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/20210302000133.272579-3-axelrasmussen@xxxxxxxxxx
Signed-off-by: Axel Rasmussen <axelrasmussen@xxxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Brian Geffon <bgeffon@xxxxxxxxxx>
Cc: Cannon Matthews <cannonmatthews@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: "Dr . David Alan Gilbert" <dgilbert@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Jerome Glisse <jglisse@xxxxxxxxxx>
Cc: Joe Perches <joe@xxxxxxxxxxx>
Cc: Lokesh Gidra <lokeshgidra@xxxxxxxxxx>
Cc: Michel Lespinasse <walken@xxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Cc: Mina Almasry <almasrymina@xxxxxxxxxx>
Cc: Oliver Upton <oupton@xxxxxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Cc: Shaohua Li <shli@xxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Cc: Wang Qing <wangqing@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/vm/userfaultfd.c | 35 ++++++++++++++++++---
1 file changed, 30 insertions(+), 5 deletions(-)
--- 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;
@@ -297,12 +298,20 @@ static int shmem_release_pages(char *rel
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) {
- fprintf(stderr, "shared memory mmap failed\n");
- *alloc_area = NULL;
+ perror("mmap of memfd failed");
+ goto fail;
}
+
+ return;
+
+fail:
+ *alloc_area = NULL;
}
struct uffd_test_ops {
@@ -1672,15 +1681,31 @@ int main(int argc, char **argv)
usage();
huge_fd = open(argv[4], O_CREAT | O_RDWR, 0755);
if (huge_fd < 0) {
- fprintf(stderr, "Open of %s failed", argv[3]);
+ fprintf(stderr, "Open of %s failed", argv[4]);
perror("open");
exit(1);
}
if (ftruncate(huge_fd, 0)) {
- fprintf(stderr, "ftruncate %s to size 0 failed", argv[3]);
+ fprintf(stderr, "ftruncate %s to size 0 failed", argv[4]);
perror("ftruncate");
exit(1);
}
+ } else if (test_type == TEST_SHMEM) {
+ shm_fd = memfd_create(argv[0], 0);
+ if (shm_fd < 0) {
+ perror("memfd_create");
+ exit(1);
+ }
+ if (ftruncate(shm_fd, nr_pages * page_size * 2)) {
+ perror("ftruncate");
+ exit(1);
+ }
+ if (fallocate(shm_fd,
+ FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, 0,
+ nr_pages * page_size * 2)) {
+ perror("fallocate");
+ exit(1);
+ }
}
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-add-minor-fault-registration-mode.patch
userfaultfd-disable-huge-pmd-sharing-for-minor-registered-vmas.patch
userfaultfd-hugetlbfs-only-compile-uffd-helpers-if-config-enabled.patch
userfaultfd-add-uffdio_continue-ioctl.patch
userfaultfd-update-documentation-to-describe-minor-fault-handling.patch
userfaultfd-selftests-add-test-exercising-minor-fault-handling.patch
userfaultfd-support-minor-fault-handling-for-shmem.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
