20  * buckets. Initially, a new flow starts as non-heavy-hitter. Once classified
37  *    - For a heavy-hitter flow: *all* of its k array counters must be large.
38  *    - For a non-heavy-hitter flow: some of its k array counters can be large
59  * Once a flow is classified as heavy-hitter, we also save its per-flow state
60  * in an exact-matching flow table so that its subsequent packets can be
66  *   - If the flow-id of p (e.g., TCP 5-tuple) is already in the exact-matching
67  *     heavy-hitter flow table, denoted table T, then send p to the heavy-hitter
70  *        + If F decides that p belongs to a non-heavy-hitter flow, then send p
72  *        + Otherwise, if F decides that p belongs to a new heavy-hitter flow,
73  *          then set up a new flow entry for the flow-id of p in the table T and
112 /* Heavy-hitter per-flow state */
114 	u32		 hash_id;	/* hash of flow-id (e.g. TCP 5-tuple) */
179 /* Looks up a heavy-hitter flow in a chaining list of table T. */
184 	struct hh_flow_state *flow, *next;  in seek_list()  local
190 	list_for_each_entry_safe(flow, next, head, flowchain) {  in seek_list()
191 		u32 prev = flow->hit_timestamp + q->hhf_evict_timeout;  in seek_list()
197 			if (list_is_last(&flow->flowchain, head))  in seek_list()
199 			list_del(&flow->flowchain);  in seek_list()
200 			kfree(flow);  in seek_list()
202 		} else if (flow->hash_id == hash) {  in seek_list()
203 			return flow;  in seek_list()
209 /* Returns a flow state entry for a new heavy-hitter.  Either reuses an expired
215 	struct hh_flow_state *flow;  in alloc_new_hh()  local
219 		/* Find an expired heavy-hitter flow entry. */  in alloc_new_hh()
220 		list_for_each_entry(flow, head, flowchain) {  in alloc_new_hh()
221 			u32 prev = flow->hit_timestamp + q->hhf_evict_timeout;  in alloc_new_hh()
224 				return flow;  in alloc_new_hh()
233 	flow = kzalloc(sizeof(struct hh_flow_state), GFP_ATOMIC);  in alloc_new_hh()
234 	if (!flow)  in alloc_new_hh()
238 	INIT_LIST_HEAD(&flow->flowchain);  in alloc_new_hh()
239 	list_add_tail(&flow->flowchain, head);  in alloc_new_hh()
241 	return flow;  in alloc_new_hh()
252 	struct hh_flow_state *flow;  in hhf_classify()  local
266 	/* Get hashed flow-id of the skb. */  in hhf_classify()
269 	/* Check if this packet belongs to an already established HH flow. */  in hhf_classify()
271 	flow = seek_list(hash, &q->hh_flows[flow_pos], q);  in hhf_classify()
272 	if (flow) { /* found its HH flow */  in hhf_classify()
273 		flow->hit_timestamp = now;  in hhf_classify()
307 		flow = alloc_new_hh(&q->hh_flows[flow_pos], q);  in hhf_classify()
308 		if (!flow) /* memory alloc problem */  in hhf_classify()
310 		flow->hash_id = hash;  in hhf_classify()
311 		flow->hit_timestamp = now;  in hhf_classify()
485 		struct hh_flow_state *flow, *next;  in hhf_destroy()  local
490 		list_for_each_entry_safe(flow, next, head, flowchain) {  in hhf_destroy()
491 			list_del(&flow->flowchain);  in hhf_destroy()
492 			kfree(flow);  in hhf_destroy()
600 		/* Initialize heavy-hitter flow table. */  in hhf_init()