8165808: Add release barriers when allocating objects with concurrent collection
Summary: Add release_set_klass, use in slow-path allocators.
Reviewed-by: jmasa, dholmes
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#ifndef SHARE_VM_GC_SHARED_COLLECTEDHEAP_INLINE_HPP
#define SHARE_VM_GC_SHARED_COLLECTEDHEAP_INLINE_HPP
#include "classfile/javaClasses.hpp"
#include "gc/shared/allocTracer.hpp"
#include "gc/shared/collectedHeap.hpp"
#include "gc/shared/threadLocalAllocBuffer.inline.hpp"
#include "memory/universe.hpp"
#include "oops/arrayOop.hpp"
#include "oops/oop.inline.hpp"
#include "prims/jvmtiExport.hpp"
#include "runtime/sharedRuntime.hpp"
#include "runtime/thread.inline.hpp"
#include "services/lowMemoryDetector.hpp"
#include "utilities/copy.hpp"
// Inline allocation implementations.
void CollectedHeap::post_allocation_setup_common(KlassHandle klass,
HeapWord* obj_ptr) {
post_allocation_setup_no_klass_install(klass, obj_ptr);
oop obj = (oop)obj_ptr;
#if ! INCLUDE_ALL_GCS
obj->set_klass(klass());
#else
// Need a release store to ensure array/class length, mark word, and
// object zeroing are visible before setting the klass non-NULL, for
// concurrent collectors.
obj->release_set_klass(klass());
#endif
}
void CollectedHeap::post_allocation_setup_no_klass_install(KlassHandle klass,
HeapWord* obj_ptr) {
oop obj = (oop)obj_ptr;
assert(obj != NULL, "NULL object pointer");
if (UseBiasedLocking && (klass() != NULL)) {
obj->set_mark(klass->prototype_header());
} else {
// May be bootstrapping
obj->set_mark(markOopDesc::prototype());
}
}
// Support for jvmti and dtrace
inline void post_allocation_notify(KlassHandle klass, oop obj, int size) {
// support low memory notifications (no-op if not enabled)
LowMemoryDetector::detect_low_memory_for_collected_pools();
// support for JVMTI VMObjectAlloc event (no-op if not enabled)
JvmtiExport::vm_object_alloc_event_collector(obj);
if (DTraceAllocProbes) {
// support for Dtrace object alloc event (no-op most of the time)
if (klass() != NULL && klass()->name() != NULL) {
SharedRuntime::dtrace_object_alloc(obj, size);
}
}
}
void CollectedHeap::post_allocation_setup_obj(KlassHandle klass,
HeapWord* obj_ptr,
int size) {
post_allocation_setup_common(klass, obj_ptr);
oop obj = (oop)obj_ptr;
assert(Universe::is_bootstrapping() ||
!obj->is_array(), "must not be an array");
// notify jvmti and dtrace
post_allocation_notify(klass, obj, size);
}
void CollectedHeap::post_allocation_setup_class(KlassHandle klass,
HeapWord* obj_ptr,
int size) {
// Set oop_size field before setting the _klass field because a
// non-NULL _klass field indicates that the object is parsable by
// concurrent GC.
oop new_cls = (oop)obj_ptr;
assert(size > 0, "oop_size must be positive.");
java_lang_Class::set_oop_size(new_cls, size);
post_allocation_setup_common(klass, obj_ptr);
assert(Universe::is_bootstrapping() ||
!new_cls->is_array(), "must not be an array");
// notify jvmti and dtrace
post_allocation_notify(klass, new_cls, size);
}
void CollectedHeap::post_allocation_setup_array(KlassHandle klass,
HeapWord* obj_ptr,
int length) {
// Set array length before setting the _klass field because a
// non-NULL klass field indicates that the object is parsable by
// concurrent GC.
assert(length >= 0, "length should be non-negative");
((arrayOop)obj_ptr)->set_length(length);
post_allocation_setup_common(klass, obj_ptr);
oop new_obj = (oop)obj_ptr;
assert(new_obj->is_array(), "must be an array");
// notify jvmti and dtrace (must be after length is set for dtrace)
post_allocation_notify(klass, new_obj, new_obj->size());
}
HeapWord* CollectedHeap::common_mem_allocate_noinit(KlassHandle klass, size_t size, TRAPS) {
// Clear unhandled oops for memory allocation. Memory allocation might
// not take out a lock if from tlab, so clear here.
