src/hotspot/share/gc/shenandoah/shenandoahConcurrentMark.inline.hpp - platform/libcore - Git at Google

 /*
  * Copyright (c) 2015, 2019, Red Hat, Inc. All rights reserved.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */

 #ifndef SHARE_GC_SHENANDOAH_SHENANDOAHCONCURRENTMARK_INLINE_HPP
 #define SHARE_GC_SHENANDOAH_SHENANDOAHCONCURRENTMARK_INLINE_HPP

 #include "gc/shenandoah/shenandoahAsserts.hpp"
 #include "gc/shenandoah/shenandoahBarrierSet.inline.hpp"
 #include "gc/shenandoah/shenandoahConcurrentMark.hpp"
 #include "gc/shenandoah/shenandoahMarkingContext.inline.hpp"
 #include "gc/shenandoah/shenandoahStringDedup.inline.hpp"
 #include "gc/shenandoah/shenandoahTaskqueue.inline.hpp"
 #include "memory/iterator.inline.hpp"
 #include "oops/compressedOops.inline.hpp"
 #include "oops/oop.inline.hpp"
 #include "runtime/prefetch.inline.hpp"

 template <class T>
 void ShenandoahConcurrentMark::do_task(ShenandoahObjToScanQueue* q, T* cl, jushort* live_data, ShenandoahMarkTask* task) {
   oop obj = task->obj();

   shenandoah_assert_not_forwarded_except(NULL, obj, _heap->is_concurrent_traversal_in_progress() && _heap->cancelled_gc());
   shenandoah_assert_marked(NULL, obj);
   shenandoah_assert_not_in_cset_except(NULL, obj, _heap->cancelled_gc());

   if (task->is_not_chunked()) {
     if (obj->is_instance()) {
       // Case 1: Normal oop, process as usual.
       obj->oop_iterate(cl);
     } else if (obj->is_objArray()) {
       // Case 2: Object array instance and no chunk is set. Must be the first
       // time we visit it, start the chunked processing.
       do_chunked_array_start<T>(q, cl, obj);
     } else {
       // Case 3: Primitive array. Do nothing, no oops there. We use the same
       // performance tweak TypeArrayKlass::oop_oop_iterate_impl is using:
       // We skip iterating over the klass pointer since we know that
       // Universe::TypeArrayKlass never moves.
       assert (obj->is_typeArray(), "should be type array");
     }
     // Count liveness the last: push the outstanding work to the queues first
     count_liveness(live_data, obj);
   } else {
     // Case 4: Array chunk, has sensible chunk id. Process it.
     do_chunked_array<T>(q, cl, obj, task->chunk(), task->pow());
   }
 }

 inline void ShenandoahConcurrentMark::count_liveness(jushort* live_data, oop obj) {
   size_t region_idx = _heap->heap_region_index_containing(obj);
   ShenandoahHeapRegion* region = _heap->get_region(region_idx);
   size_t size = obj->size();

   if (!region->is_humongous_start()) {
     assert(!region->is_humongous(), "Cannot have continuations here");
     size_t max = (1 << (sizeof(jushort) * 8)) - 1;
     if (size >= max) {
       // too big, add to region data directly
       region->increase_live_data_gc_words(size);
     } else {
       jushort cur = live_data[region_idx];
       size_t new_val = cur + size;
       if (new_val >= max) {
         // overflow, flush to region data
         region->increase_live_data_gc_words(new_val);
         live_data[region_idx] = 0;
       } else {
         // still good, remember in locals
         live_data[region_idx] = (jushort) new_val;
       }
     }
   } else {
     shenandoah_assert_in_correct_region(NULL, obj);
     size_t num_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);

     for (size_t i = region_idx; i < region_idx + num_regions; i++) {
       ShenandoahHeapRegion* chain_reg = _heap->get_region(i);
       assert(chain_reg->is_humongous(), "Expecting a humongous region");
       chain_reg->increase_live_data_gc_words(chain_reg->used() >> LogHeapWordSize);
     }
   }
 }

 template <class T>
 inline void ShenandoahConcurrentMark::do_chunked_array_start(ShenandoahObjToScanQueue* q, T* cl, oop obj) {
   assert(obj->is_objArray(), "expect object array");
   objArrayOop array = objArrayOop(obj);
   int len = array->length();

   if (len <= (int) ObjArrayMarkingStride*2) {
     // A few slices only, process directly
     array->oop_iterate_range(cl, 0, len);
   } else {
     int bits = log2_long((size_t) len);
     // Compensate for non-power-of-two arrays, cover the array in excess:
     if (len != (1 << bits)) bits++;

