aboutsummaryrefslogtreecommitdiffhomepage
path: root/src/core/lib
diff options
context:
space:
mode:
Diffstat (limited to 'src/core/lib')
-rw-r--r--src/core/lib/iomgr/async_execution_lock.c137
-rw-r--r--src/core/lib/iomgr/async_execution_lock.h63
-rw-r--r--src/core/lib/support/mpscq.c80
-rw-r--r--src/core/lib/support/mpscq.h65
4 files changed, 345 insertions, 0 deletions
diff --git a/src/core/lib/iomgr/async_execution_lock.c b/src/core/lib/iomgr/async_execution_lock.c
new file mode 100644
index 0000000000..96ba175a5a
--- /dev/null
+++ b/src/core/lib/iomgr/async_execution_lock.c
@@ -0,0 +1,137 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ * * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "src/core/lib/iomgr/async_execution_lock.h"
+
+#include <string.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+
+typedef struct grpc_aelock_qnode {
+ gpr_mpscq_node mpscq_node;
+ grpc_aelock_action action;
+ void *arg;
+} grpc_aelock_qnode;
+
+struct grpc_aelock {
+ grpc_workqueue *optional_workqueue;
+ gpr_mpscq queue;
+ // state is:
+ // lower bit - zero if orphaned
+ // other bits - number of items queued on the lock
+ gpr_atm state;
+ grpc_closure continue_finishing;
+};
+
+static void continue_finishing(grpc_exec_ctx *exec_ctx, void *arg,
+ bool success);
+
+grpc_aelock *grpc_aelock_create(grpc_workqueue *optional_workqueue) {
+ grpc_aelock *lock = gpr_malloc(sizeof(*lock));
+ lock->optional_workqueue = optional_workqueue;
+ gpr_atm_no_barrier_store(&lock->state, 1);
+ gpr_mpscq_init(&lock->queue);
+ grpc_closure_init(&lock->continue_finishing, continue_finishing, lock);
+ return lock;
+}
+
+static void really_destroy(grpc_aelock *lock) {
+ GPR_ASSERT(gpr_atm_no_barrier_load(&lock->state) == 0);
+ gpr_mpscq_destroy(&lock->queue);
+ gpr_free(lock);
+}
+
+void grpc_aelock_destroy(grpc_aelock *lock) {
+ if (gpr_atm_full_fetch_add(&lock->state, -1) == 1) {
+ really_destroy(lock);
+ }
+}
+
+static bool maybe_finish_one(grpc_exec_ctx *exec_ctx, grpc_aelock *lock) {
+ gpr_mpscq_node *n = gpr_mpscq_pop(&lock->queue);
+ if (n == NULL) {
+ // queue is in an inconsistant state: use this as a cue that we should
+ // go off and do something else for a while (and come back later)
+ grpc_exec_ctx_enqueue(exec_ctx, &lock->continue_finishing, true,
+ lock->optional_workqueue);
+ return false;
+ }
+ grpc_aelock_qnode *ln = (grpc_aelock_qnode *)n;
+ ln->action(exec_ctx, ln->arg);
+ gpr_free(ln);
+ return true;
+}
+
+static void finish(grpc_exec_ctx *exec_ctx, grpc_aelock *lock) {
+ do {
+ switch (gpr_atm_full_fetch_add(&lock->state, -2)) {
+ case 3: // had one count, one unorphaned --> unlocked unorphaned
+ return;
+ case 2: // and one count, one orphaned --> unlocked and orphaned
+ really_destroy(lock);
+ return;
+ case 1:
+ case 0:
+ // these values are illegal - representing an already unlocked or
+ // deleted lock
+ GPR_UNREACHABLE_CODE(return );
+ }
+ } while (maybe_finish_one(exec_ctx, lock));
+}
+
+static void continue_finishing(grpc_exec_ctx *exec_ctx, void *arg,
+ bool success) {
+ if (maybe_finish_one(exec_ctx, arg)) finish(exec_ctx, arg);
+}
+
+void grpc_aelock_execute(grpc_exec_ctx *exec_ctx, grpc_aelock *lock,
+ grpc_aelock_action action, void *arg,
+ size_t sizeof_arg) {
+ gpr_atm last = gpr_atm_full_fetch_add(&lock->state, 2);
+ GPR_ASSERT(last & 1); // ensure lock has not been destroyed
+ if (last == 1) {
+ action(exec_ctx, arg);
+ finish(exec_ctx, lock);
+ } else {
+ grpc_aelock_qnode *n = gpr_malloc(sizeof(*n) + sizeof_arg);
+ n->action = action;
+ if (sizeof_arg > 0) {
+ memcpy(n + 1, arg, sizeof_arg);
+ n->arg = n + 1;
+ } else {
+ n->arg = arg;
+ }
+ gpr_mpscq_push(&lock->queue, &n->mpscq_node);
+ }
+}
diff --git a/src/core/lib/iomgr/async_execution_lock.h b/src/core/lib/iomgr/async_execution_lock.h
new file mode 100644
index 0000000000..e52762f443
--- /dev/null
+++ b/src/core/lib/iomgr/async_execution_lock.h
@@ -0,0 +1,63 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ * * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_IOMGR_ASYNC_EXECUTION_LOCK_H
+#define GRPC_CORE_LIB_IOMGR_ASYNC_EXECUTION_LOCK_H
+
+#include <stddef.h>
+
+#include <grpc/support/atm.h>
+#include "src/core/lib/iomgr/exec_ctx.h"
+#include "src/core/lib/support/mpscq.h"
+
+typedef struct grpc_aelock grpc_aelock;
+
+// Provides serialized access to some resource.
