[heap] Use AdvanceOnAllocation() in ReportExternalMemoryPressure()

Heap::ReportExternalMemoryPressure() uses a slightly different
behavior for incremental marking steps than AdvanceFromTask() or
AdvanceOnAllocation(). This CL switches this method to use
AdvanceOnAllocation().

Bug: v8:12775
Change-Id: If9bb2c2cf3048196286e4b1443129025fbfdf984
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3825780
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82385}

src/heap/heap.cc

@@ -1715,17 +1715,10 @@ void Heap::ReportExternalMemoryPressure() {
                         kGCCallbackFlagsForExternalMemory);
     }
   } else {
-    // Incremental marking is turned on an has already been started.
-    const double kMinStepSize = 5;
-    const double kMaxStepSize = 10;
-    const double ms_step = std::min(
-        kMaxStepSize, std::max(kMinStepSize, static_cast<double>(current) /
-                                                 limit * kMinStepSize));
-    const double deadline = MonotonicallyIncreasingTimeInMs() + ms_step;
-    // Extend the gc callback flags with external memory flags.
+    // Incremental marking is turned on and has already been started.
     current_gc_callback_flags_ = static_cast<GCCallbackFlags>(
         current_gc_callback_flags_ | kGCCallbackFlagsForExternalMemory);
-    incremental_marking()->AdvanceWithDeadline(deadline, StepOrigin::kV8);
+    incremental_marking()->AdvanceOnAllocation();
   }
 }
 

src/heap/incremental-marking.h

@@ -126,6 +126,10 @@ class V8_EXPORT_PRIVATE IncrementalMarking final {
   // Performs incremental marking step and finalizes marking if complete.
   void AdvanceFromTask();
 
+  // Performs incremental marking step and schedules job for finalization if
+  // marking completes.
+  void AdvanceOnAllocation();
+
   StepResult Step(double max_step_size_in_ms, StepOrigin step_origin);
 
   // This function is used to color the object black before it undergoes an
@@ -215,8 +219,6 @@ class V8_EXPORT_PRIVATE IncrementalMarking final {
 
   void MarkRoots();
 
-  void AdvanceOnAllocation();
-
   // Returns true if the function succeeds in transitioning the object
   // from white to grey.
   bool WhiteToGreyAndPush(HeapObject obj);