All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=921239

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=0dbd4d5dc44606e616922ba897087628c6c85fd1e990069c1c4740312be589a8


Bot(s) for this bug's original alert(s):

mac-10_12_laptop_low_end-perf
mac-10_13_laptop_high_end-perf

memory.long_running_idle_gmail_tbmv2 - Benchmark documentation link:
  None

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/16e23b63940000

📍 Found a significant difference after 1 commit.
https://pinpoint-dot-chromeperf.appspot.com/job/16e23b63940000

[heap] Remove bailout marking worklist. by ulan@chromium.org
https://chromium.googlesource.com/v8/v8/+/68a8bdd82988d6ae1d9769748d58fc8b266e8c9a
memory:chrome:renderer_processes:reported_by_chrome:v8:effective_size: 7.49e+07 → 8.951e+07 (+1.461e+07)

Understanding performance regressions:
  http://g.co/ChromePerformanceRegressions

Benchmark documentation link:
  None

The following revision refers to this bug:
  https://chromium.googlesource.com/v8/v8.git/+/13e07389ff53633e613ac98fab62cc7265222425

commit 13e07389ff53633e613ac98fab62cc7265222425
Author: Ulan Degenbaev <ulan@chromium.org>
Date: Mon Jan 14 15:00:11 2019

Revert "[heap] Remove bailout marking worklist."

This reverts commit 68a8bdd82988d6ae1d9769748d58fc8b266e8c9a.

Reason for revert: memory regression: crbug.com/921239

Original change's description:
> [heap] Remove bailout marking worklist.
> 
> The concurrent marker can now process all objects.
> This patch also eagerly visits the objects that undergo layout
> changes. This is because previously such objects were pushed
> onto the bailout worklist, which is gone now.
> To preserve the incremental step accounting, the patch introduces
> a new GC tracer scope called MC_INCREMENTAL_LAYOUT_CHANGE.
> 
> Bug: v8:8486
> Change-Id: Ic1c2f0d4e2ac0602fc945f3258af9624247bd65f
> Reviewed-on: https://chromium-review.googlesource.com/c/1386486
> Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
> Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#58712}

TBR=ulan@chromium.org,mlippautz@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: v8:8486, chromium:921239
Change-Id: I1f851b948f4ce403316e469999f0b16e8dfdb62d
Reviewed-on: https://chromium-review.googlesource.com/c/1408990
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58787}
[modify] https://crrev.com/13e07389ff53633e613ac98fab62cc7265222425/src/heap-symbols.h
[modify] https://crrev.com/13e07389ff53633e613ac98fab62cc7265222425/src/heap/concurrent-marking.cc
[modify] https://crrev.com/13e07389ff53633e613ac98fab62cc7265222425/src/heap/concurrent-marking.h
[modify] https://crrev.com/13e07389ff53633e613ac98fab62cc7265222425/src/heap/gc-tracer.cc
[modify] https://crrev.com/13e07389ff53633e613ac98fab62cc7265222425/src/heap/gc-tracer.h
[modify] https://crrev.com/13e07389ff53633e613ac98fab62cc7265222425/src/heap/heap.cc
[modify] https://crrev.com/13e07389ff53633e613ac98fab62cc7265222425/src/heap/incremental-marking.cc
[modify] https://crrev.com/13e07389ff53633e613ac98fab62cc7265222425/src/heap/incremental-marking.h
[modify] https://crrev.com/13e07389ff53633e613ac98fab62cc7265222425/src/heap/mark-compact.cc
[modify] https://crrev.com/13e07389ff53633e613ac98fab62cc7265222425/src/heap/mark-compact.h
[modify] https://crrev.com/13e07389ff53633e613ac98fab62cc7265222425/test/cctest/heap/test-concurrent-marking.cc

 Issue 921572  has been merged into this issue.

 Issue 921586  has been merged into this issue.

 Issue 921587  has been merged into this issue.

 Issue 921571  has been merged into this issue.