diff mbox series

[v3,2/8] x86/resctrl: Remove hard code of RDT_RESOURCE_L3 in monitor.c

Message ID 20230713163207.219710-3-tony.luck@intel.com
State New
Headers
Series x86/resctrl: Add support for Sub-NUMA cluster (SNC) systems |

Commit Message

Luck, Tony July 13, 2023, 4:32 p.m. UTC 
  Scope of monitoring may be scoped at L3 cache granularity (legacy) or
at the node level (systems with Sub NUMA Cluster enabled).

Save the struct rdt_resource pointer that was used to initialize
the monitor sections of code and use that value instead of the
hard-coded RDT_RESOURCE_L3.

No functional change.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Peter Newman <peternewman@google.com>
---
 arch/x86/kernel/cpu/resctrl/monitor.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

Comments

Reinette Chatre July 18, 2023, 8:37 p.m. UTC | #1 
Hi Tony,

Regarding subject and change: Why is the focus on just monitor.c?
Hardcoding of RDT_RESOURCE_L3 as monitoring resource is done
elsewhere also (rdtgroup.c:rdt_get_tree()) - why not treat all
hardcoding?

On 7/13/2023 9:32 AM, Tony Luck wrote:

...

> @@ -759,9 +761,9 @@ static struct mon_evt mbm_local_event = {
>  /*
>   * Initialize the event list for the resource.
>   *
> - * Note that MBM events are also part of RDT_RESOURCE_L3 resource
> - * because as per the SDM the total and local memory bandwidth
> - * are enumerated as part of L3 monitoring.
> + * Monitor events can either be part of RDT_RESOURCE_L3 resource,
> + * or they may be per NUMA node on systems with sub-NUMA cluster
> + * enabled and are then in the RDT_RESOURCE_NODE resource.
>   */
>  static void l3_mon_evt_init(struct rdt_resource *r)
>  {
> @@ -773,6 +775,8 @@ static void l3_mon_evt_init(struct rdt_resource *r)
>  		list_add_tail(&mbm_total_event.list, &r->evt_list);
>  	if (is_mbm_local_enabled())
>  		list_add_tail(&mbm_local_event.list, &r->evt_list);
> +
> +	mon_resource = r;
>  }
>  

This does not seem like the right place for this initialization.
mon_evt_init() has a single job that the function comment clearly
states: "Initialize the event list for the resource". What does
the global mon_resource have to do with the event list?

Would get_rdt_mon_resources() not be more appropriate?

Although, looking ahead it is not clear to me why this is needed.
I'll try to focus my responses to the individual patches in this
regard.

>  int __init rdt_get_mon_l3_config(struct rdt_resource *r)

Reinette
diff mbox series

Patch

diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index ded1fc7cb7cb..9be6ffdd01ae 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -30,6 +30,8 @@  struct rmid_entry {
 	struct list_head		list;
 };
 
+static struct rdt_resource *mon_resource;
+
 /**
  * @rmid_free_lru    A least recently used list of free RMIDs
  *     These RMIDs are guaranteed to have an occupancy less than the
@@ -268,7 +270,7 @@  int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain *d,
  */
 void __check_limbo(struct rdt_domain *d, bool force_free)
 {
-	struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
+	struct rdt_resource *r = mon_resource;
 	struct rmid_entry *entry;
 	u32 crmid = 1, nrmid;
 	bool rmid_dirty;
@@ -333,7 +335,7 @@  int alloc_rmid(void)
 
 static void add_rmid_to_limbo(struct rmid_entry *entry)
 {
-	struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
+	struct rdt_resource *r = mon_resource;
 	struct rdt_domain *d;
 	int cpu, err;
 	u64 val = 0;
@@ -645,7 +647,7 @@  void cqm_handle_limbo(struct work_struct *work)
 
 	mutex_lock(&rdtgroup_mutex);
 
-	r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
+	r = mon_resource;
 	d = container_of(work, struct rdt_domain, cqm_limbo.work);
 
 	__check_limbo(d, false);
@@ -681,7 +683,7 @@  void mbm_handle_overflow(struct work_struct *work)
 	if (!static_branch_likely(&rdt_mon_enable_key))
 		goto out_unlock;
 
-	r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
+	r = mon_resource;
 	d = container_of(work, struct rdt_domain, mbm_over.work);
 
 	list_for_each_entry(prgrp, &rdt_all_groups, rdtgroup_list) {
@@ -759,9 +761,9 @@  static struct mon_evt mbm_local_event = {
 /*
  * Initialize the event list for the resource.
  *
- * Note that MBM events are also part of RDT_RESOURCE_L3 resource
- * because as per the SDM the total and local memory bandwidth
- * are enumerated as part of L3 monitoring.
+ * Monitor events can either be part of RDT_RESOURCE_L3 resource,
+ * or they may be per NUMA node on systems with sub-NUMA cluster
+ * enabled and are then in the RDT_RESOURCE_NODE resource.
  */
 static void l3_mon_evt_init(struct rdt_resource *r)
 {
@@ -773,6 +775,8 @@  static void l3_mon_evt_init(struct rdt_resource *r)
 		list_add_tail(&mbm_total_event.list, &r->evt_list);
 	if (is_mbm_local_enabled())
 		list_add_tail(&mbm_local_event.list, &r->evt_list);
+
+	mon_resource = r;
 }
 
 int __init rdt_get_mon_l3_config(struct rdt_resource *r)