diff options
Diffstat (limited to 'src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc')
| -rw-r--r-- | src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc | 607 |
1 files changed, 384 insertions, 223 deletions
diff --git a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc index 5849ac9d2d..1317cdcf75 100644 --- a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc +++ b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc @@ -54,7 +54,7 @@ * operations in progress over the old RR instance. This is done by * decreasing the reference count on the old policy. The moment no more * references are held on the old RR policy, it'll be destroyed and \a - * on_rr_connectivity_changed notified with a \a GRPC_CHANNEL_SHUTDOWN + * glb_rr_connectivity_changed notified with a \a GRPC_CHANNEL_SHUTDOWN * state. At this point we can transition to a new RR instance safely, which * is done once again via \a rr_handover_locked(). * @@ -128,48 +128,187 @@ grpc_core::TraceFlag grpc_lb_glb_trace(false, "glb"); -struct glb_lb_policy; +/* add lb_token of selected subchannel (address) to the call's initial + * metadata */ +static grpc_error* initial_metadata_add_lb_token( + grpc_metadata_batch* initial_metadata, + grpc_linked_mdelem* lb_token_mdelem_storage, grpc_mdelem lb_token) { + GPR_ASSERT(lb_token_mdelem_storage != nullptr); + GPR_ASSERT(!GRPC_MDISNULL(lb_token)); + return grpc_metadata_batch_add_tail(initial_metadata, lb_token_mdelem_storage, + lb_token); +} -namespace { +static void destroy_client_stats(void* arg) { + grpc_grpclb_client_stats_unref((grpc_grpclb_client_stats*)arg); +} -/// Linked list of pending pick requests. It stores all information needed to -/// eventually call (Round Robin's) pick() on them. They mainly stay pending -/// waiting for the RR policy to be created. -/// -/// Note that when a pick is sent to the RR policy, we inject our own -/// on_complete callback, so that we can intercept the result before -/// invoking the original on_complete callback. This allows us to set the -/// LB token metadata and add client_stats to the call context. -/// See \a pending_pick_complete() for details. -struct pending_pick { - // Our on_complete closure and the original one. - grpc_closure on_complete; - grpc_closure* original_on_complete; - // The original pick. - grpc_lb_policy_pick_state* pick; - // Stats for client-side load reporting. Note that this holds a - // reference, which must be either passed on via context or unreffed. +typedef struct wrapped_rr_closure_arg { + /* the closure instance using this struct as argument */ + grpc_closure wrapper_closure; + + /* the original closure. Usually a on_complete/notify cb for pick() and ping() + * calls against the internal RR instance, respectively. */ + grpc_closure* wrapped_closure; + + /* the pick's initial metadata, kept in order to append the LB token for the + * pick */ + grpc_metadata_batch* initial_metadata; + + /* the picked target, used to determine which LB token to add to the pick's + * initial metadata */ + grpc_connected_subchannel** target; + + /* the context to be populated for the subchannel call */ + grpc_call_context_element* context; + + /* Stats for client-side load reporting. Note that this holds a + * reference, which must be either passed on via context or unreffed. */ grpc_grpclb_client_stats* client_stats; - // The LB token associated with the pick. This is set via user_data in - // the pick. + + /* the LB token associated with the pick */ grpc_mdelem lb_token; - // The grpclb instance that created the wrapping. This instance is not owned, - // reference counts are untouched. It's used only for logging purposes. - glb_lb_policy* glb_policy; - // Next pending pick. + + /* storage for the lb token initial metadata mdelem */ + grpc_linked_mdelem* lb_token_mdelem_storage; + + /* The RR instance related to the closure */ + grpc_lb_policy* rr_policy; + + /* The grpclb instance that created the wrapping. This instance is not owned, + * reference counts are untouched. It's used only for logging purposes. */ + grpc_lb_policy* glb_policy; + + /* heap memory to be freed upon closure execution. */ + void* free_when_done; +} wrapped_rr_closure_arg; + +/* The \a on_complete closure passed as part of the pick requires keeping a + * reference to its associated round robin instance. We wrap this closure in + * order to unref the round robin instance upon its invocation */ +static void wrapped_rr_closure(void* arg, grpc_error* error) { + wrapped_rr_closure_arg* wc_arg = (wrapped_rr_closure_arg*)arg; + + GPR_ASSERT(wc_arg->wrapped_closure != nullptr); + GRPC_CLOSURE_SCHED(wc_arg->wrapped_closure, GRPC_ERROR_REF(error)); + + if (wc_arg->rr_policy != nullptr) { + /* if *target is nullptr, no pick has been made by the RR policy (eg, all + * addresses failed to connect). There won't be any user_data/token + * available */ + if (*wc_arg->target != nullptr) { + if (!GRPC_MDISNULL(wc_arg->lb_token)) { + initial_metadata_add_lb_token(wc_arg->initial_metadata, + wc_arg->lb_token_mdelem_storage, + GRPC_MDELEM_REF(wc_arg->lb_token)); + } else { + gpr_log( + GPR_ERROR, + "[grpclb %p] No LB token for connected subchannel pick %p (from RR " + "instance %p).", + wc_arg->glb_policy, *wc_arg->target, wc_arg->rr_policy); + abort(); + } + // Pass on client stats via context. Passes ownership of the reference. + GPR_ASSERT(wc_arg->client_stats != nullptr); + wc_arg->context[GRPC_GRPCLB_CLIENT_STATS].value = wc_arg->client_stats; + wc_arg->context[GRPC_GRPCLB_CLIENT_STATS].destroy = destroy_client_stats; + } else { + grpc_grpclb_client_stats_unref(wc_arg->client_stats); + } + if (grpc_lb_glb_trace.enabled()) { + gpr_log(GPR_INFO, "[grpclb %p] Unreffing RR %p", wc_arg->glb_policy, + wc_arg->rr_policy); + } + GRPC_LB_POLICY_UNREF(wc_arg->rr_policy, "wrapped_rr_closure"); + } + GPR_ASSERT(wc_arg->free_when_done != nullptr); + gpr_free(wc_arg->free_when_done); +} + +namespace { +/* Linked list of pending pick requests. It stores all information needed to + * eventually call (Round Robin's) pick() on them. They mainly stay pending + * waiting for the RR policy to be created/updated. + * + * One particularity is the wrapping of the user-provided \a on_complete closure + * (in \a wrapped_on_complete and \a wrapped_on_complete_arg). This is needed in + * order to correctly unref the RR policy instance upon completion of the pick. + * See \a wrapped_rr_closure for details. */ +struct pending_pick { struct pending_pick* next; + + /* original pick()'s arguments */ + grpc_lb_policy_pick_args pick_args; + + /* output argument where to store the pick()ed connected subchannel, or + * nullptr upon error. */ + grpc_connected_subchannel** target; + + /* args for wrapped_on_complete */ + wrapped_rr_closure_arg wrapped_on_complete_arg; }; +} // namespace + +static void add_pending_pick(pending_pick** root, + const grpc_lb_policy_pick_args* pick_args, + grpc_connected_subchannel** target, + grpc_call_context_element* context, + grpc_closure* on_complete) { + pending_pick* pp = (pending_pick*)gpr_zalloc(sizeof(*pp)); + pp->next = *root; + pp->pick_args = *pick_args; + pp->target = target; + pp->wrapped_on_complete_arg.wrapped_closure = on_complete; + pp->wrapped_on_complete_arg.target = target; + pp->wrapped_on_complete_arg.context = context; + pp->wrapped_on_complete_arg.initial_metadata = pick_args->initial_metadata; + pp->wrapped_on_complete_arg.lb_token_mdelem_storage = + pick_args->lb_token_mdelem_storage; + pp->wrapped_on_complete_arg.free_when_done = pp; + GRPC_CLOSURE_INIT(&pp->wrapped_on_complete_arg.wrapper_closure, + wrapped_rr_closure, &pp->wrapped_on_complete_arg, + grpc_schedule_on_exec_ctx); + *root = pp; +} -/// A linked list of pending pings waiting for the RR policy to be created. -struct pending_ping { - grpc_closure* on_initiate; - grpc_closure* on_ack; +/* Same as the \a pending_pick struct but for ping operations */ +typedef struct pending_ping { struct pending_ping* next; -}; -} // namespace + /* args for sending the ping */ + wrapped_rr_closure_arg* on_initiate; + wrapped_rr_closure_arg* on_ack; +} pending_ping; + +static void add_pending_ping(pending_ping** root, grpc_closure* on_initiate, + grpc_closure* on_ack) { + pending_ping* pping = (pending_ping*)gpr_zalloc(sizeof(*pping)); + if (on_initiate != nullptr) { + pping->on_initiate = + (wrapped_rr_closure_arg*)gpr_zalloc(sizeof(*pping->on_initiate)); + pping->on_initiate->wrapped_closure = on_initiate; + pping->on_initiate->free_when_done = pping->on_initiate; + GRPC_CLOSURE_INIT(&pping->on_initiate->wrapper_closure, wrapped_rr_closure, + &pping->on_initiate, grpc_schedule_on_exec_ctx); + } + if (on_ack != nullptr) { + pping->on_ack = (wrapped_rr_closure_arg*)gpr_zalloc(sizeof(*pping->on_ack)); + pping->on_ack->wrapped_closure = on_ack; + pping->on_ack->free_when_done = pping->on_ack; + GRPC_CLOSURE_INIT(&pping->on_ack->wrapper_closure, wrapped_rr_closure, + &pping->on_ack, grpc_schedule_on_exec_ctx); + } + pping->next = *root; + *root = pping; +} -struct glb_lb_policy { +/* + * glb_lb_policy + */ +typedef struct rr_connectivity_data rr_connectivity_data; + +typedef struct glb_lb_policy { /** base policy: must be first */ grpc_lb_policy base; @@ -194,9 +333,6 @@ struct glb_lb_policy { /** the RR policy to use of the backend servers returned by the LB server */ grpc_lb_policy* rr_policy; - grpc_closure on_rr_connectivity_changed; - grpc_connectivity_state rr_connectivity_state; - bool started_picking; /** our connectivity state tracker */ @@ -301,84 +437,14 @@ struct glb_lb_policy { grpc_closure client_load_report_closure; /* Client load report message payload. */ grpc_byte_buffer* client_load_report_payload; -}; - -/* add lb_token of selected subchannel (address) to the call's initial - * metadata */ -static grpc_error* initial_metadata_add_lb_token( - grpc_metadata_batch* initial_metadata, - grpc_linked_mdelem* lb_token_mdelem_storage, grpc_mdelem lb_token) { - GPR_ASSERT(lb_token_mdelem_storage != nullptr); - GPR_ASSERT(!GRPC_MDISNULL(lb_token)); - return grpc_metadata_batch_add_tail(initial_metadata, lb_token_mdelem_storage, - lb_token); -} - -static void destroy_client_stats(void* arg) { - grpc_grpclb_client_stats_unref((grpc_grpclb_client_stats*)arg); -} +} glb_lb_policy; -static