemap_file, &paddr, sizeof(paddr),((long)vaddr >> pageshift) * sizeof(paddr));
- if (!pagemap_fd || !kpageflags_fd)
return 0;
The same in patch 2.
if (kpageflags_file) {pread(kpageflags_file, &page_flags, sizeof(page_flags),PAGEMAP_PFN(paddr) * sizeof(page_flags));
- pfn = pagemap_get_pfn(pagemap_fd, vaddr);
return !!(page_flags & KPF_THP);}
- if (pfn == -1UL)
return 0;- if (get_pfn_flags(pfn, kpageflags_fd, &pfn_flags))
return 0;- if (!order) {
if (pfn_flags & (KPF_THP | KPF_COMPOUND_HEAD | KPF_COMPOUND_TAIL))return 0;return 1;
- return 0;
- if (!(pfn_flags & KPF_THP))
return 0;- pfn_head = pfn & ~((1 << order) - 1);
- if (get_pfn_flags(pfn_head, kpageflags_fd, &pfn_flags))
return 0;- if (!(pfn_flags & (KPF_THP | KPF_COMPOUND_HEAD)))
return 0;- for (i = 1; i < (1UL << order) - 1; i++) {
Do we miss the last tail?
if (get_pfn_flags(pfn_head + i, kpageflags_fd, &pfn_flags))return 0;if (!(pfn_flags & (KPF_THP | KPF_COMPOUND_TAIL)))return 0;- }
If this folio is larger than order, would it still return 1?
- return 1;
}
static void write_file(const char *path, const char *buf, size_t buflen) @@ -233,7 +259,7 @@ void split_pte_mapped_thp(void) thp_size = 0; for (i = 0; i < pagesize * 4; i++) if (i % pagesize == 0 &&
is_backed_by_thp(&pte_mapped[i], pagemap_fd, kpageflags_fd))
is_backed_by_folio(&pte_mapped[i], pmd_order, pagemap_fd, kpageflags_fd)) thp_size++;if (thp_size != 4)
@@ -250,7 +276,7 @@ void split_pte_mapped_thp(void) ksft_exit_fail_msg("%ld byte corrupted\n", i);
if (i % pagesize == 0 &&
is_backed_by_thp(&pte_mapped[i], pagemap_fd, kpageflags_fd))
!is_backed_by_folio(&pte_mapped[i], 0, pagemap_fd, kpageflags_fd)) thp_size++;@@ -522,7 +548,6 @@ int main(int argc, char **argv) const char *fs_loc; bool created_tmp; int offset;
- unsigned int max_order; unsigned int nr_pages; unsigned int tests;
@@ -543,28 +568,28 @@ int main(int argc, char **argv) ksft_exit_fail_msg("Reading PMD pagesize failed\n");
nr_pages = pmd_pagesize / pagesize;
- max_order = GET_ORDER(nr_pages);
- tests = 2 + (max_order - 1) + (2 * max_order) + (max_order - 1) * 4 + 2;
pmd_order = GET_ORDER(nr_pages);
tests = 2 + (pmd_order - 1) + (2 * pmd_order) + (pmd_order - 1) * 4 + 2; ksft_set_plan(tests);
fd_size = 2 * pmd_pagesize;
split_pmd_zero_pages();
- for (i = 0; i < max_order; i++)
for (i = 0; i < pmd_order; i++) if (i != 1) split_pmd_thp_to_order(i);
split_pte_mapped_thp();
- for (i = 0; i < max_order; i++)
for (i = 0; i < pmd_order; i++) split_file_backed_thp(i);
created_tmp = prepare_thp_fs(optional_xfs_path, fs_loc_template, &fs_loc);
- for (i = max_order - 1; i >= 0; i--)
- for (i = pmd_order - 1; i >= 0; i--) split_thp_in_pagecache_to_order_at(fd_size, fs_loc, i, -1);
- for (i = 0; i < max_order; i++)
- for (i = 0; i < pmd_order; i++) for (offset = 0; offset < nr_pages; offset += MAX(nr_pages / 4, 1 << i))
diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c index 4d952d1bc96d..193ba1a1a3cc 100644 --- a/tools/testing/selftests/mm/vm_util.c +++ b/tools/testing/selftests/mm/vm_util.c @@ -338,7 +338,7 @@ int detect_hugetlb_page_sizes(size_t sizes[], int max) return count; }
-static int get_pfn_flags(unsigned long pfn, int kpageflags_fd, uint64_t *flags) +int get_pfn_flags(unsigned long pfn, int kpageflags_fd, uint64_t *flags) { size_t count;
diff --git a/tools/testing/selftests/mm/vm_util.h b/tools/testing/selftests/mm/vm_util.h index 02e3f1e7065b..148b792cff0f 100644 --- a/tools/testing/selftests/mm/vm_util.h +++ b/tools/testing/selftests/mm/vm_util.h @@ -92,6 +92,7 @@ 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 get_pfn_flags(unsigned long pfn, int kpageflags_fd, uint64_t *flags);
int uffd_register(int uffd, void *addr, uint64_t len, bool miss, bool wp, bool minor); -- 2.47.2