[RFC PATCH v2 13/19] fs/resctrl: Check RMID limbo on every resource with occupancy

[Jinjie Ruan]

An RMID is only reused once the L3 occupancy counter shows the cache has
gone cold. When occupancy is monitored on more than one resource, the
RMID has to wait for all of them.

Mark the RMID busy in the domains of every resource that has the
occupancy event, and have the limbo worker read the occupancy of the
resource its domain belongs to. The threshold is one byte value for all
of them; MPAM already sets the limit from the smallest monitored cache.

Signed-off-by: Jinjie Ruan <ruanjinjie at huawei.com>
---
 fs/resctrl/monitor.c | 33 ++++++++++++++++++++-------------
 1 file changed, 20 insertions(+), 13 deletions(-)

diff --git a/fs/resctrl/monitor.c b/fs/resctrl/monitor.c
index 4d90f784a4cf..739134e2ff77 100644
--- a/fs/resctrl/monitor.c
+++ b/fs/resctrl/monitor.c
@@ -126,13 +126,13 @@ static void limbo_release_entry(struct rmid_entry *entry)
 
 /*
  * Check the RMIDs that are marked as busy for this domain. If the
- * reported LLC occupancy is below the threshold clear the busy bit and
+ * reported occupancy is below the threshold clear the busy bit and
  * decrement the count. If the busy count gets to zero on an RMID, we
  * free the RMID
  */
 void __check_limbo(struct rdt_l3_mon_domain *d, bool force_free)
 {
-	struct rdt_resource *r = resctrl_arch_get_resource(RDT_RESOURCE_L3);
+	struct rdt_resource *r = resctrl_arch_get_resource(d->hdr.rid);
 	u32 idx_limit = resctrl_arch_system_num_rmid_idx();
 	struct rmid_entry *entry;
 	bool rmid_dirty = true;
@@ -297,8 +297,8 @@ int alloc_rmid(u32 closid)
 
 static void add_rmid_to_limbo(struct rmid_entry *entry)
 {
-	struct rdt_resource *r = resctrl_arch_get_resource(RDT_RESOURCE_L3);
 	struct rdt_l3_mon_domain *d;
+	struct rdt_resource *r;
 	u32 idx;
 
 	lockdep_assert_held(&rdtgroup_mutex);
@@ -309,16 +309,23 @@ static void add_rmid_to_limbo(struct rmid_entry *entry)
 	idx = resctrl_arch_rmid_idx_encode(entry->closid, entry->rmid);
 
 	entry->busy = 0;
-	list_for_each_entry_rcu(d, &r->mon_domains, hdr.list, lockdep_is_cpus_held()) {
-		/*
-		 * For the first limbo RMID in the domain,
-		 * setup up the limbo worker.
-		 */
-		if (!has_busy_rmid(d))
-			cqm_setup_limbo_handler(d, CQM_LIMBOCHECK_INTERVAL,
-						RESCTRL_PICK_ANY_CPU);
-		set_bit(idx, d->rmid_busy_llc);
-		entry->busy++;
+	for_each_mon_capable_rdt_resource(r) {
+		/* Only resources with the occupancy event have a busy bitmap */
+		if (!resctrl_is_mon_event_enabled(r, QOS_OCCUP_EVENT_ID))
+			continue;
+
+		list_for_each_entry_rcu(d, &r->mon_domains, hdr.list,
+					lockdep_is_cpus_held()) {
+			/*
+			 * For the first limbo RMID in the domain,
+			 * setup up the limbo worker.
+			 */
+			if (!has_busy_rmid(d))
+				cqm_setup_limbo_handler(d, CQM_LIMBOCHECK_INTERVAL,
+							RESCTRL_PICK_ANY_CPU);
+			set_bit(idx, d->rmid_busy_llc);
+			entry->busy++;
+		}
 	}
 
 	rmid_limbo_count++;
-- 
2.34.1