Re: [PATCH] tests/throtl: add a new test 006

[Ming Lei <ming.lei@redhat.com>]

On Tue, Mar 04, 2025 at 10:46:40AM +0800, Yu Kuai wrote:
> Hi,
> 
> 在 2025/02/25 10:07, Yu Kuai 写道:
> > Hi,
> > 
> > 在 2025/02/24 21:54, Ming Lei 写道:
> > > > Do you run this test without the kernel patch? If I remembered
> > > > correctly, ext4 issue the meta IO from jbd2 by default, which is from
> > > > root cgroup, and root cgroup can only throttled from cgroup v1.
> > > It passes on v6.14-rc1, does META/SWAP IO only route from cgroup v1?
> > 
> > Of course not, it's just ext4 will issue such IO from root cgroup, and
> > there is no IO can be throttled here.
> > 
> > You might want to bind jbd2 to the test cgroup as well.

But the issue still can't be reproduced by adding the following delta
change, meantime revert 29390bb5661d ("blk-throttle: support prioritized
processing of metadata") on kernel side.

diff --git a/tests/throtl/006 b/tests/throtl/006
index 4baadaf..bb09eb2 100755
--- a/tests/throtl/006
+++ b/tests/throtl/006
@@ -43,7 +43,11 @@ test() {

        _throtl_set_limits wbps=$((1024 * 1024))
        {
+               local jbd2_pid
+
+               jbd2_pid=$(ps -eo pid,comm |grep "jbd2/${THROTL_DEV}" |awk '{print $1}')
                echo "$BASHPID" > "$CGROUP2_DIR/$THROTL_DIR/cgroup.procs"
+               echo "$jbd2_pid" > "$CGROUP2_DIR/$THROTL_DIR/cgroup.procs"
                _throtl_issue_fs_io  "${TMPDIR}/mnt/test.img" write 64K 64 &
                sleep 2
                test_meta_io "${TMPDIR}/mnt"


Thanks,
Ming