CHECK_UNHANDLED_OOPS_ONLY(THREAD->clear_unhandled_oops();)
if (HAS_PENDING_EXCEPTION) {
NOT_PRODUCT(guarantee(false, "Should not allocate with exception pending"));
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);
if (result != NULL) {
NOT_PRODUCT(Universe::heap()->
check_for_non_bad_heap_word_value(result, size));
assert(!HAS_PENDING_EXCEPTION,
"Unexpected exception, will result in uninitialized storage");
THREAD->incr_allocated_bytes(size * HeapWordSize);
AllocTracer::send_allocation_outside_tlab_event(klass, size * HeapWordSize);
return result;
}
if (!gc_overhead_limit_was_exceeded) {
// -XX:+HeapDumpOnOutOfMemoryError and -XX:OnOutOfMemoryError support
report_java_out_of_memory("Java heap space");
if (JvmtiExport::should_post_resource_exhausted()) {
JvmtiExport::post_resource_exhausted(
JVMTI_RESOURCE_EXHAUSTED_OOM_ERROR | JVMTI_RESOURCE_EXHAUSTED_JAVA_HEAP,
"Java heap space");
}
THROW_OOP_0(Universe::out_of_memory_error_java_heap());
} else {
// -XX:+HeapDumpOnOutOfMemoryError and -XX:OnOutOfMemoryError support
report_java_out_of_memory("GC overhead limit exceeded");
if (JvmtiExport::should_post_resource_exhausted()) {
JvmtiExport::post_resource_exhausted(
JVMTI_RESOURCE_EXHAUSTED_OOM_ERROR | JVMTI_RESOURCE_EXHAUSTED_JAVA_HEAP,
"GC overhead limit exceeded");
}
THROW_OOP_0(Universe::out_of_memory_error_gc_overhead_limit());
}
}
HeapWord* CollectedHeap::common_mem_allocate_init(KlassHandle klass, size_t size, TRAPS) {
HeapWord* obj = common_mem_allocate_noinit(klass, size, CHECK_NULL);
init_obj(obj, size);
return obj;
}
HeapWord* CollectedHeap::allocate_from_tlab(KlassHandle klass, Thread* thread, size_t size) {
assert(UseTLAB, "should use UseTLAB");
HeapWord* obj = thread->tlab().allocate(size);
if (obj != NULL) {
return obj;
}
// Otherwise...
return allocate_from_tlab_slow(klass, thread, size);
}
void CollectedHeap::init_obj(HeapWord* obj, size_t size) {
assert(obj != NULL, "cannot initialize NULL object");
const size_t hs = oopDesc::header_size();
assert(size >= hs, "unexpected object size");
((oop)obj)->set_klass_gap(0);
Copy::fill_to_aligned_words(obj + hs, size - hs);
}
oop CollectedHeap::obj_allocate(KlassHandle klass, int size, TRAPS) {
debug_only(check_for_valid_allocation_state());
assert(!Universe::heap()->is_gc_active(), "Allocation during gc not allowed");
assert(size >= 0, "int won't convert to size_t");
HeapWord* obj = common_mem_allocate_init(klass, size, CHECK_NULL);
post_allocation_setup_obj(klass, obj, size);
NOT_PRODUCT(Universe::heap()->check_for_bad_heap_word_value(obj, size));
return (oop)obj;
}
oop CollectedHeap::class_allocate(KlassHandle klass, int size, TRAPS) {
debug_only(check_for_valid_allocation_state());
assert(!Universe::heap()->is_gc_active(), "Allocation during gc not allowed");
assert(size >= 0, "int won't convert to size_t");
HeapWord* obj = common_mem_allocate_init(klass, size, CHECK_NULL);
post_allocation_setup_class(klass, obj, size); // set oop_size
NOT_PRODUCT(Universe::heap()->check_for_bad_heap_word_value(obj, size));
return (oop)obj;
}
oop CollectedHeap::array_allocate(KlassHandle klass,
