| /* |
| * |
| * Copyright 2015-2016 gRPC authors. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| * |
| */ |
| #include <grpc/support/port_platform.h> |
| |
| #include "src/core/lib/surface/completion_queue.h" |
| |
| #include <inttypes.h> |
| #include <stdio.h> |
| #include <string.h> |
| |
| #include <grpc/support/alloc.h> |
| #include <grpc/support/atm.h> |
| #include <grpc/support/log.h> |
| #include <grpc/support/string_util.h> |
| #include <grpc/support/time.h> |
| #include <grpc/support/tls.h> |
| |
| #include "src/core/lib/debug/stats.h" |
| #include "src/core/lib/gpr/spinlock.h" |
| #include "src/core/lib/gpr/string.h" |
| #include "src/core/lib/iomgr/pollset.h" |
| #include "src/core/lib/iomgr/timer.h" |
| #include "src/core/lib/profiling/timers.h" |
| #include "src/core/lib/surface/api_trace.h" |
| #include "src/core/lib/surface/call.h" |
| #include "src/core/lib/surface/event_string.h" |
| |
| grpc_core::TraceFlag grpc_trace_operation_failures(false, "op_failure"); |
| grpc_core::DebugOnlyTraceFlag grpc_trace_pending_tags(false, "pending_tags"); |
| grpc_core::DebugOnlyTraceFlag grpc_trace_cq_refcount(false, "cq_refcount"); |
| |
| // Specifies a cq thread local cache. |
| // The first event that occurs on a thread |
| // with a cq cache will go into that cache, and |
| // will only be returned on the thread that initialized the cache. |
| // NOTE: Only one event will ever be cached. |
| GPR_TLS_DECL(g_cached_event); |
| GPR_TLS_DECL(g_cached_cq); |
| |
| typedef struct { |
| grpc_pollset_worker** worker; |
| void* tag; |
| } plucker; |
| |
| typedef struct { |
| bool can_get_pollset; |
| bool can_listen; |
| size_t (*size)(void); |
| void (*init)(grpc_pollset* pollset, gpr_mu** mu); |
| grpc_error* (*kick)(grpc_pollset* pollset, |
| grpc_pollset_worker* specific_worker); |
| grpc_error* (*work)(grpc_pollset* pollset, grpc_pollset_worker** worker, |
| grpc_millis deadline); |
| void (*shutdown)(grpc_pollset* pollset, grpc_closure* closure); |
| void (*destroy)(grpc_pollset* pollset); |
| } cq_poller_vtable; |
| |
| typedef struct non_polling_worker { |
| gpr_cv cv; |
| bool kicked; |
| struct non_polling_worker* next; |
| struct non_polling_worker* prev; |
| } non_polling_worker; |
| |
| typedef struct { |
| gpr_mu mu; |
| non_polling_worker* root; |
| grpc_closure* shutdown; |
| } non_polling_poller; |
| |
| static size_t non_polling_poller_size(void) { |
| return sizeof(non_polling_poller); |
| } |
| |
| static void non_polling_poller_init(grpc_pollset* pollset, gpr_mu** mu) { |
| non_polling_poller* npp = (non_polling_poller*)pollset; |
| gpr_mu_init(&npp->mu); |
| *mu = &npp->mu; |
| } |
| |
| static void non_polling_poller_destroy(grpc_pollset* pollset) { |
| non_polling_poller* npp = (non_polling_poller*)pollset; |
| gpr_mu_destroy(&npp->mu); |
| } |
| |
| static grpc_error* non_polling_poller_work(grpc_pollset* pollset, |
| grpc_pollset_worker** worker, |
| grpc_millis deadline) { |
| non_polling_poller* npp = (non_polling_poller*)pollset; |
| if (npp->shutdown) return GRPC_ERROR_NONE; |
| non_polling_worker w; |
| gpr_cv_init(&w.cv); |
| if (worker != nullptr) *worker = (grpc_pollset_worker*)&w; |
| if (npp->root == nullptr) { |
| npp->root = w.next = w.prev = &w; |
| } else { |
| w.next = npp->root; |
| w.prev = w.next->prev; |
| w.next->prev = w.prev->next = &w; |
| } |
| w.kicked = false; |
| gpr_timespec deadline_ts = |
| grpc_millis_to_timespec(deadline, GPR_CLOCK_MONOTONIC); |
| while (!npp->shutdown && !w.kicked && |
| !gpr_cv_wait(&w.cv, &npp->mu, deadline_ts)) |
| ; |
| grpc_core::ExecCtx::Get()->InvalidateNow(); |
| if (&w == npp->root) { |
| npp->root = w.next; |
| if (&w == npp->root) { |
| if (npp->shutdown) { |
| GRPC_CLOSURE_SCHED(npp->shutdown, GRPC_ERROR_NONE); |
| } |
| npp->root = nullptr; |
| } |
| } |
| w.next->prev = w.prev; |
| w.prev->next = w.next; |
| gpr_cv_destroy(&w.cv); |
| if (worker != nullptr) *worker = nullptr; |
| return GRPC_ERROR_NONE; |
| } |
| |
| static grpc_error* non_polling_poller_kick( |
| grpc_pollset* pollset, grpc_pollset_worker* specific_worker) { |
| non_polling_poller* p = (non_polling_poller*)pollset; |
| if (specific_worker == nullptr) |
| specific_worker = (grpc_pollset_worker*)p->root; |
| if (specific_worker != nullptr) { |
| non_polling_worker* w = (non_polling_worker*)specific_worker; |
| if (!w->kicked) { |
| w->kicked = true; |
| gpr_cv_signal(&w->cv); |
| } |
| } |
| return GRPC_ERROR_NONE; |
| } |
| |
| static void non_polling_poller_shutdown(grpc_pollset* pollset, |
| grpc_closure* closure) { |
| non_polling_poller* p = (non_polling_poller*)pollset; |
| GPR_ASSERT(closure != nullptr); |
| p->shutdown = closure; |
| if (p->root == nullptr) { |
| GRPC_CLOSURE_SCHED(closure, GRPC_ERROR_NONE); |
| } else { |
| non_polling_worker* w = p->root; |
| do { |
| gpr_cv_signal(&w->cv); |
| w = w->next; |
| } while (w != p->root); |
| } |
| } |
| |
| static const cq_poller_vtable g_poller_vtable_by_poller_type[] = { |
| /* GRPC_CQ_DEFAULT_POLLING */ |
| {true, true, grpc_pollset_size, grpc_pollset_init, grpc_pollset_kick, |
| grpc_pollset_work, grpc_pollset_shutdown, grpc_pollset_destroy}, |
| /* GRPC_CQ_NON_LISTENING */ |
| {true, false, grpc_pollset_size, grpc_pollset_init, grpc_pollset_kick, |
