turnidge@google.com
c658fa60f9
Deadlock looks like: Regular Isolate -> paused at breakpoint in debug message loop -> holds debug message queue lock to get message notifications -> handles an service message -> waits for portmap lock to send response Service Isolate -> receives request for paused isolate -> holds portmap lock to send message -> runs custom message notifier to wake debug message loop -> waits for debug message queue lock I've solved this by releasing the debug message queue lock while handling service messages. This requires me to poll for new service messages after reacquiring the debug message queue lock to make sure I haven't dropped any notifications. It's a little weird that the embedder (runtime/bin) needs to be aware of the locking in the core vm (runtime/vm), but this seemed like the simplest fix for now. BUG= R=johnmccutchan@google.com Review URL: https://codereview.chromium.org//629533002 git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@41326 260f80e4-7a28-3924-810f-c04153c831b5
111 lines
2.8 KiB
C++
111 lines
2.8 KiB
C++
// Copyright (c) 2011, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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#ifndef VM_MESSAGE_H_
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#define VM_MESSAGE_H_
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#include "platform/assert.h"
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#include "vm/globals.h"
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// Duplicated from dart_api.h to avoid including the whole header.
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typedef int64_t Dart_Port;
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namespace dart {
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class Message {
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public:
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typedef enum {
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kNormalPriority = 0, // Deliver message when idle.
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kOOBPriority = 1, // Deliver message asap.
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// Iteration.
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kFirstPriority = 0,
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kNumPriorities = 2,
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} Priority;
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// Values defining the type of OOB messages. OOB messages can only be
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// fixed length arrays where the first element is a Smi with one of the
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// valid values below.
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typedef enum {
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kIllegalOOB = 0,
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kServiceOOBMsg = 1,
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kIsolateLibOOBMsg = 2
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} OOBMsgTag;
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// A port number which is never used.
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static const Dart_Port kIllegalPort = 0;
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// A new message to be sent between two isolates. The data handed to this
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// message will be disposed by calling free() once the message object is
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// being destructed (after delivery or when the receiving port is closed).
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Message(Dart_Port dest_port,
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uint8_t* data,
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intptr_t len,
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Priority priority,
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Dart_Port delivery_failure_port = kIllegalPort)
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: next_(NULL),
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dest_port_(dest_port),
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delivery_failure_port_(delivery_failure_port),
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data_(data),
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len_(len),
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priority_(priority) {
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ASSERT(dest_port != kIllegalPort);
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ASSERT((priority == kNormalPriority) ||
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(delivery_failure_port == kIllegalPort));
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}
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~Message() {
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ASSERT(delivery_failure_port_ == kIllegalPort);
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free(data_);
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}
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Dart_Port dest_port() const { return dest_port_; }
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uint8_t* data() const { return data_; }
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intptr_t len() const { return len_; }
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Priority priority() const { return priority_; }
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bool IsOOB() const { return priority_ == Message::kOOBPriority; }
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bool RedirectToDeliveryFailurePort();
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private:
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friend class MessageQueue;
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Message* next_;
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Dart_Port dest_port_;
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Dart_Port delivery_failure_port_;
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uint8_t* data_;
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intptr_t len_;
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Priority priority_;
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DISALLOW_COPY_AND_ASSIGN(Message);
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};
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// There is a message queue per isolate.
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class MessageQueue {
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public:
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MessageQueue();
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~MessageQueue();
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void Enqueue(Message* msg);
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// Gets the next message from the message queue or NULL if no
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// message is available. This function will not block.
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Message* Dequeue();
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bool IsEmpty() { return head_ == NULL; }
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// Clear all messages from the message queue.
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void Clear();
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private:
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Message* head_;
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Message* tail_;
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DISALLOW_COPY_AND_ASSIGN(MessageQueue);
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};
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} // namespace dart
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#endif // VM_MESSAGE_H_
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