To prepare for additional types of monitoring domains, move all the L3
resource monitoring domain initialization out of domain_add_cpu_mon()
and into a new helper function l3_mon_domain_setup() (name chosen
as the partner of existing l3_mon_domain_free()).

Signed-off-by: Tony Luck <tony.luck@intel.com>
---
 arch/x86/kernel/cpu/resctrl/core.c | 55 ++++++++++++++++++------------
 1 file changed, 33 insertions(+), 22 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 420e4eb7c160..20b6f2bbf858 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -496,34 +496,13 @@ static void domain_add_cpu_ctrl(int cpu, struct rdt_resource *r)
 	}
 }
 
-static void domain_add_cpu_mon(int cpu, struct rdt_resource *r)
+static void l3_mon_domain_setup(int cpu, int id, struct rdt_resource *r, struct list_head *add_pos)
 {
-	int id = get_domain_id_from_scope(cpu, r->mon_scope);
-	struct list_head *add_pos = NULL;
 	struct rdt_hw_mon_domain *hw_dom;
-	struct rdt_domain_hdr *hdr;
 	struct rdt_mon_domain *d;
 	struct cacheinfo *ci;
 	int err;
 
-	lockdep_assert_held(&domain_list_lock);
-
-	if (id < 0) {
-		pr_warn_once("Can't find monitor domain id for CPU:%d scope:%d for resource %s\n",
-			     cpu, r->mon_scope, r->name);
-		return;
-	}
-
-	hdr = resctrl_find_domain(&r->mon_domains, id, &add_pos);
-	if (hdr) {
-		if (!domain_header_is_valid(hdr, RESCTRL_MON_DOMAIN, r->rid))
-			return;
-		d = container_of(hdr, struct rdt_mon_domain, hdr);
-
-		cpumask_set_cpu(cpu, &d->hdr.cpu_mask);
-		return;
-	}
-
 	hw_dom = kzalloc_node(sizeof(*hw_dom), GFP_KERNEL, cpu_to_node(cpu));
 	if (!hw_dom)
 		return;
@@ -558,6 +537,38 @@ static void domain_add_cpu_mon(int cpu, struct rdt_resource *r)
 	}
 }
 
+static void domain_add_cpu_mon(int cpu, struct rdt_resource *r)
+{
+	int id = get_domain_id_from_scope(cpu, r->mon_scope);
+	struct list_head *add_pos = NULL;
+	struct rdt_domain_hdr *hdr;
+
+	lockdep_assert_held(&domain_list_lock);
+
+	if (id < 0) {
+		pr_warn_once("Can't find monitor domain id for CPU:%d scope:%d for resource %s\n",
+			     cpu, r->mon_scope, r->name);
+		return;
+	}
+
+	hdr = resctrl_find_domain(&r->mon_domains, id, &add_pos);
+	if (hdr) {
+		if (!domain_header_is_valid(hdr, RESCTRL_MON_DOMAIN, r->rid))
+			return;
+		cpumask_set_cpu(cpu, &hdr->cpu_mask);
+
+		return;
+	}
+
+	switch (r->rid) {
+	case RDT_RESOURCE_L3:
+		l3_mon_domain_setup(cpu, id, r, add_pos);
+		break;
+	default:
+		WARN_ON_ONCE(1);
+	}
+}
+
 static void domain_add_cpu(int cpu, struct rdt_resource *r)
 {
 	if (r->alloc_capable)
-- 
2.49.0

Hi Tony,

I do not think the subject is accurate since this patch does not
actually move L3 initialization out of domain_add_cpu_mon().
L3 initialization is still done in domain_add_cpu_mon() but
instead of being open coded it is done in function called
by domain_add_cpu_mon(). Perhaps something like:
"x86/resctrl: Move L3 initialization into function"?


On 6/26/25 9:49 AM, Tony Luck wrote:
> To prepare for additional types of monitoring domains, move all the L3
> resource monitoring domain initialization out of domain_add_cpu_mon()
> and into a new helper function l3_mon_domain_setup() (name chosen
> as the partner of existing l3_mon_domain_free()).

Similar comment as with subject. Also please note that l3_mon_domain_free()
does not exist at this point in the series. How about something like below,
(please feel free to improve):

	To prepare for additional types of monitoring domains, move open coded
	L3 resource monitoring domain initialization from domain_add_cpu_mon()             
	into a new helper function l3_mon_domain_setup() called by                      
	domain_add_cpu_mon().

> 
> Signed-off-by: Tony Luck <tony.luck@intel.com>
> ---

Patch looks good to me.

Reinette