Split cq_data into cq_next_data, cq_pluck_data

3 files changed, 217 insertions, 173 deletions

diff --git a/src/core/lib/surface/completion_queue.c b/src/core/lib/surface/completion_queue.c
index bfce9d274c..769a700b66 100644
--- a/src/core/lib/surface/completion_queue.c
+++ b/src/core/lib/surface/completion_queue.c
@@ -203,7 +203,10 @@ static const cq_poller_vtable g_poller_vtable_by_poller_type[] = {
 
 typedef struct cq_vtable {
   grpc_cq_completion_type cq_completion_type;
-  size_t (*size)();
+  size_t data_size;
+  void (*init)(void *data);
+  void (*shutdown)(grpc_exec_ctx *exec_ctx, grpc_completion_queue *cq);
+  void (*destroy)(void *data);
   void (*begin_op)(grpc_completion_queue *cq, void *tag);
   void (*end_op)(grpc_exec_ctx *exec_ctx, grpc_completion_queue *cq, void *tag,
                  grpc_error *error,
@@ -232,25 +235,30 @@ typedef struct grpc_cq_event_queue {
   gpr_atm num_queue_items;
 } grpc_cq_event_queue;
 
-/* TODO: sreek Refactor this based on the completion_type. Put completion-type
- * specific data in a different structure (and co-allocate memory for it along
- * with completion queue + pollset )*/
-typedef struct cq_data {
-  gpr_mu *mu;
+typedef struct cq_next_data {
+  /** Completed events for completion-queues of type GRPC_CQ_NEXT */
+  grpc_cq_event_queue queue;
+
+  /** Number of pending events (+1 if we're not shutdown) */
+  gpr_refcount 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've begun shutting down */
+  gpr_atm shutdown;
+  int 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;
 
-  /** Completed events for completion-queues of type GRPC_CQ_NEXT */
-  grpc_cq_event_queue queue;
-
   /** Number of pending events (+1 if we're not shutdown) */
   gpr_refcount pending_events;
 
-  /** Once owning_refs drops to zero, we will destroy the cq */
-  gpr_refcount owning_refs;
-
   /** 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;
@@ -259,34 +267,42 @@ typedef struct cq_data {
   gpr_atm shutdown;
   int shutdown_called;
 
-  int is_server_cq;
-
   int num_pluckers;
-  int num_polls;
   plucker pluckers[GRPC_MAX_COMPLETION_QUEUE_PLUCKERS];
-  grpc_closure pollset_shutdown_done;
+} 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
-} cq_data;
 
-/* Completion queue structure */
-struct grpc_completion_queue {
-  cq_data data;
-  const cq_vtable *vtable;
-  const cq_poller_vtable *poller_vtable;
+  grpc_closure pollset_shutdown_done;
+  int num_polls;
 };
 
 /* Forward declarations */
-static void cq_finish_shutdown(grpc_exec_ctx *exec_ctx,
-                               grpc_completion_queue *cq);
-
-static size_t cq_size(grpc_completion_queue *cq);
-
-static void cq_begin_op(grpc_completion_queue *cq, void *tag);
+static void cq_finish_shutdown_next(grpc_exec_ctx *exec_ctx,
+                                    grpc_completion_queue *cq);
+static void cq_finish_shutdown_pluck(grpc_exec_ctx *exec_ctx,
+                                     grpc_completion_queue *cq);
+static void cq_shutdown_next(grpc_exec_ctx *exec_ctx,
+                             grpc_completion_queue *cq);
+static void cq_shutdown_pluck(grpc_exec_ctx *exec_ctx,
+                              grpc_completion_queue *cq);
+
+static void cq_begin_op_for_next(grpc_completion_queue *cq, void *tag);
+static void cq_begin_op_for_pluck(grpc_completion_queue *cq, void *tag);
 
