On 01.12.23 10:29, Ryan Roberts wrote:
On 21/11/2023 17:16, Suren Baghdasaryan wrote:
Add tests for new UFFDIO_MOVE ioctl which uses uffd to move source
into destination buffer while checking the contents of both after
the move. After the operation the content of the destination buffer
should match the original source buffer's content while the source
buffer should be zeroed. Separate tests are designed for PMD aligned and
unaligned cases because they utilize different code paths in the kernel.
Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
---
tools/testing/selftests/mm/uffd-common.c | 24 +++
tools/testing/selftests/mm/uffd-common.h | 1 +
tools/testing/selftests/mm/uffd-unit-tests.c | 189 +++++++++++++++++++
3 files changed, 214 insertions(+)
diff --git a/tools/testing/selftests/mm/uffd-common.c b/tools/testing/selftests/mm/uffd-common.c
index fb3bbc77fd00..b0ac0ec2356d 100644
--- a/tools/testing/selftests/mm/uffd-common.c
+++ b/tools/testing/selftests/mm/uffd-common.c
@@ -631,6 +631,30 @@ int copy_page(int ufd, unsigned long offset, bool wp)
return __copy_page(ufd, offset, false, wp);
}
+int move_page(int ufd, unsigned long offset, unsigned long len)
+{
+ struct uffdio_move uffdio_move;
+
+ if (offset + len > nr_pages * page_size)
+ err("unexpected offset %lu and length %lu\n", offset, len);
+ uffdio_move.dst = (unsigned long) area_dst + offset;
+ uffdio_move.src = (unsigned long) area_src + offset;
+ uffdio_move.len = len;
+ uffdio_move.mode = UFFDIO_MOVE_MODE_ALLOW_SRC_HOLES;
+ uffdio_move.move = 0;
+ if (ioctl(ufd, UFFDIO_MOVE, &uffdio_move)) {
+ /* real retval in uffdio_move.move */
+ if (uffdio_move.move != -EEXIST)
+ err("UFFDIO_MOVE error: %"PRId64,
+ (int64_t)uffdio_move.move);
Hi Suren,
FYI this error is triggering in mm-unstable (715b67adf4c8):
Testing move-pmd on anon... ERROR: UFFDIO_MOVE error: -16 (errno=16,
@uffd-common.c:648)
I'm running in a VM on Apple M2 (arm64). I haven't debugged any further, but
happy to go deeper if you can direct.
Does it trigger reliably? Which pagesize is that kernel using?
I can spot that uffd_move_pmd_test()/uffd_move_pmd_handle_fault() uses
default_huge_page_size(), which reads the default hugetlb size.
That, however, does not necessarily correspond to the THP size. That one
can be obtained using read_pmd_pagesize() in vm_util.c
I quickly scanned the code (still want to take a deeper look), but all
PAE checks looked sane to me.
I think the issue is folio split handling. I replied to the patch.
--
Cheers,
David / dhildenb
