On 12/20/24 11:55 AM, Amery Hung wrote:
+static int fq_new_flow(void *flow_map, struct fq_stashed_flow **sflow, u64 hash)
+{
+ struct fq_stashed_flow tmp = {};
+ struct fq_flow_node *flow;
+ int ret;
+
+ flow = bpf_obj_new(typeof(*flow));
+ if (!flow)
+ return -ENOMEM;
+
+ flow->credit = q.initial_quantum,
+ flow->qlen = 0,
+ flow->age = 1,
+ flow->time_next_packet = 0,
+
+ ret = bpf_map_update_elem(flow_map, &hash, &tmp, 0);
+ if (ret == -ENOMEM) {
-E2BIG needs to be checked also to handle the flow_map is full case.
+ fq_gc();
+ bpf_map_update_elem(&fq_nonprio_flows, &hash, &tmp, 0);
+ }
+
+ *sflow = bpf_map_lookup_elem(flow_map, &hash);
+ if (!*sflow) {
+ bpf_obj_drop(flow);
+ return -ENOMEM;
+ }
+
+ bpf_kptr_xchg_back(&(*sflow)->flow, flow);
+ return 0;
+}
[ ... ]
+static int
+fq_remove_flows(struct bpf_map *flow_map, u64 *hash,
+ struct fq_stashed_flow *sflow, struct remove_flows_ctx *ctx)
+{
+ struct fq_flow_node *flow = NULL;
+
+ flow = bpf_kptr_xchg(&sflow->flow, flow);
+ if (flow) {
+ if (!ctx->gc_only || fq_gc_candidate(flow)) {
+ bpf_obj_drop(flow);
afaik, the hash value (i.e. sflow here) is still in the flow_map.
Instead of xchg and then drop, I think this should be
bpf_map_delete_elem(flow_map, hash) which deletes the sflow value from the
flow_map and also takes care of the bpf_obj_drop() also.
+ ctx->reset_cnt++;
+ } else {
+ bpf_kptr_xchg_back(&sflow->flow, flow);
+ }
+ }
+
+ return ctx->reset_cnt < ctx->reset_max ? 0 : 1;
+}
+
+static void fq_gc(void)
+{
+ struct remove_flows_ctx cb_ctx = {
+ .gc_only = true,
+ .reset_cnt = 0,
+ .reset_max = FQ_GC_MAX,
+ };
+
+ bpf_for_each_map_elem(&fq_nonprio_flows, fq_remove_flows, &cb_ctx, 0);
+}
+
+SEC("struct_ops/bpf_fq_reset")
+void BPF_PROG(bpf_fq_reset, struct Qdisc *sch)
+{
+ struct unset_throttled_flows_ctx utf_ctx = {
+ .unset_all = true,
+ };
+ struct remove_flows_ctx rf_ctx = {
+ .gc_only = false,
+ .reset_cnt = 0,
+ .reset_max = NUM_QUEUE,
+ };
+ struct fq_stashed_flow *sflow;
+ u64 hash = 0;
+
+ sch->q.qlen = 0;
+ sch->qstats.backlog = 0;
+
+ bpf_for_each_map_elem(&fq_nonprio_flows, fq_remove_flows, &rf_ctx, 0);
+
+ rf_ctx.reset_cnt = 0;
+ bpf_for_each_map_elem(&fq_prio_flows, fq_remove_flows, &rf_ctx, 0);
+ fq_new_flow(&fq_prio_flows, &sflow, hash);
+
+ bpf_loop(NUM_QUEUE, fq_remove_flows_in_list, NULL, 0);
+ q.new_flow_cnt = 0;
+ q.old_flow_cnt = 0;
+
+ bpf_loop(NUM_QUEUE, fq_unset_throttled_flows, &utf_ctx, 0);
+
+ return;
+}