 static void cq_end_op_for_next(grpc_exec_ctx *exec_ctx,
                                grpc_completion_queue *cq, void *tag,
@@ -310,26 +326,36 @@ static grpc_event cq_next(grpc_completion_queue *cq, gpr_timespec deadline,
 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 */
     {.cq_completion_type = GRPC_CQ_NEXT,
-     .size = cq_size,
-     .begin_op = cq_begin_op,
+     .init = cq_init_next,
+     .shutdown = cq_shutdown_next,
+     .destroy = cq_destroy_next,
+     .begin_op = cq_begin_op_for_next,
      .end_op = cq_end_op_for_next,
      .next = cq_next,
      .pluck = NULL},
     /* GRPC_CQ_PLUCK */
     {.cq_completion_type = GRPC_CQ_PLUCK,
-     .size = cq_size,
-     .begin_op = cq_begin_op,
+     .init = cq_init_pluck,
+     .shutdown = cq_shutdown_pluck,
+     .destroy = cq_destroy_pluck,
+     .begin_op = cq_begin_op_for_pluck,
      .end_op = cq_end_op_for_pluck,
      .next = NULL,
      .pluck = cq_pluck},
 };
 
-#define POLLSET_FROM_CQ(cq) ((grpc_pollset *)(cq + 1))
-#define CQ_FROM_POLLSET(ps) (((grpc_completion_queue *)ps) - 1)
+#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_tracer_flag grpc_cq_pluck_trace = GRPC_TRACER_INITIALIZER(true);
 grpc_tracer_flag grpc_cq_event_timeout_trace = GRPC_TRACER_INITIALIZER(true);
@@ -381,12 +407,6 @@ static long cq_event_queue_num_items(grpc_cq_event_queue *q) {
   return (long)gpr_atm_no_barrier_load(&q->num_queue_items);
 }
 
-static size_t cq_size(grpc_completion_queue *cq) {
-  /* Size of the completion queue and the size of the pollset whose memory is
-     allocated right after that of completion queue */
-  return sizeof(grpc_completion_queue) + cq->poller_vtable->size();
-}
-
 grpc_completion_queue *grpc_completion_queue_create_internal(
     grpc_cq_completion_type completion_type,
     grpc_cq_polling_type polling_type) {
@@ -403,41 +423,57 @@ grpc_completion_queue *grpc_completion_queue_create_internal(
   const cq_poller_vtable *poller_vtable =
       &g_poller_vtable_by_poller_type[polling_type];
 
-  cq = gpr_zalloc(sizeof(grpc_completion_queue) + poller_vtable->size());
-  cq_data *cqd = &cq->data;
+  cq = gpr_zalloc(sizeof(grpc_completion_queue) + vtable->data_size +
+                  poller_vtable->size());
 
   cq->vtable = vtable;
   cq->poller_vtable = poller_vtable;
 
-  poller_vtable->init(POLLSET_FROM_CQ(cq), &cq->data.mu);
+  /* One for destroy(), one for pollset_shutdown */
+  gpr_ref_init(&cq->owning_refs, 2);
 
-#ifndef NDEBUG
-  cqd->outstanding_tags = NULL;
-  cqd->outstanding_tag_capacity = 0;
-#endif
+  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);
 
+  GPR_TIMER_END("grpc_completion_queue_create_internal", 0);
+
+  return cq;
+}
+
+static void cq_init_next(void *ptr) {
+  cq_next_data *cqd = ptr;
+  /* Initial ref is dropped by grpc_completion_queue_shutdown */
+  gpr_ref_init(&cqd->pending_events, 1);
+  gpr_atm_no_barrier_store(&cqd->shutdown, 0);
+  cqd->shutdown_called = 0;
+  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 = 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 = ptr;
   /* Initial ref is dropped by grpc_completion_queue_shutdown */
   gpr_ref_init(&cqd->pending_events, 1);
-  /* One for destroy(), one for pollset_shutdown */
-  gpr_ref_init(&cqd->owning_refs, 2);
   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 = 0;
-  cqd->is_server_cq = 0;
   cqd->num_pluckers = 0;
-  cqd->num_polls = 0;
   gpr_atm_no_barrier_store(&cqd->things_queued_ever, 0);
-#ifndef NDEBUG
-  cqd->outstanding_tag_count = 0;
-#endif
-  cq_event_queue_init(&cqd->queue);
-  grpc_closure_init(&cqd->pollset_shutdown_done, on_pollset_shutdown_done, cq,
-                    grpc_schedule_on_exec_ctx);
-
-  GPR_TIMER_END("grpc_completion_queue_create_internal", 0);
+}
 