| grpc_pollset_work, grpc_pollset_shutdown, grpc_pollset_destroy}, |
| /* GRPC_CQ_NON_POLLING */ |
| {false, false, non_polling_poller_size, non_polling_poller_init, |
| non_polling_poller_kick, non_polling_poller_work, |
| non_polling_poller_shutdown, non_polling_poller_destroy}, |
| }; |
| |
| typedef struct cq_vtable { |
| grpc_cq_completion_type cq_completion_type; |
| size_t data_size; |
| void (*init)(void* data); |
| void (*shutdown)(grpc_completion_queue* cq); |
| void (*destroy)(void* data); |
| bool (*begin_op)(grpc_completion_queue* cq, void* tag); |
| void (*end_op)(grpc_completion_queue* cq, void* tag, grpc_error* error, |
| void (*done)(void* done_arg, grpc_cq_completion* storage), |
| void* done_arg, grpc_cq_completion* storage); |
| grpc_event (*next)(grpc_completion_queue* cq, gpr_timespec deadline, |
| void* reserved); |
| grpc_event (*pluck)(grpc_completion_queue* cq, void* tag, |
| gpr_timespec deadline, void* reserved); |
| } cq_vtable; |
| |
| /* Queue that holds the cq_completion_events. Internally uses gpr_mpscq queue |
| * (a lockfree multiproducer single consumer queue). It uses a queue_lock |
| * to support multiple consumers. |
| * Only used in completion queues whose completion_type is GRPC_CQ_NEXT */ |
| typedef struct grpc_cq_event_queue { |
| /* Spinlock to serialize consumers i.e pop() operations */ |
| gpr_spinlock queue_lock; |
| |
| gpr_mpscq queue; |
| |
| /* A lazy counter of number of items in the queue. This is NOT atomically |
| incremented/decremented along with push/pop operations and hence is only |
| eventually consistent */ |
| gpr_atm num_queue_items; |
| } grpc_cq_event_queue; |
| |
| typedef struct cq_next_data { |
| /** Completed events for completion-queues of type GRPC_CQ_NEXT */ |
| grpc_cq_event_queue queue; |
| |
| /** Counter of how many things have ever been queued on this completion queue |
| useful for avoiding locks to check the queue */ |
| gpr_atm things_queued_ever; |
| |
| /* Number of outstanding events (+1 if not shut down) */ |
| gpr_atm pending_events; |
| |
| /** 0 initially. 1 once we initiated shutdown */ |
| bool shutdown_called; |
| } cq_next_data; |
| |
| typedef struct cq_pluck_data { |
| /** Completed events for completion-queues of type GRPC_CQ_PLUCK */ |
| grpc_cq_completion completed_head; |
| grpc_cq_completion* completed_tail; |
| |
| /** Number of pending events (+1 if we're not shutdown) */ |
| gpr_atm pending_events; |
| |
| /** Counter of how many things have ever been queued on this completion queue |
| useful for avoiding locks to check the queue */ |
| gpr_atm things_queued_ever; |
| |
| /** 0 initially. 1 once we completed shutting */ |
| /* TODO: (sreek) This is not needed since (shutdown == 1) if and only if |
| * (pending_events == 0). So consider removing this in future and use |
| * pending_events */ |
| gpr_atm shutdown; |
| |
| /** 0 initially. 1 once we initiated shutdown */ |
| bool shutdown_called; |
| |
| int num_pluckers; |
| plucker pluckers[GRPC_MAX_COMPLETION_QUEUE_PLUCKERS]; |
| } cq_pluck_data; |
| |
| /* Completion queue structure */ |
| struct grpc_completion_queue { |
| /** Once owning_refs drops to zero, we will destroy the cq */ |
| gpr_refcount owning_refs; |
| |
| gpr_mu* mu; |
| |
| const cq_vtable* vtable; |
| const cq_poller_vtable* poller_vtable; |
| |
| #ifndef NDEBUG |
| void** outstanding_tags; |
| size_t outstanding_tag_count; |
| size_t outstanding_tag_capacity; |
| #endif |
| |
| grpc_closure pollset_shutdown_done; |
| int num_polls; |
| }; |
| |
| /* Forward declarations */ |
| static void cq_finish_shutdown_next(grpc_completion_queue* cq); |
| static void cq_finish_shutdown_pluck(grpc_completion_queue* cq); |
| static void cq_shutdown_next(grpc_completion_queue* cq); |
| static void cq_shutdown_pluck(grpc_completion_queue* cq); |
| |
| static bool cq_begin_op_for_next(grpc_completion_queue* cq, void* tag); |
| static bool cq_begin_op_for_pluck(grpc_completion_queue* cq, void* tag); |
| |
| static void cq_end_op_for_next(grpc_completion_queue* cq, void* tag, |
| grpc_error* error, |
| void (*done)(void* done_arg, |
| grpc_cq_completion* storage), |
| void* done_arg, grpc_cq_completion* storage); |
| |
| static void cq_end_op_for_pluck(grpc_completion_queue* cq, void* tag, |
| grpc_error* error, |
| void (*done)(void* done_arg, |
| grpc_cq_completion* storage), |
| void* done_arg, grpc_cq_completion* storage); |
| |
| static grpc_event cq_next(grpc_completion_queue* cq, gpr_timespec deadline, |
| void* reserved); |
| |
| static grpc_event cq_pluck(grpc_completion_queue* cq, void* tag, |
| gpr_timespec deadline, void* reserved); |
| |
| static void cq_init_next(void* data); |
| static void cq_init_pluck(void* data); |
| static void cq_destroy_next(void* data); |
| static void cq_destroy_pluck(void* data); |
| |
| /* Completion queue vtables based on the completion-type */ |
| static const cq_vtable g_cq_vtable[] = { |
| /* GRPC_CQ_NEXT */ |
| {GRPC_CQ_NEXT, sizeof(cq_next_data), cq_init_next, cq_shutdown_next, |
| cq_destroy_next, cq_begin_op_for_next, cq_end_op_for_next, cq_next, |
| nullptr}, |
| /* GRPC_CQ_PLUCK */ |
| {GRPC_CQ_PLUCK, sizeof(cq_pluck_data), cq_init_pluck, cq_shutdown_pluck, |
| cq_destroy_pluck, cq_begin_op_for_pluck, cq_end_op_for_pluck, nullptr, |
