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![Ben Konyi](/assets/img/avatar_default.png)
This reverts commit b6c659ae8f
.
TEST=CQ
Change-Id: I49056d510a9365c7aed83388430949a630c0f4b7
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/216740
Commit-Queue: Ben Konyi <bkonyi@google.com>
Reviewed-by: Siva Annamalai <asiva@google.com>
148 lines
4.3 KiB
C++
148 lines
4.3 KiB
C++
// Copyright (c) 2013, 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 RUNTIME_VM_THREAD_INTERRUPTER_H_
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#define RUNTIME_VM_THREAD_INTERRUPTER_H_
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#include "vm/allocation.h"
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#include "vm/os_thread.h"
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#include "vm/signal_handler.h"
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#include "vm/thread.h"
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namespace dart {
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struct InterruptedThreadState {
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uintptr_t pc;
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uintptr_t csp;
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uintptr_t dsp;
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uintptr_t fp;
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uintptr_t lr;
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};
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class ThreadInterrupter : public AllStatic {
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public:
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static void Init();
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static void Startup();
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static void Cleanup();
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// Delay between interrupts.
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static void SetInterruptPeriod(intptr_t period);
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// Wake up the thread interrupter thread.
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static void WakeUp();
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// Interrupt a thread.
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static void InterruptThread(OSThread* thread);
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class SampleBufferWriterScope : public ValueObject {
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public:
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SampleBufferWriterScope() {
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intptr_t old_value = sample_buffer_lock_.load(std::memory_order_relaxed);
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intptr_t new_value;
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do {
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if (old_value < 0) {
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entered_lock_ = false;
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return;
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}
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new_value = old_value + 1;
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} while (!sample_buffer_lock_.compare_exchange_weak(
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old_value, new_value, std::memory_order_acquire));
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entered_lock_ = true;
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}
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~SampleBufferWriterScope() {
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if (!entered_lock_) return;
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intptr_t old_value = sample_buffer_lock_.load(std::memory_order_relaxed);
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intptr_t new_value;
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do {
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ASSERT(old_value > 0);
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new_value = old_value - 1;
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} while (!sample_buffer_lock_.compare_exchange_weak(
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old_value, new_value, std::memory_order_release));
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}
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bool CanSample() const {
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return entered_lock_ &&
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sample_buffer_waiters_.load(std::memory_order_relaxed) == 0;
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}
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private:
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bool entered_lock_;
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DISALLOW_COPY_AND_ASSIGN(SampleBufferWriterScope);
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};
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class SampleBufferReaderScope : public ValueObject {
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public:
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SampleBufferReaderScope() { EnterSampleReader(); }
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~SampleBufferReaderScope() { ExitSampleReader(); }
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private:
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DISALLOW_COPY_AND_ASSIGN(SampleBufferReaderScope);
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};
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private:
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static const intptr_t kMaxThreads = 4096;
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static bool initialized_;
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static bool shutdown_;
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static bool thread_running_;
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static bool woken_up_;
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static ThreadJoinId interrupter_thread_id_;
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static Monitor* monitor_;
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static intptr_t interrupt_period_;
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static intptr_t current_wait_time_;
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// Something like a reader-writer lock. Positive values indictate there are
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// outstanding signal handlers that can write to the sample buffer. Negative
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// values indicate there are outstanding sample buffer processors that can
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// read from the sample buffer. A reader will spin-wait to enter the lock. A
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// writer will give up if it fails to enter lock, causing samples to be
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// skipping while we are processing the sample buffer or trying to shut down.
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static std::atomic<intptr_t> sample_buffer_lock_;
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static std::atomic<intptr_t> sample_buffer_waiters_;
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static bool InDeepSleep() {
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return current_wait_time_ == Monitor::kNoTimeout;
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}
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static void ThreadMain(uword parameters);
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static void InstallSignalHandler();
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static void RemoveSignalHandler();
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static void EnterSampleReader() {
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sample_buffer_waiters_.fetch_add(1, std::memory_order_relaxed);
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intptr_t old_value = sample_buffer_lock_.load(std::memory_order_relaxed);
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intptr_t new_value;
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do {
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while (old_value > 0) {
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// Spin waiting for outstanding SIGPROFs to complete.
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old_value = sample_buffer_lock_.load(std::memory_order_relaxed);
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}
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new_value = old_value - 1;
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} while (!sample_buffer_lock_.compare_exchange_weak(
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old_value, new_value, std::memory_order_acquire));
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}
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static void ExitSampleReader() {
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sample_buffer_waiters_.fetch_sub(1, std::memory_order_relaxed);
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intptr_t old_value = sample_buffer_lock_.load(std::memory_order_relaxed);
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intptr_t new_value;
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do {
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ASSERT(old_value < 0);
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new_value = old_value + 1;
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} while (!sample_buffer_lock_.compare_exchange_weak(
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old_value, new_value, std::memory_order_release));
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}
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friend class ThreadInterrupterVisitIsolates;
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};
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} // namespace dart
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#endif // RUNTIME_VM_THREAD_INTERRUPTER_H_
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