-  return cq;
+static void cq_destroy_pluck(void *ptr) {
+  cq_pluck_data *cqd = 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) {
@@ -446,23 +482,21 @@ grpc_cq_completion_type grpc_get_cq_completion_type(grpc_completion_queue *cq) {
 
 int grpc_get_cq_poll_num(grpc_completion_queue *cq) {
   int cur_num_polls;
-  gpr_mu_lock(cq->data.mu);
-  cur_num_polls = cq->data.num_polls;
-  gpr_mu_unlock(cq->data.mu);
+  gpr_mu_lock(cq->mu);
+  cur_num_polls = cq->num_polls;
+  gpr_mu_unlock(cq->mu);
   return cur_num_polls;
 }
 
 #ifdef GRPC_CQ_REF_COUNT_DEBUG
 void grpc_cq_internal_ref(grpc_completion_queue *cq, const char *reason,
                           const char *file, int line) {
-  cq_data *cqd = &cq->data;
   gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG, "CQ:%p   ref %d -> %d %s", cq,
-          (int)cqd->owning_refs.count, (int)cqd->owning_refs.count + 1, reason);
+          (int)cq->owning_refs.count, (int)cq->owning_refs.count + 1, reason);
 #else
 void grpc_cq_internal_ref(grpc_completion_queue *cq) {
-  cq_data *cqd = &cq->data;
 #endif
-  gpr_ref(&cqd->owning_refs);
+  gpr_ref(&cq->owning_refs);
 }
 
 static void on_pollset_shutdown_done(grpc_exec_ctx *exec_ctx, void *arg,
@@ -480,61 +514,63 @@ void grpc_cq_internal_unref(grpc_completion_queue *cq, const char *reason,
 #else
 void grpc_cq_internal_unref(grpc_exec_ctx *exec_ctx,
                             grpc_completion_queue *cq) {
-  cq_data *cqd = &cq->data;
 #endif
-  if (gpr_unref(&cqd->owning_refs)) {
-    GPR_ASSERT(cqd->completed_head.next == (uintptr_t)&cqd->completed_head);
+  if (gpr_unref(&cq->owning_refs)) {
+    cq->vtable->destroy(DATA_FROM_CQ(cq));
     cq->poller_vtable->destroy(exec_ctx, POLLSET_FROM_CQ(cq));
-    cq_event_queue_destroy(&cqd->queue);
 #ifndef NDEBUG
-    gpr_free(cqd->outstanding_tags);
+    gpr_free(cq->outstanding_tags);
 #endif
     gpr_free(cq);
   }
 }
 
-static void cq_begin_op(grpc_completion_queue *cq, void *tag) {
-  cq_data *cqd = &cq->data;
-#ifndef NDEBUG
-  gpr_mu_lock(cqd->mu);
+static void cq_begin_op_for_next(grpc_completion_queue *cq, void *tag) {
+  cq_next_data *cqd = DATA_FROM_CQ(cq);
+  GPR_ASSERT(!cqd->shutdown_called);
+  gpr_ref(&cqd->pending_events);
+}
+
+static void cq_begin_op_for_pluck(grpc_completion_queue *cq, void *tag) {
+  cq_pluck_data *cqd = DATA_FROM_CQ(cq);
   GPR_ASSERT(!cqd->shutdown_called);
-  if (cqd->outstanding_tag_count == cqd->outstanding_tag_capacity) {
-    cqd->outstanding_tag_capacity =
-        GPR_MAX(4, 2 * cqd->outstanding_tag_capacity);
-    cqd->outstanding_tags =
-        gpr_realloc(cqd->outstanding_tags, sizeof(*cqd->outstanding_tags) *
-                                               cqd->outstanding_tag_capacity);
-  }
-  cqd->outstanding_tags[cqd->outstanding_tag_count++] = tag;
-  gpr_mu_unlock(cqd->mu);
-#endif
   gpr_ref(&cqd->pending_events);
 }
 
 void 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 =
+        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
   cq->vtable->begin_op(cq, tag);
 }
 
 #ifndef NDEBUG
 static void cq_check_tag(grpc_completion_queue *cq, void *tag, bool lock_cq) {
-  cq_data *cqd = &cq->data;
   int found = 0;
   if (lock_cq) {
-    gpr_mu_lock(cqd->mu);
+    gpr_mu_lock(cq->mu);
   }
 
