[cppgc, cppgc-js] Implement GC on allocation failure

So far Oilpan garbage collection was only ever triggered via growing
strategies in either V8 or stand-alone heap growing. This CL
implements a fallback for GC on allocation.

- Stand-alone implementation will defer to GCInvoker which is aware of
  stack support.
- CppHeap implementation will just trigger a full V8 GC.

Bug: chromium:1352649
Change-Id: If92f705b4e272290ca7022864fd7b90f0fcb809e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3865148Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82844}

include/v8-internal.h

@@ -855,7 +855,7 @@ class BackingStoreBase {};
 
 // The maximum value in enum GarbageCollectionReason, defined in heap.h.
 // This is needed for histograms sampling garbage collection reasons.
-constexpr int kGarbageCollectionReasonMaxValue = 25;
+constexpr int kGarbageCollectionReasonMaxValue = 27;
 
 }  // namespace internal
 

src/heap/cppgc-js/cpp-heap.cc

@@ -47,6 +47,7 @@
 #include "src/heap/embedder-tracing.h"
 #include "src/heap/gc-tracer.h"
 #include "src/heap/global-handle-marking-visitor.h"
+#include "src/heap/heap.h"
 #include "src/heap/marking-worklist.h"
 #include "src/heap/sweeper.h"
 #include "src/init/v8.h"
@@ -485,7 +486,7 @@ CppHeap::CppHeap(
           std::make_shared<CppgcPlatformAdapter>(platform), custom_spaces,
           cppgc::internal::HeapBase::StackSupport::
               kSupportsConservativeStackScan,
-          marking_support, sweeping_support),
+          marking_support, sweeping_support, *this),
       wrapper_descriptor_(wrapper_descriptor) {
   CHECK_NE(WrapperDescriptor::kUnknownEmbedderId,
            wrapper_descriptor_.embedder_id_for_garbage_collected);
@@ -1004,5 +1005,24 @@ CppHeap::PauseConcurrentMarkingScope::PauseConcurrentMarkingScope(
   }
 }
 
+void CppHeap::CollectGarbage(Config config) {
+  if (in_no_gc_scope() || !isolate_) return;
+
+  // TODO(mlippautz): Respect full config.
+  const int flags = (config.free_memory_handling ==
+                     Config::FreeMemoryHandling::kDiscardWherePossible)
+                        ? Heap::kReduceMemoryFootprintMask
+                        : Heap::kNoGCFlags;
+  isolate_->heap()->CollectAllGarbage(
+      flags, GarbageCollectionReason::kCppHeapAllocationFailure);
+}
+
+const cppgc::EmbedderStackState* CppHeap::override_stack_state() const {
+  return HeapBase::override_stack_state();
+}
+
+void CppHeap::StartIncrementalGarbageCollection(Config) { UNIMPLEMENTED(); }
+size_t CppHeap::epoch() const { UNIMPLEMENTED(); }
+
 }  // namespace internal
 }  // namespace v8

src/heap/cppgc-js/cpp-heap.h

@@ -33,7 +33,8 @@ class CppMarkingState;
 class V8_EXPORT_PRIVATE CppHeap final
     : public cppgc::internal::HeapBase,
       public v8::CppHeap,
-      public cppgc::internal::StatsCollector::AllocationObserver {
+      public cppgc::internal::StatsCollector::AllocationObserver,
+      public cppgc::internal::GarbageCollector {
  public:
   enum GarbageCollectionFlagValues : uint8_t {
     kNoFlags = 0,
@@ -166,6 +167,12 @@ class V8_EXPORT_PRIVATE CppHeap final
   std::unique_ptr<CppMarkingState> CreateCppMarkingState();
   std::unique_ptr<CppMarkingState> CreateCppMarkingStateForMutatorThread();
 
+  // cppgc::internal::GarbageCollector interface.
+  void CollectGarbage(Config) override;
+  const cppgc::EmbedderStackState* override_stack_state() const override;
+  void StartIncrementalGarbageCollection(Config) override;
+  size_t epoch() const override;
+
  private:
   void ReduceGCCapabilititesFromFlags();
 

