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Message-Id: <20210408234327.624367-6-axelrasmussen@google.com>
Date: Thu, 8 Apr 2021 16:43:23 -0700
From: Axel Rasmussen <axelrasmussen@...gle.com>
To: Alexander Viro <viro@...iv.linux.org.uk>,
Andrea Arcangeli <aarcange@...hat.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Daniel Colascione <dancol@...gle.com>,
Hugh Dickins <hughd@...gle.com>,
Jerome Glisse <jglisse@...hat.com>,
Joe Perches <joe@...ches.com>,
Lokesh Gidra <lokeshgidra@...gle.com>,
Mike Kravetz <mike.kravetz@...cle.com>,
Mike Rapoport <rppt@...ux.vnet.ibm.com>,
Peter Xu <peterx@...hat.com>, Shaohua Li <shli@...com>,
Shuah Khan <shuah@...nel.org>,
Stephen Rothwell <sfr@...b.auug.org.au>,
Wang Qing <wangqing@...o.com>
Cc: linux-api@...r.kernel.org, linux-fsdevel@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org,
linux-mm@...ck.org, Axel Rasmussen <axelrasmussen@...gle.com>,
Brian Geffon <bgeffon@...gle.com>,
"Dr . David Alan Gilbert" <dgilbert@...hat.com>,
Mina Almasry <almasrymina@...gle.com>,
Oliver Upton <oupton@...gle.com>
Subject: [PATCH 5/9] 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.
Signed-off-by: Axel Rasmussen <axelrasmussen@...gle.com>
---
tools/testing/selftests/vm/userfaultfd.c | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c
index 310fc617c383..b0af88b258d7 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;
@@ -278,10 +279,13 @@ static void 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)
- err("shared memory mmap failed");
+ err("mmap of memfd failed");
}
struct uffd_test_ops {
@@ -1446,6 +1450,16 @@ 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);
--
2.31.1.295.g9ea45b61b8-goog
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