Signal a blocked futex if the isolate is interrupted; don't busy-wait

src/execution.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/execution.h"
 
 #include "src/bootstrapper.h"
 #include "src/codegen.h"
 #include "src/deoptimizer.h"
 #include "src/messages.h"
@@ skipping 395 matching lines @@
   ExecutionAccess access(isolate_);
   // Check the chain of PostponeInterruptsScopes for interception.
   if (thread_local_.postpone_interrupts_ &&
       thread_local_.postpone_interrupts_->Intercept(flag)) {
     return;
   }
 
   // Not intercepted.  Set as active interrupt flag.
   thread_local_.interrupt_flags_ |= flag;
   set_interrupt_limits(access);
+
+  // If this isolate is waiting in a futex, notify it to wake up.
+  if (isolate_->futex_wait_list_node()->waiting()) {
+    // Release the execution lock to prevent potential deadlock due to lock
+    // order inversion with the futex lock.
+    ExecutionAccess::Unlock(isolate_);
+    isolate_->futex_wait_list_node()->NotifyWake();
+    ExecutionAccess::Lock(isolate_);
+  }
 }
 
 
 void StackGuard::ClearInterrupt(InterruptFlag flag) {
   ExecutionAccess access(isolate_);
   // Clear the interrupt flag from the chain of PostponeInterruptsScopes.
   for (PostponeInterruptsScope* current = thread_local_.postpone_interrupts_;
        current != NULL;
        current = current->prev_) {
     current->intercepted_flags_ &= ~flag;
@@ skipping 237 matching lines @@
 
   isolate_->counters()->stack_interrupts()->Increment();
   isolate_->counters()->runtime_profiler_ticks()->Increment();
   isolate_->runtime_profiler()->OptimizeNow();
 
   return isolate_->heap()->undefined_value();
 }
 
 }  // namespace internal
 }  // namespace v8