The patch titled
Subject: userfaultfd/selftests: use memfd_create for shmem test type
has been added to the -mm tree. Its filename is
userfaultfd-selftests-use-memfd_create-for-shmem-test-type.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/userfaultfd-selftests-use-memfd_create-for-shmem-test-type.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/userfaultfd-selftests-use-memfd_create-for-shmem-test-type.patch
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------------------------------------------------------
From: Axel Rasmussen <axelrasmussen@xxxxxxxxxx>
Subject: userfaultfd/selftests: use memfd_create for shmem test type
This is a preparatory commit. In the future, we want to be able to setup
alias mappings for area_src and area_dst in the shmem test, like we do in
the hugetlb_shared test. With a VMA obtained via mmap(MAP_ANONYMOUS |
MAP_SHARED), it isn't clear how to do this.
So, mmap() with an fd, so we can create alias mappings. Use memfd_create
instead of actually passing in a tmpfs path like hugetlb does, since it's
more convenient / simpler to run, and works just as well.
Future commits will:
1. Setup the alias mappings.
2. Extend our tests to actually take advantage of this, to test new
userfaultfd behavior being introduced in this series.
Also, a small fix in the area we're changing: when the hugetlb setup fails
in main(), pass in the right argv[] so we actually print out the hugetlb
file path.
Link: https://lkml.kernel.org/r/20210503180737.2487560-8-axelrasmussen@xxxxxxxxxx
Signed-off-by: Axel Rasmussen <axelrasmussen@xxxxxxxxxx>
Reviewed-by: Peter Xu <peterx@xxxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Brian Geffon <bgeffon@xxxxxxxxxx>
Cc: "Dr . David Alan Gilbert" <dgilbert@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Jerome Glisse <jglisse@xxxxxxxxxx>
Cc: Joe Perches <joe@xxxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx>
Cc: Lokesh Gidra <lokeshgidra@xxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Cc: Mina Almasry <almasrymina@xxxxxxxxxx>
Cc: Oliver Upton <oupton@xxxxxxxxxx>
Cc: Shaohua Li <shli@xxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Cc: Wang Qing <wangqing@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/vm/userfaultfd.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
--- a/tools/testing/selftests/vm/userfaultfd.c~userfaultfd-selftests-use-memfd_create-for-shmem-test-type
+++ a/tools/testing/selftests/vm/userfaultfd.c
@@ -85,6 +85,7 @@ static bool test_uffdio_wp = false;
static bool test_uffdio_minor = false;
static bool map_shared;
+static int shm_fd;
static int huge_fd;
static char *huge_fd_off0;
static unsigned long long *count_verify;
@@ -277,8 +278,11 @@ static void shmem_release_pages(char *re
static void shmem_allocate_area(void **alloc_area)
{
+ unsigned long offset =
+ alloc_area == (void **)&area_src ? 0 : nr_pages * page_size;
+
*alloc_area = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE,
- MAP_ANONYMOUS | MAP_SHARED, -1, 0);
+ MAP_SHARED, shm_fd, offset);
if (*alloc_area == MAP_FAILED)
err("mmap of memfd failed");
}
@@ -1602,6 +1606,16 @@ int main(int argc, char **argv)
err("Open of %s failed", argv[4]);
if (ftruncate(huge_fd, 0))
err("ftruncate %s to size 0 failed", argv[4]);
+ } else if (test_type == TEST_SHMEM) {
+ shm_fd = memfd_create(argv[0], 0);
+ if (shm_fd < 0)
+ err("memfd_create");
+ if (ftruncate(shm_fd, nr_pages * page_size * 2))
+ err("ftruncate");
+ if (fallocate(shm_fd,
+ FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, 0,
+ nr_pages * page_size * 2))
+ err("fallocate");
}
printf("nr_pages: %lu, nr_pages_per_cpu: %lu\n",
nr_pages, nr_pages_per_cpu);
_
Patches currently in -mm which might be from axelrasmussen@xxxxxxxxxx are
userfaultfd-release-page-in-error-path-to-avoid-bug_on.patch
userfaultfd-hugetlbfs-avoid-including-userfaultfd_kh-in-hugetlbh.patch
userfaultfd-shmem-combine-shmem_mcopy_atomicmfill_zeropage_pte.patch
userfaultfd-shmem-support-minor-fault-registration-for-shmem.patch
userfaultfd-shmem-support-uffdio_continue-for-shmem.patch
userfaultfd-shmem-advertise-shmem-minor-fault-support.patch
userfaultfd-shmem-modify-shmem_mfill_atomic_pte-to-use-install_pte.patch
userfaultfd-selftests-use-memfd_create-for-shmem-test-type.patch
userfaultfd-selftests-create-alias-mappings-in-the-shmem-test.patch
userfaultfd-selftests-reinitialize-test-context-in-each-test.patch
userfaultfd-selftests-exercise-minor-fault-handling-shmem-support.patch
