diff --git a/src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.c b/src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.c
index dfd2b513b12a265e23d170fa35d7935aaafd2fe7..3e34257ea7e72ce7185069fd70d46c6a10397c6a 100644
--- a/src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.c
+++ b/src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.c
@@ -191,6 +191,21 @@ static void rr_subchannel_list_unref(grpc_exec_ctx *exec_ctx,
}
}
+static rr_subchannel_list *rr_subchannel_list_create(round_robin_lb_policy *p,
+ size_t num_subchannels) {
+ rr_subchannel_list *subchannel_list = gpr_zalloc(sizeof(*subchannel_list));
+ subchannel_list->policy = p;
+ subchannel_list->subchannels =
+ gpr_zalloc(sizeof(subchannel_data) * num_subchannels);
+ subchannel_list->num_subchannels = num_subchannels;
+ gpr_ref_init(&subchannel_list->refcount, 1);
+ if (GRPC_TRACER_ON(grpc_lb_round_robin_trace)) {
+ gpr_log(GPR_DEBUG, "Created subchannel list %p for %lu subchannels",
+ (void *)subchannel_list, (unsigned long)num_subchannels);
+ }
+ return subchannel_list;
+}
+
/** Mark \a subchannel_list as discarded. Unsubscribes all its subchannels. The
* watcher's callback will ultimately unref \a subchannel_list. */
static void rr_subchannel_list_shutdown(grpc_exec_ctx *exec_ctx,
@@ -217,7 +232,8 @@ static void rr_subchannel_list_shutdown(grpc_exec_ctx *exec_ctx,
&sd->connectivity_changed_closure);
}
}
- rr_subchannel_list_unref(exec_ctx, subchannel_list, reason);
+ // Corresponds to the creation ref.
+ rr_subchannel_list_unref(exec_ctx, subchannel_list, "creation");
}
/** Returns the index into p->subchannel_list->subchannels of the next
@@ -316,14 +332,16 @@ static void rr_shutdown_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
rr_subchannel_list_shutdown(exec_ctx, p->subchannel_list,
"sl_shutdown_rr_shutdown");
rr_subchannel_list_unref(exec_ctx, p->subchannel_list,
- "sl_unref_rr_shutdown");
+ "sl_shutdown_current+make_pending");
if (!latest_is_current && p->latest_pending_subchannel_list != NULL &&
!p->latest_pending_subchannel_list->shutting_down) {
rr_subchannel_list_shutdown(exec_ctx, p->latest_pending_subchannel_list,
"sl_shutdown_pending_rr_shutdown");
+ rr_subchannel_list_unref(exec_ctx, p->latest_pending_subchannel_list,
+ "sl_shutdown_pending+make_pending");
+ p->latest_pending_subchannel_list = NULL;
}
p->subchannel_list = NULL;
- p->latest_pending_subchannel_list = NULL;
}
static void rr_cancel_pick_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
@@ -380,7 +398,7 @@ static void start_picking_locked(grpc_exec_ctx *exec_ctx,
for (size_t i = 0; i < p->subchannel_list->num_subchannels; i++) {
subchannel_data *sd = &p->subchannel_list->subchannels[i];
GRPC_LB_POLICY_WEAK_REF(&p->base, "start_picking_locked");
- rr_subchannel_list_ref(sd->subchannel_list, "start_picking_locked");
+ rr_subchannel_list_ref(sd->subchannel_list, "started_picking");
grpc_subchannel_notify_on_state_change(
exec_ctx, sd->subchannel, p->base.interested_parties,
&sd->pending_connectivity_state_unsafe,
@@ -548,15 +566,18 @@ static void rr_connectivity_changed_locked(grpc_exec_ctx *exec_ctx, void *arg,
}
// If the policy is shutting down, unref and return.
if (p->shutdown) {
- rr_subchannel_list_unref(exec_ctx, sd->subchannel_list, "pol_shutdown");
+ rr_subchannel_list_unref(exec_ctx, sd->subchannel_list,
+ "pol_shutdown+started_picking");
GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &p->base, "pol_shutdown");
return;
}
if (sd->subchannel_list->shutting_down && error == GRPC_ERROR_CANCELLED) {
// the subchannel list associated with sd has been discarded. This callback
- // corresponds to the unsubscription.
- rr_subchannel_list_unref(exec_ctx, sd->subchannel_list, "sl_shutdown");
- GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &p->base, "sl_shutdown");
+ // corresponds to the unsubscription. The unrefs correspond to the picking
+ // ref (start_picking_locked or update_started_picking).
+ rr_subchannel_list_unref(exec_ctx, sd->subchannel_list,
+ "sl_shutdown+started_picking");
+ GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &p->base, "sl_shutdown+picking");
return;
}
// Dispose of outdated subchannel lists.