| cq_pluck}, |
| }; |
| |
| #define DATA_FROM_CQ(cq) ((void*)(cq + 1)) |
| #define POLLSET_FROM_CQ(cq) \ |
| ((grpc_pollset*)(cq->vtable->data_size + (char*)DATA_FROM_CQ(cq))) |
| |
| grpc_core::TraceFlag grpc_cq_pluck_trace(true, "queue_pluck"); |
| grpc_core::TraceFlag grpc_cq_event_timeout_trace(true, "queue_timeout"); |
| |
| #define GRPC_SURFACE_TRACE_RETURNED_EVENT(cq, event) \ |
| if (grpc_api_trace.enabled() && (grpc_cq_pluck_trace.enabled() || \ |
| (event)->type != GRPC_QUEUE_TIMEOUT)) { \ |
| char* _ev = grpc_event_string(event); \ |
| gpr_log(GPR_INFO, "RETURN_EVENT[%p]: %s", cq, _ev); \ |
| gpr_free(_ev); \ |
| } |
| |
| static void on_pollset_shutdown_done(void* cq, grpc_error* error); |
| |
| void grpc_cq_global_init() { |
| gpr_tls_init(&g_cached_event); |
| gpr_tls_init(&g_cached_cq); |
| } |
| |
| void grpc_completion_queue_thread_local_cache_init(grpc_completion_queue* cq) { |
| if ((grpc_completion_queue*)gpr_tls_get(&g_cached_cq) == nullptr) { |
| gpr_tls_set(&g_cached_event, (intptr_t)0); |
| gpr_tls_set(&g_cached_cq, (intptr_t)cq); |
| } |
| } |
| |
| int grpc_completion_queue_thread_local_cache_flush(grpc_completion_queue* cq, |
| void** tag, int* ok) { |
| grpc_cq_completion* storage = |
| (grpc_cq_completion*)gpr_tls_get(&g_cached_event); |
| int ret = 0; |
| if (storage != nullptr && |
| (grpc_completion_queue*)gpr_tls_get(&g_cached_cq) == cq) { |
| *tag = storage->tag; |
| grpc_core::ExecCtx exec_ctx; |
| *ok = (storage->next & (uintptr_t)(1)) == 1; |
| storage->done(storage->done_arg, storage); |
| ret = 1; |
| cq_next_data* cqd = (cq_next_data*)DATA_FROM_CQ(cq); |
| if (gpr_atm_full_fetch_add(&cqd->pending_events, -1) == 1) { |
| GRPC_CQ_INTERNAL_REF(cq, "shutting_down"); |
| gpr_mu_lock(cq->mu); |
| cq_finish_shutdown_next(cq); |
| gpr_mu_unlock(cq->mu); |
| GRPC_CQ_INTERNAL_UNREF(cq, "shutting_down"); |
| } |
| } |
| gpr_tls_set(&g_cached_event, (intptr_t)0); |
| gpr_tls_set(&g_cached_cq, (intptr_t)0); |
| |
| return ret; |
| } |
| |
| static void cq_event_queue_init(grpc_cq_event_queue* q) { |
| gpr_mpscq_init(&q->queue); |
| q->queue_lock = GPR_SPINLOCK_INITIALIZER; |
| gpr_atm_no_barrier_store(&q->num_queue_items, 0); |
| } |
| |
| static void cq_event_queue_destroy(grpc_cq_event_queue* q) { |
| gpr_mpscq_destroy(&q->queue); |
| } |
| |
| static bool cq_event_queue_push(grpc_cq_event_queue* q, grpc_cq_completion* c) { |
| gpr_mpscq_push(&q->queue, (gpr_mpscq_node*)c); |
| return gpr_atm_no_barrier_fetch_add(&q->num_queue_items, 1) == 0; |
| } |
| |
| static grpc_cq_completion* cq_event_queue_pop(grpc_cq_event_queue* q) { |
| grpc_cq_completion* c = nullptr; |
| grpc_core::ExecCtx exec_ctx; |
| |
| if (gpr_spinlock_trylock(&q->queue_lock)) { |
| GRPC_STATS_INC_CQ_EV_QUEUE_TRYLOCK_SUCCESSES(); |
| |
| bool is_empty = false; |
| c = (grpc_cq_completion*)gpr_mpscq_pop_and_check_end(&q->queue, &is_empty); |
| gpr_spinlock_unlock(&q->queue_lock); |
| |
| if (c == nullptr && !is_empty) { |
| GRPC_STATS_INC_CQ_EV_QUEUE_TRANSIENT_POP_FAILURES(); |
| } |
| } else { |
| GRPC_STATS_INC_CQ_EV_QUEUE_TRYLOCK_FAILURES(); |
| } |
| |
| if (c) { |
| gpr_atm_no_barrier_fetch_add(&q->num_queue_items, -1); |
| } |
| |
| return c; |
| } |
| |
| /* Note: The counter is not incremented/decremented atomically with push/pop. |
| * The count is only eventually consistent */ |
| static long cq_event_queue_num_items(grpc_cq_event_queue* q) { |
| return (long)gpr_atm_no_barrier_load(&q->num_queue_items); |
| } |
| |
| grpc_completion_queue* grpc_completion_queue_create_internal( |
| grpc_cq_completion_type completion_type, |
| grpc_cq_polling_type polling_type) { |
| GPR_TIMER_SCOPE("grpc_completion_queue_create_internal", 0); |
| |
| grpc_completion_queue* cq; |
| |
| GRPC_API_TRACE( |
| "grpc_completion_queue_create_internal(completion_type=%d, " |
| "polling_type=%d)", |
| 2, (completion_type, polling_type)); |
| |
| const cq_vtable* vtable = &g_cq_vtable[completion_type]; |
| const cq_poller_vtable* poller_vtable = |
| &g_poller_vtable_by_poller_type[polling_type]; |
| |
| grpc_core::ExecCtx exec_ctx; |
| GRPC_STATS_INC_CQS_CREATED(); |
| |
| cq = (grpc_completion_queue*)gpr_zalloc(sizeof(grpc_completion_queue) + |
| vtable->data_size + |
| poller_vtable->size()); |
| |
| cq->vtable = vtable; |
| cq->poller_vtable = poller_vtable; |
| |
| /* One for destroy(), one for pollset_shutdown */ |
| gpr_ref_init(&cq->owning_refs, 2); |
| |
| poller_vtable->init(POLLSET_FROM_CQ(cq), &cq->mu); |
| vtable->init(DATA_FROM_CQ(cq)); |
| |
| GRPC_CLOSURE_INIT(&cq->pollset_shutdown_done, on_pollset_shutdown_done, cq, |
| grpc_schedule_on_exec_ctx); |
| return cq; |
| } |
| |
| static void cq_init_next(void* ptr) { |
| cq_next_data* cqd = (cq_next_data*)ptr; |
| /* Initial count is dropped by grpc_completion_queue_shutdown */ |
| gpr_atm_no_barrier_store(&cqd->pending_events, 1); |
| cqd->shutdown_called = false; |
| gpr_atm_no_barrier_store(&cqd->things_queued_ever, 0); |
| cq_event_queue_init(&cqd->queue); |
| } |
| |
| static void cq_destroy_next(void* ptr) { |
| cq_next_data* cqd = (cq_next_data*)ptr; |
| GPR_ASSERT(cq_event_queue_num_items(&cqd->queue) == 0); |
| cq_event_queue_destroy(&cqd->queue); |
| } |
| |
| static void cq_init_pluck(void* ptr) { |
