Re: [RFC v2 PATCH 7/7] x86/resctrl: Add debug files when mounted with debug option

[Moger, Babu]

Hi Fenghua,

On 2/16/2023 7:50 PM, Fenghua Yu wrote:
> Hi, Babu,
>
> On 2/2/23 13:47, Babu Moger wrote:
> > Add the debug files to the resctrl hierarchy.
> >
> > Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
> > ---
> >   arch/x86/kernel/cpu/resctrl/rdtgroup.c |   27 
> > +++++++++++++++++++++++++++
> >   1 file changed, 27 insertions(+)
> >
> > diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c 
> > b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> > index c35d91b04de6..b7c72b011264 100644
> > --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> > +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> > @@ -2398,6 +2398,31 @@ static int mkdir_mondata_all(struct 
> > kernfs_node *parent_kn,
> >                    struct rdtgroup *prgrp,
> >                    struct kernfs_node **mon_data_kn);
> >   +void resctrl_add_debug_file(struct kernfs_node *parent_kn,
> > +                const char *config, unsigned long fflags,
> > +                bool debug)
> > +{
> > +    struct rftype *rft;
> > +
> > +    rft = rdtgroup_get_rftype_by_name(config);
> > +    if (debug && rft) {
> > +        rft->fflags |= fflags;
> > +        rdtgroup_add_file(parent_kn, rft);
> > +    } else if (rft) {
> > +        rft->fflags &= ~fflags;
> > +        kernfs_remove_by_name(parent_kn, config);
> > +    }
> > +}
> > +
> > +static void resctrl_add_debug_files(bool debug)
> > +{
> > +    resctrl_add_debug_file(rdtgroup_default.kn, "rmid",
> > +                   RFTYPE_BASE, debug);
> > +    resctrl_add_debug_file(rdtgroup_default.kn, "closid",
> > +                   RFTYPE_BASE_CTRL, debug);
> > +    kernfs_activate(rdtgroup_default.kn);
> > +}
> > +
> >   static int rdt_enable_ctx(struct rdt_fs_context *ctx)
> >   {
> >       int ret = 0;
> > @@ -2411,6 +2436,8 @@ static int rdt_enable_ctx(struct rdt_fs_context 
> > *ctx)
> >       if (!ret && ctx->enable_mba_mbps)
> >           ret = set_mba_sc(true);
> >    > +    resctrl_add_debug_files(ctx->debug);
>
> It's better to change to:
> +    if (ctx->debug)
> +        resctrl_add_debug_files();
>
> Then the functions in the call chain can remove 'debug' parameter and 
> can be simpler.

Actually, debug parameter is required in the resctrl_add_debug_file to 
delete the file if it was mounted with debug option last time.

Thanks

Babu