src/heap/cppgc/heap-base.cc

@@ -96,7 +96,7 @@ HeapBase::HeapBase(
     std::shared_ptr<cppgc::Platform> platform,
     const std::vector<std::unique_ptr<CustomSpaceBase>>& custom_spaces,
     StackSupport stack_support, MarkingType marking_support,
-    SweepingType sweeping_support)
+    SweepingType sweeping_support, GarbageCollector& garbage_collector)
     : raw_heap_(this, custom_spaces),
       platform_(std::move(platform)),
       oom_handler_(std::make_unique<FatalOutOfMemoryHandler>(this)),
@@ -111,7 +111,8 @@ HeapBase::HeapBase(
       prefinalizer_handler_(std::make_unique<PreFinalizerHandler>(*this)),
       compactor_(raw_heap_),
       object_allocator_(raw_heap_, *page_backend_, *stats_collector_,
-                        *prefinalizer_handler_),
+                        *prefinalizer_handler_, *oom_handler_,
+                        garbage_collector),
       sweeper_(*this),
       strong_persistent_region_(*oom_handler_.get()),
       weak_persistent_region_(*oom_handler_.get()),

src/heap/cppgc/heap-base.h

@@ -15,7 +15,6 @@
 #include "include/cppgc/macros.h"
 #include "src/base/macros.h"
 #include "src/heap/cppgc/compactor.h"
-#include "src/heap/cppgc/garbage-collector.h"
 #include "src/heap/cppgc/heap-object-header.h"
 #include "src/heap/cppgc/marker.h"
 #include "src/heap/cppgc/metric-recorder.h"
@@ -60,6 +59,7 @@ class Platform;
 namespace internal {
 
 class FatalOutOfMemoryHandler;
+class GarbageCollector;
 class PageBackend;
 class PreFinalizerHandler;
 class StatsCollector;
@@ -83,7 +83,7 @@ class V8_EXPORT_PRIVATE HeapBase : public cppgc::HeapHandle {
   HeapBase(std::shared_ptr<cppgc::Platform> platform,
            const std::vector<std::unique_ptr<CustomSpaceBase>>& custom_spaces,
            StackSupport stack_support, MarkingType marking_support,
-           SweepingType sweeping_support);
+           SweepingType sweeping_support, GarbageCollector& garbage_collector);
   virtual ~HeapBase();
 
   HeapBase(const HeapBase&) = delete;

src/heap/cppgc/heap-page.cc

@@ -5,6 +5,7 @@
 #include "src/heap/cppgc/heap-page.h"
 
 #include <algorithm>
+#include <cstddef>
 
 #include "include/cppgc/internal/api-constants.h"
 #include "src/base/logging.h"
@@ -132,9 +133,11 @@ BasePage::BasePage(HeapBase& heap, BaseSpace& space, PageType type)
 }
 
 // static
-NormalPage* NormalPage::Create(PageBackend& page_backend,
-                               NormalPageSpace& space) {
-  void* memory = page_backend.AllocateNormalPageMemory();
+NormalPage* NormalPage::TryCreate(PageBackend& page_backend,
+                                  NormalPageSpace& space) {
+  void* memory = page_backend.TryAllocateNormalPageMemory();
+  if (!memory) return nullptr;
+
   auto* normal_page = new (memory) NormalPage(*space.raw_heap()->heap(), space);
   normal_page->SynchronizedStore();
   normal_page->heap().stats_collector()->NotifyAllocatedMemory(kPageSize);
@@ -226,8 +229,8 @@ size_t LargePage::AllocationSize(size_t payload_size) {
 }
 
 // static
-LargePage* LargePage::Create(PageBackend& page_backend, LargePageSpace& space,
-                             size_t size) {
+LargePage* LargePage::TryCreate(PageBackend& page_backend,
+                                LargePageSpace& space, size_t size) {
   // Ensure that the API-provided alignment guarantees does not violate the
   // internally guaranteed alignment of large page allocations.
   static_assert(kGuaranteedObjectAlignment <=
@@ -239,7 +242,9 @@ LargePage* LargePage::Create(PageBackend& page_backend, LargePageSpace& space,
   const size_t allocation_size = AllocationSize(size);
 
   auto* heap = space.raw_heap()->heap();
-  void* memory = page_backend.AllocateLargePageMemory(allocation_size);
+  void* memory = page_backend.TryAllocateLargePageMemory(allocation_size);
+  if (!memory) return nullptr;
+
   LargePage* page = new (memory) LargePage(*heap, space, size);
   page->SynchronizedStore();
 #if defined(CPPGC_CAGED_HEAP)

src/heap/cppgc/heap-page.h

@@ -151,7 +151,7 @@ class V8_EXPORT_PRIVATE NormalPage final : public BasePage {
   using const_iterator = IteratorImpl<const HeapObjectHeader>;
 