| cq_pluck_data* cqd = (cq_pluck_data*)ptr; |
| /* Initial count is dropped by grpc_completion_queue_shutdown */ |
| gpr_atm_no_barrier_store(&cqd->pending_events, 1); |
| cqd->completed_tail = &cqd->completed_head; |
| cqd->completed_head.next = (uintptr_t)cqd->completed_tail; |
| gpr_atm_no_barrier_store(&cqd->shutdown, 0); |
| cqd->shutdown_called = false; |
| cqd->num_pluckers = 0; |
| gpr_atm_no_barrier_store(&cqd->things_queued_ever, 0); |
| } |
| |
| static void cq_destroy_pluck(void* ptr) { |
| cq_pluck_data* cqd = (cq_pluck_data*)ptr; |
| GPR_ASSERT(cqd->completed_head.next == (uintptr_t)&cqd->completed_head); |
| } |
| |
| grpc_cq_completion_type grpc_get_cq_completion_type(grpc_completion_queue* cq) { |
| return cq->vtable->cq_completion_type; |
| } |
| |
| int grpc_get_cq_poll_num(grpc_completion_queue* cq) { |
| int cur_num_polls; |
| gpr_mu_lock(cq->mu); |
| cur_num_polls = cq->num_polls; |
| gpr_mu_unlock(cq->mu); |
| return cur_num_polls; |
| } |
| |
| #ifndef NDEBUG |
| void grpc_cq_internal_ref(grpc_completion_queue* cq, const char* reason, |
| const char* file, int line) { |
| if (grpc_trace_cq_refcount.enabled()) { |
| gpr_atm val = gpr_atm_no_barrier_load(&cq->owning_refs.count); |
| gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG, |
| "CQ:%p ref %" PRIdPTR " -> %" PRIdPTR " %s", cq, val, val + 1, |
| reason); |
| } |
| #else |
| void grpc_cq_internal_ref(grpc_completion_queue* cq) { |
| #endif |
| gpr_ref(&cq->owning_refs); |
| } |
| |
| static void on_pollset_shutdown_done(void* arg, grpc_error* error) { |
| grpc_completion_queue* cq = (grpc_completion_queue*)arg; |
| GRPC_CQ_INTERNAL_UNREF(cq, "pollset_destroy"); |
| } |
| |
| #ifndef NDEBUG |
| void grpc_cq_internal_unref(grpc_completion_queue* cq, const char* reason, |
| const char* file, int line) { |
| if (grpc_trace_cq_refcount.enabled()) { |
| gpr_atm val = gpr_atm_no_barrier_load(&cq->owning_refs.count); |
| gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG, |
| "CQ:%p unref %" PRIdPTR " -> %" PRIdPTR " %s", cq, val, val - 1, |
| reason); |
| } |
| #else |
| void grpc_cq_internal_unref(grpc_completion_queue* cq) { |
| #endif |
| if (gpr_unref(&cq->owning_refs)) { |
| cq->vtable->destroy(DATA_FROM_CQ(cq)); |
| cq->poller_vtable->destroy(POLLSET_FROM_CQ(cq)); |
| #ifndef NDEBUG |
| gpr_free(cq->outstanding_tags); |
| #endif |
| gpr_free(cq); |
| } |
| } |
| |
| #ifndef NDEBUG |
| static void cq_check_tag(grpc_completion_queue* cq, void* tag, bool lock_cq) { |
| int found = 0; |
| if (lock_cq) { |
| gpr_mu_lock(cq->mu); |
| } |
| |
| for (int i = 0; i < (int)cq->outstanding_tag_count; i++) { |
| if (cq->outstanding_tags[i] == tag) { |
| cq->outstanding_tag_count--; |
| GPR_SWAP(void*, cq->outstanding_tags[i], |
| cq->outstanding_tags[cq->outstanding_tag_count]); |
| found = 1; |
| break; |
| } |
| } |
| |
| if (lock_cq) { |
| gpr_mu_unlock(cq->mu); |
| } |
| |
| GPR_ASSERT(found); |
| } |
| #else |
| static void cq_check_tag(grpc_completion_queue* cq, void* tag, bool lock_cq) {} |
| #endif |
| |
| /* Atomically increments a counter only if the counter is not zero. Returns |
| * true if the increment was successful; false if the counter is zero */ |
| static bool atm_inc_if_nonzero(gpr_atm* counter) { |
| while (true) { |
| gpr_atm count = gpr_atm_acq_load(counter); |
| /* If zero, we are done. If not, we must to a CAS (instead of an atomic |
| * increment) to maintain the contract: do not increment the counter if it |
| * is zero. */ |
| if (count == 0) { |
| return false; |
| } else if (gpr_atm_full_cas(counter, count, count + 1)) { |
| break; |
| } |
| } |
| |
| return true; |
| } |
| |
| static bool cq_begin_op_for_next(grpc_completion_queue* cq, void* tag) { |
| cq_next_data* cqd = (cq_next_data*)DATA_FROM_CQ(cq); |
| return atm_inc_if_nonzero(&cqd->pending_events); |
| } |
| |
| static bool cq_begin_op_for_pluck(grpc_completion_queue* cq, void* tag) { |
| cq_pluck_data* cqd = (cq_pluck_data*)DATA_FROM_CQ(cq); |
| return atm_inc_if_nonzero(&cqd->pending_events); |
| } |
| |
| bool grpc_cq_begin_op(grpc_completion_queue* cq, void* tag) { |
| #ifndef NDEBUG |
| gpr_mu_lock(cq->mu); |
| if (cq->outstanding_tag_count == cq->outstanding_tag_capacity) { |
| cq->outstanding_tag_capacity = GPR_MAX(4, 2 * cq->outstanding_tag_capacity); |
| cq->outstanding_tags = (void**)gpr_realloc( |
| cq->outstanding_tags, |
| sizeof(*cq->outstanding_tags) * cq->outstanding_tag_capacity); |
| } |
| cq->outstanding_tags[cq->outstanding_tag_count++] = tag; |
| gpr_mu_unlock(cq->mu); |
| #endif |
| return cq->vtable->begin_op(cq, tag); |
| } |
| |
| /* Queue a GRPC_OP_COMPLETED operation to a completion queue (with a |
| * completion |
| * type of GRPC_CQ_NEXT) */ |
| static void cq_end_op_for_next(grpc_completion_queue* cq, void* tag, |
| grpc_error* error, |
| void (*done)(void* done_arg, |
| grpc_cq_completion* storage), |
| void* done_arg, grpc_cq_completion* storage) { |
| GPR_TIMER_SCOPE("cq_end_op_for_next", 0); |
| |
| if (grpc_api_trace.enabled() || |
| (grpc_trace_operation_failures.enabled() && error != GRPC_ERROR_NONE)) { |
| const char* errmsg = grpc_error_string(error); |
| GRPC_API_TRACE( |
| "cq_end_op_for_next(cq=%p, tag=%p, error=%s, " |
| "done=%p, done_arg=%p, storage=%p)", |
