Merge tag 'x86_cache_for_6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 resctrl update from Dave Hansen:
 "Reduce redundant counter reads with resctrl refactoring"

* tag 'x86_cache_for_6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/resctrl: Avoid redundant counter read in __mon_event_count()

arch/x86/kernel/cpu/resctrl/monitor.c

@@ -383,41 +383,36 @@ void free_rmid(u32 rmid)
 		list_add_tail(&entry->list, &rmid_free_lru);
 }
 
-static int __mon_event_count(u32 rmid, struct rmid_read *rr)
+static struct mbm_state *get_mbm_state(struct rdt_domain *d, u32 rmid,
+				       enum resctrl_event_id evtid)
 {
-	struct mbm_state *m;
-	u64 tval = 0;
-
-	if (rr->first)
-		resctrl_arch_reset_rmid(rr->r, rr->d, rmid, rr->evtid);
-
-	rr->err = resctrl_arch_rmid_read(rr->r, rr->d, rmid, rr->evtid, &tval);
-	if (rr->err)
-		return rr->err;
-
-	switch (rr->evtid) {
-	case QOS_L3_OCCUP_EVENT_ID:
-		rr->val += tval;
-		return 0;
+	switch (evtid) {
 	case QOS_L3_MBM_TOTAL_EVENT_ID:
-		m = &rr->d->mbm_total[rmid];
-		break;
+		return &d->mbm_total[rmid];
 	case QOS_L3_MBM_LOCAL_EVENT_ID:
-		m = &rr->d->mbm_local[rmid];
-		break;
+		return &d->mbm_local[rmid];
 	default:
-		/*
-		 * Code would never reach here because an invalid
-		 * event id would fail in resctrl_arch_rmid_read().
-		 */
-		return -EINVAL;
+		return NULL;
 	}
+}
+
+static int __mon_event_count(u32 rmid, struct rmid_read *rr)
+{
+	struct mbm_state *m;
+	u64 tval = 0;
 
 	if (rr->first) {
+		resctrl_arch_reset_rmid(rr->r, rr->d, rmid, rr->evtid);
+		m = get_mbm_state(rr->d, rmid, rr->evtid);
+		if (m)
 			memset(m, 0, sizeof(struct mbm_state));
 		return 0;
 	}
 
+	rr->err = resctrl_arch_rmid_read(rr->r, rr->d, rmid, rr->evtid, &tval);
+	if (rr->err)
+		return rr->err;
+
 	rr->val += tval;
 
 	return 0;