     // Only allow full chunks on the queue. This frees do_chunked_array() from checking from/to
     // boundaries against array->length(), touching the array header on every chunk.
     //
     // To do this, we cut the prefix in full-sized chunks, and submit them on the queue.
     // If the array is not divided in chunk sizes, then there would be an irregular tail,
     // which we will process separately.

     int last_idx = 0;

     int chunk = 1;
     int pow = bits;

     // Handle overflow
     if (pow >= 31) {
       assert (pow == 31, "sanity");
       pow--;
       chunk = 2;
       last_idx = (1 << pow);
       bool pushed = q->push(ShenandoahMarkTask(array, 1, pow));
       assert(pushed, "overflow queue should always succeed pushing");
     }

     // Split out tasks, as suggested in ObjArrayChunkedTask docs. Record the last
     // successful right boundary to figure out the irregular tail.
     while ((1 << pow) > (int)ObjArrayMarkingStride &&
            (chunk*2 < ShenandoahMarkTask::chunk_size())) {
       pow--;
       int left_chunk = chunk*2 - 1;
       int right_chunk = chunk*2;
       int left_chunk_end = left_chunk * (1 << pow);
       if (left_chunk_end < len) {
         bool pushed = q->push(ShenandoahMarkTask(array, left_chunk, pow));
         assert(pushed, "overflow queue should always succeed pushing");
         chunk = right_chunk;
         last_idx = left_chunk_end;
       } else {
         chunk = left_chunk;
       }
     }

     // Process the irregular tail, if present
     int from = last_idx;
     if (from < len) {
       array->oop_iterate_range(cl, from, len);
     }
   }
 }

 template <class T>
 inline void ShenandoahConcurrentMark::do_chunked_array(ShenandoahObjToScanQueue* q, T* cl, oop obj, int chunk, int pow) {
   assert(obj->is_objArray(), "expect object array");
   objArrayOop array = objArrayOop(obj);

   assert (ObjArrayMarkingStride > 0, "sanity");

   // Split out tasks, as suggested in ObjArrayChunkedTask docs. Avoid pushing tasks that
   // are known to start beyond the array.
   while ((1 << pow) > (int)ObjArrayMarkingStride && (chunk*2 < ShenandoahMarkTask::chunk_size())) {
     pow--;
     chunk *= 2;
     bool pushed = q->push(ShenandoahMarkTask(array, chunk - 1, pow));
     assert(pushed, "overflow queue should always succeed pushing");
   }

   int chunk_size = 1 << pow;

   int from = (chunk - 1) * chunk_size;
   int to = chunk * chunk_size;

 #ifdef ASSERT
   int len = array->length();
   assert (0 <= from && from < len, "from is sane: %d/%d", from, len);
   assert (0 < to && to <= len, "to is sane: %d/%d", to, len);
 #endif

   array->oop_iterate_range(cl, from, to);
 }

 class ShenandoahSATBBufferClosure : public SATBBufferClosure {
 private:
   ShenandoahObjToScanQueue* _queue;
   ShenandoahHeap* _heap;
   ShenandoahMarkingContext* const _mark_context;
 public:
   ShenandoahSATBBufferClosure(ShenandoahObjToScanQueue* q) :
     _queue(q),
     _heap(ShenandoahHeap::heap()),
     _mark_context(_heap->marking_context())
   {
   }

   void do_buffer(void **buffer, size_t size) {
     if (_heap->has_forwarded_objects()) {
       if (ShenandoahStringDedup::is_enabled()) {
         do_buffer_impl<RESOLVE, ENQUEUE_DEDUP>(buffer, size);
       } else {
         do_buffer_impl<RESOLVE, NO_DEDUP>(buffer, size);
       }
     } else {
       if (ShenandoahStringDedup::is_enabled()) {
         do_buffer_impl<NONE, ENQUEUE_DEDUP>(buffer, size);
       } else {
         do_buffer_impl<NONE, NO_DEDUP>(buffer, size);
       }
     }
   }

   template<UpdateRefsMode UPDATE_REFS, StringDedupMode STRING_DEDUP>
   void do_buffer_impl(void **buffer, size_t size) {
     for (size_t i = 0; i < size; ++i) {
       oop *p = (oop *) &buffer[i];
       ShenandoahConcurrentMark::mark_through_ref<oop, UPDATE_REFS, STRING_DEDUP>(p, _heap, _queue, _mark_context);
     }
   }
 };

