From: mstarzinger@chromium.org <mstarzinger@chromium.org@ce2b1a6d-e550-0410-aec6-3dcde31c8c00>
Date: Fri, 12 Apr 2013 08:58:22 +0000 (+0000)
Subject: Support full deoptimization during GC via stack guard.
X-Git-Tag: upstream/4.7.83~14604
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=4a9c3d4a66f8dcb7ce2cfe602428af5f1ff00b4f;p=platform%2Fupstream%2Fv8.git

Support full deoptimization during GC via stack guard.

This adds support to the stack guard to trigger a full deoptimization of
all optimized code when the GC kicks into high promotion mode. Global
pretenuring decisions in optimized code can then be based on the high
promotion mode.

R=ulan@chromium.org

Review URL: https://codereview.chromium.org/14173007

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14243 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
---

diff --git a/src/execution.cc b/src/execution.cc
index dee3112..f343868 100644
--- a/src/execution.cc
+++ b/src/execution.cc
@@ -33,6 +33,7 @@
 #include "bootstrapper.h"
 #include "codegen.h"
 #include "debug.h"
+#include "deoptimizer.h"
 #include "isolate-inl.h"
 #include "runtime-profiler.h"
 #include "simulator.h"
@@ -448,6 +449,19 @@ void StackGuard::RequestGC() {
 }
 
 
+bool StackGuard::IsFullDeopt() {
+  ExecutionAccess access(isolate_);
+  return (thread_local_.interrupt_flags_ & FULL_DEOPT) != 0;
+}
+
+
+void StackGuard::FullDeopt() {
+  ExecutionAccess access(isolate_);
+  thread_local_.interrupt_flags_ |= FULL_DEOPT;
+  set_interrupt_limits(access);
+}
+
+
 #ifdef ENABLE_DEBUGGER_SUPPORT
 bool StackGuard::IsDebugBreak() {
   ExecutionAccess access(isolate_);
@@ -880,7 +894,6 @@ MaybeObject* Execution::HandleStackGuardInterrupt(Isolate* isolate) {
     stack_guard->Continue(GC_REQUEST);
   }
 
-
   isolate->counters()->stack_interrupts()->Increment();
   isolate->counters()->runtime_profiler_ticks()->Increment();
   isolate->runtime_profiler()->OptimizeNow();
@@ -898,6 +911,10 @@ MaybeObject* Execution::HandleStackGuardInterrupt(Isolate* isolate) {
     stack_guard->Continue(INTERRUPT);
     return isolate->StackOverflow();
   }
+  if (stack_guard->IsFullDeopt()) {
+    stack_guard->Continue(FULL_DEOPT);
+    Deoptimizer::DeoptimizeAll(isolate);
+  }
   return isolate->heap()->undefined_value();
 }
 
diff --git a/src/execution.h b/src/execution.h
index b104180..9cf8ac6 100644
--- a/src/execution.h
+++ b/src/execution.h
@@ -41,7 +41,8 @@ enum InterruptFlag {
   DEBUGCOMMAND = 1 << 2,
   PREEMPT = 1 << 3,
   TERMINATE = 1 << 4,
-  GC_REQUEST = 1 << 5
+  GC_REQUEST = 1 << 5,
+  FULL_DEOPT = 1 << 6
 };
 
 
@@ -197,6 +198,8 @@ class StackGuard {
 #endif
   bool IsGCRequest();
   void RequestGC();
+  bool IsFullDeopt();
+  void FullDeopt();
   void Continue(InterruptFlag after_what);
 
   // This provides an asynchronous read of the stack limits for the current
diff --git a/src/heap.cc b/src/heap.cc
index 76f0a3c..3c88980 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -952,6 +952,13 @@ bool Heap::PerformGarbageCollection(GarbageCollector collector,
       PrintPID("Limited new space size due to high promotion rate: %d MB\n",
                new_space_.InitialCapacity() / MB);
     }
+    // Support for global pre-tenuring uses the high promotion mode as a
+    // heuristic indicator of whether to pretenure or not, we trigger
+    // deoptimization here to take advantage of pre-tenuring as soon as
+    // possible.
+    if (FLAG_pretenure_literals) {
+      isolate_->stack_guard()->FullDeopt();
+    }
   } else if (new_space_high_promotion_mode_active_ &&
       IsStableOrDecreasingSurvivalTrend() &&
       IsLowSurvivalRate()) {
diff --git a/src/heap.h b/src/heap.h
index 9e758aa..46c75fe 100644
--- a/src/heap.h
+++ b/src/heap.h
@@ -1498,6 +1498,12 @@ class Heap {
   MUST_USE_RESULT MaybeObject* AllocateRawFixedArray(int length,
                                                      PretenureFlag pretenure);
 
+  // Predicate that governs global pre-tenuring decisions based on observed
+  // promotion rates of previous collections.
+  inline bool ShouldGloballyPretenure() {
+    return new_space_high_promotion_mode_active_;
+  }
+
   inline intptr_t PromotedTotalSize() {
     return PromotedSpaceSizeOfObjects() + PromotedExternalMemorySize();
   }