AuroraMiddleware/v8
1
0
Fork 0
Code Issues 2 Pull Requests Releases Wiki Activity

Add a flag for enabling the single generation mode in V8

Browse Source 
This flag ensures that all allocations are performed in the old generation. This only works when inline allocation and allocation folding are both disabled.

Bug: v8:9533

Change-Id: I9ad5e8bf492c43603ab2a4a1292198e1b9882dfe
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1710335
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62893}
This commit is contained in:
Rong Wang 2019-07-24 15:03:35 +10:00 committed by Commit Bot
parent e8571c6ab1
commit b2140c59d0
6 changed files with 28 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
AUTHORS
View File

@ -163,6 +163,7 @@ Rob Wu <rob@robwu.nl>
Robert Meijer <robert.s.meijer@gmail.com>
Robert Mustacchi <rm@fingolfin.org>
Robert Nagy <robert.nagy@gmail.com>
Rong Wang <wangrong089@gmail.com>
Ross Kirsling <rkirsling@gmail.com>
Ruben Bridgewater <ruben@bridgewater.de>
Ryan Dahl <ry@tinyclouds.org>

6
BUILD.gn
View File

@ -187,6 +187,9 @@ declare_args() {
# Enable sharing read-only space across isolates.
# Sets -DV8_SHARED_RO_HEAP.
v8_enable_shared_ro_heap = ""
# Redirect allocation in young generation so that there will be only one single generation.
v8_enable_single_generation = false
}
# Derived defaults.
@ -415,6 +418,9 @@ config("features") {
defines += [ "V8_SNAPSHOT_NATIVE_CODE_COUNTERS" ]
}
}
if (v8_enable_single_generation) {
defines += [ "V8_ENABLE_SINGLE_GENERATION" ]
}
if (v8_use_external_startup_data) {
defines += [ "V8_USE_EXTERNAL_STARTUP_DATA" ]
}

2
src/codegen/code-stub-assembler.cc
View File

@ -4341,6 +4341,7 @@ TNode<FixedArray> CodeStubAssembler::ExtractToFixedArray(
var_target_map.value());
var_result.Bind(to_elements);
#ifndef V8_ENABLE_SINGLE_GENERATION
#ifdef DEBUG
TNode<IntPtrT> object_word = BitcastTaggedToWord(to_elements);
TNode<IntPtrT> object_page = PageFromAddress(object_word);
@ -4353,6 +4354,7 @@ TNode<FixedArray> CodeStubAssembler::ExtractToFixedArray(
WordAnd(page_flags,
IntPtrConstant(MemoryChunk::kIsInYoungGenerationMask)),
IntPtrConstant(0)));
#endif
#endif
if (convert_holes == HoleConversionMode::kDontConvert &&

14
src/flags/flag-definitions.h
View File

@ -307,6 +307,20 @@ DEFINE_IMPLICATION(lite_mode, lazy_feedback_allocation)
DEFINE_IMPLICATION(lite_mode, enable_lazy_source_positions)
DEFINE_IMPLICATION(lite_mode, optimize_for_size)
#ifdef V8_ENABLE_SINGLE_GENERATION
#define V8_GENERATION_BOOL true
#else
#define V8_GENERATION_BOOL false
#endif
DEFINE_BOOL_READONLY(
single_generation, V8_GENERATION_BOOL,
"allocate all objects from young generation to old generation")
// Prevent inline allocation into new space
DEFINE_NEG_IMPLICATION(single_generation, inline_new)
DEFINE_NEG_IMPLICATION(single_generation, turbo_allocation_folding)
#ifdef V8_ENABLE_FUTURE
#define FUTURE_BOOL true
#else

3
src/heap/factory.cc
View File

@ -2010,7 +2010,8 @@ Handle<JSObject> Factory::CopyJSObjectWithAllocationSite(
HeapObject raw_clone = isolate()->heap()->AllocateRawWithRetryOrFail(
adjusted_object_size, AllocationType::kYoung);
DCHECK(Heap::InYoungGeneration(raw_clone));
DCHECK(Heap::InYoungGeneration(raw_clone) || FLAG_single_generation);
// Since we know the clone is allocated in new space, we can copy
// the contents without worrying about updating the write barrier.
Heap::CopyBlock(raw_clone.address(), source->address(), object_size);

3
src/heap/heap-inl.h
View File

@ -179,6 +179,9 @@ AllocationResult Heap::AllocateRaw(int size_in_bytes, AllocationType type,
HeapObject object;
AllocationResult allocation;
if (FLAG_single_generation && type == AllocationType::kYoung)
type = AllocationType::kOld;
if (AllocationType::kYoung == type) {
if (large_object) {
if (FLAG_young_generation_large_objects) {