-  for (int i = 0; i < (int)cqd->outstanding_tag_count; i++) {
-    if (cqd->outstanding_tags[i] == tag) {
-      cqd->outstanding_tag_count--;
-      GPR_SWAP(void *, cqd->outstanding_tags[i],
-               cqd->outstanding_tags[cqd->outstanding_tag_count]);
+  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(cqd->mu);
+    gpr_mu_unlock(cq->mu);
   }
 
   GPR_ASSERT(found);
@@ -568,7 +604,7 @@ static void cq_end_op_for_next(grpc_exec_ctx *exec_ctx,
     }
   }
 
-  cq_data *cqd = &cq->data;
+  cq_next_data *cqd = DATA_FROM_CQ(cq);
   int is_success = (error == GRPC_ERROR_NONE);
 
   storage->tag = tag;
@@ -586,10 +622,10 @@ static void cq_end_op_for_next(grpc_exec_ctx *exec_ctx,
   if (!shutdown) {
     /* Only kick if this is the first item queued */
     if (is_first) {
-      gpr_mu_lock(cqd->mu);
+      gpr_mu_lock(cq->mu);
       grpc_error *kick_error =
           cq->poller_vtable->kick(POLLSET_FROM_CQ(cq), NULL);
-      gpr_mu_unlock(cqd->mu);
+      gpr_mu_unlock(cq->mu);
 
       if (kick_error != GRPC_ERROR_NONE) {
         const char *msg = grpc_error_string(kick_error);
@@ -598,9 +634,9 @@ static void cq_end_op_for_next(grpc_exec_ctx *exec_ctx,
       }
     }
   } else {
-    gpr_mu_lock(cqd->mu);
-    cq_finish_shutdown(exec_ctx, cq);
-    gpr_mu_unlock(cqd->mu);
+    gpr_mu_lock(cq->mu);
+    cq_finish_shutdown_next(exec_ctx, cq);
+    gpr_mu_unlock(cq->mu);
   }
 
   GPR_TIMER_END("cq_end_op_for_next", 0);
@@ -617,7 +653,7 @@ static void cq_end_op_for_pluck(grpc_exec_ctx *exec_ctx,
                                              void *done_arg,
                                              grpc_cq_completion *storage),
                                 void *done_arg, grpc_cq_completion *storage) {
-  cq_data *cqd = &cq->data;
+  cq_pluck_data *cqd = DATA_FROM_CQ(cq);
   int is_success = (error == GRPC_ERROR_NONE);
 
   GPR_TIMER_BEGIN("cq_end_op_for_pluck", 0);
@@ -641,7 +677,7 @@ static void cq_end_op_for_pluck(grpc_exec_ctx *exec_ctx,
   storage->done_arg = done_arg;
   storage->next = ((uintptr_t)&cqd->completed_head) | ((uintptr_t)(is_success));
 
-  gpr_mu_lock(cqd->mu);
+  gpr_mu_lock(cq->mu);
   cq_check_tag(cq, tag, false); /* Used in debug builds only */
 
   /* Add to the list of completions */
@@ -663,7 +699,7 @@ static void cq_end_op_for_pluck(grpc_exec_ctx *exec_ctx,
     grpc_error *kick_error =
         cq->poller_vtable->kick(POLLSET_FROM_CQ(cq), pluck_worker);
 
-    gpr_mu_unlock(cqd->mu);
+    gpr_mu_unlock(cq->mu);
 
     if (kick_error != GRPC_ERROR_NONE) {
       const char *msg = grpc_error_string(kick_error);
@@ -672,8 +708,8 @@ static void cq_end_op_for_pluck(grpc_exec_ctx *exec_ctx,
       GRPC_ERROR_UNREF(kick_error);
     }
   } else {
-    cq_finish_shutdown(exec_ctx, cq);
-    gpr_mu_unlock(cqd->mu);
+    cq_finish_shutdown_pluck(exec_ctx, cq);
+    gpr_mu_unlock(cq->mu);
   }
 