 template<class T, UpdateRefsMode UPDATE_REFS, StringDedupMode STRING_DEDUP>
 inline void ShenandoahConcurrentMark::mark_through_ref(T *p, ShenandoahHeap* heap, ShenandoahObjToScanQueue* q, ShenandoahMarkingContext* const mark_context) {
   T o = RawAccess<>::oop_load(p);
   if (!CompressedOops::is_null(o)) {
     oop obj = CompressedOops::decode_not_null(o);
     switch (UPDATE_REFS) {
     case NONE:
       break;
     case RESOLVE:
       obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
       break;
     case SIMPLE:
       // We piggy-back reference updating to the marking tasks.
       obj = heap->update_with_forwarded_not_null(p, obj);
       break;
     case CONCURRENT:
       obj = heap->maybe_update_with_forwarded_not_null(p, obj);
       break;
     default:
       ShouldNotReachHere();
     }

     // Note: Only when concurrently updating references can obj become NULL here.
     // It happens when a mutator thread beats us by writing another value. In that
     // case we don't need to do anything else.
     if (UPDATE_REFS != CONCURRENT || !CompressedOops::is_null(obj)) {
       shenandoah_assert_not_forwarded(p, obj);
       shenandoah_assert_not_in_cset_except(p, obj, heap->cancelled_gc());

       if (mark_context->mark(obj)) {
         bool pushed = q->push(ShenandoahMarkTask(obj));
         assert(pushed, "overflow queue should always succeed pushing");

         if ((STRING_DEDUP == ENQUEUE_DEDUP) && ShenandoahStringDedup::is_candidate(obj)) {
           assert(ShenandoahStringDedup::is_enabled(), "Must be enabled");
           ShenandoahStringDedup::enqueue_candidate(obj);
         }
       }

       shenandoah_assert_marked(p, obj);
     }
   }
 }

 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHCONCURRENTMARK_INLINE_HPP
	/*
	* Copyright (c) 2015, 2019, Red Hat, Inc. All rights reserved.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*
	*/

	#ifndef SHARE_GC_SHENANDOAH_SHENANDOAHCONCURRENTMARK_INLINE_HPP
	#define SHARE_GC_SHENANDOAH_SHENANDOAHCONCURRENTMARK_INLINE_HPP

	#include "gc/shenandoah/shenandoahAsserts.hpp"
	#include "gc/shenandoah/shenandoahBarrierSet.inline.hpp"
	#include "gc/shenandoah/shenandoahConcurrentMark.hpp"
	#include "gc/shenandoah/shenandoahMarkingContext.inline.hpp"
	#include "gc/shenandoah/shenandoahStringDedup.inline.hpp"
	#include "gc/shenandoah/shenandoahTaskqueue.inline.hpp"
	#include "memory/iterator.inline.hpp"
	#include "oops/compressedOops.inline.hpp"
	#include "oops/oop.inline.hpp"
	#include "runtime/prefetch.inline.hpp"

	template <class T>
	void ShenandoahConcurrentMark::do_task(ShenandoahObjToScanQueue* q, T* cl, jushort* live_data, ShenandoahMarkTask* task) {
	oop obj = task->obj();

	shenandoah_assert_not_forwarded_except(NULL, obj, _heap->is_concurrent_traversal_in_progress() && _heap->cancelled_gc());
	shenandoah_assert_marked(NULL, obj);
	shenandoah_assert_not_in_cset_except(NULL, obj, _heap->cancelled_gc());

	if (task->is_not_chunked()) {
	if (obj->is_instance()) {
	// Case 1: Normal oop, process as usual.
	obj->oop_iterate(cl);
	} else if (obj->is_objArray()) {
	// Case 2: Object array instance and no chunk is set. Must be the first
	// time we visit it, start the chunked processing.
	do_chunked_array_start<T>(q, cl, obj);
	} else {
	// Case 3: Primitive array. Do nothing, no oops there. We use the same
	// performance tweak TypeArrayKlass::oop_oop_iterate_impl is using:
	// We skip iterating over the klass pointer since we know that
	// Universe::TypeArrayKlass never moves.
	assert (obj->is_typeArray(), "should be type array");
	}
	// Count liveness the last: push the outstanding work to the queues first
	count_liveness(live_data, obj);
	} else {
	// Case 4: Array chunk, has sensible chunk id. Process it.
	do_chunked_array<T>(q, cl, obj, task->chunk(), task->pow());
	}
	}

	inline void ShenandoahConcurrentMark::count_liveness(jushort* live_data, oop obj) {
	size_t region_idx = _heap->heap_region_index_containing(obj);
	ShenandoahHeapRegion* region = _heap->get_region(region_idx);
	size_t size = obj->size();

