Re: [PATCH v6 5/8] riscv_cbqri: resctrl: Add cache allocation via capacity block mask

[Chen Pei]

Hi Drew,

Thanks for the quick pointer.

To clarify our report: we were not testing the series on a new core. We
backported v6 onto a 6.6 LTS tree, whose resctrl core still predates
dbc58f7eec40 ("x86/resctrl: Generate default_ctrl instead of sharing
it"): struct rdt_resource still carries a default_ctrl member there and
resctrl_get_default_ctrl() merely returns that stored value, so an
uninitialized default_ctrl shows up as cbm_mask=0 / L3:0=0 exactly as
we observed.

> I think you may be looking at an older version. The function in this
> patch is:
>
> static void cbqri_resctrl_control_init(struct cbqri_resctrl_res *cbqri_res)
>
> struct rdt_resource no longer has a default_ctrl member. Commit
> dbc58f7eec40 ("x86/resctrl: Generate default_ctrl instead of sharing
> it") removed it and derives the value instead.

Right - on the new core the value is derived, so the series needs no
initialization. Our report came from a backport of v6 onto a 6.6 LTS
tree, whose older resctrl core still requires the driver to initialize
default_ctrl; that is a porting issue on our side and has been handled
in our tree. Sorry for the noise.

> I will send v7 today as I have now rebased on v7.3-rc1. It is already
> available as a branch [2]. Please give that a try and let me know of
> any problems.

We will give the v7 branch a try on our QEMU and on the FPGA board,
and report back with results. Thanks again for maintaining this series.

Best regards,
Pei