From 16a980b4c4271902e50c99e66b5693f1d1556e38 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C3=ABl=20Zasso?= <targos@protonmail.com>
Date: Wed, 25 Oct 2017 15:52:20 +0200
Subject: [PATCH] deps: cherry-pick 2c75616 from upstream V8

Original commit message:

    [heap] Ensure progress in unmapping memory chunks.

    If sweeping is not making progress and there are many young generation
    GCs happening, then this can lead to accumulation of memory chunks in
    the unmapper queue.

    Bug: chromium:771966
    Change-Id: Ief73ada0d17198a80b668850c6d2e7ea413113e7
    Reviewed-on: https://chromium-review.googlesource.com/702479
    Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
    Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
    Cr-Commit-Position: refs/heads/master@{#48312}

Refs: https://github.com/v8/v8/commit/2c75616028e75883e28df2c6d8dd2a6bfe47f718
Refs: https://github.com/nodejs/help/issues/917#issuecomment-339292642
Refs: https://bugs.chromium.org/p/chromium/issues/detail?id=771966

PR-URL: https://github.com/nodejs/node/pull/16490
Backport-PR-URL: https://github.com/nodejs/node/pull/16413
Reviewed-By: Franziska Hinkelmann <franziska.hinkelmann@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ali Ijaz Sheikh <ofrobots@google.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
---
 deps/v8/src/heap/heap.cc  | 6 ++++++
 deps/v8/src/heap/spaces.h | 5 +++++
 2 files changed, 11 insertions(+)

diff --git a/deps/v8/src/heap/heap.cc b/deps/v8/src/heap/heap.cc
index 0b5a90afb08b1c..9f29717803a0ab 100644
--- a/deps/v8/src/heap/heap.cc
+++ b/deps/v8/src/heap/heap.cc
@@ -1885,6 +1885,12 @@ void Heap::Scavenge() {
   IncrementalMarking::PauseBlackAllocationScope pause_black_allocation(
       incremental_marking());
 
+  if (mark_compact_collector()->sweeper().sweeping_in_progress() &&
+      memory_allocator_->unmapper()->NumberOfDelayedChunks() >
+          kMaxSemiSpaceSizeInKB / Page::kPageSize) {
+    mark_compact_collector()->EnsureSweepingCompleted();
+  }
+
   mark_compact_collector()->sweeper().EnsureNewSpaceCompleted();
 
   SetGCState(SCAVENGE);
diff --git a/deps/v8/src/heap/spaces.h b/deps/v8/src/heap/spaces.h
index d5dc5b1115cccb..230a127809a697 100644
--- a/deps/v8/src/heap/spaces.h
+++ b/deps/v8/src/heap/spaces.h
@@ -1199,6 +1199,11 @@ class V8_EXPORT_PRIVATE MemoryAllocator {
 
     bool has_delayed_chunks() { return delayed_regular_chunks_.size() > 0; }
 
+    int NumberOfDelayedChunks() {
+      base::LockGuard<base::Mutex> guard(&mutex_);
+      return static_cast<int>(delayed_regular_chunks_.size());
+    }
+
    private:
     static const int kReservedQueueingSlots = 64;
     static const int kMaxUnmapperTasks = 24;