From: Axel Rasmussen <axelrasmussen@google.com>
To: Alexander Viro <viro@zeniv.linux.org.uk>,
Andrea Arcangeli <aarcange@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Hugh Dickins <hughd@google.com>,
Jerome Glisse <jglisse@redhat.com>, Joe Perches <joe@perches.com>,
Lokesh Gidra <lokeshgidra@google.com>,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
Peter Xu <peterx@redhat.com>, Shaohua Li <shli@fb.com>,
Shuah Khan <shuah@kernel.org>, Wang Qing <wangqing@vivo.com>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org, linux-kselftest@vger.kernel.org,
Axel Rasmussen <axelrasmussen@google.com>,
Cannon Matthews <cannonmatthews@google.com>,
"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
David Rientjes <rientjes@google.com>,
Michel Lespinasse <walken@google.com>,
Mina Almasry <almasrymina@google.com>,
Oliver Upton <oupton@google.com>
Subject: [PATCH 2/5] userfaultfd/selftests: use memfd_create for shmem test type
Date: Wed, 24 Feb 2021 18:14:17 -0800 [thread overview]
Message-ID: <20210225021420.2290912-3-axelrasmussen@google.com> (raw)
In-Reply-To: <20210225021420.2290912-1-axelrasmussen@google.com>
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.
Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
---
tools/testing/selftests/vm/userfaultfd.c | 35 ++++++++++++++++++++----
1 file changed, 30 insertions(+), 5 deletions(-)
diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c
index f5ab5e0312e7..859398efb4fe 100644
--- a/tools/testing/selftests/vm/userfaultfd.c
+++ b/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_area)
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);
--
2.30.0.617.g56c4b15f3c-goog
next prev parent reply other threads:[~2021-02-25 2:16 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-25 2:14 [PATCH 0/5] userfaultfd: support minor fault handling for shmem Axel Rasmussen
2021-02-25 2:14 ` [PATCH 1/5] " Axel Rasmussen
2021-02-25 19:16 ` Axel Rasmussen
2021-02-25 2:14 ` Axel Rasmussen [this message]
2021-02-25 2:14 ` [PATCH 3/5] userfaultfd/selftests: create alias mappings in the shmem test Axel Rasmussen
2021-02-25 2:14 ` [PATCH 4/5] userfaultfd/selftests: reinitialize test context in each test Axel Rasmussen
2021-02-25 2:14 ` [PATCH 5/5] userfaultfd/selftests: exercise minor fault handling shmem support Axel Rasmussen
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