| 6, (cq, tag, errmsg, done, done_arg, storage)); |
| if (grpc_trace_operation_failures.enabled() && error != GRPC_ERROR_NONE) { |
| gpr_log(GPR_ERROR, "Operation failed: tag=%p, error=%s", tag, errmsg); |
| } |
| } |
| cq_next_data* cqd = (cq_next_data*)DATA_FROM_CQ(cq); |
| int is_success = (error == GRPC_ERROR_NONE); |
| |
| storage->tag = tag; |
| storage->done = done; |
| storage->done_arg = done_arg; |
| storage->next = (uintptr_t)(is_success); |
| |
| cq_check_tag(cq, tag, true); /* Used in debug builds only */ |
| |
| if ((grpc_completion_queue*)gpr_tls_get(&g_cached_cq) == cq && |
| (grpc_cq_completion*)gpr_tls_get(&g_cached_event) == nullptr) { |
| gpr_tls_set(&g_cached_event, (intptr_t)storage); |
| } else { |
| /* Add the completion to the queue */ |
| bool is_first = cq_event_queue_push(&cqd->queue, storage); |
| gpr_atm_no_barrier_fetch_add(&cqd->things_queued_ever, 1); |
| |
| /* Since we do not hold the cq lock here, it is important to do an 'acquire' |
| load here (instead of a 'no_barrier' load) to match with the release |
| store |
| (done via gpr_atm_full_fetch_add(pending_events, -1)) in cq_shutdown_next |
| */ |
| bool will_definitely_shutdown = gpr_atm_acq_load(&cqd->pending_events) == 1; |
| |
| if (!will_definitely_shutdown) { |
| /* Only kick if this is the first item queued */ |
| if (is_first) { |
| gpr_mu_lock(cq->mu); |
| grpc_error* kick_error = |
| cq->poller_vtable->kick(POLLSET_FROM_CQ(cq), nullptr); |
| gpr_mu_unlock(cq->mu); |
| |
| if (kick_error != GRPC_ERROR_NONE) { |
| const char* msg = grpc_error_string(kick_error); |
| gpr_log(GPR_ERROR, "Kick failed: %s", msg); |
| GRPC_ERROR_UNREF(kick_error); |
| } |
| } |
| if (gpr_atm_full_fetch_add(&cqd->pending_events, -1) == 1) { |
| GRPC_CQ_INTERNAL_REF(cq, "shutting_down"); |
| gpr_mu_lock(cq->mu); |
| cq_finish_shutdown_next(cq); |
| gpr_mu_unlock(cq->mu); |
| GRPC_CQ_INTERNAL_UNREF(cq, "shutting_down"); |
| } |
| } else { |
| GRPC_CQ_INTERNAL_REF(cq, "shutting_down"); |
| gpr_atm_rel_store(&cqd->pending_events, 0); |
| gpr_mu_lock(cq->mu); |
| cq_finish_shutdown_next(cq); |
| gpr_mu_unlock(cq->mu); |
| GRPC_CQ_INTERNAL_UNREF(cq, "shutting_down"); |
| } |
| } |
| |
| GRPC_ERROR_UNREF(error); |
| } |
| |
| /* Queue a GRPC_OP_COMPLETED operation to a completion queue (with a |
| * completion |
| * type of GRPC_CQ_PLUCK) */ |
| static void cq_end_op_for_pluck(grpc_completion_queue* cq, void* tag, |
| grpc_error* error, |
| void (*done)(void* done_arg, |
| grpc_cq_completion* storage), |
| void* done_arg, grpc_cq_completion* storage) { |
| GPR_TIMER_SCOPE("cq_end_op_for_pluck", 0); |
| |
| cq_pluck_data* cqd = (cq_pluck_data*)DATA_FROM_CQ(cq); |
| int is_success = (error == GRPC_ERROR_NONE); |
| |
| if (grpc_api_trace.enabled() || |
| (grpc_trace_operation_failures.enabled() && error != GRPC_ERROR_NONE)) { |
| const char* errmsg = grpc_error_string(error); |
| GRPC_API_TRACE( |
| "cq_end_op_for_pluck(cq=%p, tag=%p, error=%s, " |
| "done=%p, done_arg=%p, storage=%p)", |
| 6, (cq, tag, errmsg, done, done_arg, storage)); |
| if (grpc_trace_operation_failures.enabled() && error != GRPC_ERROR_NONE) { |
| gpr_log(GPR_ERROR, "Operation failed: tag=%p, error=%s", tag, errmsg); |
| } |
| } |
| |
| storage->tag = tag; |
| storage->done = done; |
| storage->done_arg = done_arg; |
| storage->next = ((uintptr_t)&cqd->completed_head) | ((uintptr_t)(is_success)); |
| |
| gpr_mu_lock(cq->mu); |
| cq_check_tag(cq, tag, false); /* Used in debug builds only */ |
| |
| /* Add to the list of completions */ |
| gpr_atm_no_barrier_fetch_add(&cqd->things_queued_ever, 1); |
| cqd->completed_tail->next = |
| ((uintptr_t)storage) | (1u & (uintptr_t)cqd->completed_tail->next); |
| cqd->completed_tail = storage; |
| |
| if (gpr_atm_full_fetch_add(&cqd->pending_events, -1) == 1) { |
| cq_finish_shutdown_pluck(cq); |
| gpr_mu_unlock(cq->mu); |
| } else { |
| grpc_pollset_worker* pluck_worker = nullptr; |
| for (int i = 0; i < cqd->num_pluckers; i++) { |
| if (cqd->pluckers[i].tag == tag) { |
| pluck_worker = *cqd->pluckers[i].worker; |
| break; |
| } |
| } |
| |
| grpc_error* kick_error = |
| cq->poller_vtable->kick(POLLSET_FROM_CQ(cq), pluck_worker); |
| |
| gpr_mu_unlock(cq->mu); |
| |
| if (kick_error != GRPC_ERROR_NONE) { |
| const char* msg = grpc_error_string(kick_error); |
| gpr_log(GPR_ERROR, "Kick failed: %s", msg); |
| |
| GRPC_ERROR_UNREF(kick_error); |
| } |
| } |
| |
| GRPC_ERROR_UNREF(error); |
| } |
| |
| void grpc_cq_end_op(grpc_completion_queue* cq, void* tag, grpc_error* error, |
| void (*done)(void* done_arg, grpc_cq_completion* storage), |
| void* done_arg, grpc_cq_completion* storage) { |
| cq->vtable->end_op(cq, tag, error, done, done_arg, storage); |
| } |
| |
| typedef struct { |
| gpr_atm last_seen_things_queued_ever; |
| grpc_completion_queue* cq; |
| grpc_millis deadline; |
| grpc_cq_completion* stolen_completion; |
| void* tag; /* for pluck */ |
| bool first_loop; |
| } cq_is_finished_arg; |
| |
| class ExecCtxNext : public grpc_core::ExecCtx { |
| public: |
| ExecCtxNext(void* arg) : ExecCtx(0), check_ready_to_finish_arg_(arg) {} |
| |
| bool CheckReadyToFinish() override { |
| cq_is_finished_arg* a = (cq_is_finished_arg*)check_ready_to_finish_arg_; |
| grpc_completion_queue* cq = a->cq; |