void pending_pick_set_metadata_and_context(pending_pick* pp) { - /* if connected_subchannel is nullptr, no pick has been made by the RR - * policy (e.g., all addresses failed to connect). There won't be any - * user_data/token available */ - if (pp->pick->connected_subchannel != nullptr) { - if (!GRPC_MDISNULL(pp->lb_token)) { - initial_metadata_add_lb_token(pp->pick->initial_metadata, - &pp->pick->lb_token_mdelem_storage, - GRPC_MDELEM_REF(pp->lb_token)); - } else { - gpr_log(GPR_ERROR, - "[grpclb %p] No LB token for connected subchannel pick %p", - pp->glb_policy, pp->pick); - abort(); - } - // Pass on client stats via context. Passes ownership of the reference. - GPR_ASSERT(pp->client_stats != nullptr); - pp->pick->subchannel_call_context[GRPC_GRPCLB_CLIENT_STATS].value = - pp->client_stats; - pp->pick->subchannel_call_context[GRPC_GRPCLB_CLIENT_STATS].destroy = - destroy_client_stats; - } else { - grpc_grpclb_client_stats_unref(pp->client_stats); - } -} - -/* The \a on_complete closure passed as part of the pick requires keeping a - * reference to its associated round robin instance. We wrap this closure in - * order to unref the round robin instance upon its invocation */ -static void pending_pick_complete(void* arg, grpc_error* error) { - pending_pick* pp = (pending_pick*)arg; - pending_pick_set_metadata_and_context(pp); - GRPC_CLOSURE_SCHED(pp->original_on_complete, GRPC_ERROR_REF(error)); - gpr_free(pp); -} - -static pending_pick* pending_pick_create(glb_lb_policy* glb_policy, - grpc_lb_policy_pick_state* pick) { - pending_pick* pp = (pending_pick*)gpr_zalloc(sizeof(*pp)); - pp->pick = pick; - pp->glb_policy = glb_policy; - GRPC_CLOSURE_INIT(&pp->on_complete, pending_pick_complete, pp, - grpc_schedule_on_exec_ctx); - pp->original_on_complete = pick->on_complete; - pp->pick->on_complete = &pp->on_complete; - return pp; -} - -static void pending_pick_add(pending_pick** root, pending_pick* new_pp) { - new_pp->next = *root; - *root = new_pp; -} - -static void pending_ping_add(pending_ping** root, grpc_closure* on_initiate, - grpc_closure* on_ack) { - pending_ping* pping = (pending_ping*)gpr_zalloc(sizeof(*pping)); - pping->on_initiate = on_initiate; - pping->on_ack = on_ack; - pping->next = *root; - *root = pping; -} +/* Keeps track and reacts to changes in connectivity of the RR instance */ +struct rr_connectivity_data { + grpc_closure on_change; + grpc_connectivity_state state; + glb_lb_policy* glb_policy; +}; static bool is_server_valid(const grpc_grpclb_server* server, size_t idx, bool log) { @@ -491,6 +557,7 @@ static grpc_lb_addresses* process_serverlist_locked( gpr_free(uri); user_data = (void*)GRPC_MDELEM_LB_TOKEN_EMPTY.payload; } + grpc_lb_addresses_set_address(lb_addresses, addr_idx, &addr.addr, addr.len, false /* is_balancer */, nullptr /* balancer_name */, user_data); @@ -531,6 +598,7 @@ static void update_lb_connectivity_status_locked( grpc_error* rr_state_error) { const grpc_connectivity_state curr_glb_state = grpc_connectivity_state_check(&glb_policy->state_tracker); + /* The new connectivity status is a function of the previous one and the new * input coming from the status of the RR policy. * @@ -560,6 +628,7 @@ static void update_lb_connectivity_status_locked( * * (*) This function mustn't be called during shutting down. */ GPR_ASSERT(curr_glb_state != GRPC_CHANNEL_SHUTDOWN); + switch (rr_state) { case GRPC_CHANNEL_TRANSIENT_FAILURE: case GRPC_CHANNEL_SHUTDOWN: @@ -570,6 +639,7 @@ static void update_lb_connectivity_status_locked( case GRPC_CHANNEL_READY: GPR_ASSERT(rr_state_error == GRPC_ERROR_NONE); } + if (grpc_lb_glb_trace.enabled()) { gpr_log( GPR_INFO, @@ -587,8 +657,10 @@ static void update_lb_connectivity_status_locked( * cleanups this callback would otherwise be responsible for. * If \a force_async is true, then we will manually schedule the * completion callback even if the pick is available immediately. */ -static bool pick_from_internal_rr_locked(glb_lb_policy* glb_policy, - bool force_async, pending_pick* pp) { +static bool pick_from_internal_rr_locked( + glb_lb_policy* glb_policy, const grpc_lb_policy_pick_args* pick_args, + bool force_async, grpc_connected_subchannel** target, + wrapped_rr_closure_arg* wc_arg) { // Check for drops if we are not using fallback backend addresses. if (glb_policy->serverlist != nullptr) { // Look at the index into the serverlist to see if we should drop this call. @@ -598,36 +670,57 @@ static bool pick_from_internal_rr_locked(glb_lb_policy* glb_policy, glb_policy->serverlist_index = 0; // Wrap-around. } if (server->drop) { + // Not using the RR policy, so unref it. + if (grpc_lb_glb_trace.enabled()) { + gpr_log(GPR_INFO, "[grpclb %p] Unreffing RR %p for drop", glb_policy, + wc_arg->rr_policy); + } + GRPC_LB_POLICY_UNREF(wc_arg->rr_policy, "glb_pick_sync"); // Update client load reporting stats to indicate the number of // dropped calls. Note that we have to do this here instead of in // the client_load_reporting filter, because we do not create a // subchannel call (and therefore no client_load_reporting filter) // for dropped