@@ -565,7 +586,7 @@ static void rr_connectivity_changed_locked(grpc_exec_ctx *exec_ctx, void *arg,
// sd belongs to an outdated subchannel_list: get rid of it.
rr_subchannel_list_shutdown(exec_ctx, sd->subchannel_list, "sl_outdated");
rr_subchannel_list_unref(exec_ctx, sd->subchannel_list,
- "sl_outdated+unref");
+ "sl_outdated+started_picking");
GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &p->base, "sl_outdated");
return;
}
@@ -589,7 +610,7 @@ static void rr_connectivity_changed_locked(grpc_exec_ctx *exec_ctx, void *arg,
sd->user_data = NULL;
}
if (new_policy_connectivity_state == GRPC_CHANNEL_SHUTDOWN) {
- /* the policy is shutting down. Flush all the pending picks... */
+ // the policy is shutting down. Flush all the pending picks...
pending_pick *pp;
while ((pp = p->pending_picks)) {
p->pending_picks = pp->next;
@@ -598,8 +619,9 @@ static void rr_connectivity_changed_locked(grpc_exec_ctx *exec_ctx, void *arg,
gpr_free(pp);
}
}
- /* unref the "rr_connectivity" weak ref from start_picking */
- rr_subchannel_list_unref(exec_ctx, sd->subchannel_list, "sd_shutdown");
+ rr_subchannel_list_unref(exec_ctx, sd->subchannel_list,
+ "sd_shutdown+started_picking");
+ // unref the "rr_connectivity_update" weak ref from start_picking.
GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &p->base,
"rr_connectivity_sd_shutdown");
} else { // sd not in SHUTDOWN
@@ -627,10 +649,11 @@ static void rr_connectivity_changed_locked(grpc_exec_ctx *exec_ctx, void *arg,
rr_subchannel_list_shutdown(exec_ctx, p->subchannel_list,
"sl_phase_out_shutdown");
rr_subchannel_list_unref(exec_ctx, p->subchannel_list,
- "sl_phase_out_shutdown+unref");
+ "sl_phase_out_shutdown+started_picking");
}
- rr_subchannel_list_ref(p->latest_pending_subchannel_list,
- "sl_promotion");
+ // Promote pending list: No need to take a ref on
+ // p->latest_pending_subchannel_list: reusing its "make_pending"
+ // one.
p->subchannel_list = p->latest_pending_subchannel_list;
p->latest_pending_subchannel_list = NULL;
}
@@ -665,8 +688,8 @@ static void rr_connectivity_changed_locked(grpc_exec_ctx *exec_ctx, void *arg,
gpr_free(pp);
}
}
- /* renew notification: reuses the "rr_connectivity" weak ref on the policy
- * as well as the sd->subchannel_list ref. */
+ /* renew notification: reuses the "rr_connectivity_update" weak ref on the
+ * policy as well as the sd->subchannel_list ref. */
grpc_subchannel_notify_on_state_change(
exec_ctx, sd->subchannel, p->base.interested_parties,
&sd->pending_connectivity_state_unsafe,
@@ -744,18 +767,13 @@ static void rr_update_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
rr_subchannel_list_shutdown(exec_ctx, p->subchannel_list,
"sl_shutdown_empty_update");
rr_subchannel_list_unref(exec_ctx, p->subchannel_list,
- "sl_shutdown_empty_update+unref");
+ "sl_shutdown_empty_update+make_pending");
p->subchannel_list = NULL;
}
return;
}
size_t subchannel_index = 0;
- rr_subchannel_list *subchannel_list = gpr_zalloc(sizeof(*subchannel_list));
- subchannel_list->policy = p;
- subchannel_list->subchannels =
- gpr_zalloc(sizeof(subchannel_data) * num_addrs);
- subchannel_list->num_subchannels = num_addrs;
- gpr_ref_init(&subchannel_list->refcount, 1);
+ rr_subchannel_list *subchannel_list = rr_subchannel_list_create(p, num_addrs);
if (p->latest_pending_subchannel_list != NULL && p->started_picking) {
if (GRPC_TRACER_ON(grpc_lb_round_robin_trace)) {
gpr_log(GPR_DEBUG,
@@ -766,12 +784,11 @@ static void rr_update_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
}
rr_subchannel_list_shutdown(exec_ctx, p->latest_pending_subchannel_list,
"sl_outdated_dont_smash");
+ rr_subchannel_list_unref(exec_ctx, p->latest_pending_subchannel_list,
+ "sl_outdated_dont_smash+make_pending");
}
p->latest_pending_subchannel_list = subchannel_list;
- if (GRPC_TRACER_ON(grpc_lb_round_robin_trace)) {
- gpr_log(GPR_DEBUG, "Created subchannel list %p for %lu subchannels",
- (void *)subchannel_list, (unsigned long)num_addrs);
- }
+ rr_subchannel_list_ref(p->latest_pending_subchannel_list, "make_pending");
grpc_subchannel_args sc_args;
/* We need to remove the LB addresses in order to be able to compare the
* subchannel keys of subchannels from a different batch of addresses. */
@@ -840,8 +857,10 @@ static void rr_update_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
if (p->subchannel_list != NULL) {
rr_subchannel_list_shutdown(exec_ctx, p->subchannel_list,
"rr_update_before_started_picking");
+ rr_subchannel_list_unref(exec_ctx, subchannel_list,
+ "rr_update_before_started_picking+make_pending");
}
- rr_subchannel_list_ref(subchannel_list, "sl_initial_promotion");
+ // Recycles "make_pending" reference.
p->subchannel_list = subchannel_list;
p->latest_pending_subchannel_list = NULL;
}