| cq_next_data* cqd = (cq_next_data*)DATA_FROM_CQ(cq); |
| GPR_ASSERT(a->stolen_completion == nullptr); |
| |
| gpr_atm current_last_seen_things_queued_ever = |
| gpr_atm_no_barrier_load(&cqd->things_queued_ever); |
| |
| if (current_last_seen_things_queued_ever != |
| a->last_seen_things_queued_ever) { |
| a->last_seen_things_queued_ever = |
| gpr_atm_no_barrier_load(&cqd->things_queued_ever); |
| |
| /* Pop a cq_completion from the queue. Returns NULL if the queue is empty |
| * might return NULL in some cases even if the queue is not empty; but |
| * that |
| * is ok and doesn't affect correctness. Might effect the tail latencies a |
| * bit) */ |
| a->stolen_completion = cq_event_queue_pop(&cqd->queue); |
| if (a->stolen_completion != nullptr) { |
| return true; |
| } |
| } |
| return !a->first_loop && a->deadline < grpc_core::ExecCtx::Get()->Now(); |
| } |
| |
| private: |
| void* check_ready_to_finish_arg_; |
| }; |
| |
| #ifndef NDEBUG |
| static void dump_pending_tags(grpc_completion_queue* cq) { |
| if (!grpc_trace_pending_tags.enabled()) return; |
| |
| gpr_strvec v; |
| gpr_strvec_init(&v); |
| gpr_strvec_add(&v, gpr_strdup("PENDING TAGS:")); |
| gpr_mu_lock(cq->mu); |
| for (size_t i = 0; i < cq->outstanding_tag_count; i++) { |
| char* s; |
| gpr_asprintf(&s, " %p", cq->outstanding_tags[i]); |
| gpr_strvec_add(&v, s); |
| } |
| gpr_mu_unlock(cq->mu); |
| char* out = gpr_strvec_flatten(&v, nullptr); |
| gpr_strvec_destroy(&v); |
| gpr_log(GPR_DEBUG, "%s", out); |
| gpr_free(out); |
| } |
| #else |
| static void dump_pending_tags(grpc_completion_queue* cq) {} |
| #endif |
| |
| static grpc_event cq_next(grpc_completion_queue* cq, gpr_timespec deadline, |
| void* reserved) { |
| GPR_TIMER_SCOPE("grpc_completion_queue_next", 0); |
| |
| grpc_event ret; |
| cq_next_data* cqd = (cq_next_data*)DATA_FROM_CQ(cq); |
| |
| GRPC_API_TRACE( |
| "grpc_completion_queue_next(" |
| "cq=%p, " |
| "deadline=gpr_timespec { tv_sec: %" PRId64 |
| ", tv_nsec: %d, clock_type: %d }, " |
| "reserved=%p)", |
| 5, |
| (cq, deadline.tv_sec, deadline.tv_nsec, (int)deadline.clock_type, |
| reserved)); |
| GPR_ASSERT(!reserved); |
| |
| dump_pending_tags(cq); |
| |
| GRPC_CQ_INTERNAL_REF(cq, "next"); |
| |
| grpc_millis deadline_millis = grpc_timespec_to_millis_round_up(deadline); |
| cq_is_finished_arg is_finished_arg = { |
| gpr_atm_no_barrier_load(&cqd->things_queued_ever), |
| cq, |
| deadline_millis, |
| nullptr, |
| nullptr, |
| true}; |
| ExecCtxNext exec_ctx(&is_finished_arg); |
| for (;;) { |
| grpc_millis iteration_deadline = deadline_millis; |
| |
| if (is_finished_arg.stolen_completion != nullptr) { |
| grpc_cq_completion* c = is_finished_arg.stolen_completion; |
| is_finished_arg.stolen_completion = nullptr; |
| ret.type = GRPC_OP_COMPLETE; |
| ret.success = c->next & 1u; |
| ret.tag = c->tag; |
| c->done(c->done_arg, c); |
| break; |
| } |
| |
| grpc_cq_completion* c = cq_event_queue_pop(&cqd->queue); |
| |
| if (c != nullptr) { |
| ret.type = GRPC_OP_COMPLETE; |
| ret.success = c->next & 1u; |
| ret.tag = c->tag; |
| c->done(c->done_arg, c); |
| break; |
| } else { |
| /* If c == NULL it means either the queue is empty OR in an transient |
| inconsistent state. If it is the latter, we shold do a 0-timeout poll |
| so that the thread comes back quickly from poll to make a second |
| attempt at popping. Not doing this can potentially deadlock this |
| thread forever (if the deadline is infinity) */ |
| if (cq_event_queue_num_items(&cqd->queue) > 0) { |
| iteration_deadline = 0; |
| } |
| } |
| |
| if (gpr_atm_acq_load(&cqd->pending_events) == 0) { |
| /* Before returning, check if the queue has any items left over (since |
| gpr_mpscq_pop() can sometimes return NULL even if the queue is not |
| empty. If so, keep retrying but do not return GRPC_QUEUE_SHUTDOWN */ |
| if (cq_event_queue_num_items(&cqd->queue) > 0) { |
| /* Go to the beginning of the loop. No point doing a poll because |
| (cq->shutdown == true) is only possible when there is no pending |
| work (i.e cq->pending_events == 0) and any outstanding completion |
| events should have already been queued on this cq */ |
| continue; |
| } |
| |
| memset(&ret, 0, sizeof(ret)); |
| ret.type = GRPC_QUEUE_SHUTDOWN; |
| break; |
| } |
| |
| if (!is_finished_arg.first_loop && |
| grpc_core::ExecCtx::Get()->Now() >= deadline_millis) { |
| memset(&ret, 0, sizeof(ret)); |
| ret.type = GRPC_QUEUE_TIMEOUT; |
| dump_pending_tags(cq); |
| break; |
| } |
| |
| /* The main polling work happens in grpc_pollset_work */ |
| gpr_mu_lock(cq->mu); |
| cq->num_polls++; |
| grpc_error* err = cq->poller_vtable->work(POLLSET_FROM_CQ(cq), nullptr, |
| iteration_deadline); |
| gpr_mu_unlock(cq->mu); |
| |
| if (err != GRPC_ERROR_NONE) { |
| const char* msg = grpc_error_string(err); |
| gpr_log(GPR_ERROR, "Completion queue next failed: %s", msg); |
| |
| GRPC_ERROR_UNREF(err); |
| memset(&ret, 0, sizeof(ret)); |
| ret.type = GRPC_QUEUE_TIMEOUT; |
| dump_pending_tags(cq); |
| break; |
| } |
| is_finished_arg.first_loop = false; |
| } |
| |
| if (cq_event_queue_num_items(&cqd->queue) > 0 && |
| gpr_atm_acq_load(&cqd->pending_events) > 0) { |
| gpr_mu_lock(cq->mu); |
| cq->poller_vtable->kick(POLLSET_FROM_CQ(cq), nullptr); |
| gpr_mu_unlock(cq->mu); |
| } |
| |
