On 19 Aug 2025, at 12:50, Zi Yan wrote:
On 19 Aug 2025, at 4:54, David Hildenbrand wrote:
On 18.08.25 20:46, 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 Reviewed-by: Wei Yang richard.weiyang@gmail.com Reviewed-by: wang lian lianux.mm@gmail.com
.../selftests/mm/split_huge_page_test.c | 88 ++++++++++++++----- tools/testing/selftests/mm/vm_util.c | 13 +++ tools/testing/selftests/mm/vm_util.h | 4 + 3 files changed, 81 insertions(+), 24 deletions(-)
diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c index 089e146efeab..56d1eaf9a860 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" @@ -34,26 +35,66 @@ 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)
-static int is_backed_by_thp(char *vaddr, int pagemap_file, int kpageflags_file) +static bool 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;
Final nit (sorry!) :)
const unsigned long nr_pages = 1ul << order;
so you can make some of the code below easier to read.
Sure. Will send a fixup.
Acked-by: David Hildenbrand david@redhat.com
Thanks.
Hi Andrew,
The fixup below replaced 1 << order with nr_pages based on David's suggestion. Do you mind folding it in?
Thanks.
From c07eb882465b938a70acb84e4cdc5b6598536322 Mon Sep 17 00:00:00 2001 From: Zi Yan ziy@nvidia.com Date: Tue, 19 Aug 2025 12:52:13 -0400 Subject: [PATCH] fixup: selftests/mm: use nr_pages instead of 1UL << order.
Signed-off-by: Zi Yan ziy@nvidia.com --- tools/testing/selftests/mm/split_huge_page_test.c | 7 ++++--- 1 file changed, 4 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 56d1eaf9a860..f2882cfab568 100644 --- a/tools/testing/selftests/mm/split_huge_page_test.c +++ b/tools/testing/selftests/mm/split_huge_page_test.c @@ -38,6 +38,7 @@ unsigned int pmd_order; static bool is_backed_by_folio(char *vaddr, int order, int pagemap_fd, int kpageflags_fd) { + const unsigned long nr_pages = 1UL << order; unsigned long pfn_head; uint64_t pfn_flags; unsigned long pfn; @@ -63,7 +64,7 @@ static bool is_backed_by_folio(char *vaddr, int order, int pagemap_fd, if (!(pfn_flags & KPF_THP)) return false;
- pfn_head = pfn & ~((1 << order) - 1); + pfn_head = pfn & ~(nr_pages - 1);
if (pageflags_get(pfn_head, kpageflags_fd, &pfn_flags)) goto fail; @@ -73,7 +74,7 @@ static bool is_backed_by_folio(char *vaddr, int order, int pagemap_fd, return false;
/* check all tail PFN flags */ - for (i = 1; i < 1UL << order; i++) { + for (i = 1; i < nr_pages; i++) { if (pageflags_get(pfn_head + i, kpageflags_fd, &pfn_flags)) goto fail; if (!(pfn_flags & (KPF_THP | KPF_COMPOUND_TAIL))) @@ -84,7 +85,7 @@ static bool is_backed_by_folio(char *vaddr, int order, int pagemap_fd, * check the PFN after this folio, but if its flags cannot be obtained, * assume this folio has the expected order */ - if (pageflags_get(pfn_head + (1UL << order), kpageflags_fd, &pfn_flags)) + if (pageflags_get(pfn_head + nr_pages, kpageflags_fd, &pfn_flags)) return true;
/* this folio is bigger than the given order */