1 files changed, 30 insertions, 0 deletions
diff --git a/runtime/thread_list.cc b/runtime/thread_list.cc
index bddebbd5e7..ac5750b01c 100644
--- a/runtime/thread_list.cc
+++ b/runtime/thread_list.cc
@@ -269,6 +269,36 @@ size_t ThreadList::RunCheckpoint(Closure* checkpoint_function) {
   return count + suspended_count_modified_threads.size() + 1;
 }
 
+// Request that a checkpoint function be run on all active (non-suspended)
+// threads.  Returns the number of successful requests.
+size_t ThreadList::RunCheckpointOnRunnableThreads(Closure* checkpoint_function) {
+  Thread* self = Thread::Current();
+  if (kIsDebugBuild) {
+    Locks::mutator_lock_->AssertNotExclusiveHeld(self);
+    Locks::thread_list_lock_->AssertNotHeld(self);
+    Locks::thread_suspend_count_lock_->AssertNotHeld(self);
+    CHECK_NE(self->GetState(), kRunnable);
+  }
+
+  size_t count = 0;
+  {
+    // Call a checkpoint function for each non-suspended thread.
+    MutexLock mu(self, *Locks::thread_list_lock_);
+    MutexLock mu2(self, *Locks::thread_suspend_count_lock_);
+    for (const auto& thread : list_) {
+      if (thread != self) {
+        if (thread->RequestCheckpoint(checkpoint_function)) {
+          // This thread will run its checkpoint some time in the near future.
+          count++;
+        }
+      }
+    }
+  }
+
+  // Return the number of threads that will run the checkpoint function.
+  return count;
+}
+
 void ThreadList::SuspendAll() {
   Thread* self = Thread::Current();
   DCHECK(self != nullptr);