Reland "[heap] Skip memory reducer on AdjustAmountOfExternalAllocateM…

…emory"

This is a reland of 7ae30cb

Original change's description:
> [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}

Bug: chromium:1072746
Tbr: mlippautz@chromium.org,hpayer@chromium.org
Change-Id: Ieccd77c868a8b5d5613e6c4b7e70fdb4bcff3044
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2165763
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67409}

include/v8.h

@@ -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();