perf trace: Beautify mount's first pathname arg

The pathname beautifiers so far support just one augmented pathname per
syscall, so do it just for mount's first arg, later this will get fixed.

With:

  # perf probe -l
  probe:vfs_getname    (on getname_flags:73@acme/git/linux/fs/namei.c with pathname)
  #

Later this will get added to augmented_syscalls.c (eBPF):

In one xterm:

  # perf trace -e mount,umount
  2687.331 ( 3.544 ms): mount/8892 mount(dev_name: /mnt, dir_name: 0x561f9ac184a0, type: 0x561f9ac1b170, flags: BIND) = 0
  3912.126 ( 8.807 ms): umount/8895 umount2(name: /mnt) = 0
  ^C#

In the other:

  $ sudo mount --bind /proc /mnt
  $ sudo umount /mnt

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Benjamin Peterson <benjamin@python.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-qsvhrm2es635cl4zicqjeth2@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index d286f73ef2e5b8b07066984411f0fcec9910bf79..dc8a6c4986ce2066b0e76cd58e0edb2f7f09852a 100644 (file)
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -727,7 +727,8 @@ static struct syscall_fmt {
                   [2] = { .scnprintf = SCA_MMAP_PROT,  /* prot */ },
                   [3] = { .scnprintf = SCA_MMAP_FLAGS, /* flags */ }, }, },
        { .name     = "mount",
-         .arg = { [3] = { .scnprintf = SCA_MOUNT_FLAGS, /* flags */
+         .arg = { [0] = { .scnprintf = SCA_FILENAME, /* dev_name */ },
+                  [3] = { .scnprintf = SCA_MOUNT_FLAGS, /* flags */
                           .mask_val  = SCAMV_MOUNT_FLAGS, /* flags */ }, }, },
        { .name     = "mprotect",
          .arg = { [0] = { .scnprintf = SCA_HEX,        /* start */ },