+// Each action queued on an aelock is executed serially in a borrowed thread.
+// The actual thread executing actions may change over time (but there will only
+// every be one at a time).
+
+typedef void (*grpc_aelock_action)(grpc_exec_ctx *exec_ctx, void *arg);
+
+// Initialize the lock, with an optional workqueue to shift load to when
+// necessary
+grpc_aelock *grpc_aelock_create(grpc_workqueue *optional_workqueue);
+// Destroy the lock
+void grpc_aelock_destroy(grpc_aelock *lock);
+// Execute \a action within the lock. \a arg is the argument to pass to \a
+// action and sizeof_arg is the sizeof(*arg), or 0 if arg is non-copyable.
+void grpc_aelock_execute(grpc_exec_ctx *exec_ctx, grpc_aelock *lock,
+ grpc_aelock_action action, void *arg,
+ size_t sizeof_arg);
+
+#endif /* GRPC_CORE_LIB_IOMGR_ASYNC_EXECUTION_LOCK_H */
diff --git a/src/core/lib/support/mpscq.c b/src/core/lib/support/mpscq.c
new file mode 100644
index 0000000000..25b055b172
--- /dev/null
+++ b/src/core/lib/support/mpscq.c
@@ -0,0 +1,80 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ * * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "src/core/lib/support/mpscq.h"
+
+#include <grpc/support/log.h>
+
+void gpr_mpscq_init(gpr_mpscq *q) {
+ gpr_atm_no_barrier_store(&q->head, (gpr_atm)&q->stub);
+ q->tail = &q->stub;
+ gpr_atm_no_barrier_store(&q->stub.next, 0);
+}
+
+void gpr_mpscq_destroy(gpr_mpscq *q) {
+ GPR_ASSERT(gpr_atm_no_barrier_load(&q->head) == (gpr_atm)&q->stub);
+ GPR_ASSERT(q->tail == &q->stub);
+}
+
+void gpr_mpscq_push(gpr_mpscq *q, gpr_mpscq_node *n) {
+ gpr_atm_no_barrier_store(&n->next, 0);
+ gpr_mpscq_node *prev =
+ (gpr_mpscq_node *)gpr_atm_full_xchg(&q->head, (gpr_atm)n);
+ gpr_atm_rel_store(&prev->next, (gpr_atm)n);
+}
+
+gpr_mpscq_node *gpr_mpscq_pop(gpr_mpscq *q) {
+ gpr_mpscq_node *tail = q->tail;
+ gpr_mpscq_node *next = (gpr_mpscq_node *)gpr_atm_acq_load(&tail->next);
+ if (tail == &q->stub) {
+ if (next == NULL) return NULL;
+ q->tail = next;
+ tail = next;
+ next = (gpr_mpscq_node *)gpr_atm_acq_load(&tail->next);
+ }
+ if (next != NULL) {
+ q->tail = next;
+ return tail;
+ }
+ gpr_mpscq_node *head = (gpr_mpscq_node *)gpr_atm_acq_load(&q->head);
+ if (tail != head) {
+ return 0;
+ }
+ gpr_mpscq_push(q, &q->stub);
+ next = (gpr_mpscq_node *)gpr_atm_acq_load(&tail->next);
+ if (next != NULL) {
+ q->tail = next;
+ return tail;
+ }
+ return NULL;
+}
diff --git a/src/core/lib/support/mpscq.h b/src/core/lib/support/mpscq.h
new file mode 100644
index 0000000000..1201edceb1
--- /dev/null
+++ b/src/core/lib/support/mpscq.h
@@ -0,0 +1,65 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ * * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_SUPPORT_MPSCQ_H
+#define GRPC_CORE_LIB_SUPPORT_MPSCQ_H
+
+#include <grpc/support/atm.h>
+#include <stddef.h>
+
+// Multiple-producer single-consumer lock free queue, based upon the
+// implementation from Dmitry Vyukov here:
+// http://www.1024cores.net/home/lock-free-algorithms/queues/intrusive-mpsc-node-based-queue
+
+// List node (include this in a data structure and dangle the rest of the
+// interesting bits off the end)
+typedef struct gpr_mpscq_node { gpr_atm next; } gpr_mpscq_node;
+
+// Actual queue type
+typedef struct gpr_mpscq {
+ gpr_atm head;
+ // make sure head & tail don't share a cacheline
+ char padding[GPR_CACHELINE_SIZE];
+ gpr_mpscq_node *tail;
+ gpr_mpscq_node stub;
+} gpr_mpscq;
+
+void gpr_mpscq_init(gpr_mpscq *q);
+void gpr_mpscq_destroy(gpr_mpscq *q);
+// Push a node
+void gpr_mpscq_push(gpr_mpscq *q, gpr_mpscq_node *n);
+// Pop a node (returns NULL if no node is ready - which doesn't indicate that
+// the queue is empty!!)
+gpr_mpscq_node *gpr_mpscq_pop(gpr_mpscq *q);
+
+#endif /* GRPC_CORE_LIB_SUPPORT_MPSCQ_H */
generated by cgit v1.2.3 (git 2.39.1) at 2025-01-31 04:41:21 +0000