calls. - GPR_ASSERT(glb_policy->client_stats != nullptr); + GPR_ASSERT(wc_arg->client_stats != nullptr); grpc_grpclb_client_stats_add_call_dropped_locked( - server->load_balance_token, glb_policy->client_stats); + server->load_balance_token, wc_arg->client_stats); + grpc_grpclb_client_stats_unref(wc_arg->client_stats); if (force_async) { - GRPC_CLOSURE_SCHED(pp->original_on_complete, GRPC_ERROR_NONE); - gpr_free(pp); + GPR_ASSERT(wc_arg->wrapped_closure != nullptr); + GRPC_CLOSURE_SCHED(wc_arg->wrapped_closure, GRPC_ERROR_NONE); + gpr_free(wc_arg->free_when_done); return false; } - gpr_free(pp); + gpr_free(wc_arg->free_when_done); return true; } } - // Set client_stats and user_data. - pp->client_stats = grpc_grpclb_client_stats_ref(glb_policy->client_stats); - GPR_ASSERT(pp->pick->user_data == nullptr); - pp->pick->user_data = (void**)&pp->lb_token; // Pick via the RR policy. - bool pick_done = grpc_lb_policy_pick_locked(glb_policy->rr_policy, pp->pick); + const bool pick_done = grpc_lb_policy_pick_locked( + wc_arg->rr_policy, pick_args, target, wc_arg->context, + (void**)&wc_arg->lb_token, &wc_arg->wrapper_closure); if (pick_done) { - pending_pick_set_metadata_and_context(pp); + /* synchronous grpc_lb_policy_pick call. Unref the RR policy. */ + if (grpc_lb_glb_trace.enabled()) { + gpr_log(GPR_INFO, "[grpclb %p] Unreffing RR %p", glb_policy, + wc_arg->rr_policy); + } + GRPC_LB_POLICY_UNREF(wc_arg->rr_policy, "glb_pick_sync"); + /* add the load reporting initial metadata */ + initial_metadata_add_lb_token(pick_args->initial_metadata, + pick_args->lb_token_mdelem_storage, + GRPC_MDELEM_REF(wc_arg->lb_token)); + // Pass on client stats via context. Passes ownership of the reference. + GPR_ASSERT(wc_arg->client_stats != nullptr); + wc_arg->context[GRPC_GRPCLB_CLIENT_STATS].value = wc_arg->client_stats; + wc_arg->context[GRPC_GRPCLB_CLIENT_STATS].destroy = destroy_client_stats; if (force_async) { - GRPC_CLOSURE_SCHED(pp->original_on_complete, GRPC_ERROR_NONE); - pick_done = false; + GPR_ASSERT(wc_arg->wrapped_closure != nullptr); + GRPC_CLOSURE_SCHED(wc_arg->wrapped_closure, GRPC_ERROR_NONE); + gpr_free(wc_arg->free_when_done); + return false; } - gpr_free(pp); + gpr_free(wc_arg->free_when_done); } /* else, the pending pick will be registered and taken care of by the * pending pick list inside the RR policy (glb_policy->rr_policy). @@ -669,7 +762,7 @@ static void lb_policy_args_destroy(grpc_lb_policy_args* args) { gpr_free(args); } -static void on_rr_connectivity_changed_locked(void* arg, grpc_error* error); +static void glb_rr_connectivity_changed_locked(void* arg, grpc_error* error); static void create_rr_locked(glb_lb_policy* glb_policy, grpc_lb_policy_args* args) { GPR_ASSERT(glb_policy->rr_policy == nullptr); @@ -691,46 +784,72 @@ static void create_rr_locked(glb_lb_policy* glb_policy, glb_policy->base.request_reresolution = nullptr; glb_policy->rr_policy = new_rr_policy; grpc_error* rr_state_error = nullptr; - glb_policy->rr_connectivity_state = grpc_lb_policy_check_connectivity_locked( - glb_policy->rr_policy, &rr_state_error); + const grpc_connectivity_state rr_state = + grpc_lb_policy_check_connectivity_locked(glb_policy->rr_policy, + &rr_state_error); /* Connectivity state is a function of the RR policy updated/created */ - update_lb_connectivity_status_locked( - glb_policy, glb_policy->rr_connectivity_state, rr_state_error); + update_lb_connectivity_status_locked(glb_policy, rr_state, rr_state_error); /* Add the gRPC LB's interested_parties pollset_set to that of the newly * created RR policy. This will make the RR policy progress upon activity on * gRPC LB, which in turn is tied to the application's call */ grpc_pollset_set_add_pollset_set(glb_policy->rr_policy->interested_parties, glb_policy->base.interested_parties); - GRPC_CLOSURE_INIT(&glb_policy->on_rr_connectivity_changed, - on_rr_connectivity_changed_locked, glb_policy, + + /* Allocate the data for the tracking of the new RR policy's connectivity. + * It'll be deallocated in glb_rr_connectivity_changed() */ + rr_connectivity_data* rr_connectivity = + (rr_connectivity_data*)gpr_zalloc(sizeof(rr_connectivity_data)); + GRPC_CLOSURE_INIT(&rr_connectivity->on_change, + glb_rr_connectivity_changed_locked, rr_connectivity, grpc_combiner_scheduler(glb_policy->base.combiner)); + rr_connectivity->glb_policy = glb_policy; + rr_connectivity->state = rr_state; + /* Subscribe to changes to the connectivity of the new RR */ - GRPC_LB_POLICY_REF(&glb_policy->base, "glb_rr_connectivity_cb"); - grpc_lb_policy_notify_on_state_change_locked( - glb_policy->rr_policy, &glb_policy->rr_connectivity_state, - &glb_policy->on_rr_connectivity_changed); + GRPC_LB_POLICY_WEAK_REF(&glb_policy->base, "glb_rr_connectivity_cb"); + grpc_lb_policy_notify_on_state_change_locked(glb_policy->rr_policy, + &rr_connectivity->state, + &rr_connectivity->on_change); grpc_lb_policy_exit_idle_locked(glb_policy->rr_policy); - // Send pending picks to RR policy. + + /* Update picks and pings in wait */ pending_pick* pp; while ((pp = glb_policy->pending_picks)) { glb_policy->pending_picks = pp->next; + GRPC_LB_POLICY_REF(glb_policy->rr_policy, "rr_handover_pending_pick"); + pp->wrapped_on_complete_arg.rr_policy = glb_policy->rr_policy; + pp->wrapped_on_complete_arg.client_stats = + grpc_grpclb_client_stats_ref(glb_policy->client_stats); if (grpc_lb_glb_trace.enabled()) { gpr_log(GPR_INFO, "[grpclb %p] Pending pick about to (async) PICK from RR %p", glb_policy, glb_policy->rr_policy); } - pick_from_internal_rr_locked(glb_policy, true /* force_async */, pp); + pick_from_internal_rr_locked(glb_policy, &pp->pick_args, + true /* force_async */, pp->target, + &pp->wrapped_on_complete_arg); } - // Send pending pings to RR policy. + pending_ping* pping; while ((pping = glb_policy->pending_pings)) { glb_policy->pending_pings = pping->next; + grpc_closure* on_initiate = nullptr; + grpc_closure* on_ack = nullptr; + if (pping->on_initiate != nullptr) { + GRPC_LB_POLICY_REF(glb_policy->rr_policy, "rr_handover_pending_ping"); + pping->on_initiate->rr_policy = glb_policy->rr_policy; + on_initiate = &pping->on_initiate->wrapper_closure; + } + if (pping->on_ack != nullptr) { + GRPC_LB_POLICY_REF(glb_policy->rr_policy, "rr_handover_pending_ping"); + pping->on_ack->rr_policy = glb_policy->rr_policy; + on_ack = &pping->on_ack->wrapper_closure; + } if (grpc_lb_glb_trace.enabled()) { gpr_log(GPR_INFO, "[grpclb %p] Pending ping about to PING from RR %p", glb_policy, glb_policy->rr_policy); } - grpc_lb_policy_ping_one_locked(glb_policy->rr_policy, pping->on_initiate, - pping->on_ack); + grpc_lb_policy_ping_one_locked(glb_policy->rr_policy, on_initiate, on_ack); gpr_free(pping); } } @@ -756,28 +875,31 @@ static void rr_handover_locked(glb_lb_policy* glb_policy) { lb_policy_args_destroy(args); } -static void on_rr_connectivity_changed_locked(void* arg, grpc_error* error) { - glb_lb_policy* glb_policy = (glb_lb_policy*)arg; +static void glb_rr_connectivity_changed_locked(void* arg, grpc_error* error) { + rr_connectivity_data* rr_connectivity = (rr_connectivity_data*)arg; + glb_lb_policy* glb_policy = rr_connectivity->glb_policy; if (glb_policy->shutting_down) { - GRPC_LB_POLICY_UNREF(&glb_policy->base, "glb_rr_connectivity_cb"); + GRPC_LB_POLICY_WEAK_UNREF(&glb_policy->base, "glb_rr_connectivity_cb"); + gpr_free(rr_connectivity); return; } - if (glb_policy->rr_connectivity_state == GRPC_CHANNEL_SHUTDOWN) { + if (rr_connectivity->state == GRPC_CHANNEL_SHUTDOWN) { /* An RR policy that has transitioned into the SHUTDOWN connectivity state * should not be considered for picks or updates: the SHUTDOWN state is a * sink, policies can't transition back from it. .*/ GRPC_LB_POLICY_UNREF(glb_policy->rr_policy, "rr_connectivity_shutdown"); glb_policy->rr_policy = nullptr; - GRPC_LB_POLICY_UNREF(&glb_policy->base, "glb_rr_connectivity_cb"); + GRPC_LB_POLICY_WEAK_UNREF(&glb_policy->base, "glb_rr_connectivity_cb"); + gpr_free(rr_connectivity); return; } /* rr state != SHUTDOWN && !glb_policy->shutting down: biz as usual */ - update_lb_connectivity_status_locked( - glb_policy, glb_policy->rr_connectivity_state, GRPC_ERROR_REF(error)); - /* Resubscribe. Reuse the "glb_rr_connectivity_cb" ref. */ - grpc_lb_policy_notify_on_state_change_locked( - glb_policy->rr_policy, &glb_policy->rr_connectivity_state, - &glb_policy->on_rr_connectivity_changed); + update_lb_connectivity_status_locked(glb_policy, rr_connectivity->state, + GRPC_ERROR_REF(error)); + /* Resubscribe. Reuse the "glb_rr_connectivity_cb" weak ref. */ + grpc_lb_policy_notify_on_state_change_locked(glb_policy->rr_policy, + &rr_connectivity->state, + &rr_connectivity->on_change); } static void destroy_balancer_name(void* balancer_name) { @@ -885,17 +1007,22 @@ static void glb_destroy(grpc_lb_policy* pol) { gpr_free(glb_policy); } -static void glb_shutdown_locked(grpc_lb_policy* pol, - grpc_lb_policy* new_policy) { +static void glb_shutdown_locked(grpc_lb_policy* pol) { glb_lb_policy* glb_policy = (glb_lb_policy*)pol; grpc_error* error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("Channel shutdown"); glb_policy->shutting_down = true; + + /* We need a copy of the lb_call pointer because we can't cancell the call + * while holding glb_policy->mu: lb_on_server_status_received, invoked due to + * the cancel, needs to acquire that same lock */ + grpc_call* lb_call = glb_policy->lb_call; + /* glb_policy->lb_call and this local lb_call must be consistent at this point * because glb_policy->lb_call is only assigned in lb_call_init_locked as part * of query_for_backends_locked, which can only be invoked while * glb_policy->shutting_down is false. */ - if (glb_policy->lb_call != nullptr) { - grpc_call_cancel(glb_policy->lb_call, nullptr); + if (lb_call != nullptr) { + grpc_call_cancel(lb_call, nullptr); /* lb_on_server_status_received will pick up the cancel and clean up */ } if (glb_policy->retry_timer_callback_pending) { @@ -904,8 +1031,12 @@ static void glb_shutdown_locked(grpc_lb_policy* pol, if (glb_policy->fallback_timer_callback_pending) { grpc_timer_cancel(&glb_policy->lb_fallback_timer); } + + pending_pick* pp = glb_policy->pending_picks; + glb_policy->pending_picks = nullptr; + pending_ping* pping = glb_policy->pending_pings; + glb_policy->pending_pings = nullptr; if (glb_policy->rr_policy != nullptr) { - grpc_lb_policy_shutdown_locked(glb_policy->rr_policy, nullptr); GRPC_LB_POLICY_UNREF(glb_policy->rr_policy, "glb_shutdown"); } else { grpc_lb_policy_try_reresolve(pol, &grpc_lb_glb_trace, GRPC_ERROR_CANCELLED); @@ -920,33 +1051,28 @@ static void glb_shutdown_locked(grpc_lb_policy* pol, } grpc_connectivity_state_set(&glb_policy->state_tracker, GRPC_CHANNEL_SHUTDOWN, GRPC_ERROR_REF(error), "glb_shutdown"); - // Clear pending picks. - pending_pick* pp = glb_policy->pending_picks; - glb_policy->pending_picks = nullptr; + while (pp != nullptr) { pending_pick* next = pp->next; - if (new_policy != nullptr) { - // Hand pick over to new policy. - grpc_grpclb_client_stats_unref(pp->client_stats); - pp->pick->on_complete = pp->original_on_complete; - if (grpc_lb_policy_pick_locked(new_policy, pp->pick)) { - // Synchronous return; schedule callback. - GRPC_CLOSURE_SCHED(pp->pick->on_complete, GRPC_ERROR_NONE); - } - gpr_free(pp); - } else { - pp->pick->connected_subchannel = nullptr; - GRPC_CLOSURE_SCHED(&pp->on_complete, GRPC_ERROR_REF(error)); - } + *pp->target = nullptr; + GRPC_CLOSURE_SCHED(&pp->wrapped_on_complete_arg.wrapper_closure, + GRPC_ERROR_REF(error)); + gpr_free(pp); pp = next; } - // Clear pending pings. - pending_ping* pping = glb_policy->pending_pings; - glb_policy->pending_pings = nullptr; + while (pping != nullptr) { pending_ping* next = pping->next; - GRPC_CLOSURE_SCHED(pping->on_initiate, GRPC_ERROR_REF(error)); - GRPC_CLOSURE_SCHED(pping->on_ack, GRPC_ERROR_REF(error)); + if (pping->on_initiate != nullptr) { + GRPC_CLOSURE_SCHED(&pping->on_initiate->wrapper_closure, + GRPC_ERROR_REF(error)); + gpr_free(pping->on_initiate); + } + if (pping->on_ack != nullptr) { + GRPC_CLOSURE_SCHED(&pping->on_ack->wrapper_closure, + GRPC_ERROR_REF(error)); + gpr_free(pping->on_ack); + } gpr_free(pping); pping = next; } @@ -964,16 +1090,16 @@ static void glb_shutdown_locked(grpc_lb_policy* pol, // level (grpclb), inside the glb_policy->pending_picks list. To cancel these, // we invoke the completion closure and set *target to nullptr right here. static void glb_cancel_pick_locked(grpc_lb_policy* pol, - grpc_lb_policy_pick_state* pick, + grpc_connected_subchannel** target, grpc_error* error) { glb_lb_policy* glb_policy = (glb_lb_policy*)pol; pending_pick* pp = glb_policy->pending_picks; glb_policy->pending_picks = nullptr; while (pp != nullptr) { pending_pick* next = pp->next; - if (pp->pick == pick) { - pick->connected_subchannel = nullptr; - GRPC_CLOSURE_SCHED(&pp->on_complete, + if (pp->target == target) { + *target = nullptr; + GRPC_CLOSURE_SCHED(&pp->wrapped_on_complete_arg.wrapper_closure, GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING( "Pick Cancelled", &error, 1)); } else { @@ -983,7 +1109,7 @@ static void glb_cancel_pick_locked(grpc_lb_policy* pol, pp = next; } if (glb_policy->rr_policy != nullptr) { - grpc_lb_policy_cancel_pick_locked(glb_policy->rr_policy, pick, + grpc_lb_policy_cancel_pick_locked(glb_policy->rr_policy, target, GRPC_ERROR_REF(error)); } GRPC_ERROR_UNREF(error); @@ -1008,9 +1134,9 @@ static void glb_cancel_picks_locked(grpc_lb_policy* pol, glb_policy->pending_picks = nullptr; while (pp != nullptr) { pending_pick* next = pp->next; - if ((pp->pick->initial_metadata_flags & initial_metadata_flags_mask) == + if ((pp->pick_args.initial_metadata_flags & initial_metadata_flags_mask) == initial_metadata_flags_eq) { - GRPC_CLOSURE_SCHED(&pp->on_complete, + GRPC_CLOSURE_SCHED(&pp->wrapped_on_complete_arg.wrapper_closure, GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING( "Pick Cancelled", &error, 1)); } else { @@ -1036,7 +1162,7 @@ static void start_picking_locked(glb_lb_policy* glb_policy) { !glb_policy->fallback_timer_callback_pending) { grpc_millis deadline = grpc_core::ExecCtx::Get()->Now() + glb_policy->lb_fallback_timeout_ms; - GRPC_LB_POLICY_REF(&glb_policy->base, "grpclb_fallback_timer"); + GRPC_LB_POLICY_WEAK_REF(&glb_policy->base, "grpclb_fallback_timer"); GRPC_CLOSURE_INIT(&glb_policy->lb_on_fallback, lb_on_fallback_timer_locked, glb_policy, grpc_combiner_scheduler(glb_policy->base.combiner)); @@ -1058,9 +1184,19 @@ static void glb_exit_idle_locked(grpc_lb_policy* pol) { } static int glb_pick_locked(grpc_lb_policy* pol, - grpc_lb_policy_pick_state* pick) { + const grpc_lb_policy_pick_args* pick_args, + grpc_connected_subchannel** target, + grpc_call_context_element* context, void** user_data, + grpc_closure* on_complete) { + if (pick_args->lb_token_mdelem_storage == nullptr) { + *target = nullptr; + GRPC_CLOSURE_SCHED(on_complete, + GRPC_ERROR_CREATE_FROM_STATIC_STRING( + "No mdelem storage for the LB token. Load reporting " + "won't work without it. Failing")); + return 0; + } glb_lb_policy* glb_policy = (glb_lb_policy*)pol; - pending_pick* pp = pending_pick_create(glb_policy, pick); bool pick_done = false; if (glb_policy->rr_policy != nullptr) { const grpc_connectivity_state rr_connectivity_state = @@ -1068,7 +1204,7 @@ static int glb_pick_locked(grpc_lb_policy* pol, nullptr); // The glb_policy->rr_policy may have transitioned to SHUTDOWN