   // Allocates a new page in the detached state.
-  static NormalPage* Create(PageBackend&, NormalPageSpace&);
+  static NormalPage* TryCreate(PageBackend&, NormalPageSpace&);
   // Destroys and frees the page. The page must be detached from the
   // corresponding space (i.e. be swept when called).
   static void Destroy(NormalPage*);
@@ -221,7 +221,7 @@ class V8_EXPORT_PRIVATE LargePage final : public BasePage {
   // Returns the allocation size required for a payload of size |size|.
   static size_t AllocationSize(size_t size);
   // Allocates a new page in the detached state.
-  static LargePage* Create(PageBackend&, LargePageSpace&, size_t);
+  static LargePage* TryCreate(PageBackend&, LargePageSpace&, size_t);
   // Destroys and frees the page. The page must be detached from the
   // corresponding space (i.e. be swept when called).
   static void Destroy(LargePage*);

src/heap/cppgc/heap.cc

@@ -79,7 +79,7 @@ void CheckConfig(Heap::Config config, HeapBase::MarkingType marking_support,
 Heap::Heap(std::shared_ptr<cppgc::Platform> platform,
            cppgc::Heap::HeapOptions options)
     : HeapBase(platform, options.custom_spaces, options.stack_support,
-               options.marking_support, options.sweeping_support),
+               options.marking_support, options.sweeping_support, gc_invoker_),
       gc_invoker_(this, platform_.get(), options.stack_support),
       growing_(&gc_invoker_, stats_collector_.get(),
                options.resource_constraints, options.marking_support,

src/heap/cppgc/object-allocator.cc

@@ -17,6 +17,7 @@
 #include "src/heap/cppgc/memory.h"
 #include "src/heap/cppgc/object-start-bitmap.h"
 #include "src/heap/cppgc/page-memory.h"
+#include "src/heap/cppgc/platform.h"
 #include "src/heap/cppgc/prefinalizer-handler.h"
 #include "src/heap/cppgc/stats-collector.h"
 #include "src/heap/cppgc/sweeper.h"
@@ -79,10 +80,12 @@ void ReplaceLinearAllocationBuffer(NormalPageSpace& space,
   }
 }
 
-void* AllocateLargeObject(PageBackend& page_backend, LargePageSpace& space,
-                          StatsCollector& stats_collector, size_t size,
-                          GCInfoIndex gcinfo) {
-  LargePage* page = LargePage::Create(page_backend, space, size);
+void* TryAllocateLargeObject(PageBackend& page_backend, LargePageSpace& space,
+                             StatsCollector& stats_collector, size_t size,
+                             GCInfoIndex gcinfo) {
+  LargePage* page = LargePage::TryCreate(page_backend, space, size);
+  if (!page) return nullptr;
+
   space.AddPage(page);
 
   auto* header = new (page->ObjectHeader())
@@ -100,11 +103,15 @@ constexpr size_t ObjectAllocator::kSmallestSpaceSize;
 
 ObjectAllocator::ObjectAllocator(RawHeap& heap, PageBackend& page_backend,
                                  StatsCollector& stats_collector,
-                                 PreFinalizerHandler& prefinalizer_handler)
+                                 PreFinalizerHandler& prefinalizer_handler,
+                                 FatalOutOfMemoryHandler& oom_handler,
+                                 GarbageCollector& garbage_collector)
     : raw_heap_(heap),
       page_backend_(page_backend),
       stats_collector_(stats_collector),
-      prefinalizer_handler_(prefinalizer_handler) {}
+      prefinalizer_handler_(prefinalizer_handler),
+      oom_handler_(oom_handler),
+      garbage_collector_(garbage_collector) {}
 
 void* ObjectAllocator::OutOfLineAllocate(NormalPageSpace& space, size_t size,
                                          AlignVal alignment,
@@ -138,8 +145,20 @@ void* ObjectAllocator::OutOfLineAllocateImpl(NormalPageSpace& space,
         *raw_heap_.Space(RawHeap::RegularSpaceType::kLarge));
     // LargePage has a natural alignment that already satisfies
     // `kMaxSupportedAlignment`.
-    return AllocateLargeObject(page_backend_, large_space, stats_collector_,
-                               size, gcinfo);
+    void* result = TryAllocateLargeObject(page_backend_, large_space,
+                                          stats_collector_, size, gcinfo);
+    if (!result) {
+      auto config = GarbageCollector::Config::ConservativeAtomicConfig();
+      config.free_memory_handling =
+          GarbageCollector::Config::FreeMemoryHandling::kDiscardWherePossible;
+      garbage_collector_.CollectGarbage(config);
+      result = TryAllocateLargeObject(page_backend_, large_space,
+                                      stats_collector_, size, gcinfo);
+      if (!result) {
+        oom_handler_("Oilpan: Large allocation.");
+      }
+    }
+    return result;
   }
 
   size_t request_size = size;
@@ -150,7 +169,15 @@ void* ObjectAllocator::OutOfLineAllocateImpl(NormalPageSpace& space,
     request_size += kAllocationGranularity;
   }
 
