As many other projects, we use some shmalloc allocator.
At some point we need to make a part of allocated pages back private to
process. And it should be populated straight away.
Check that (MAP_PRIVATE | MAP_POPULATE) actually copies the private page.
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Dmitry Safonov <0x7f454...@gmail.com>
Cc: Hua Zhong <hzh...@arista.com>
Cc: Shuah Khan <sh...@kernel.org>
Cc: Stuart Ritchie <sritc...@arista.com>
Cc: linux-kselft...@vger.kernel.org
Signed-off-by: Dmitry Safonov <d...@arista.com>
---
tools/testing/selftests/vm/.gitignore | 1 +
tools/testing/selftests/vm/Makefile | 1 +
tools/testing/selftests/vm/map_populate.c | 113 ++++++++++++++++++++++++++++++
tools/testing/selftests/vm/run_vmtests | 11 +++
4 files changed, 126 insertions(+)
create mode 100644 tools/testing/selftests/vm/map_populate.c
diff --git a/tools/testing/selftests/vm/.gitignore
b/tools/testing/selftests/vm/.gitignore
index 342c7bc9dc8c..af5ff83f6d7f 100644
--- a/tools/testing/selftests/vm/.gitignore
+++ b/tools/testing/selftests/vm/.gitignore
@@ -1,6 +1,7 @@
hugepage-mmap
hugepage-shm
map_hugetlb
+map_populate
thuge-gen
compaction_test
mlock2-tests
diff --git a/tools/testing/selftests/vm/Makefile
b/tools/testing/selftests/vm/Makefile
index fdefa2295ddc..9881876d2aa0 100644
--- a/tools/testing/selftests/vm/Makefile
+++ b/tools/testing/selftests/vm/Makefile
@@ -12,6 +12,7 @@ TEST_GEN_FILES += gup_benchmark
TEST_GEN_FILES += hugepage-mmap
TEST_GEN_FILES += hugepage-shm
TEST_GEN_FILES += map_hugetlb
+TEST_GEN_FILES += map_populate
TEST_GEN_FILES += mlock-random-test
TEST_GEN_FILES += mlock2-tests
TEST_GEN_FILES += on-fault-limit
diff --git a/tools/testing/selftests/vm/map_populate.c
b/tools/testing/selftests/vm/map_populate.c
new file mode 100644
index 000000000000..df3eacc8eecb
--- /dev/null
+++ b/tools/testing/selftests/vm/map_populate.c
@@ -0,0 +1,113 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2018 Dmitry Safonov, Arista Networks
+ *
+ * MAP_POPULATE | MAP_PRIVATE should COW VMA pages.
+ */
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#ifndef MMAP_SZ
+#define MMAP_SZ 4096
+#endif
+
+#define BUG_ON(condition, description) \
+ do { \
+ if (condition) { \
+ fprintf(stderr, "[FAIL]\t%s:%d\t%s:%s\n", __func__, \
+ __LINE__, (description), strerror(errno)); \
+ exit(1); \
+ } \
+ } while (0)
+
+static int parent_f(int sock, unsigned long *smap, int child)
+{
+ int status, ret;
+
+ ret = read(sock, &status, sizeof(int));
+ BUG_ON(ret <= 0, "read(sock)");
+
+ *smap = 0x22222BAD;
+ ret = msync(smap, MMAP_SZ, MS_SYNC);
+ BUG_ON(ret, "msync()");
+
+ ret = write(sock, &status, sizeof(int));
+ BUG_ON(ret <= 0, "write(sock)");
+
+ waitpid(child, &status, 0);
+ BUG_ON(!WIFEXITED(status), "child hasn't suicide by own will");
+
+ return WEXITSTATUS(status);
+}
+
+static int child_f(int sock, unsigned long *smap, int fd)
+{
+ int ret, buf = 0;
+
+ smap = mmap(0, MMAP_SZ, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_POPULATE, fd, 0);
+ BUG_ON(smap == MAP_FAILED, "mmap()");
+
+ BUG_ON(*smap != 0xdeadbabe, "MAP_PRIVATE | MAP_POPULATE changed file");
+
+ ret = write(sock, &buf, sizeof(int));
+ BUG_ON(ret <= 0, "write(sock)");
+
+ ret = read(sock, &buf, sizeof(int));
+ BUG_ON(ret <= 0, "read(sock)");
+
+ BUG_ON(*smap == 0x22222BAD, "MAP_POPULATE didn't COW private page");
+ BUG_ON(*smap != 0xdeadbabe, "mapping was corrupted");
+
+ return 0;
+}
+
+int main(int argc, char **argv)
+{
+ int sock[2], child, ret;
+ FILE *ftmp;
+ unsigned long *smap;
+
+ ftmp = tmpfile();
+ BUG_ON(ftmp == 0, "tmpfile()");
+
+ ret = ftruncate(fileno(ftmp), MMAP_SZ);
+ BUG_ON(ret, "ftruncate()");
+
+ smap = mmap(0, MMAP_SZ, PROT_READ | PROT_WRITE,
+ MAP_SHARED, fileno(ftmp), 0);
+ BUG_ON(smap == MAP_FAILED, "mmap()");
+
+ *smap = 0xdeadbabe;
+ /* Probably unnecessary, but let it be. */
+ ret = msync(smap, MMAP_SZ, MS_SYNC);
+ BUG_ON(ret, "msync()");
+
+ ret = socketpair(PF_LOCAL, SOCK_SEQPACKET, 0, sock);
+ BUG_ON(ret, "socketpair()");
+
+ child = fork();
+ BUG_ON(child == -1, "fork()");
+
+ if (child) {
+ ret = close(sock[0]);
+ BUG_ON(ret, "close()");
+
+ return parent_f(sock[1], smap, child);
+ }
+
+ ret = close(sock[1]);
+ BUG_ON(ret, "close()");
+
+ return child_f(sock[0], smap, fileno(ftmp));
+}
diff --git a/tools/testing/selftests/vm/run_vmtests
b/tools/testing/selftests/vm/run_vmtests
index 88cbe5575f0c..584a91ae4a8f 100755
--- a/tools/testing/selftests/vm/run_vmtests
+++ b/tools/testing/selftests/vm/run_vmtests
@@ -168,6 +168,17 @@ else
fi
echo "--------------------"
+echo "running map_populate"
+echo "--------------------"
+./map_populate
+if [ $? -ne 0 ]; then
+ echo "[FAIL]"
+ exitcode=1
+else
+ echo "[PASS]"
+fi
+
+echo "--------------------"
echo "running mlock2-tests"
echo "--------------------"
./mlock2-tests
--
2.13.6
