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

[ptr-compr][Fuchsia] Adapt V8 heap reservation for Fuchsia

Browse Source 
... which doesn't respect address hints when reserving an address space
region and therefore makes it impossible to fulfill V8 heap alignment
requirements.

As a workaround we just overreserve address space to ensure that we
will be able to find a properly aligned 4GB subregion.

Bug: v8:7703
Change-Id: Ibf54e5e13131c2640a448944e3a3bae937c8b938
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1547861
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60574}
This commit is contained in:
Igor Sheludko 2019-04-02 15:29:12 +02:00 committed by Commit Bot
parent 0d8bea8fcf
commit d341a1a7c5
2 changed files with 26 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

42
src/isolate-allocator.cc
View File

@ -14,8 +14,8 @@ namespace internal {
IsolateAllocator::IsolateAllocator(IsolateAllocationMode mode) {
#if V8_TARGET_ARCH_64_BIT
if (mode == IsolateAllocationMode::kInV8Heap) {
Address heap_base = InitReservation();
CommitPagesForIsolate(heap_base);
Address heap_reservation_address = InitReservation();
CommitPagesForIsolate(heap_reservation_address);
return;
}
#endif // V8_TARGET_ARCH_64_BIT
@ -68,6 +68,15 @@ Address IsolateAllocator::InitReservation() {
kPtrComprIsolateRootBias;
CHECK(padded_reservation.InVM(address, reservation_size));
#if defined(V8_OS_FUCHSIA)
// Fuchsia does not respect given hints so as a workaround we will use
// overreserved address space region instead of trying to re-reserve
// a subregion.
if (padded_reservation.InVM(address, reservation_size)) {
reservation_ = std::move(padded_reservation);
return address;
}
#else
// Now free the padded reservation and immediately try to reserve an exact
// region at aligned address. We have to do this dancing because the
// reservation address requirement is more complex than just a certain
@ -88,23 +97,22 @@ Address IsolateAllocator::InitReservation() {
if (reservation.address() == aligned_address) {
reservation_ = std::move(reservation);
break;
CHECK_EQ(reservation_.size(), reservation_size);
return aligned_address;
}
#endif
}
if (!reservation_.IsReserved()) {
V8::FatalProcessOutOfMemory(nullptr,
"Failed to reserve memory for new V8 Isolate");
}
CHECK_EQ(reservation_.size(), reservation_size);
Address heap_base = reservation_.address() + kPtrComprIsolateRootBias;
CHECK(IsAligned(heap_base, base_alignment));
return heap_base;
V8::FatalProcessOutOfMemory(nullptr,
"Failed to reserve memory for new V8 Isolate");
return kNullAddress;
}
void IsolateAllocator::CommitPagesForIsolate(Address heap_base) {
void IsolateAllocator::CommitPagesForIsolate(Address heap_address) {
CHECK(reservation_.InVM(heap_address, kPtrComprHeapReservationSize));
Address isolate_root = heap_address + kPtrComprIsolateRootBias;
CHECK(IsAligned(isolate_root, kPtrComprIsolateRootAlignment));
v8::PageAllocator* platform_page_allocator = GetPlatformPageAllocator();
// Simplify BoundedPageAllocator's life by configuring it to use same page
@ -113,11 +121,11 @@ void IsolateAllocator::CommitPagesForIsolate(Address heap_base) {
platform_page_allocator->AllocatePageSize());
page_allocator_instance_ = base::make_unique<base::BoundedPageAllocator>(
platform_page_allocator, reservation_.address(), reservation_.size(),
platform_page_allocator, heap_address, kPtrComprHeapReservationSize,
page_size);
page_allocator_ = page_allocator_instance_.get();
Address isolate_address = heap_base - Isolate::isolate_root_bias();
Address isolate_address = isolate_root - Isolate::isolate_root_bias();
Address isolate_end = isolate_address + sizeof(Isolate);
// Inform the bounded page allocator about reserved pages.

2
src/isolate-allocator.h
View File

@ -46,7 +46,7 @@ class V8_EXPORT_PRIVATE IsolateAllocator final {
private:
Address InitReservation();
void CommitPagesForIsolate(Address heap_base);
void CommitPagesForIsolate(Address heap_address);
// The allocated memory for Isolate instance.
void* isolate_memory_ = nullptr;