linux-kernel - [PATCH 07/10] x86/resctrl: Update rmdir_mondata_subdir

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Date: Wed, 27 Mar 2024 13:03:49 -0700
From: Tony Luck <tony.luck@...el.com>
To: Fenghua Yu <fenghua.yu@...el.com>,
	Reinette Chatre <reinette.chatre@...el.com>,
	Maciej Wieczor-Retman <maciej.wieczor-retman@...el.com>,
	Peter Newman <peternewman@...gle.com>,
	James Morse <james.morse@....com>,
	Babu Moger <babu.moger@....com>,
	Drew Fustini <dfustini@...libre.com>
Cc: x86@...nel.org,
	linux-kernel@...r.kernel.org,
	patches@...ts.linux.dev,
	Tony Luck <tony.luck@...el.com>
Subject: [PATCH 07/10] x86/resctrl: Update rmdir_mondata_subdir_allrdtgrp() for Sub-NUMA domains

Old code could simply remove the mon_L3_XX directory with all
contents when a domain was taken offline. With Sub-NUMA cluster
enabled this becomes a multi-stage process.

While the parent L3 domain is still online the offline process for
a SUBL3 domain removes just one directory from mon_L3_XX. When the
last such domain goes offline the whole mon_L3_XX must be removed.

Signed-off-by: Tony Luck <tony.luck@...el.com>
---
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 46 ++++++++++++++++++++++----
 1 file changed, 39 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 22effd8dc207..399dc3175292 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -3012,17 +3012,49 @@ static int mon_addfile(struct kernfs_node *parent_kn, const char *name,
  * and monitor groups with given domain id.
  */
 static void rmdir_mondata_subdir_allrdtgrp(struct rdt_resource *r,
-					   unsigned int dom_id)
+					   struct rdt_domain *d)
 {
 	struct rdtgroup *prgrp, *crgrp;
-	char name[32];
+	char pname[32], name[32];
+	bool remove_all = false;
+	struct kernfs_node *kn;
+	struct rdt_domain *pd;
+
+	sprintf(name, "mon_%s_%02d", r->name, d->id);
+
+	if (!r->parent) {
+		list_for_each_entry(prgrp, &rdt_all_groups, rdtgroup_list) {
+			kernfs_remove_by_name(prgrp->mon.mon_data_kn, name);
+
+			list_for_each_entry(crgrp, &prgrp->mon.crdtgrp_list, mon.crdtgrp_list)
+				kernfs_remove_by_name(crgrp->mon.mon_data_kn, name);
+		}
+		return;
+	}
+
+	sprintf(pname, "mon_%s_%02d", r->parent->name, d->parent);
+	pd = get_parent_domain(r, d);
+	if (!pd)
+		remove_all = true;
 
 	list_for_each_entry(prgrp, &rdt_all_groups, rdtgroup_list) {
-		sprintf(name, "mon_%s_%02d", r->name, dom_id);
-		kernfs_remove_by_name(prgrp->mon.mon_data_kn, name);
+		if (remove_all) {
+			kernfs_remove_by_name(prgrp->mon.mon_data_kn, pname);
+		} else {
+			kn = kernfs_find_and_get_ns(prgrp->mon.mon_data_kn, pname, NULL);
+			if (kn)
+				kernfs_remove_by_name(kn, name);
+		}
 
-		list_for_each_entry(crgrp, &prgrp->mon.crdtgrp_list, mon.crdtgrp_list)
-			kernfs_remove_by_name(crgrp->mon.mon_data_kn, name);
+		list_for_each_entry(crgrp, &prgrp->mon.crdtgrp_list, mon.crdtgrp_list) {
+			if (remove_all) {
+				kernfs_remove_by_name(crgrp->mon.mon_data_kn, pname);
+			} else {
+				kn = kernfs_find_and_get_ns(crgrp->mon.mon_data_kn, pname, NULL);
+				if (kn)
+					kernfs_remove_by_name(kn, name);
+			}
+		}
 	}
 }
 
@@ -3979,7 +4011,7 @@ void resctrl_offline_domain(struct rdt_resource *r, struct rdt_domain *d)
 	 * per domain monitor data directories.
 	 */
 	if (resctrl_mounted && resctrl_arch_mon_capable())
-		rmdir_mondata_subdir_allrdtgrp(r, d->id);
+		rmdir_mondata_subdir_allrdtgrp(r, d);
 
 	if (is_mbm_enabled())
 		cancel_delayed_work(&d->mbm_over);
-- 
2.44.0