Re: [PATCH v19 00/20] Add support for Sub-NUMA cluster (SNC) systems

Tony Luck
2024-05-29T20:20:32Z

On Tue, May 28, 2024 at 03:55:29PM -0700, Reinette Chatre wrote:
> Hi Tony,
> > 13: Wordsmith commit into imperative.
> > I looked at using kobject_has_children() to check for empty
> > directory, but it needs a "struct kobject *" and all I have
> > is "struct kernfs_node *". I'm now checking how many CPUs
>
> Consider how kobject_has_children() uses that struct kobject *.
> Specifically:
> return kobj->sd && kobj->sd->dir.subdirs
>
> It operates on kobj->sd, which is exactly what you have: struct kernfs_node.

So right. My turn to grumble about other peoples choice of names. If
that field was named "kn" instead of "sd" I would have spotted this
too.

> > remain in ci->shared_cpu_map to detect whether this is the
> > last SNC node.
>
> hmmm, ok, will take a look ... but please finalize discussion of a patch series
> before submitting a new series that rejects feedback without discussion and
> does something completely different in new version.

Reinette,

So here's what rmdir_mondata_subdir_allrdtgrp() looks like using the
subdirs check. It might need an update/better header comment.

-Tony

---

/*
* Remove all subdirectories of mon_data of ctrl_mon groups
* and monitor groups with given domain id.
*/
static void rmdir_mondata_subdir_allrdtgrp(struct rdt_resource *r,
struct rdt_mon_domain *d)
{
struct rdtgroup *prgrp, *crgrp;
struct kernfs_node *kn;
char subname[32];
char name[32];

sprintf(name, "mon_%s_%02d", r->name, d->ci->id);
if (r->mon_scope != RESCTRL_L3_CACHE) {
/*
* SNC mode: Unless the last domain is being removed must
* just remove the SNC subdomain.
*/
sprintf(subname, "mon_sub_%s_%02d", r->name, d->hdr.id);
}

list_for_each_entry(prgrp, &rdt_all_groups, rdtgroup_list) {
kn = kernfs_find_and_get(prgrp->mon.mon_data_kn, name);
if (!kn)
continue;

if (kn->dir.subdirs <= 1)
kernfs_remove(kn);
else
kernfs_remove_by_name(kn, subname);

list_for_each_entry(crgrp, &prgrp->mon.crdtgrp_list, mon.crdtgrp_list) {
kn = kernfs_find_and_get(crgrp->mon.mon_data_kn, name);
if (!kn)
continue;

if (kn->dir.subdirs <= 1)
kernfs_remove(kn);
else
kernfs_remove_by_name(kn, subname);
}
}
}