but the // callback registered to capture this event - // (on_rr_connectivity_changed_locked) may not have been invoked yet. We + // (glb_rr_connectivity_changed_locked) may not have been invoked yet. We // need to make sure we aren't trying to pick from a RR policy instance // that's in shutdown. if (rr_connectivity_state == GRPC_CHANNEL_SHUTDOWN) { @@ -1078,16 +1214,32 @@ static int glb_pick_locked(grpc_lb_policy* pol, glb_policy, glb_policy->rr_policy, grpc_connectivity_state_name(rr_connectivity_state)); } - pending_pick_add(&glb_policy->pending_picks, pp); + add_pending_pick(&glb_policy->pending_picks, pick_args, target, context, + on_complete); pick_done = false; } else { // RR not in shutdown if (grpc_lb_glb_trace.enabled()) { gpr_log(GPR_INFO, "[grpclb %p] about to PICK from RR %p", glb_policy, glb_policy->rr_policy); } + GRPC_LB_POLICY_REF(glb_policy->rr_policy, "glb_pick"); + wrapped_rr_closure_arg* wc_arg = + (wrapped_rr_closure_arg*)gpr_zalloc(sizeof(wrapped_rr_closure_arg)); + GRPC_CLOSURE_INIT(&wc_arg->wrapper_closure, wrapped_rr_closure, wc_arg, + grpc_schedule_on_exec_ctx); + wc_arg->rr_policy = glb_policy->rr_policy; + wc_arg->target = target; + wc_arg->context = context; GPR_ASSERT(glb_policy->client_stats != nullptr); - pick_done = - pick_from_internal_rr_locked(glb_policy, false /* force_async */, pp); + wc_arg->client_stats = + grpc_grpclb_client_stats_ref(glb_policy->client_stats); + wc_arg->wrapped_closure = on_complete; + wc_arg->lb_token_mdelem_storage = pick_args->lb_token_mdelem_storage; + wc_arg->initial_metadata = pick_args->initial_metadata; + wc_arg->free_when_done = wc_arg; + wc_arg->glb_policy = pol; + pick_done = pick_from_internal_rr_locked( + glb_policy, pick_args, false /* force_async */, target, wc_arg); } } else { // glb_policy->rr_policy == NULL if (grpc_lb_glb_trace.enabled()) { @@ -1095,7 +1247,8 @@ static int glb_pick_locked(grpc_lb_policy* pol, "[grpclb %p] No RR policy. Adding to grpclb's pending picks", glb_policy); } - pending_pick_add(&glb_policy->pending_picks, pp); + add_pending_pick(&glb_policy->pending_picks, pick_args, target, context, + on_complete); if (!glb_policy->started_picking) { start_picking_locked(glb_policy); } @@ -1117,7 +1270,7 @@ static void glb_ping_one_locked(grpc_lb_policy* pol, grpc_closure* on_initiate, if (glb_policy->rr_policy) { grpc_lb_policy_ping_one_locked(glb_policy->rr_policy, on_initiate, on_ack); } else { - pending_ping_add(&glb_policy->pending_pings, on_initiate, on_ack); + add_pending_ping(&glb_policy->pending_pings, on_initiate, on_ack); if (!glb_policy->started_picking) { start_picking_locked(glb_policy); } @@ -1142,7 +1295,7 @@ static void lb_call_on_retry_timer_locked(void* arg, grpc_error* error) { } query_for_backends_locked(glb_policy); } - GRPC_LB_POLICY_UNREF(&glb_policy->base, "grpclb_retry_timer"); + GRPC_LB_POLICY_WEAK_UNREF(&glb_policy->base, "grpclb_retry_timer"); } static void maybe_restart_lb_call(glb_lb_policy* glb_policy) { @@ -1168,7 +1321,7 @@ static void maybe_restart_lb_call(glb_lb_policy* glb_policy) { glb_policy); } } - GRPC_LB_POLICY_REF(&glb_policy->base, "grpclb_retry_timer"); + GRPC_LB_POLICY_WEAK_REF(&glb_policy->base, "grpclb_retry_timer"); GRPC_CLOSURE_INIT(&glb_policy->lb_on_call_retry, lb_call_on_retry_timer_locked, glb_policy, grpc_combiner_scheduler(glb_policy->base.combiner)); @@ -1176,8 +1329,8 @@ static void maybe_restart_lb_call(glb_lb_policy* glb_policy) { grpc_timer_init(&glb_policy->lb_call_retry_timer, next_try, &glb_policy->lb_on_call_retry); } - GRPC_LB_POLICY_UNREF(&glb_policy->base, - "lb_on_server_status_received_locked"); + GRPC_LB_POLICY_WEAK_UNREF(&glb_policy->base, + "lb_on_server_status_received_locked"); } static void send_client_load_report_locked(void* arg, grpc_error* error); @@ -1200,7 +1353,7 @@ static void client_load_report_done_locked(void* arg, grpc_error* error) { glb_policy->client_load_report_payload = nullptr; if (error != GRPC_ERROR_NONE || glb_policy->lb_call == nullptr) { glb_policy->client_load_report_timer_callback_pending = false; - GRPC_LB_POLICY_UNREF(&glb_policy->base, "client_load_report"); + GRPC_LB_POLICY_WEAK_UNREF(&glb_policy->base, "client_load_report"); if (glb_policy->lb_call == nullptr) { maybe_restart_lb_call(glb_policy); } @@ -1241,7 +1394,7 @@ static void send_client_load_report_locked(void* arg, grpc_error* error) { glb_lb_policy* glb_policy = (glb_lb_policy*)arg; if (error == GRPC_ERROR_CANCELLED || glb_policy->lb_call == nullptr) { glb_policy->client_load_report_timer_callback_pending = false; - GRPC_LB_POLICY_UNREF(&glb_policy->base, "client_load_report"); + GRPC_LB_POLICY_WEAK_UNREF(&glb_policy->base, "client_load_report"); if (glb_policy->lb_call == nullptr) { maybe_restart_lb_call(glb_policy); } @@ -1394,8 +1547,10 @@ static void query_for_backends_locked(glb_lb_policy* glb_policy) { op->flags = 0; op->reserved = nullptr; op++; - /* take a ref to be released in lb_on_sent_initial_request_locked() */ - GRPC_LB_POLICY_REF(&glb_policy->base, "lb_on_sent_initial_request_locked"); + /* take a weak ref (won't prevent calling of \a glb_shutdown if the strong ref + * count goes to zero) to be unref'd in lb_on_sent_initial_request_locked() */ + GRPC_LB_POLICY_WEAK_REF(&glb_policy->base, + "lb_on_sent_initial_request_locked"); call_error = grpc_call_start_batch_and_execute( glb_policy->lb_call, ops, (size_t)(op - ops), &glb_policy->lb_on_sent_initial_request); @@ -1411,8 +1566,10 @@ static void query_for_backends_locked(glb_lb_policy* glb_policy) { op->flags = 0; op->reserved = nullptr; op++; - /* take a ref to be released in lb_on_server_status_received_locked() */ - GRPC_LB_POLICY_REF(&glb_policy->base, "lb_on_server_status_received_locked"); + /* take a weak ref (won't prevent calling of \a glb_shutdown if the strong ref + * count goes to zero) to be unref'd in lb_on_server_status_received_locked */ + GRPC_LB_POLICY_WEAK_REF(&glb_policy->base, + "lb_on_server_status_received_locked"); call_error = grpc_call_start_batch_and_execute( glb_policy->lb_call, ops, (size_t)(op - ops), &glb_policy->lb_on_server_status_received); @@ -1424,8 +1581,9 @@ static void query_for_backends_locked(glb_lb_policy* glb_policy) { op->flags = 0; op->reserved = nullptr; op++; - /* take a ref to be unref'd/reused in lb_on_response_received_locked() */ - GRPC_LB_POLICY_REF(&glb_policy->base, "lb_on_response_received_locked"); + /* take another weak ref to be unref'd/reused in + * lb_on_response_received_locked */ + GRPC_LB_POLICY_WEAK_REF(&glb_policy->base, "lb_on_response_received_locked"); call_error = grpc_call_start_batch_and_execute( glb_policy->lb_call, ops, (size_t)(op - ops), &glb_policy->lb_on_response_received); @@ -1440,7 +1598,8 @@ static void lb_on_sent_initial_request_locked(void* arg, grpc_error* error) { if (glb_policy->client_load_report_payload != nullptr) { do_send_client_load_report_locked(glb_policy); } - GRPC_LB_POLICY_UNREF(&glb_policy->base, "lb_on_sent_initial_request_locked"); + GRPC_LB_POLICY_WEAK_UNREF(&glb_policy->base, + "lb_on_sent_initial_request_locked"); } static void lb_on_response_received_locked(void* arg, grpc_error* error) { @@ -1472,9 +1631,11 @@ static void lb_on_response_received_locked(void* arg, grpc_error* error) { "client load reporting interval = %" PRIdPTR " milliseconds", glb_policy, glb_policy->client_stats_report_interval); } - /* take a ref to be unref'd in send_client_load_report_locked() */ + /* take a weak ref (won't prevent calling of \a glb_shutdown() if the + * strong ref count goes to zero) to be unref'd in + * send_client_load_report_locked() */ glb_policy->client_load_report_timer_callback_pending = true; - GRPC_LB_POLICY_REF(&glb_policy->base, "client_load_report"); + GRPC_LB_POLICY_WEAK_REF(&glb_policy->base, "client_load_report"); schedule_next_client_load_report(glb_policy); } else if (grpc_lb_glb_trace.enabled()) { gpr_log(GPR_INFO, @@ -1556,21 +1717,21 @@ static void lb_on_response_received_locked(void* arg, grpc_error* error) { op->flags = 0; op->reserved = nullptr; op++; - /* reuse the "lb_on_response_received_locked" ref taken in + /* reuse the "lb_on_response_received_locked" weak ref taken in * query_for_backends_locked() */ const grpc_call_error call_error = grpc_call_start_batch_and_execute( glb_policy->lb_call, ops, (size_t)(op - ops), &glb_policy->lb_on_response_received); /* loop */ GPR_ASSERT(GRPC_CALL_OK == call_error); } else { - GRPC_LB_POLICY_UNREF(&glb_policy->base, - "lb_on_response_received_locked_shutdown"); + GRPC_LB_POLICY_WEAK_UNREF(&glb_policy->base, + "lb_on_response_received_locked_shutdown"); } } else { /* empty payload: call cancelled. */ - /* dispose of the "lb_on_response_received_locked" ref taken in + /* dispose of the "lb_on_response_received_locked" weak ref taken in * query_for_backends_locked() and reused in every reception loop */ - GRPC_LB_POLICY_UNREF(&glb_policy->base, - "lb_on_response_received_locked_empty_payload"); + GRPC_LB_POLICY_WEAK_UNREF(&glb_policy->base, + "lb_on_response_received_locked_empty_payload"); } } @@ -1590,7 +1751,7 @@ static void lb_on_fallback_timer_locked(void* arg, grpc_error* error) { rr_handover_locked(glb_policy); } } - GRPC_LB_POLICY_UNREF(&glb_policy->base, "grpclb_fallback_timer"); + GRPC_LB_POLICY_WEAK_UNREF(&glb_policy->base, "grpclb_fallback_timer"); } static void lb_on_server_status_received_locked(void* arg, grpc_error* error) { @@ -1674,7 +1835,7 @@ static void glb_update_locked(grpc_lb_policy* policy, grpc_channel_get_channel_stack(glb_policy->lb_channel)); GPR_ASSERT(client_channel_elem->filter == &grpc_client_channel_filter); glb_policy->watching_lb_channel = true; - GRPC_LB_POLICY_REF(&glb_policy->base, "watch_lb_channel_connectivity"); + GRPC_LB_POLICY_WEAK_REF(&glb_policy->base, "watch_lb_channel_connectivity"); grpc_client_channel_watch_connectivity_state( client_channel_elem, grpc_polling_entity_create_from_pollset_set( @@ -1730,8 +1891,8 @@ static void glb_lb_channel_on_connectivity_changed_cb(void* arg, case GRPC_CHANNEL_SHUTDOWN: done: glb_policy->watching_lb_channel = false; - GRPC_LB_POLICY_UNREF(&glb_policy->base, - "watch_lb_channel_connectivity_cb_shutdown"); + GRPC_LB_POLICY_WEAK_UNREF(&glb_policy->base, + "watch_lb_channel_connectivity_cb_shutdown"); break; } } |