Computing the bandwidth for an event is cheap, and only done once
per second. Doing so simplifies switching between events and allows
choosing different events per ctrl_mon group.

Suggested-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
---
 arch/x86/kernel/cpu/resctrl/monitor.c | 38 ++++++++++++++++++++++-----
 1 file changed, 31 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index 851b561850e0..3ef339e405c2 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -663,9 +663,12 @@ static int __mon_event_count(u32 closid, u32 rmid, struct rmid_read *rr)
  */
 static void mbm_bw_count(u32 closid, u32 rmid, struct rmid_read *rr)
 {
-	u32 idx = resctrl_arch_rmid_idx_encode(closid, rmid);
-	struct mbm_state *m = &rr->d->mbm_local[idx];
 	u64 cur_bw, bytes, cur_bytes;
+	struct mbm_state *m;
+
+	m = get_mbm_state(rr->d, closid, rmid, rr->evtid);
+	if (WARN_ON_ONCE(!m))
+		return;
 
 	cur_bytes = rr->val;
 	bytes = cur_bytes - m->prev_bw_bytes;
@@ -752,20 +755,31 @@ static void update_mba_bw(struct rdtgroup *rgrp, struct rdt_mon_domain *dom_mbm)
 	u32 closid, rmid, cur_msr_val, new_msr_val;
 	struct mbm_state *pmbm_data, *cmbm_data;
 	struct rdt_ctrl_domain *dom_mba;
+	enum resctrl_event_id evt_id;
 	struct rdt_resource *r_mba;
-	u32 cur_bw, user_bw, idx;
 	struct list_head *head;
 	struct rdtgroup *entry;
+	u32 cur_bw, user_bw;
 
-	if (!is_mbm_local_enabled())
+	if (!is_mbm_enabled())
 		return;
 
 	r_mba = &rdt_resources_all[RDT_RESOURCE_MBA].r_resctrl;
+	evt_id = rgrp->mba_mbps_event;
+
+	if (WARN_ON_ONCE(!is_mbm_event(evt_id)))
+		return;
+	if (WARN_ON_ONCE(evt_id == QOS_L3_MBM_LOCAL_EVENT_ID && !is_mbm_local_enabled()))
+		return;
+	if (WARN_ON_ONCE(evt_id == QOS_L3_MBM_TOTAL_EVENT_ID && !is_mbm_total_enabled()))
+		return;
+
 
 	closid = rgrp->closid;
 	rmid = rgrp->mon.rmid;
-	idx = resctrl_arch_rmid_idx_encode(closid, rmid);
-	pmbm_data = &dom_mbm->mbm_local[idx];
+	pmbm_data = get_mbm_state(dom_mbm, closid, rmid, evt_id);
+	if (WARN_ON_ONCE(!pmbm_data))
+		return;
 
 	dom_mba = get_ctrl_domain_from_cpu(smp_processor_id(), r_mba);
 	if (!dom_mba) {
@@ -784,7 +798,9 @@ static void update_mba_bw(struct rdtgroup *rgrp, struct rdt_mon_domain *dom_mbm)
 	 */
 	head = &rgrp->mon.crdtgrp_list;
 	list_for_each_entry(entry, head, mon.crdtgrp_list) {
-		cmbm_data = &dom_mbm->mbm_local[entry->mon.rmid];
+		cmbm_data = get_mbm_state(dom_mbm, entry->closid, entry->mon.rmid, evt_id);
+		if (WARN_ON_ONCE(!cmbm_data))
+			return;
 		cur_bw += cmbm_data->prev_bw;
 	}
 
@@ -837,6 +853,14 @@ static void mbm_update(struct rdt_resource *r, struct rdt_mon_domain *d,
 
 		__mon_event_count(closid, rmid, &rr);
 
+		/*
+		 * Call the MBA software controller only for the
+		 * control groups and when user has enabled
+		 * the software controller explicitly.
+		 */
+		if (is_mba_sc(NULL))
+			mbm_bw_count(closid, rmid, &rr);
+
 		resctrl_arch_mon_ctx_free(rr.r, rr.evtid, rr.arch_mon_ctx);
 	}
 	if (is_mbm_local_enabled()) {
-- 
2.47.0

Hi Tony,

On 10/29/24 10:28 AM, Tony Luck wrote:
> Computing the bandwidth for an event is cheap, and only done once
> per second. Doing so simplifies switching between events and allows
> choosing different events per ctrl_mon group.
> 

If I understand correctly this changelog only describes the first and the
last hunks of this patch. Further, it is the last hunk that introduces the
duplicate code that prompts the refactoring in next patch "x86/resctrl:
Refactor mbm_update()". Inserting the duplicate code and then refactoring it
out does not seem necessary. What if the second hunk of this patch is extracted
into its own patch and the refactoring squashed with what remains?
In the cover letter your motivation for the separate refactor was "to make it
easier to review", but I wonder if separating the unrelated code in second
hunk would make this separate refactor unnecessary while remaining easy to
review?

Reinette