On Fri, May 10, 2024 at 12:33:39PM +0800, Zorro Lang wrote:
> To avoid the dependence of debugfs, tracefs is mounted on another
> place -- /sys/kernel/tracing now. But for the compatibility, the
> /sys/kernel/debug/tracing is still there. So change _require_ftrace
> helper, try to use the new /sys/kernel/tracing path at first, or
> fallback to the old one if it's not supported.
>
> xfs/499 uses ftrace, so call _require_ftrace in it.
>
> Signed-off-by: Zorro Lang <zlang@xxxxxxxxxx>
> ---
> common/tracing | 13 +++++++++----
> tests/xfs/499 | 6 +++---
> 2 files changed, 12 insertions(+), 7 deletions(-)
>
> diff --git a/common/tracing b/common/tracing
> index b3051c27..8613d044 100644
> --- a/common/tracing
> +++ b/common/tracing
> @@ -4,11 +4,16 @@
> #
> # Routines for dealing with ftrace (or any other tracing).
>
> -FTRACE_INSTANCES_DIR="/sys/kernel/debug/tracing/instances/"
> -
> _require_ftrace() {
> - test -d "$FTRACE_INSTANCES_DIR" || \
> - _notrun "kernel does not support ftrace"
> + if [ -d /sys/kernel/tracing/instances/ ];then
> + FTRACE_ROOT="/sys/kernel/tracing"
> + FTRACE_INSTANCES_DIR="/sys/kernel/tracing/instances"
To answer my own question, this new path has been in Debian since at
least 2021.
> + elif [ -d /sys/kernel/debug/tracing/instances/ ];then
> + FTRACE_ROOT="/sys/kernel/debug/tracing"
> + FTRACE_INSTANCES_DIR="/sys/kernel/debug/tracing/instances"
> + else
> + _notrun "The ftrace is not supported, or tracefs is not mounted"
> + fi
> }
>
> _ftrace_cleanup() {
> diff --git a/tests/xfs/499 b/tests/xfs/499
> index 9672f95d..883415dc 100755
> --- a/tests/xfs/499
> +++ b/tests/xfs/499
> @@ -14,18 +14,18 @@ _begin_fstest auto quick
> _register_cleanup "_cleanup" BUS
>
> # Import common functions.
> +. ./common/tracing
You could probably get rid of the "Import common functions" comment.
This looks good!
Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>
--D
>
> # real QA test starts here
> _supported_fs xfs
> +_require_ftrace
> _require_command "$CC_PROG" "cc"
>
> cprog=$tmp.ftrace.c
> oprog=$tmp.ftrace
> sedprog=$tmp.ftrace.sed
>
> -ftrace_dir=$DEBUGFS_MNT/tracing/events/xfs
> -
> -test -d $ftrace_dir || _notrun "ftrace not enabled"
> +ftrace_dir=$FTRACE_ROOT/events/xfs
>
> # The second argument to __print_symbolic is stringified in the tracepoint's
> # fmt file, so we look for "{ NUM, STRING }" and try to separate each of them
> --
> 2.44.0
>
>