-  RefillLinearAllocationBuffer(space, request_size);
+  if (!TryRefillLinearAllocationBuffer(space, request_size)) {
+    auto config = GarbageCollector::Config::ConservativeAtomicConfig();
+    config.free_memory_handling =
+        GarbageCollector::Config::FreeMemoryHandling::kDiscardWherePossible;
+    garbage_collector_.CollectGarbage(config);
+    if (!TryRefillLinearAllocationBuffer(space, request_size)) {
+      oom_handler_("Oilpan: Normal allocation.");
+    }
+  }
 
   // The allocation must succeed, as we just refilled the LAB.
   void* result = (dynamic_alignment == kAllocationGranularity)
@@ -160,10 +187,10 @@ void* ObjectAllocator::OutOfLineAllocateImpl(NormalPageSpace& space,
   return result;
 }
 
-void ObjectAllocator::RefillLinearAllocationBuffer(NormalPageSpace& space,
-                                                   size_t size) {
+bool ObjectAllocator::TryRefillLinearAllocationBuffer(NormalPageSpace& space,
+                                                      size_t size) {
   // Try to allocate from the freelist.
-  if (RefillLinearAllocationBufferFromFreeList(space, size)) return;
+  if (TryRefillLinearAllocationBufferFromFreeList(space, size)) return true;
 
   // Lazily sweep pages of this heap until we find a freed area for this
   // allocation or we finish sweeping all pages of this heap.
@@ -179,22 +206,26 @@ void ObjectAllocator::RefillLinearAllocationBuffer(NormalPageSpace& space,
     // may only potentially fit the block. For the bucket that may exactly fit
     // the allocation of `size` bytes (no overallocation), only the first
     // entry is checked.
-    if (RefillLinearAllocationBufferFromFreeList(space, size)) return;
+    if (TryRefillLinearAllocationBufferFromFreeList(space, size)) return true;
   }
 
   sweeper.FinishIfRunning();
   // TODO(chromium:1056170): Make use of the synchronously freed memory.
 
-  auto* new_page = NormalPage::Create(page_backend_, space);
-  space.AddPage(new_page);
+  auto* new_page = NormalPage::TryCreate(page_backend_, space);
+  if (!new_page) {
+    return false;
+  }
 
+  space.AddPage(new_page);
   // Set linear allocation buffer to new page.
   ReplaceLinearAllocationBuffer(space, stats_collector_,
                                 new_page->PayloadStart(),
                                 new_page->PayloadSize());
+  return true;
 }
 
-bool ObjectAllocator::RefillLinearAllocationBufferFromFreeList(
+bool ObjectAllocator::TryRefillLinearAllocationBufferFromFreeList(
     NormalPageSpace& space, size_t size) {
   const FreeList::Block entry = space.free_list().Allocate(size);
   if (!entry.address) return false;

src/heap/cppgc/object-allocator.h

@@ -34,14 +34,14 @@ namespace internal {
 
 class StatsCollector;
 class PageBackend;
+class GarbageCollector;
 
 class V8_EXPORT_PRIVATE ObjectAllocator final : public cppgc::AllocationHandle {
  public:
   static constexpr size_t kSmallestSpaceSize = 32;
 
-  ObjectAllocator(RawHeap& heap, PageBackend& page_backend,
-                  StatsCollector& stats_collector,
-                  PreFinalizerHandler& prefinalizer_handler);
+  ObjectAllocator(RawHeap&, PageBackend&, StatsCollector&, PreFinalizerHandler&,
+                  FatalOutOfMemoryHandler&, GarbageCollector&);
 
   inline void* AllocateObject(size_t size, GCInfoIndex gcinfo);
   inline void* AllocateObject(size_t size, AlignVal alignment,
@@ -71,13 +71,15 @@ class V8_EXPORT_PRIVATE ObjectAllocator final : public cppgc::AllocationHandle {
   void* OutOfLineAllocate(NormalPageSpace&, size_t, AlignVal, GCInfoIndex);
   void* OutOfLineAllocateImpl(NormalPageSpace&, size_t, AlignVal, GCInfoIndex);
 
-  void RefillLinearAllocationBuffer(NormalPageSpace&, size_t);
-  bool RefillLinearAllocationBufferFromFreeList(NormalPageSpace&, size_t);
+  bool TryRefillLinearAllocationBuffer(NormalPageSpace&, size_t);
+  bool TryRefillLinearAllocationBufferFromFreeList(NormalPageSpace&, size_t);
 