| GRPC_SURFACE_TRACE_RETURNED_EVENT(cq, &ret); |
| GRPC_CQ_INTERNAL_UNREF(cq, "next"); |
| |
| GPR_ASSERT(is_finished_arg.stolen_completion == nullptr); |
| |
| return ret; |
| } |
| |
| /* Finishes the completion queue shutdown. This means that there are no more |
| completion events / tags expected from the completion queue |
| - Must be called under completion queue lock |
| - Must be called only once in completion queue's lifetime |
| - grpc_completion_queue_shutdown() MUST have been called before calling |
| this function */ |
| static void cq_finish_shutdown_next(grpc_completion_queue* cq) { |
| cq_next_data* cqd = (cq_next_data*)DATA_FROM_CQ(cq); |
| |
| GPR_ASSERT(cqd->shutdown_called); |
| GPR_ASSERT(gpr_atm_no_barrier_load(&cqd->pending_events) == 0); |
| |
| cq->poller_vtable->shutdown(POLLSET_FROM_CQ(cq), &cq->pollset_shutdown_done); |
| } |
| |
| static void cq_shutdown_next(grpc_completion_queue* cq) { |
| cq_next_data* cqd = (cq_next_data*)DATA_FROM_CQ(cq); |
| |
| /* Need an extra ref for cq here because: |
| * We call cq_finish_shutdown_next() below, that would call pollset shutdown. |
| * Pollset shutdown decrements the cq ref count which can potentially destroy |
| * the cq (if that happens to be the last ref). |
| * Creating an extra ref here prevents the cq from getting destroyed while |
| * this function is still active */ |
| GRPC_CQ_INTERNAL_REF(cq, "shutting_down"); |
| gpr_mu_lock(cq->mu); |
| if (cqd->shutdown_called) { |
| gpr_mu_unlock(cq->mu); |
| GRPC_CQ_INTERNAL_UNREF(cq, "shutting_down"); |
| return; |
| } |
| cqd->shutdown_called = true; |
| /* Doing a full_fetch_add (i.e acq/release) here to match with |
| * cq_begin_op_for_next and and cq_end_op_for_next functions which read/write |
| * on this counter without necessarily holding a lock on cq */ |
| if (gpr_atm_full_fetch_add(&cqd->pending_events, -1) == 1) { |
| cq_finish_shutdown_next(cq); |
| } |
| gpr_mu_unlock(cq->mu); |
| GRPC_CQ_INTERNAL_UNREF(cq, "shutting_down"); |
| } |
| |
| grpc_event grpc_completion_queue_next(grpc_completion_queue* cq, |
| gpr_timespec deadline, void* reserved) { |
| return cq->vtable->next(cq, deadline, reserved); |
| } |
| |
| static int add_plucker(grpc_completion_queue* cq, void* tag, |
| grpc_pollset_worker** worker) { |
| cq_pluck_data* cqd = (cq_pluck_data*)DATA_FROM_CQ(cq); |
| if (cqd->num_pluckers == GRPC_MAX_COMPLETION_QUEUE_PLUCKERS) { |
| return 0; |
| } |
| cqd->pluckers[cqd->num_pluckers].tag = tag; |
| cqd->pluckers[cqd->num_pluckers].worker = worker; |
| cqd->num_pluckers++; |
| return 1; |
| } |
| |
| static void del_plucker(grpc_completion_queue* cq, void* tag, |
| grpc_pollset_worker** worker) { |
| cq_pluck_data* cqd = (cq_pluck_data*)DATA_FROM_CQ(cq); |
| for (int i = 0; i < cqd->num_pluckers; i++) { |
| if (cqd->pluckers[i].tag == tag && cqd->pluckers[i].worker == worker) { |
| cqd->num_pluckers--; |
| GPR_SWAP(plucker, cqd->pluckers[i], cqd->pluckers[cqd->num_pluckers]); |
| return; |
| } |
| } |
| GPR_UNREACHABLE_CODE(return ); |
| } |
| |
| class ExecCtxPluck : public grpc_core::ExecCtx { |
| public: |
| ExecCtxPluck(void* arg) : ExecCtx(0), check_ready_to_finish_arg_(arg) {} |
| |
| bool CheckReadyToFinish() override { |
| cq_is_finished_arg* a = (cq_is_finished_arg*)check_ready_to_finish_arg_; |
| grpc_completion_queue* cq = a->cq; |
| cq_pluck_data* cqd = (cq_pluck_data*)DATA_FROM_CQ(cq); |
| |
| GPR_ASSERT(a->stolen_completion == nullptr); |
| gpr_atm current_last_seen_things_queued_ever = |
| gpr_atm_no_barrier_load(&cqd->things_queued_ever); |
| if (current_last_seen_things_queued_ever != |
| a->last_seen_things_queued_ever) { |
| gpr_mu_lock(cq->mu); |
| a->last_seen_things_queued_ever = |
| gpr_atm_no_barrier_load(&cqd->things_queued_ever); |
| grpc_cq_completion* c; |
| grpc_cq_completion* prev = &cqd->completed_head; |
| while ((c = (grpc_cq_completion*)(prev->next & ~(uintptr_t)1)) != |
| &cqd->completed_head) { |
| if (c->tag == a->tag) { |
| prev->next = (prev->next & (uintptr_t)1) | (c->next & ~(uintptr_t)1); |
| if (c == cqd->completed_tail) { |
| cqd->completed_tail = prev; |
| } |
| gpr_mu_unlock(cq->mu); |
| a->stolen_completion = c; |
| return true; |
| } |
| prev = c; |
| } |
| gpr_mu_unlock(cq->mu); |
| } |
| return !a->first_loop && a->deadline < grpc_core::ExecCtx::Get()->Now(); |
| } |
| |
| private: |
| void* check_ready_to_finish_arg_; |
| }; |
| |
| static grpc_event cq_pluck(grpc_completion_queue* cq, void* tag, |
| gpr_timespec deadline, void* reserved) { |
| GPR_TIMER_SCOPE("grpc_completion_queue_pluck", 0); |
| |
| grpc_event ret; |
| grpc_cq_completion* c; |
| grpc_cq_completion* prev; |
| grpc_pollset_worker* worker = nullptr; |
| cq_pluck_data* cqd = (cq_pluck_data*)DATA_FROM_CQ(cq); |
| |
| if (grpc_cq_pluck_trace.enabled()) { |
| GRPC_API_TRACE( |
| "grpc_completion_queue_pluck(" |
| "cq=%p, tag=%p, " |
| "deadline=gpr_timespec { tv_sec: %" PRId64 |
| ", tv_nsec: %d, clock_type: %d }, " |
| "reserved=%p)", |
| 6, |
| (cq, tag, deadline.tv_sec, deadline.tv_nsec, (int)deadline.clock_type, |
| reserved)); |
| } |
| GPR_ASSERT(!reserved); |
| |
| dump_pending_tags(cq); |
| |
| GRPC_CQ_INTERNAL_REF(cq, "pluck"); |
| gpr_mu_lock(cq->mu); |
| grpc_millis deadline_millis = grpc_timespec_to_millis_round_up(deadline); |
