RE: [PATCH v4 7/7] x86/resctrl: Add debug files when mounted with debug option

Moger, Babu
2023-04-21T18:48:08Z

[AMD Official Use Only - General]

> -----Original Message-----
> From: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
> Sent: Thursday, April 20, 2023 3:59 AM
> To: Moger, Babu <Babu.Moger@amd.com>
> Cc: corbet@lwn.net; Reinette Chatre <reinette.chatre@intel.com>;
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> Subject: Re: [PATCH v4 7/7] x86/resctrl: Add debug files when mounted with
> debug option
>
> On Wed, 19 Apr 2023, Moger, Babu wrote:
>
> >
> >
> > On 4/19/23 08:20, Ilpo Järvinen wrote:
> > > On Mon, 17 Apr 2023, Babu Moger wrote:
> > >
> > >> Add the debug files to the resctrl hierarchy.
> > >>
> > >> Signed-off-by: Babu Moger <babu.moger@amd.com>
> > >> ---
> > >> arch/x86/kernel/cpu/resctrl/internal.h | 1 +
> > >> arch/x86/kernel/cpu/resctrl/rdtgroup.c | 54
> +++++++++++++++++++++++++++++++-
> > >> 2 files changed, 54 insertions(+), 1 deletion(-)
> > >>
> > >> diff --git a/arch/x86/kernel/cpu/resctrl/internal.h
> > >> b/arch/x86/kernel/cpu/resctrl/internal.h
> > >> index 1eac07ebc31b..855109abb480 100644
> > >> --- a/arch/x86/kernel/cpu/resctrl/internal.h
> > >> +++ b/arch/x86/kernel/cpu/resctrl/internal.h
> > >> @@ -288,6 +288,7 @@ struct rdtgroup {
> > >> #define RFTYPE_TOP BIT(4)
> > >> #define RFTYPE_RES_CACHE BIT(5)
> > >> #define RFTYPE_RES_MB BIT(6)
> > >> +#define RFTYPE_DEBUG BIT(7)
> > >> #define RFTYPE_CTRL_INFO (RFTYPE_INFO |
> RFTYPE_CTRL)
> > >> #define RFTYPE_MON_INFO (RFTYPE_INFO |
> RFTYPE_MON)
> > >> #define RFTYPE_TOP_INFO (RFTYPE_INFO |
> RFTYPE_TOP)
> > >> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> > >> b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> > >> index 15ded0dd5b09..1ec4359348c2 100644
> > >> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> > >> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> > >> @@ -1880,6 +1880,7 @@ static struct rftype res_common_files[] = {
> > >> .mode = 0444,
> > >> .kf_ops = &rdtgroup_kf_single_ops,
> > >> .seq_show = rdtgroup_rmid_show,
> > >> + .fflags = RFTYPE_BASE | RFTYPE_DEBUG,
> > >> },
> > >> {
> > >> .name = "schemata",
> > >> @@ -1909,6 +1910,7 @@ static struct rftype res_common_files[] = {
> > >> .mode = 0444,
> > >> .kf_ops = &rdtgroup_kf_single_ops,
> > >> .seq_show = rdtgroup_closid_show,
> > >> + .fflags = RFTYPE_CTRL_BASE | RFTYPE_DEBUG,
> > >> },
> > >>
> > >> };
> > >> @@ -2420,6 +2422,49 @@ static int mkdir_mondata_all(struct
> kernfs_node *parent_kn,
> > >> struct rdtgroup *prgrp,
> > >> struct kernfs_node **mon_data_kn);
> > >>
> > >> +static void resctrl_add_debug_files(void) {
> > >> + struct rftype *rfts, *rft;
> > >> + int len;
> > >> +
> > >> + rfts = res_common_files;
> > >> + len = ARRAY_SIZE(res_common_files);
> > >> +
> > >> + lockdep_assert_held(&rdtgroup_mutex);
> > >> +
> > >> + for (rft = rfts; rft < rfts + len; rft++) {
> > >> + if (rft->fflags & RFTYPE_DEBUG) {
> > >> + rft->fflags &= ~RFTYPE_DEBUG;
> > >
> > > I don't fully follow why you need to play with ->fflags like this.
> > >
> > > Is it for the ->fflags test in rdtgroup_add_files()? Can't you just
> > > do some extra masking there for RFTYPE_DEBUG based on resctrl_debug
> > > which you already keep?
> >
> > Actually with this change, I can remove all these tricks here.
> > I don't have to change the check "if (rft->fflags && ((fflags &
> > rft->fflags) == rft->fflags)) {"
> >
> > diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> > b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> > index 1ec4359348c2..b560c44817bb 100644
> > --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> > +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> > @@ -1925,6 +1925,9 @@ static int rdtgroup_add_files(struct kernfs_node
> > *kn, unsigned long fflags)
> >
> > lockdep_assert_held(&rdtgroup_mutex);
> >
> > + if (resctrl_debug)
> > + fflags |= RFTYPE_DEBUG;
>
> Yes, looks good.
>
> It matches to the idea I had in my mind but doesn't require putting it into the if
> condition itself.
Without if condition? How? Let me know.
Thanks
Babu