Ivan Posva
e47ac24c79
BUG= R=asiva@google.com, srdjan@google.com Review URL: https://codereview.chromium.org/1533023002 .
104 lines
4.0 KiB
C++
104 lines
4.0 KiB
C++
// Copyright (c) 2015, 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_THREAD_REGISTRY_H_
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#define VM_THREAD_REGISTRY_H_
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#include "vm/globals.h"
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#include "vm/growable_array.h"
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#include "vm/isolate.h"
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#include "vm/lockers.h"
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#include "vm/stack_frame.h"
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#include "vm/thread.h"
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namespace dart {
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// Unordered collection of threads relating to a particular isolate.
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class ThreadRegistry {
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public:
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ThreadRegistry()
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: monitor_(new Monitor()),
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active_list_(NULL),
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free_list_(NULL),
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mutator_thread_(NULL),
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in_rendezvous_(false),
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remaining_(0),
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round_(0) {}
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~ThreadRegistry();
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Thread* active_list() const { return active_list_; }
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// Bring all threads in this isolate to a safepoint. The caller is
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// expected to be implicitly at a safepoint. The threads will wait
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// until ResumeAllThreads is called. First participates in any
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// already pending rendezvous requested by another thread. Any
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// thread that tries to enter this isolate during rendezvous will
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// wait in RestoreStateTo. Nesting is not supported: the caller must
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// call ResumeAllThreads before making further calls to
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// SafepointThreads.
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void SafepointThreads();
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// Unblocks all threads participating in the rendezvous that was organized
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// by a prior call to SafepointThreads.
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// TODO(koda): Consider adding a scope helper to avoid omitting this call.
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void ResumeAllThreads();
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// Indicate that the current thread is at a safepoint, and offer to wait for
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// any pending rendezvous request (if none, returns immediately).
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void CheckSafepoint() {
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MonitorLocker ml(monitor_);
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CheckSafepointLocked();
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}
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bool AtSafepoint() const { return in_rendezvous_; }
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Thread* Schedule(Isolate* isolate, bool is_mutator, bool bypass_safepoint);
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void Unschedule(Thread* thread, bool is_mutator, bool bypass_safepoint);
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void VisitObjectPointers(ObjectPointerVisitor* visitor, bool validate_frames);
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void PrepareForGC();
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private:
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void AddThreadToActiveList(Thread* thread);
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void RemoveThreadFromActiveList(Thread* thread);
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Thread* GetThreadFromFreelist(Isolate* isolate);
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void ReturnThreadToFreelist(Thread* thread);
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// Note: Lock should be taken before this function is called.
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void CheckSafepointLocked();
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// Returns the number threads that are scheduled on this isolate.
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// Note: Lock should be taken before this function is called.
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intptr_t CountScheduledLocked();
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Monitor* monitor_; // All access is synchronized through this monitor.
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Thread* active_list_; // List of active threads in the isolate.
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Thread* free_list_; // Free list of Thread objects that can be reused.
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// TODO(asiva): Currently we treat a mutator thread as a special thread
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// and always schedule execution of Dart code on the same mutator thread
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// object. The ApiLocalScope has been made thread specific but we still
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// have scenarios where we do a temporary exit of an Isolate with live
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// zones/handles in the the API scope :
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// - Dart_RunLoop()
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// - IsolateSaver in Dart_NewNativePort
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// - Isolate spawn (function/uri) under FLAG_i_like_slow_isolate_spawn
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// We probably need a mechanism to return to the specific thread only
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// for these specific cases. We should also determine if the embedder
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// should allow exiting an isolate with live state in zones/handles in
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// which case a new API for returning to the specific thread needs to be
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// added.
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Thread* mutator_thread_;
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// Safepoint rendezvous state.
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bool in_rendezvous_; // A safepoint rendezvous request is in progress.
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intptr_t remaining_; // Number of threads yet to reach their safepoint.
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int64_t round_; // Counter, to prevent missing updates to remaining_
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// (see comments in CheckSafepointLocked).
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DISALLOW_COPY_AND_ASSIGN(ThreadRegistry);
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};
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} // namespace dart
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#endif // VM_THREAD_REGISTRY_H_
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