[heap] Skip memory reducer on AdjustAmountOfExternalAllocateMemory

V8 performs GC based on external memory limit. Additionally triggering
memory reducing GCs may be problematic for large heaps and increases
the chances of multiple V8 isolates performing GCs after
IsolateInBackgroundNotification.

Bug: chromium:1072746

Change-Id: I7649a176504803ba666e6367b008593bbcfe6312
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2159488
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67398}

include/v8.h

@@ -24,9 +24,9 @@
 #include <utility>
 #include <vector>
 
-#include "v8-internal.h"  // NOLINT(build/include)
-#include "v8-version.h"   // NOLINT(build/include)
-#include "v8config.h"     // NOLINT(build/include)
+#include "v8-internal.h"  // NOLINT(build/include_directory)
+#include "v8-version.h"   // NOLINT(build/include_directory)
+#include "v8config.h"     // NOLINT(build/include_directory)
 
 // We reserve the V8_* prefix for macros defined in V8 public API and
 // assume there are no name conflicts with the embedder's code.
@@ -9530,7 +9530,6 @@ class V8_EXPORT Isolate {
 
   internal::Address* GetDataFromSnapshotOnce(size_t index);
   void ReportExternalAllocationLimitReached();
-  void CheckMemoryPressure();
 };
 
 class V8_EXPORT StartupData {
@@ -11968,7 +11967,6 @@ MaybeLocal<T> Isolate::GetDataFromSnapshotOnce(size_t index) {
 int64_t Isolate::AdjustAmountOfExternalAllocatedMemory(
     int64_t change_in_bytes) {
   typedef internal::Internals I;
-  constexpr int64_t kMemoryReducerActivationLimit = 32 * 1024 * 1024;
   int64_t* external_memory = reinterpret_cast<int64_t*>(
       reinterpret_cast<uint8_t*>(this) + I::kExternalMemoryOffset);
   int64_t* external_memory_limit = reinterpret_cast<int64_t*>(
@@ -11991,14 +11989,6 @@ int64_t Isolate::AdjustAmountOfExternalAllocatedMemory(
 
   if (change_in_bytes <= 0) return *external_memory;
 
-  int64_t allocation_diff_since_last_mc = static_cast<int64_t>(
-      static_cast<uint64_t>(*external_memory) -
-      static_cast<uint64_t>(*external_memory_low_since_mc));
-  // Only check memory pressure and potentially trigger GC if the amount of
-  // external memory increased.
-  if (allocation_diff_since_last_mc > kMemoryReducerActivationLimit) {
-    CheckMemoryPressure();
-  }
   if (amount > *external_memory_limit) {
     ReportExternalAllocationLimitReached();
   }

src/api/api.cc

@@ -8038,12 +8038,6 @@ void Isolate::ReportExternalAllocationLimitReached() {
   heap->ReportExternalMemoryPressure();
 }
 
-void Isolate::CheckMemoryPressure() {
-  i::Heap* heap = reinterpret_cast<i::Isolate*>(this)->heap();
-  if (heap->gc_state() != i::Heap::NOT_IN_GC) return;
-  heap->CheckMemoryPressure();
-}
-
 HeapProfiler* Isolate::GetHeapProfiler() {
   i::HeapProfiler* heap_profiler =
       reinterpret_cast<i::Isolate*>(this)->heap_profiler();