   RawHeap& raw_heap_;
   PageBackend& page_backend_;
   StatsCollector& stats_collector_;
   PreFinalizerHandler& prefinalizer_handler_;
+  FatalOutOfMemoryHandler& oom_handler_;
+  GarbageCollector& garbage_collector_;
 };
 
 void* ObjectAllocator::AllocateObject(size_t size, GCInfoIndex gcinfo) {

src/heap/cppgc/page-memory.cc

@@ -4,6 +4,8 @@
 
 #include "src/heap/cppgc/page-memory.h"
 
+#include <cstddef>
+
 #include "src/base/macros.h"
 #include "src/base/sanitizer/asan.h"
 #include "src/heap/cppgc/platform.h"
@@ -13,50 +15,40 @@ namespace internal {
 
 namespace {
 
-void Unprotect(PageAllocator& allocator, FatalOutOfMemoryHandler& oom_handler,
-               const PageMemory& page_memory) {
+V8_WARN_UNUSED_RESULT bool TryUnprotect(PageAllocator& allocator,
+                                        const PageMemory& page_memory) {
   if (SupportsCommittingGuardPages(allocator)) {
-    if (!allocator.SetPermissions(page_memory.writeable_region().base(),
-                                  page_memory.writeable_region().size(),
-                                  PageAllocator::Permission::kReadWrite)) {
-      oom_handler("Oilpan: Unprotecting memory.");
-    }
-  } else {
-    // No protection in case the allocator cannot commit at the required
-    // granularity. Only protect if the allocator supports committing at that
-    // granularity.
-    //
-    // The allocator needs to support committing the overall range.
-    CHECK_EQ(0u,
-             page_memory.overall_region().size() % allocator.CommitPageSize());
-    if (!allocator.SetPermissions(page_memory.overall_region().base(),
-                                  page_memory.overall_region().size(),
-                                  PageAllocator::Permission::kReadWrite)) {
-      oom_handler("Oilpan: Unprotecting memory.");
-    }
+    return allocator.SetPermissions(page_memory.writeable_region().base(),
+                                    page_memory.writeable_region().size(),
+                                    PageAllocator::Permission::kReadWrite);
   }
+  // No protection using guard pages in case the allocator cannot commit at
+  // the required granularity. Only protect if the allocator supports
+  // committing at that granularity.
+  //
+  // The allocator needs to support committing the overall range.
+  CHECK_EQ(0u,
+           page_memory.overall_region().size() % allocator.CommitPageSize());
+  return allocator.SetPermissions(page_memory.overall_region().base(),
+                                  page_memory.overall_region().size(),
+                                  PageAllocator::Permission::kReadWrite);
 }
 
-void Protect(PageAllocator& allocator, FatalOutOfMemoryHandler& oom_handler,
-             const PageMemory& page_memory) {
+V8_WARN_UNUSED_RESULT bool TryProtect(PageAllocator& allocator,
+                                      const PageMemory& page_memory) {
   if (SupportsCommittingGuardPages(allocator)) {
     // Swap the same region, providing the OS with a chance for fast lookup and
     // change.
-    if (!allocator.SetPermissions(page_memory.writeable_region().base(),
-                                  page_memory.writeable_region().size(),
-                                  PageAllocator::Permission::kNoAccess)) {
-      oom_handler("Oilpan: Protecting memory.");
-    }
-  } else {
-    // See Unprotect().
-    CHECK_EQ(0u,
-             page_memory.overall_region().size() % allocator.CommitPageSize());
-    if (!allocator.SetPermissions(page_memory.overall_region().base(),
-                                  page_memory.overall_region().size(),
-                                  PageAllocator::Permission::kNoAccess)) {
-      oom_handler("Oilpan: Protecting memory.");
-    }
+    return allocator.SetPermissions(page_memory.writeable_region().base(),
+                                    page_memory.writeable_region().size(),
+                                    PageAllocator::Permission::kNoAccess);
   }
+  // See Unprotect().
+  CHECK_EQ(0u,
+           page_memory.overall_region().size() % allocator.CommitPageSize());
+  return allocator.SetPermissions(page_memory.overall_region().base(),
+                                  page_memory.overall_region().size(),
+                                  PageAllocator::Permission::kNoAccess);
 }
 
 MemoryRegion ReserveMemoryRegion(PageAllocator& allocator,
@@ -84,10 +76,8 @@ void FreeMemoryRegion(PageAllocator& allocator,
 }  // namespace
 
 PageMemoryRegion::PageMemoryRegion(PageAllocator& allocator,
-                                   FatalOutOfMemoryHandler& oom_handler,
                                    MemoryRegion reserved_region, bool is_large)
     : allocator_(allocator),
-      oom_handler_(oom_handler),
       reserved_region_(reserved_region),
       is_large_(is_large) {}
 
