Re: [PATCH v2 32/32] selftests/ftrace: Add blktrace testcase

[Steven Rostedt <rostedt@goodmis.org>]

On Fri, 17 Aug 2018 01:44:18 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:

> Add a basic testcase for blktrace. For making it portable,
> this test uses a loop device.

blktrace is a bit special, as it's maintained by the block subsystem
and not really truly part of ftrace. It lives in the tracing directory,
but the changes go through Jens's tree. I'm guessing that Jens already
has tests for this. Not sure we should add a test to the ftrace
selftests for this tracer.

Jens, you have thoughts on this?

-- Steve

> 
> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> ---
>  tools/testing/selftests/ftrace/config              |    1 
>  .../testing/selftests/ftrace/test.d/tracer/blk.tc  |   91 ++++++++++++++++++++
>  2 files changed, 92 insertions(+)
>  create mode 100644 tools/testing/selftests/ftrace/test.d/tracer/blk.tc
> 
> diff --git a/tools/testing/selftests/ftrace/config b/tools/testing/selftests/ftrace/config
> index c2c8de4fafff..d999032442e1 100644
> --- a/tools/testing/selftests/ftrace/config
> +++ b/tools/testing/selftests/ftrace/config
> @@ -5,6 +5,7 @@ CONFIG_TRACER_SNAPSHOT=y
>  CONFIG_STACK_TRACER=y
>  CONFIG_HIST_TRIGGERS=y
>  CONFIG_SCHED_TRACER=y
> +CONFIG_BLK_DEV_IO_TRACE=y
>  CONFIG_PREEMPT_TRACER=y
>  CONFIG_IRQSOFF_TRACER=y
>  CONFIG_PREEMPTIRQ_DELAY_TEST=m
> diff --git a/tools/testing/selftests/ftrace/test.d/tracer/blk.tc b/tools/testing/selftests/ftrace/test.d/tracer/blk.tc
> new file mode 100644
> index 000000000000..9d6e72810c8a
> --- /dev/null
> +++ b/tools/testing/selftests/ftrace/test.d/tracer/blk.tc
> @@ -0,0 +1,91 @@
> +#!/bin/sh
> +# SPDX-License-Identifier: GPL2.0
> +# description: Test blktrace
> +
> +IMG=$TMPDIR/fs.img
> +MNTDIR=$TMPDIR/mnt
> +
> +if ! grep -wq "blk" available_tracers ; then
> +  echo "blktrace is not supported"
> +  exit_unsupported
> +fi
> +
> +available_fs() { #fstype
> +  grep -q $1 /proc/filesystems && which mkfs.$1
> +}
> +
> +if available_fs ext3; then
> +  FSTYPE=ext3
> +elif available_fs ext4; then
> +  FSTYPE=ext4
> +elif available_fs ext2; then
> +  FSTYPE=ext2
> +elif available_fs xfs; then
> +  FSTYPE=xfs
> +elif available_fs btrfs; then
> +  FSTYPE=btrfs
> +else
> +  echo "No available block-based filesystems"
> +  exit_unresolved
> +fi
> +
> +if ! which losetup; then
> +  echo "No losetup found"
> +  exit_unresolved
> +fi
> +LODEV=`losetup -f`
> +LODEVTRACE=/sys/block/`basename $LODEV`/trace
> +
> +do_cleanup() {
> +  if [ -d $MNTDIR ]; then
> +   umount $MNTDIR ||:
> +  fi
> +  losetup -d $LODEV ||:
> +  rm -f $IMG
> +}
> +
> +# workload failure is not a tracer's failure
> +workload_fail() {
> +  do_cleanup
> +  echo "Failed to run workload"
> +  exit_unresolved
> +}
> +
> +do_fail() {
> +  do_cleanup
> +  echo "Test failed"
> +  exit 1
> +}
> +
> +enable_lodevtrace() {
> +  if [ `cat $LODEVTRACE/enable` -ne 1 ]; then
> +    echo 1 > $LODEVTRACE/enable
> +  fi
> +}
> +
> +echo blk > current_tracer
> +
> +dd if=/dev/zero of=$IMG bs=1M count=10 &&\
> +losetup $LODEV $IMG &&\
> +mkfs.$FSTYPE $LODEV &&\
> +mkdir -p $MNTDIR &&\
> +mount -t $FSTYPE $LODEV $MNTDIR &&\
> +enable_lodevtrace &&\
> +dd if=/dev/urandom of=$MNTDIR/testfile bs=1M count=1 &&\
> +sync &&\
> +umount $MNTDIR || workload_fail
> +
> +grep -q "[dd]" trace || do_fail
> +grep -q "[umount]" trace || do_fail
> +echo > trace
> +
> +losetup $LODEV $IMG &&\
> +mount -t $FSTYPE $LODEV $MNTDIR &&\
> +cat $MNTDIR/testfile > /dev/null &&\
> +echo 0 > $LODEVTRACE/enable &&\
> +umount $MNTDIR || workload_fail
> +
> +grep -q "[cat]" trace || do_fail
> +grep -q "[mount]" trace || do_fail
> +
> +do_cleanup