tools/testing/selftests/vm/gup_benchmark.c: allow user specified file

Allow a user to specify a file to map by adding a new option, '-f',
providing a means to test various file backings.

If not specified, the benchmark will use a private mapping of /dev/zero,
which produces an anonymous mapping as before.

[akpm@linux-foundation.org: avoid using comma operator]
Link: http://lkml.kernel.org/r/20181010195605.10689-4-keith.busch@intel.com
Signed-off-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Dan Williams <dan.j.williams@intel.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/gup_benchmark.c b/tools/testing/selftests/vm/gup_benchmark.c
index b2082df..43a2d60 100644 (file)
--- a/tools/testing/selftests/vm/gup_benchmark.c
+++ b/tools/testing/selftests/vm/gup_benchmark.c
@@ -31,11 +31,12 @@ int main(int argc, char **argv)
 {
        struct gup_benchmark gup;
        unsigned long size = 128 * MB;
-       int i, fd, opt, nr_pages = 1, thp = -1, repeats = 1, write = 0;
+       int i, fd, filed, opt, nr_pages = 1, thp = -1, repeats = 1, write = 0;
        int cmd = GUP_FAST_BENCHMARK;
+       char *file = "/dev/zero";
        char *p;
 
-       while ((opt = getopt(argc, argv, "m:r:n:tTLU")) != -1) {
+       while ((opt = getopt(argc, argv, "m:r:n:f:tTLU")) != -1) {
                switch (opt) {
                case 'm':
                        size = atoi(optarg) * MB;
@@ -61,11 +62,20 @@ int main(int argc, char **argv)
                case 'w':
                        write = 1;
                        break;
+               case 'f':
+                       file = optarg;
+                       break;
                default:
                        return -1;
                }
        }
 
+       filed = open(file, O_RDWR|O_CREAT);
+       if (filed < 0) {
+               perror("open");
+               exit(filed);
+       }
+
        gup.nr_pages_per_call = nr_pages;
        gup.flags = write;
 
@@ -73,8 +83,7 @@ int main(int argc, char **argv)
        if (fd == -1)
                perror("open"), exit(1);
 
-       p = mmap(NULL, size, PROT_READ | PROT_WRITE,
-                       MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+       p = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, filed, 0);
        if (p == MAP_FAILED)
                perror("mmap"), exit(1);
        gup.addr = (unsigned long)p;