@@ -101,7 +91,7 @@ constexpr size_t NormalPageMemoryRegion::kNumPageRegions;
 NormalPageMemoryRegion::NormalPageMemoryRegion(
     PageAllocator& allocator, FatalOutOfMemoryHandler& oom_handler)
     : PageMemoryRegion(
-          allocator, oom_handler,
+          allocator,
           ReserveMemoryRegion(allocator, oom_handler,
                               RoundUp(kPageSize * kNumPageRegions,
                                       allocator.AllocatePageSize())),
@@ -115,21 +105,24 @@ NormalPageMemoryRegion::NormalPageMemoryRegion(
 
 NormalPageMemoryRegion::~NormalPageMemoryRegion() = default;
 
-void NormalPageMemoryRegion::Allocate(Address writeable_base) {
+bool NormalPageMemoryRegion::TryAllocate(Address writeable_base) {
   const size_t index = GetIndex(writeable_base);
-  ChangeUsed(index, true);
-  Unprotect(allocator_, oom_handler_, GetPageMemory(index));
+  if (TryUnprotect(allocator_, GetPageMemory(index))) {
+    ChangeUsed(index, true);
+    return true;
+  }
+  return false;
 }
 
 void NormalPageMemoryRegion::Free(Address writeable_base) {
   const size_t index = GetIndex(writeable_base);
   ChangeUsed(index, false);
-  Protect(allocator_, oom_handler_, GetPageMemory(index));
+  CHECK(TryProtect(allocator_, GetPageMemory(index)));
 }
 
 void NormalPageMemoryRegion::UnprotectForTesting() {
   for (size_t i = 0; i < kNumPageRegions; ++i) {
-    Unprotect(allocator_, oom_handler_, GetPageMemory(i));
+    CHECK(TryUnprotect(allocator_, GetPageMemory(i)));
   }
 }
 
@@ -137,7 +130,7 @@ LargePageMemoryRegion::LargePageMemoryRegion(
     PageAllocator& allocator, FatalOutOfMemoryHandler& oom_handler,
     size_t length)
     : PageMemoryRegion(
-          allocator, oom_handler,
+          allocator,
           ReserveMemoryRegion(allocator, oom_handler,
                               RoundUp(length + 2 * kGuardPageSize,
                                       allocator.AllocatePageSize())),
@@ -146,7 +139,7 @@ LargePageMemoryRegion::LargePageMemoryRegion(
 LargePageMemoryRegion::~LargePageMemoryRegion() = default;
 
 void LargePageMemoryRegion::UnprotectForTesting() {
-  Unprotect(allocator_, oom_handler_, GetPageMemory());
+  CHECK(TryUnprotect(allocator_, GetPageMemory()));
 }
 
 PageMemoryRegionTree::PageMemoryRegionTree() = default;
@@ -192,7 +185,7 @@ PageBackend::PageBackend(PageAllocator& normal_page_allocator,
 
 PageBackend::~PageBackend() = default;
 
-Address PageBackend::AllocateNormalPageMemory() {
+Address PageBackend::TryAllocateNormalPageMemory() {
   v8::base::MutexGuard guard(&mutex_);
   std::pair<NormalPageMemoryRegion*, Address> result = page_pool_.Take();
   if (!result.first) {
@@ -207,8 +200,11 @@ Address PageBackend::AllocateNormalPageMemory() {
     result = page_pool_.Take();
     DCHECK(result.first);
   }
-  result.first->Allocate(result.second);
-  return result.second;
+  if (V8_LIKELY(result.first->TryAllocate(result.second))) {
+    return result.second;
+  }
+  page_pool_.Add(result.first, result.second);
+  return nullptr;
 }
 
 void PageBackend::FreeNormalPageMemory(size_t bucket, Address writeable_base) {
@@ -219,15 +215,18 @@ void PageBackend::FreeNormalPageMemory(size_t bucket, Address writeable_base) {
   page_pool_.Add(pmr, writeable_base);
 }
 
