On Tue, Jun 01, 2021 at 07:01:18AM +0000, Damien Le Moal wrote:
> On 2021/06/01 15:48, Shin'ichiro Kawasaki wrote:
> > Recent commit d2f442bc0bd5 ("ioengines: add get_max_open_zones zoned
> > block device operation") modified fio to compare --max_open_zoned option
>
> s/max_open_zoned/max_open_zones
>
> > value and max_open_zones reported by the device. The device limit is
> > fetched through sysfs or through an ioengine specific implementation.
> >
> > The test script currently try to fetch the max open zones limit using
> > libzbc tools or sg_inq. If either of these fail, default value 128 is
> > supplied. This default value can be too high when the test script is
> > run for certain zoned block devices, and can therefore result in fio
> > error and test case failure.
>
> If sysfs has the max_open_zones attribute file present, that value should be
> retrieved first. libzbc and sg_inq should be used only if the sysfs attribute is
> not present, that is, when running on older kernels.
Since we can assume that the test script and fio versions are updated in sync,
I don't see any point of duplicating the sysfs parsing in the test script.
If the test script either specifies --max_open_zones=0 or omits the parameter,
fio itself will either parse sysfs, or use libzbc to fetch the max limit.
So I think that the test script should only use those "methods" that fio
itself can't do.
Right now fio can parse sysfs and use libzbc.
The only remaining method is sg_inq. This only I assume that we want to
keep in the test. (I guess the alternative is to implement the
.get_max_open_zones() fio ioengine callback in engines/sg.c, that does
the same. But we probably don't want to do that, right?)
>
> >
> > To avoid the failure, modify the default value used in the test script
> > from 128 to 0. With this, --max_open_zoned=0 is passed to fio, and it
> > makes fio use the max_open_zones reported by the device.
>
> Why pass anything at all since now fio will use the device reported limit by
> default if the user does not specify anything ?
Sure, we can just omit the --max_open_zones parameter completely.
That might be more clear.
>
> >
> > Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@xxxxxxx>
> > ---
> > t/zbd/functions | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/t/zbd/functions b/t/zbd/functions
> > index 40ffe1de..1a7ea970 100644
> > --- a/t/zbd/functions
> > +++ b/t/zbd/functions
> > @@ -180,8 +180,8 @@ max_open_zones() {
> > if ! ${sg_inq} -e --page=0xB6 --len=20 --hex "$dev" \
> > > /dev/null 2>&1; then
> > # Non scsi device such as null_blk can not return max open zones.
>
> This comment is a little outdated since even nullblk now has a limit exposed
> through sysfs (the limit may be 0 == no limit). See above comment. sysfs should
> be the first thing to look at.
>
> > - # Use default value.
> > - echo 128
> > + # Specify 0 to indicate fio to get max open zones from the device.
> > + echo 0
> > else
> > ${sg_inq} -e --page=0xB6 --len=20 --hex "$dev" | tail -1 |
> > {
> >
>
>
> --
> Damien Le Moal
> Western Digital Research
>
