Re: [PATCH 5/5] fstests: add stress truncation + writeback test

[Luis Chamberlain <mcgrof@kernel.org>]

On Tue, Jun 11, 2024 at 07:45:03AM -0700, Darrick J. Wong wrote:
> On Mon, Jun 10, 2024 at 08:02:02PM -0700, Luis Chamberlain wrote:
> > +# Requires CONFIG_DEBUGFS and truncation knobs
> > +_require_split_debugfs()
> 
> Er... I thought "split" referred to debugfs itself.
> 
> _require_split_huge_pages_knob?

Much better, thanks.

> > +# This aims at trying to reproduce a difficult to reproduce bug found with
> > +# min order. The issue was root caused to an xarray bug when we split folios
> > +# to another order other than 0. This functionality is used to support min
> > +# order. The crash:
> > +#
> > +# https://gist.github.com/mcgrof/d12f586ec6ebe32b2472b5d634c397df
> 
> You might want to paste the stacktrace in here directly, in case the
> gist ever goes away.

Its not a simple crash trace, it is pretty enourmous considering I
decoded it, and it has all locking candidates. Even including it after
the "---" lines of the patch might make someone go: TLDR. Thoughts?

> > +if grep -q thp_split_page /proc/vmstat; then
> > +	split_count_after=$(grep ^thp_split_page /proc/vmstat | head -1 | awk '{print $2}')
> > +	split_count_failed_after=$(grep ^thp_split_page_failed /proc/vmstat | head -1 | awk '{print $2}')
> 
> I think this ought to be a separate function for cleanliness?
> 
> _proc_vmstat()
> {
> 	awk -v name="$1" '{if ($1 ~ name) {print($2)}}' /proc/vmstat
> }

> Otherwise this test looks fine to me.

Thanks!

  Luis