src/v8/src/heap/sweeper-thread.cc

   1 // Copyright 2012 the V8 project authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "src/heap/sweeper-thread.h"
   6
   7 #include "src/v8.h"
   8
   9 #include "src/isolate.h"
  10 #include "src/v8threads.h"
  11
  12 namespace v8 {
  13 namespace internal {
  14
  15 static const int kSweeperThreadStackSize = 64 * KB;
  16
  17 SweeperThread::SweeperThread(Isolate* isolate)
  18     : Thread(Thread::Options("v8:SweeperThread", kSweeperThreadStackSize)),
  19       isolate_(isolate),
  20       heap_(isolate->heap()),
  21       collector_(heap_->mark_compact_collector()),
  22       start_sweeping_semaphore_(0),
  23       end_sweeping_semaphore_(0),
  24       stop_semaphore_(0) {
  25   DCHECK(!FLAG_job_based_sweeping);
  26   base::NoBarrier_Store(&stop_thread_, static_cast<base::AtomicWord>(false));
  27 }
  28
  29
  30 void SweeperThread::Run() {
  31   Isolate::SetIsolateThreadLocals(isolate_, NULL);
  32   DisallowHeapAllocation no_allocation;
  33   DisallowHandleAllocation no_handles;
  34   DisallowHandleDereference no_deref;
  35
  36   while (true) {
  37     start_sweeping_semaphore_.Wait();
  38
  39     if (base::Acquire_Load(&stop_thread_)) {
  40       stop_semaphore_.Signal();
  41       return;
  42     }
  43
  44     collector_->SweepInParallel(heap_->old_data_space(), 0);
  45     collector_->SweepInParallel(heap_->old_pointer_space(), 0);
  46     end_sweeping_semaphore_.Signal();
  47   }
  48 }
  49
  50
  51 void SweeperThread::Stop() {
  52   base::Release_Store(&stop_thread_, static_cast<base::AtomicWord>(true));
  53   start_sweeping_semaphore_.Signal();
  54   stop_semaphore_.Wait();
  55   Join();
  56 }
  57
  58
  59 void SweeperThread::StartSweeping() { start_sweeping_semaphore_.Signal(); }
  60
  61
  62 void SweeperThread::WaitForSweeperThread() { end_sweeping_semaphore_.Wait(); }
  63
  64
  65 bool SweeperThread::SweepingCompleted() {
  66   bool value = end_sweeping_semaphore_.WaitFor(base::TimeDelta::FromSeconds(0));
  67   if (value) {
  68     end_sweeping_semaphore_.Signal();
  69   }
  70   return value;
  71 }
  72
  73
  74 int SweeperThread::NumberOfThreads(int max_available) {
  75   if (!FLAG_concurrent_sweeping && !FLAG_parallel_sweeping) return 0;
  76   if (FLAG_sweeper_threads > 0) return FLAG_sweeper_threads;
  77   if (FLAG_concurrent_sweeping) return max_available - 1;
  78   DCHECK(FLAG_parallel_sweeping);
  79   return max_available;
  80 }
  81 }
  82 }  // namespace v8::internal