   GPR_TIMER_END("cq_end_op_for_pluck", 0);
@@ -701,7 +737,7 @@ typedef struct {
 static bool cq_is_next_finished(grpc_exec_ctx *exec_ctx, void *arg) {
   cq_is_finished_arg *a = arg;
   grpc_completion_queue *cq = a->cq;
-  cq_data *cqd = &cq->data;
+  cq_next_data *cqd = DATA_FROM_CQ(cq);
   GPR_ASSERT(a->stolen_completion == NULL);
 
   gpr_atm current_last_seen_things_queued_ever =
@@ -728,18 +764,16 @@ static bool cq_is_next_finished(grpc_exec_ctx *exec_ctx, void *arg) {
 static void dump_pending_tags(grpc_completion_queue *cq) {
   if (!GRPC_TRACER_ON(grpc_trace_pending_tags)) return;
 
-  cq_data *cqd = &cq->data;
-
   gpr_strvec v;
   gpr_strvec_init(&v);
   gpr_strvec_add(&v, gpr_strdup("PENDING TAGS:"));
-  gpr_mu_lock(cqd->mu);
-  for (size_t i = 0; i < cqd->outstanding_tag_count; i++) {
+  gpr_mu_lock(cq->mu);
+  for (size_t i = 0; i < cq->outstanding_tag_count; i++) {
     char *s;
-    gpr_asprintf(&s, " %p", cqd->outstanding_tags[i]);
+    gpr_asprintf(&s, " %p", cq->outstanding_tags[i]);
     gpr_strvec_add(&v, s);
   }
-  gpr_mu_unlock(cqd->mu);
+  gpr_mu_unlock(cq->mu);
   char *out = gpr_strvec_flatten(&v, NULL);
   gpr_strvec_destroy(&v);
   gpr_log(GPR_DEBUG, "%s", out);
@@ -753,7 +787,7 @@ static grpc_event cq_next(grpc_completion_queue *cq, gpr_timespec deadline,
                           void *reserved) {
   grpc_event ret;
   gpr_timespec now;
-  cq_data *cqd = &cq->data;
+  cq_next_data *cqd = DATA_FROM_CQ(cq);
 
   GPR_TIMER_BEGIN("grpc_completion_queue_next", 0);
 
@@ -842,11 +876,11 @@ static grpc_event cq_next(grpc_completion_queue *cq, gpr_timespec deadline,
     }
 
     /* The main polling work happens in grpc_pollset_work */
-    gpr_mu_lock(cqd->mu);
-    cqd->num_polls++;
+    gpr_mu_lock(cq->mu);
+    cq->num_polls++;
     grpc_error *err = cq->poller_vtable->work(&exec_ctx, POLLSET_FROM_CQ(cq),
                                               NULL, now, iteration_deadline);
-    gpr_mu_unlock(cqd->mu);
+    gpr_mu_unlock(cq->mu);
 
     if (err != GRPC_ERROR_NONE) {
       const char *msg = grpc_error_string(err);
@@ -868,9 +902,9 @@ static grpc_event cq_next(grpc_completion_queue *cq, gpr_timespec deadline,
 
   if (cq_event_queue_num_items(&cqd->queue) > 0 &&
       gpr_atm_no_barrier_load(&cqd->shutdown) == 0) {
-    gpr_mu_lock(cqd->mu);
+    gpr_mu_lock(cq->mu);
     cq->poller_vtable->kick(POLLSET_FROM_CQ(cq), NULL);
-    gpr_mu_unlock(cqd->mu);
+    gpr_mu_unlock(cq->mu);
   }
 
   GPR_TIMER_END("grpc_completion_queue_next", 0);
@@ -885,7 +919,7 @@ grpc_event grpc_completion_queue_next(grpc_completion_queue *cq,
 
 static int add_plucker(grpc_completion_queue *cq, void *tag,
                        grpc_pollset_worker **worker) {
-  cq_data *cqd = &cq->data;
+  cq_pluck_data *cqd = DATA_FROM_CQ(cq);
   if (cqd->num_pluckers == GRPC_MAX_COMPLETION_QUEUE_PLUCKERS) {
     return 0;
   }
@@ -897,7 +931,7 @@ static int add_plucker(grpc_completion_queue *cq, void *tag,
 
 static void del_plucker(grpc_completion_queue *cq, void *tag,
                         grpc_pollset_worker **worker) {
-  cq_data *cqd = &cq->data;
+  cq_pluck_data *cqd = 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--;
@@ -911,13 +945,13 @@ static void del_plucker(grpc_completion_queue *cq, void *tag,
 static bool cq_is_pluck_finished(grpc_exec_ctx *exec_ctx, void *arg) {
   cq_is_finished_arg *a = arg;
   grpc_completion_queue *cq = a->cq;
-  cq_data *cqd = &cq->data;
+  cq_pluck_data *cqd = DATA_FROM_CQ(cq);
 
