8202776: Modularize GC allocations in runtime

Reviewed-by: eosterlund, shade

src/hotspot/share/gc/shared/collectedHeap.cpp

@@ -365,20 +365,32 @@ void CollectedHeap::check_for_valid_allocation_state() {
 }
 #endif
 
-HeapWord* CollectedHeap::allocate_from_tlab_slow(Klass* klass, Thread* thread, size_t size) {
+HeapWord* CollectedHeap::obj_allocate_raw(Klass* klass, size_t size,
+                                          bool* gc_overhead_limit_was_exceeded, TRAPS) {
+  if (UseTLAB) {
+    HeapWord* result = allocate_from_tlab(klass, size, THREAD);
+    if (result != NULL) {
+      return result;
+    }
+  }
+  return Universe::heap()->mem_allocate(size, gc_overhead_limit_was_exceeded);
+}
+
+HeapWord* CollectedHeap::allocate_from_tlab_slow(Klass* klass, size_t size, TRAPS) {
+  ThreadLocalAllocBuffer& tlab = THREAD->tlab();
 
   // Retain tlab and allocate object in shared space if
   // the amount free in the tlab is too large to discard.
-  if (thread->tlab().free() > thread->tlab().refill_waste_limit()) {
-    thread->tlab().record_slow_allocation(size);
+  if (tlab.free() > tlab.refill_waste_limit()) {
+    tlab.record_slow_allocation(size);
     return NULL;
   }
 
   // Discard tlab and allocate a new one.
   // To minimize fragmentation, the last TLAB may be smaller than the rest.
-  size_t new_tlab_size = thread->tlab().compute_size(size);
+  size_t new_tlab_size = tlab.compute_size(size);
 
-  thread->tlab().clear_before_allocation();
+  tlab.clear_before_allocation();
 
   if (new_tlab_size == 0) {
     return NULL;
@@ -397,7 +409,7 @@ HeapWord* CollectedHeap::allocate_from_tlab_slow(Klass* klass, Thread* thread, s
   assert(actual_tlab_size != 0, "Allocation succeeded but actual size not updated. obj at: " PTR_FORMAT " min: " SIZE_FORMAT ", desired: " SIZE_FORMAT,
          p2i(obj), min_tlab_size, new_tlab_size);
 
-  AllocTracer::send_allocation_in_new_tlab(klass, obj, actual_tlab_size * HeapWordSize, size * HeapWordSize, thread);
+  AllocTracer::send_allocation_in_new_tlab(klass, obj, actual_tlab_size * HeapWordSize, size * HeapWordSize, THREAD);
 
   if (ZeroTLAB) {
     // ..and clear it.
@@ -412,7 +424,7 @@ HeapWord* CollectedHeap::allocate_from_tlab_slow(Klass* klass, Thread* thread, s
     Copy::fill_to_words(obj + hdr_size, actual_tlab_size - hdr_size, badHeapWordVal);
 #endif // ASSERT
   }
-  thread->tlab().fill(obj, obj + size, actual_tlab_size);
+  tlab.fill(obj, obj + size, actual_tlab_size);
   return obj;
 }
 

src/hotspot/share/gc/shared/collectedHeap.hpp

@@ -141,8 +141,15 @@ class CollectedHeap : public CHeapObj<mtInternal> {
   virtual void resize_all_tlabs();
 
   // Allocate from the current thread's TLAB, with broken-out slow path.
-  inline static HeapWord* allocate_from_tlab(Klass* klass, Thread* thread, size_t size);
-  static HeapWord* allocate_from_tlab_slow(Klass* klass, Thread* thread, size_t size);
+  inline static HeapWord* allocate_from_tlab(Klass* klass, size_t size, TRAPS);
+  static HeapWord* allocate_from_tlab_slow(Klass* klass, size_t size, TRAPS);
+
+  // Raw memory allocation facilities
+  // The obj and array allocate methods are covers for these methods.
+  // mem_allocate() should never be
+  // called to allocate TLABs, only individual objects.
+  virtual HeapWord* mem_allocate(size_t size,
+                                 bool* gc_overhead_limit_was_exceeded) = 0;
 