| cq_is_finished_arg is_finished_arg = { |
| gpr_atm_no_barrier_load(&cqd->things_queued_ever), |
| cq, |
| deadline_millis, |
| nullptr, |
| tag, |
| true}; |
| ExecCtxPluck exec_ctx(&is_finished_arg); |
| for (;;) { |
| if (is_finished_arg.stolen_completion != nullptr) { |
| gpr_mu_unlock(cq->mu); |
| c = is_finished_arg.stolen_completion; |
| is_finished_arg.stolen_completion = nullptr; |
| ret.type = GRPC_OP_COMPLETE; |
| ret.success = c->next & 1u; |
| ret.tag = c->tag; |
| c->done(c->done_arg, c); |
| break; |
| } |
| prev = &cqd->completed_head; |
| while ((c = (grpc_cq_completion*)(prev->next & ~(uintptr_t)1)) != |
| &cqd->completed_head) { |
| if (c->tag == tag) { |
| prev->next = (prev->next & (uintptr_t)1) | (c->next & ~(uintptr_t)1); |
| if (c == cqd->completed_tail) { |
| cqd->completed_tail = prev; |
| } |
| gpr_mu_unlock(cq->mu); |
| ret.type = GRPC_OP_COMPLETE; |
| ret.success = c->next & 1u; |
| ret.tag = c->tag; |
| c->done(c->done_arg, c); |
| goto done; |
| } |
| prev = c; |
| } |
| if (gpr_atm_no_barrier_load(&cqd->shutdown)) { |
| gpr_mu_unlock(cq->mu); |
| memset(&ret, 0, sizeof(ret)); |
| ret.type = GRPC_QUEUE_SHUTDOWN; |
| break; |
| } |
| if (!add_plucker(cq, tag, &worker)) { |
| gpr_log(GPR_DEBUG, |
| "Too many outstanding grpc_completion_queue_pluck calls: maximum " |
| "is %d", |
| GRPC_MAX_COMPLETION_QUEUE_PLUCKERS); |
| gpr_mu_unlock(cq->mu); |
| memset(&ret, 0, sizeof(ret)); |
| /* TODO(ctiller): should we use a different result here */ |
| ret.type = GRPC_QUEUE_TIMEOUT; |
| dump_pending_tags(cq); |
| break; |
| } |
| if (!is_finished_arg.first_loop && |
| grpc_core::ExecCtx::Get()->Now() >= deadline_millis) { |
| del_plucker(cq, tag, &worker); |
| gpr_mu_unlock(cq->mu); |
| memset(&ret, 0, sizeof(ret)); |
| ret.type = GRPC_QUEUE_TIMEOUT; |
| dump_pending_tags(cq); |
| break; |
| } |
| cq->num_polls++; |
| grpc_error* err = |
| cq->poller_vtable->work(POLLSET_FROM_CQ(cq), &worker, deadline_millis); |
| if (err != GRPC_ERROR_NONE) { |
| del_plucker(cq, tag, &worker); |
| gpr_mu_unlock(cq->mu); |
| const char* msg = grpc_error_string(err); |
| gpr_log(GPR_ERROR, "Completion queue pluck failed: %s", msg); |
| |
| GRPC_ERROR_UNREF(err); |
| memset(&ret, 0, sizeof(ret)); |
| ret.type = GRPC_QUEUE_TIMEOUT; |
| dump_pending_tags(cq); |
| break; |
| } |
| is_finished_arg.first_loop = false; |
| del_plucker(cq, tag, &worker); |
| } |
| done: |
| GRPC_SURFACE_TRACE_RETURNED_EVENT(cq, &ret); |
| GRPC_CQ_INTERNAL_UNREF(cq, "pluck"); |
| |
| GPR_ASSERT(is_finished_arg.stolen_completion == nullptr); |
| |
| return ret; |
| } |
| |
| grpc_event grpc_completion_queue_pluck(grpc_completion_queue* cq, void* tag, |
| gpr_timespec deadline, void* reserved) { |
| return cq->vtable->pluck(cq, tag, deadline, reserved); |
| } |
| |
| static void cq_finish_shutdown_pluck(grpc_completion_queue* cq) { |
| cq_pluck_data* cqd = (cq_pluck_data*)DATA_FROM_CQ(cq); |
| |
| GPR_ASSERT(cqd->shutdown_called); |
| GPR_ASSERT(!gpr_atm_no_barrier_load(&cqd->shutdown)); |
| gpr_atm_no_barrier_store(&cqd->shutdown, 1); |
| |
| cq->poller_vtable->shutdown(POLLSET_FROM_CQ(cq), &cq->pollset_shutdown_done); |
| } |
| |
| /* NOTE: This function is almost exactly identical to cq_shutdown_next() but |
| * merging them is a bit tricky and probably not worth it */ |
| static void cq_shutdown_pluck(grpc_completion_queue* cq) { |
| cq_pluck_data* cqd = (cq_pluck_data*)DATA_FROM_CQ(cq); |
| |
| /* Need an extra ref for cq here because: |
| * We call cq_finish_shutdown_pluck() below, that would call pollset shutdown. |
| * Pollset shutdown decrements the cq ref count which can potentially destroy |
| * the cq (if that happens to be the last ref). |
| * Creating an extra ref here prevents the cq from getting destroyed while |
| * this function is still active */ |
| GRPC_CQ_INTERNAL_REF(cq, "shutting_down (pluck cq)"); |
| gpr_mu_lock(cq->mu); |
| if (cqd->shutdown_called) { |
| gpr_mu_unlock(cq->mu); |
| GRPC_CQ_INTERNAL_UNREF(cq, "shutting_down (pluck cq)"); |
| return; |
| } |
| cqd->shutdown_called = true; |
| if (gpr_atm_full_fetch_add(&cqd->pending_events, -1) == 1) { |
| cq_finish_shutdown_pluck(cq); |
| } |
| gpr_mu_unlock(cq->mu); |
| GRPC_CQ_INTERNAL_UNREF(cq, "shutting_down (pluck cq)"); |
| } |
| |
| /* Shutdown simply drops a ref that we reserved at creation time; if we drop |
| to zero here, then enter shutdown mode and wake up any waiters */ |
| void grpc_completion_queue_shutdown(grpc_completion_queue* cq) { |
| GPR_TIMER_SCOPE("grpc_completion_queue_shutdown", 0); |
| grpc_core::ExecCtx exec_ctx; |
| GRPC_API_TRACE("grpc_completion_queue_shutdown(cq=%p)", 1, (cq)); |
| cq->vtable->shutdown(cq); |
| } |
| |
| void grpc_completion_queue_destroy(grpc_completion_queue* cq) { |
| GPR_TIMER_SCOPE("grpc_completion_queue_destroy", 0); |
| GRPC_API_TRACE("grpc_completion_queue_destroy(cq=%p)", 1, (cq)); |
| grpc_completion_queue_shutdown(cq); |
| |
| grpc_core::ExecCtx exec_ctx; |
| GRPC_CQ_INTERNAL_UNREF(cq, "destroy"); |
| } |
| |
| grpc_pollset* grpc_cq_pollset(grpc_completion_queue* cq) { |
| return cq->poller_vtable->can_get_pollset ? POLLSET_FROM_CQ(cq) : nullptr; |
| } |
| |
| bool grpc_cq_can_listen(grpc_completion_queue* cq) { |
| return cq->poller_vtable->can_listen; |
| } |