   GPR_ASSERT(a->stolen_completion == NULL);
   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(cqd->mu);
+    gpr_mu_lock(cq->mu);
     a->last_seen_things_queued_ever =
         gpr_atm_no_barrier_load(&cqd->things_queued_ever);
     grpc_cq_completion *c;
@@ -929,13 +963,13 @@ static bool cq_is_pluck_finished(grpc_exec_ctx *exec_ctx, void *arg) {
         if (c == cqd->completed_tail) {
           cqd->completed_tail = prev;
         }
-        gpr_mu_unlock(cqd->mu);
+        gpr_mu_unlock(cq->mu);
         a->stolen_completion = c;
         return true;
       }
       prev = c;
     }
-    gpr_mu_unlock(cqd->mu);
+    gpr_mu_unlock(cq->mu);
   }
   return !a->first_loop &&
          gpr_time_cmp(a->deadline, gpr_now(a->deadline.clock_type)) < 0;
@@ -948,7 +982,7 @@ static grpc_event cq_pluck(grpc_completion_queue *cq, void *tag,
   grpc_cq_completion *prev;
   grpc_pollset_worker *worker = NULL;
   gpr_timespec now;
-  cq_data *cqd = &cq->data;
+  cq_pluck_data *cqd = DATA_FROM_CQ(cq);
 
   GPR_TIMER_BEGIN("grpc_completion_queue_pluck", 0);
 
@@ -969,7 +1003,7 @@ static grpc_event cq_pluck(grpc_completion_queue *cq, void *tag,
   deadline = gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC);
 
   GRPC_CQ_INTERNAL_REF(cq, "pluck");
-  gpr_mu_lock(cqd->mu);
+  gpr_mu_lock(cq->mu);
   cq_is_finished_arg is_finished_arg = {
       .last_seen_things_queued_ever =
           gpr_atm_no_barrier_load(&cqd->things_queued_ever),
@@ -982,7 +1016,7 @@ static grpc_event cq_pluck(grpc_completion_queue *cq, void *tag,
       GRPC_EXEC_CTX_INITIALIZER(0, cq_is_pluck_finished, &is_finished_arg);
   for (;;) {
     if (is_finished_arg.stolen_completion != NULL) {
-      gpr_mu_unlock(cqd->mu);
+      gpr_mu_unlock(cq->mu);
       c = is_finished_arg.stolen_completion;
       is_finished_arg.stolen_completion = NULL;
       ret.type = GRPC_OP_COMPLETE;
@@ -999,7 +1033,7 @@ static grpc_event cq_pluck(grpc_completion_queue *cq, void *tag,
         if (c == cqd->completed_tail) {
           cqd->completed_tail = prev;
         }
-        gpr_mu_unlock(cqd->mu);
+        gpr_mu_unlock(cq->mu);
         ret.type = GRPC_OP_COMPLETE;
         ret.success = c->next & 1u;
         ret.tag = c->tag;
@@ -1009,7 +1043,7 @@ static grpc_event cq_pluck(grpc_completion_queue *cq, void *tag,
       prev = c;
     }
     if (gpr_atm_no_barrier_load(&cqd->shutdown)) {
-      gpr_mu_unlock(cqd->mu);
+      gpr_mu_unlock(cq->mu);
       memset(&ret, 0, sizeof(ret));
       ret.type = GRPC_QUEUE_SHUTDOWN;
       break;
@@ -1019,7 +1053,7 @@ static grpc_event cq_pluck(grpc_completion_queue *cq, void *tag,
               "Too many outstanding grpc_completion_queue_pluck calls: maximum "
               "is %d",
               GRPC_MAX_COMPLETION_QUEUE_PLUCKERS);
-      gpr_mu_unlock(cqd->mu);
+      gpr_mu_unlock(cq->mu);
       memset(&ret, 0, sizeof(ret));
       /* TODO(ctiller): should we use a different result here */
       ret.type = GRPC_QUEUE_TIMEOUT;
@@ -1029,19 +1063,19 @@ static grpc_event cq_pluck(grpc_completion_queue *cq, void *tag,
     now = gpr_now(GPR_CLOCK_MONOTONIC);
     if (!is_finished_arg.first_loop && gpr_time_cmp(now, deadline) >= 0) {
       del_plucker(cq, tag, &worker);
-      gpr_mu_unlock(cqd->mu);
+      gpr_mu_unlock(cq->mu);
       memset(&ret, 0, sizeof(ret));
       ret.type = GRPC_QUEUE_TIMEOUT;
       dump_pending_tags(cq);
       break;
     }
 