int size,
int length,
TRAPS) {
debug_only(check_for_valid_allocation_state());
assert(!Universe::heap()->is_gc_active(), "Allocation during gc not allowed");
assert(size >= 0, "int won't convert to size_t");
HeapWord* obj = common_mem_allocate_init(klass, size, CHECK_NULL);
post_allocation_setup_array(klass, obj, length);
NOT_PRODUCT(Universe::heap()->check_for_bad_heap_word_value(obj, size));
return (oop)obj;
}
oop CollectedHeap::array_allocate_nozero(KlassHandle klass,
int size,
int length,
TRAPS) {
debug_only(check_for_valid_allocation_state());
assert(!Universe::heap()->is_gc_active(), "Allocation during gc not allowed");
assert(size >= 0, "int won't convert to size_t");
HeapWord* obj = common_mem_allocate_noinit(klass, size, CHECK_NULL);
((oop)obj)->set_klass_gap(0);
post_allocation_setup_array(klass, obj, length);
#ifndef PRODUCT
const size_t hs = oopDesc::header_size()+1;
Universe::heap()->check_for_non_bad_heap_word_value(obj+hs, size-hs);
#endif
return (oop)obj;
}
inline HeapWord* CollectedHeap::align_allocation_or_fail(HeapWord* addr,
HeapWord* end,
unsigned short alignment_in_bytes) {
if (alignment_in_bytes <= ObjectAlignmentInBytes) {
return addr;
}
assert(is_ptr_aligned(addr, HeapWordSize),
"Address " PTR_FORMAT " is not properly aligned.", p2i(addr));
assert(is_size_aligned(alignment_in_bytes, HeapWordSize),
"Alignment size %u is incorrect.", alignment_in_bytes);
HeapWord* new_addr = (HeapWord*) align_ptr_up(addr, alignment_in_bytes);
size_t padding = pointer_delta(new_addr, addr);
if (padding == 0) {
return addr;
}
if (padding < CollectedHeap::min_fill_size()) {
padding += alignment_in_bytes / HeapWordSize;
assert(padding >= CollectedHeap::min_fill_size(),
"alignment_in_bytes %u is expect to be larger "
"than the minimum object size", alignment_in_bytes);
new_addr = addr + padding;
}
assert(new_addr > addr, "Unexpected arithmetic overflow "
PTR_FORMAT " not greater than " PTR_FORMAT, p2i(new_addr), p2i(addr));
if(new_addr < end) {
CollectedHeap::fill_with_object(addr, padding);
return new_addr;
} else {
return NULL;
}
}
#ifndef PRODUCT
inline bool
CollectedHeap::promotion_should_fail(volatile size_t* count) {
// Access to count is not atomic; the value does not have to be exact.
if (PromotionFailureALot) {
const size_t gc_num = total_collections();
const size_t elapsed_gcs = gc_num - _promotion_failure_alot_gc_number;
if (elapsed_gcs >= PromotionFailureALotInterval) {
// Test for unsigned arithmetic wrap-around.
if (++*count >= PromotionFailureALotCount) {
*count = 0;
return true;
}
}
}
return false;
}
inline bool CollectedHeap::promotion_should_fail() {
return promotion_should_fail(&_promotion_failure_alot_count);
}
inline void CollectedHeap::reset_promotion_should_fail(volatile size_t* count) {
if (PromotionFailureALot) {
_promotion_failure_alot_gc_number = total_collections();
*count = 0;
}
}
inline void CollectedHeap::reset_promotion_should_fail() {
reset_promotion_should_fail(&_promotion_failure_alot_count);
}
#endif // #ifndef PRODUCT
#endif // SHARE_VM_GC_SHARED_COLLECTEDHEAP_INLINE_HPP