RE: [PATCH v20 09/18] x86/resctrl: Add a new field to struct rmid_read for summation of domains

Luck, Tony
2024-06-20T22:42:17Z

> > When a user reads a monitor file rdtgroup_mondata_show() calls
> > mon_event_read() to package up all the required details into an rmid_read
> > structure which is passed across the smp_call*() infrastructure to code
> > that will read data from hardware and return the value (or error status)
> > in the rmid_read structure.
> >
> > Sub-NUMA Cluster (SNC) mode adds files with new semantics. These require
> > the smp_call-ed code to sum event data from all domains that share an
> > L3 cache.
> >
> > Add a pointer to the L3 "cacheinfo" structure to struct rmid_read
> > for the data collection routines to use to pick the domains to be
> > summed.
> >
> > Reinette suggested that the rmid_read structure has become complex
> > enough to warrant documentation of each of its fields. Add the kerneldoc
> > documentation for struct rmid_read.
> >
> > Signed-off-by: Tony Luck <tony.luck@intel.com>
> > ---
> > arch/x86/kernel/cpu/resctrl/internal.h | 13 +++++++++++++
> > 1 file changed, 13 insertions(+)
> >
> > diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
> > index 99f601d05f3b..d29c7b58c151 100644
> > --- a/arch/x86/kernel/cpu/resctrl/internal.h
> > +++ b/arch/x86/kernel/cpu/resctrl/internal.h
> > @@ -145,12 +145,25 @@ union mon_data_bits {
> > } u;
> > };
> >
> > +/**
> > + * struct rmid_read - Data passed across smp_call*() to read event count
> > + * @rgrp: Resctrl group
> > + * @r: Resource
> > + * @d: Domain. If NULL then sum all domains in @r sharing L3 @ci.id
> > + * @evtid: Which monitor event to read
> > + * @first: Initializes MBM counter when true
> > + * @ci: Cacheinfo for L3. Used when summing domains
> > + * @err: Return error indication
> > + * @val: Return value of event counter
> > + * @arch_mon_ctx: Hardware monitor allocated for this read request (MPAM only)
> > + */
>
> Thank you for adding the kerneldoc. I understand that this file is not
> consistent on how these kerneldoc are formatted, but could you please
> pick whether you think sentences need to end with a period and then stick
> to it in this portion?

This is about the @d and @ci entries that have a "sentence" ending with period,
and then more text that doesn't (matching other lines in this block).

Maybe some other punctuation to split the parts? Do you like "colon"

* @d: Domain: If NULL then sum all domains in @r sharing L3 @ci.id
* @ci: Cacheinfo for L3: Used when summing domains

of maybe "dash"

* @d: Domain - If NULL then sum all domains in @r sharing L3 @ci.id
* @ci: Cacheinfo for L3 - Used when summing domains

Or something else?

>
> > struct rmid_read {
> > struct rdtgroup *rgrp;
> > struct rdt_resource *r;
> > struct rdt_mon_domain *d;
> > enum resctrl_event_id evtid;
> > bool first;
> > + struct cacheinfo *ci;
> > int err;
> > u64 val;
> > void *arch_mon_ctx;

-Tony