-    cqd->num_polls++;
+    cq->num_polls++;
     grpc_error *err = cq->poller_vtable->work(&exec_ctx, POLLSET_FROM_CQ(cq),
                                               &worker, now, deadline);
     if (err != GRPC_ERROR_NONE) {
       del_plucker(cq, tag, &worker);
-      gpr_mu_unlock(cqd->mu);
+      gpr_mu_unlock(cq->mu);
       const char *msg = grpc_error_string(err);
       gpr_log(GPR_ERROR, "Completion queue pluck failed: %s", msg);
 
@@ -1076,37 +1110,71 @@ grpc_event grpc_completion_queue_pluck(grpc_completion_queue *cq, void *tag,
    - 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(grpc_exec_ctx *exec_ctx,
-                               grpc_completion_queue *cq) {
-  cq_data *cqd = &cq->data;
+static void cq_finish_shutdown_next(grpc_exec_ctx *exec_ctx,
+                                    grpc_completion_queue *cq) {
+  cq_next_data *cqd = 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(exec_ctx, POLLSET_FROM_CQ(cq),
-                              &cqd->pollset_shutdown_done);
+                              &cq->pollset_shutdown_done);
 }
 
-/* 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) {
-  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
-  GPR_TIMER_BEGIN("grpc_completion_queue_shutdown", 0);
-  GRPC_API_TRACE("grpc_completion_queue_shutdown(cq=%p)", 1, (cq));
-  cq_data *cqd = &cq->data;
+static void cq_finish_shutdown_pluck(grpc_exec_ctx *exec_ctx,
+                                     grpc_completion_queue *cq) {
+  cq_pluck_data *cqd = 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(exec_ctx, POLLSET_FROM_CQ(cq),
+                              &cq->pollset_shutdown_done);
+}
+
+static void cq_shutdown_next(grpc_exec_ctx *exec_ctx,
+                             grpc_completion_queue *cq) {
+  cq_next_data *cqd = DATA_FROM_CQ(cq);
 
-  gpr_mu_lock(cqd->mu);
+  gpr_mu_lock(cq->mu);
   if (cqd->shutdown_called) {
-    gpr_mu_unlock(cqd->mu);
+    gpr_mu_unlock(cq->mu);
     GPR_TIMER_END("grpc_completion_queue_shutdown", 0);
     return;
   }
   cqd->shutdown_called = 1;
   if (gpr_unref(&cqd->pending_events)) {
-    cq_finish_shutdown(&exec_ctx, cq);
+    cq_finish_shutdown_next(exec_ctx, cq);
   }
-  gpr_mu_unlock(cqd->mu);
+  gpr_mu_unlock(cq->mu);
+}
+
+static void cq_shutdown_pluck(grpc_exec_ctx *exec_ctx,
+                              grpc_completion_queue *cq) {
+  cq_pluck_data *cqd = DATA_FROM_CQ(cq);
+
+  gpr_mu_lock(cq->mu);
+  if (cqd->shutdown_called) {
+    gpr_mu_unlock(cq->mu);
+    GPR_TIMER_END("grpc_completion_queue_shutdown", 0);
+    return;
+  }
+  cqd->shutdown_called = 1;
+  if (gpr_unref(&cqd->pending_events)) {
+    cq_finish_shutdown_pluck(exec_ctx, cq);
+  }
+  gpr_mu_unlock(cq->mu);
+}
+
+/* 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) {
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  GPR_TIMER_BEGIN("grpc_completion_queue_shutdown", 0);
+  GRPC_API_TRACE("grpc_completion_queue_shutdown(cq=%p)", 1, (cq));
+  cq->vtable->shutdown(&exec_ctx, cq);
   grpc_exec_ctx_finish(&exec_ctx);
   GPR_TIMER_END("grpc_completion_queue_shutdown", 0);
 }
@@ -1116,12 +1184,6 @@ void grpc_completion_queue_destroy(grpc_completion_queue *cq) {
   GPR_TIMER_BEGIN("grpc_completion_queue_destroy", 0);
   grpc_completion_queue_shutdown(cq);
 