   // Allocate an uninitialized block of the given size, or returns NULL if
   // this is impossible.
@@ -309,12 +316,12 @@ class CollectedHeap : public CHeapObj<mtInternal> {
   inline static oop array_allocate_nozero(Klass* klass, int size, int length, TRAPS);
   inline static oop class_allocate(Klass* klass, int size, TRAPS);
 
-  // Raw memory allocation facilities
-  // The obj and array allocate methods are covers for these methods.
-  // mem_allocate() should never be
-  // called to allocate TLABs, only individual objects.
-  virtual HeapWord* mem_allocate(size_t size,
-                                 bool* gc_overhead_limit_was_exceeded) = 0;
+  // Raw memory allocation. This may or may not use TLAB allocations to satisfy the
+  // allocation. A GC implementation may override this function to satisfy the allocation
+  // in any way. But the default is to try a TLAB allocation, and otherwise perform
+  // mem_allocate.
+  virtual HeapWord* obj_allocate_raw(Klass* klass, size_t size,
+                                     bool* gc_overhead_limit_was_exceeded, TRAPS);
 
   // Utilities for turning raw memory into filler objects.
   //

src/hotspot/share/gc/shared/collectedHeap.inline.hpp

@@ -137,18 +137,10 @@ HeapWord* CollectedHeap::common_mem_allocate_noinit(Klass* klass, size_t size, T
     return NULL;  // caller does a CHECK_0 too
   }
 
-  HeapWord* result = NULL;
-  if (UseTLAB) {
-    result = allocate_from_tlab(klass, THREAD, size);
-    if (result != NULL) {
-      assert(!HAS_PENDING_EXCEPTION,
-             "Unexpected exception, will result in uninitialized storage");
-      return result;
-    }
-  }
   bool gc_overhead_limit_was_exceeded = false;
-  result = Universe::heap()->mem_allocate(size,
-                                          &gc_overhead_limit_was_exceeded);
+  CollectedHeap* heap = Universe::heap();
+  HeapWord* result = heap->obj_allocate_raw(klass, size, &gc_overhead_limit_was_exceeded, THREAD);
+
   if (result != NULL) {
     NOT_PRODUCT(Universe::heap()->
       check_for_non_bad_heap_word_value(result, size));
@@ -161,7 +153,6 @@ HeapWord* CollectedHeap::common_mem_allocate_noinit(Klass* klass, size_t size, T
     return result;
   }
 
-
   if (!gc_overhead_limit_was_exceeded) {
     // -XX:+HeapDumpOnOutOfMemoryError and -XX:OnOutOfMemoryError support
     report_java_out_of_memory("Java heap space");
@@ -193,15 +184,18 @@ HeapWord* CollectedHeap::common_mem_allocate_init(Klass* klass, size_t size, TRA
   return obj;
 }
 
-HeapWord* CollectedHeap::allocate_from_tlab(Klass* klass, Thread* thread, size_t size) {
+HeapWord* CollectedHeap::allocate_from_tlab(Klass* klass, size_t size, TRAPS) {
   assert(UseTLAB, "should use UseTLAB");
 
-  HeapWord* obj = thread->tlab().allocate(size);
+  HeapWord* obj = THREAD->tlab().allocate(size);
   if (obj != NULL) {
     return obj;
   }
   // Otherwise...
-  return allocate_from_tlab_slow(klass, thread, size);
+  obj = allocate_from_tlab_slow(klass, size, THREAD);
+  assert(obj == NULL || !HAS_PENDING_EXCEPTION,
+         "Unexpected exception, will result in uninitialized storage");
+  return obj;
 }
 
 void CollectedHeap::init_obj(HeapWord* obj, size_t size) {