-Address PageBackend::AllocateLargePageMemory(size_t size) {
+Address PageBackend::TryAllocateLargePageMemory(size_t size) {
   v8::base::MutexGuard guard(&mutex_);
   auto pmr = std::make_unique<LargePageMemoryRegion>(large_page_allocator_,
                                                      oom_handler_, size);
   const PageMemory pm = pmr->GetPageMemory();
-  Unprotect(large_page_allocator_, oom_handler_, pm);
-  page_memory_region_tree_.Add(pmr.get());
-  large_page_memory_regions_.insert(std::make_pair(pmr.get(), std::move(pmr)));
-  return pm.writeable_region().base();
+  if (V8_LIKELY(TryUnprotect(large_page_allocator_, pm))) {
+    page_memory_region_tree_.Add(pmr.get());
+    large_page_memory_regions_.insert(
+        std::make_pair(pmr.get(), std::move(pmr)));
+    return pm.writeable_region().base();
+  }
+  return nullptr;
 }
 
 void PageBackend::FreeLargePageMemory(Address writeable_base) {

src/heap/cppgc/page-memory.h

@@ -82,11 +82,9 @@ class V8_EXPORT_PRIVATE PageMemoryRegion {
   virtual void UnprotectForTesting() = 0;
 
  protected:
-  PageMemoryRegion(PageAllocator&, FatalOutOfMemoryHandler&, MemoryRegion,
-                   bool);
+  PageMemoryRegion(PageAllocator&, MemoryRegion, bool);
 
   PageAllocator& allocator_;
-  FatalOutOfMemoryHandler& oom_handler_;
   const MemoryRegion reserved_region_;
   const bool is_large_;
 };
@@ -110,7 +108,8 @@ class V8_EXPORT_PRIVATE NormalPageMemoryRegion final : public PageMemoryRegion {
 
   // Allocates a normal page at |writeable_base| address. Changes page
   // protection.
-  void Allocate(Address writeable_base);
+  // Returns true when the allocation was successful and false otherwise.
+  V8_WARN_UNUSED_RESULT bool TryAllocate(Address writeable_base);
 
   // Frees a normal page at at |writeable_base| address. Changes page
   // protection.
@@ -203,7 +202,7 @@ class V8_EXPORT_PRIVATE PageBackend final {
   // Allocates a normal page from the backend.
   //
   // Returns the writeable base of the region.
-  Address AllocateNormalPageMemory();
+  Address TryAllocateNormalPageMemory();
 
   // Returns normal page memory back to the backend. Expects the
   // |writeable_base| returned by |AllocateNormalMemory()|.
@@ -212,7 +211,7 @@ class V8_EXPORT_PRIVATE PageBackend final {
   // Allocates a large page from the backend.
   //
   // Returns the writeable base of the region.
-  Address AllocateLargePageMemory(size_t size);
+  Address TryAllocateLargePageMemory(size_t size);
 
   // Returns large page memory back to the backend. Expects the |writeable_base|
   // returned by |AllocateLargePageMemory()|.

src/heap/heap.cc

@@ -4284,8 +4284,9 @@ const char* Heap::GarbageCollectionReasonToString(
       return "background allocation failure";
     case GarbageCollectionReason::kFinalizeMinorMC:
       return "finalize MinorMC";
+    case GarbageCollectionReason::kCppHeapAllocationFailure:
+      return "CppHeap allocation failure";
   }
-  UNREACHABLE();
 }
 
 bool Heap::Contains(HeapObject value) const {

src/heap/heap.h

@@ -178,8 +178,9 @@ enum class GarbageCollectionReason : int {
   kMeasureMemory = 24,
   kBackgroundAllocationFailure = 25,
   kFinalizeMinorMC = 26,
+  kCppHeapAllocationFailure = 27,
 
-  kLastReason = kBackgroundAllocationFailure,
+  kLastReason = kCppHeapAllocationFailure,
 };
 
 static_assert(kGarbageCollectionReasonMaxValue ==

test/unittests/heap/cppgc/heap-page-unittest.cc

@@ -188,7 +188,8 @@ TEST_F(PageTest, NormalPageCreationDestruction) {
   const PageBackend* backend = Heap::From(GetHeap())->page_backend();
   auto* space = static_cast<NormalPageSpace*>(
       heap.Space(RawHeap::RegularSpaceType::kNormal1));
-  auto* page = NormalPage::Create(GetPageBackend(), *space);
+  auto* page = NormalPage::TryCreate(GetPageBackend(), *space);
+  EXPECT_NE(nullptr, page);
   EXPECT_NE(nullptr, backend->Lookup(page->PayloadStart()));
 
   space->AddPage(page);
@@ -213,7 +214,8 @@ TEST_F(PageTest, LargePageCreationDestruction) {
   const PageBackend* backend = Heap::From(GetHeap())->page_backend();
   auto* space = static_cast<LargePageSpace*>(
       heap.Space(RawHeap::RegularSpaceType::kLarge));
-  auto* page = LargePage::Create(GetPageBackend(), *space, kObjectSize);
+  auto* page = LargePage::TryCreate(GetPageBackend(), *space, kObjectSize);
+  EXPECT_NE(nullptr, page);
   EXPECT_NE(nullptr, backend->Lookup(page->PayloadStart()));
 