-  /* TODO (sreek): This should not ideally be here. Refactor it into the
-   * cq_vtable (perhaps have a create/destroy methods in the cq vtable) */
-  if (cq->vtable->cq_completion_type == GRPC_CQ_NEXT) {
-    GPR_ASSERT(cq_event_queue_num_items(&cq->data.queue) == 0);
-  }
-
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   GRPC_CQ_INTERNAL_UNREF(&exec_ctx, cq, "destroy");
   grpc_exec_ctx_finish(&exec_ctx);
@@ -1132,18 +1194,6 @@ grpc_pollset *grpc_cq_pollset(grpc_completion_queue *cq) {
   return cq->poller_vtable->can_get_pollset ? POLLSET_FROM_CQ(cq) : NULL;
 }
 
-grpc_completion_queue *grpc_cq_from_pollset(grpc_pollset *ps) {
-  return CQ_FROM_POLLSET(ps);
-}
-
-void grpc_cq_mark_server_cq(grpc_completion_queue *cq) {
-  cq->data.is_server_cq = 1;
-}
-
-bool grpc_cq_is_server_cq(grpc_completion_queue *cq) {
-  return cq->data.is_server_cq;
-}
-
 bool grpc_cq_can_listen(grpc_completion_queue *cq) {
   return cq->poller_vtable->can_listen;
 }
diff --git a/src/core/lib/surface/completion_queue.h b/src/core/lib/surface/completion_queue.h
index 7963ea75e7..93c629c4a4 100644
--- a/src/core/lib/surface/completion_queue.h
+++ b/src/core/lib/surface/completion_queue.h
@@ -99,10 +99,7 @@ void grpc_cq_end_op(grpc_exec_ctx *exec_ctx, grpc_completion_queue *cc,
                     void *done_arg, grpc_cq_completion *storage);
 
 grpc_pollset *grpc_cq_pollset(grpc_completion_queue *cc);
-grpc_completion_queue *grpc_cq_from_pollset(grpc_pollset *ps);
 
-void grpc_cq_mark_server_cq(grpc_completion_queue *cc);
-bool grpc_cq_is_server_cq(grpc_completion_queue *cc);
 bool grpc_cq_can_listen(grpc_completion_queue *cc);
 
 grpc_cq_completion_type grpc_get_cq_completion_type(grpc_completion_queue *cc);
diff --git a/src/core/lib/surface/server.c b/src/core/lib/surface/server.c
index 7e4ae421a0..a64d043367 100644
--- a/src/core/lib/surface/server.c
+++ b/src/core/lib/surface/server.c
@@ -964,8 +964,6 @@ static void register_completion_queue(grpc_server *server,
     if (server->cqs[i] == cq) return;
   }
 
-  grpc_cq_mark_server_cq(cq);
-
   GRPC_CQ_INTERNAL_REF(cq, "server");
   n = server->cq_count++;
   server->cqs = gpr_realloc(server->cqs,
@@ -1129,9 +1127,8 @@ void grpc_server_setup_transport(grpc_exec_ctx *exec_ctx, grpc_server *s,
   chand->channel = channel;
 
   size_t cq_idx;
-  grpc_completion_queue *accepting_cq = grpc_cq_from_pollset(accepting_pollset);
   for (cq_idx = 0; cq_idx < s->cq_count; cq_idx++) {
-    if (s->cqs[cq_idx] == accepting_cq) break;
+    if (grpc_cq_pollset(s->cqs[cq_idx]) == accepting_pollset) break;
   }
   if (cq_idx == s->cq_count) {
     /* completion queue not found: pick a random one to publish new calls to */