tools/testing/selftests/vm/: add MAP_POPULATE test

As with 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.

[akpm@linux-foundation.org: change message, per review discussion]
Link: http://lkml.kernel.org/r/20180801233636.29354-1-dima@arista.com
Signed-off-by: Dmitry Safonov <dima@arista.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Hua Zhong <hzhong@arista.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Stuart Ritchie <sritchie@arista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/tools/testing/selftests/vm/.gitignore b/tools/testing/selftests/vm/.gitignore
index 342c7bc..af5ff83 100644 (file)
--- 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 fdefa22..9881876 100644 (file)
--- 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 (file)
index 0000000..6b8aeaa
--- /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 in unexpected state");
+
+       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 88cbe55..584a91a 100755 (executable)
--- a/tools/testing/selftests/vm/run_vmtests
+++ b/tools/testing/selftests/vm/run_vmtests
@@ -167,6 +167,17 @@ else
        echo "[PASS]"
 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 "--------------------"