   space->AddPage(page);
@@ -231,15 +233,17 @@ TEST_F(PageTest, UnsweptPageDestruction) {
   {
     auto* space = static_cast<NormalPageSpace*>(
         heap.Space(RawHeap::RegularSpaceType::kNormal1));
-    auto* page = NormalPage::Create(GetPageBackend(), *space);
+    auto* page = NormalPage::TryCreate(GetPageBackend(), *space);
+    EXPECT_NE(nullptr, page);
     space->AddPage(page);
     EXPECT_DEATH_IF_SUPPORTED(NormalPage::Destroy(page), "");
   }
   {
     auto* space = static_cast<LargePageSpace*>(
         heap.Space(RawHeap::RegularSpaceType::kLarge));
-    auto* page = LargePage::Create(GetPageBackend(), *space,
-                                   2 * kLargeObjectSizeThreshold);
+    auto* page = LargePage::TryCreate(GetPageBackend(), *space,
+                                      2 * kLargeObjectSizeThreshold);
+    EXPECT_NE(nullptr, page);
     space->AddPage(page);
     EXPECT_DEATH_IF_SUPPORTED(LargePage::Destroy(page), "");
     // Detach page and really destroy page in the parent process so that sweeper

test/unittests/heap/cppgc/page-memory-unittest.cc

@@ -253,10 +253,10 @@ TEST(PageBackendTest, AllocateNormalUsesPool) {
   FatalOutOfMemoryHandler oom_handler;
   PageBackend backend(allocator, allocator, oom_handler);
   constexpr size_t kBucket = 0;
-  Address writeable_base1 = backend.AllocateNormalPageMemory();
+  Address writeable_base1 = backend.TryAllocateNormalPageMemory();
   EXPECT_NE(nullptr, writeable_base1);
   backend.FreeNormalPageMemory(kBucket, writeable_base1);
-  Address writeable_base2 = backend.AllocateNormalPageMemory();
+  Address writeable_base2 = backend.TryAllocateNormalPageMemory();
   EXPECT_NE(nullptr, writeable_base2);
   EXPECT_EQ(writeable_base1, writeable_base2);
 }
@@ -265,9 +265,9 @@ TEST(PageBackendTest, AllocateLarge) {
   v8::base::PageAllocator allocator;
   FatalOutOfMemoryHandler oom_handler;
   PageBackend backend(allocator, allocator, oom_handler);
-  Address writeable_base1 = backend.AllocateLargePageMemory(13731);
+  Address writeable_base1 = backend.TryAllocateLargePageMemory(13731);
   EXPECT_NE(nullptr, writeable_base1);
-  Address writeable_base2 = backend.AllocateLargePageMemory(9478);
+  Address writeable_base2 = backend.TryAllocateLargePageMemory(9478);
   EXPECT_NE(nullptr, writeable_base2);
   EXPECT_NE(writeable_base1, writeable_base2);
   backend.FreeLargePageMemory(writeable_base1);
@@ -278,7 +278,7 @@ TEST(PageBackendTest, LookupNormal) {
   v8::base::PageAllocator allocator;
   FatalOutOfMemoryHandler oom_handler;
   PageBackend backend(allocator, allocator, oom_handler);
-  Address writeable_base = backend.AllocateNormalPageMemory();
+  Address writeable_base = backend.TryAllocateNormalPageMemory();
   if (kGuardPageSize) {
     EXPECT_EQ(nullptr, backend.Lookup(writeable_base - kGuardPageSize));
   }
@@ -299,7 +299,7 @@ TEST(PageBackendTest, LookupLarge) {
   FatalOutOfMemoryHandler oom_handler;
   PageBackend backend(allocator, allocator, oom_handler);
   constexpr size_t kSize = 7934;
-  Address writeable_base = backend.AllocateLargePageMemory(kSize);
+  Address writeable_base = backend.TryAllocateLargePageMemory(kSize);
   if (kGuardPageSize) {
     EXPECT_EQ(nullptr, backend.Lookup(writeable_base - kGuardPageSize));
   }
@@ -314,7 +314,7 @@ TEST(PageBackendDeathTest, DestructingBackendDestroysPageMemory) {
   Address base;
   {
     PageBackend backend(allocator, allocator, oom_handler);
-    base = backend.AllocateNormalPageMemory();
+    base = backend.TryAllocateNormalPageMemory();
   }
   EXPECT_DEATH_IF_SUPPORTED(access(base[0]), "");
 }