diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index d643fd8327b6..b043af7b0212 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3355,9 +3355,11 @@ static void kfree_rcu_work(struct work_struct *work)
 	}
 
 	/*
-	 * Emergency case only. It can happen under low memory
-	 * condition when an allocation gets failed, so the "bulk"
-	 * path can not be temporary maintained.
+	 * This is used when the "bulk" path can not be used for the
+	 * double-argument of kvfree_rcu().  This happens when the
+	 * page-cache is empty, which means that objects are instead
+	 * queued on a linked list through their rcu_head structures.
+	 * This list is named "Channel 3".
 	 */
 	for (; head; head = next) {
 		unsigned long offset = (unsigned long)head->func;
@@ -3403,8 +3405,8 @@ static inline bool queue_kfree_rcu_work(struct kfree_rcu_cpu *krcp)
 		if ((krcp->bkvhead[0] && !krwp->bkvhead_free[0]) ||
 			(krcp->bkvhead[1] && !krwp->bkvhead_free[1]) ||
 				(krcp->head && !krwp->head_free)) {
-			// Channel 1 corresponds to SLAB ptrs.
-			// Channel 2 corresponds to vmalloc ptrs.
+			// Channel 1 corresponds to the SLAB-pointer bulk path.
+			// Channel 2 corresponds to vmalloc-pointer bulk path.
 			for (j = 0; j < FREE_N_CHANNELS; j++) {
 				if (!krwp->bkvhead_free[j]) {
 					krwp->bkvhead_free[j] = krcp->bkvhead[j];
@@ -3412,7 +3414,8 @@ static inline bool queue_kfree_rcu_work(struct kfree_rcu_cpu *krcp)
 				}
 			}
 
-			// Channel 3 corresponds to emergency path.
+			// Channel 3 corresponds to both SLAB and vmalloc
+			// objects queued on the linked list.
 			if (!krwp->head_free) {
 				krwp->head_free = krcp->head;
 				krcp->head = NULL;