	if (!region->is_humongous_start()) {
	assert(!region->is_humongous(), "Cannot have continuations here");
	size_t max = (1 << (sizeof(jushort) * 8)) - 1;
	if (size >= max) {
	// too big, add to region data directly
	region->increase_live_data_gc_words(size);
	} else {
	jushort cur = live_data[region_idx];
	size_t new_val = cur + size;
	if (new_val >= max) {
	// overflow, flush to region data
	region->increase_live_data_gc_words(new_val);
	live_data[region_idx] = 0;
	} else {
	// still good, remember in locals
	live_data[region_idx] = (jushort) new_val;
	}
	}
	} else {
	shenandoah_assert_in_correct_region(NULL, obj);
	size_t num_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);

	for (size_t i = region_idx; i < region_idx + num_regions; i++) {
	ShenandoahHeapRegion* chain_reg = _heap->get_region(i);
	assert(chain_reg->is_humongous(), "Expecting a humongous region");
	chain_reg->increase_live_data_gc_words(chain_reg->used() >> LogHeapWordSize);
	}
	}
	}

	template <class T>
	inline void ShenandoahConcurrentMark::do_chunked_array_start(ShenandoahObjToScanQueue* q, T* cl, oop obj) {
	assert(obj->is_objArray(), "expect object array");
	objArrayOop array = objArrayOop(obj);
	int len = array->length();

	if (len <= (int) ObjArrayMarkingStride*2) {
	// A few slices only, process directly
	array->oop_iterate_range(cl, 0, len);
	} else {
	int bits = log2_long((size_t) len);
	// Compensate for non-power-of-two arrays, cover the array in excess:
	if (len != (1 << bits)) bits++;

	// Only allow full chunks on the queue. This frees do_chunked_array() from checking from/to
	// boundaries against array->length(), touching the array header on every chunk.
	//
	// To do this, we cut the prefix in full-sized chunks, and submit them on the queue.
	// If the array is not divided in chunk sizes, then there would be an irregular tail,
	// which we will process separately.

	int last_idx = 0;

	int chunk = 1;
	int pow = bits;

	// Handle overflow
	if (pow >= 31) {
	assert (pow == 31, "sanity");
	pow--;
	chunk = 2;
	last_idx = (1 << pow);
	bool pushed = q->push(ShenandoahMarkTask(array, 1, pow));
	assert(pushed, "overflow queue should always succeed pushing");
	}

	// Split out tasks, as suggested in ObjArrayChunkedTask docs. Record the last
	// successful right boundary to figure out the irregular tail.
	while ((1 << pow) > (int)ObjArrayMarkingStride &&
	(chunk*2 < ShenandoahMarkTask::chunk_size())) {
	pow--;
	int left_chunk = chunk*2 - 1;
	int right_chunk = chunk*2;
	int left_chunk_end = left_chunk * (1 << pow);
	if (left_chunk_end < len) {
	bool pushed = q->push(ShenandoahMarkTask(array, left_chunk, pow));
	assert(pushed, "overflow queue should always succeed pushing");
	chunk = right_chunk;
	last_idx = left_chunk_end;
	} else {
	chunk = left_chunk;
	}
	}

	// Process the irregular tail, if present
	int from = last_idx;
	if (from < len) {
	array->oop_iterate_range(cl, from, len);
	}
	}
	}

	template <class T>
	inline void ShenandoahConcurrentMark::do_chunked_array(ShenandoahObjToScanQueue* q, T* cl, oop obj, int chunk, int pow) {
	assert(obj->is_objArray(), "expect object array");
	objArrayOop array = objArrayOop(obj);

	assert (ObjArrayMarkingStride > 0, "sanity");

	// Split out tasks, as suggested in ObjArrayChunkedTask docs. Avoid pushing tasks that
	// are known to start beyond the array.
	while ((1 << pow) > (int)ObjArrayMarkingStride && (chunk*2 < ShenandoahMarkTask::chunk_size())) {
	pow--;
	chunk *= 2;
	bool pushed = q->push(ShenandoahMarkTask(array, chunk - 1, pow));
	assert(pushed, "overflow queue should always succeed pushing");
	}

	int chunk_size = 1 << pow;

	int from = (chunk - 1) * chunk_size;
	int to = chunk * chunk_size;

	#ifdef ASSERT
	int len = array->length();
	assert (0 <= from && from < len, "from is sane: %d/%d", from, len);
	assert (0 < to && to <= len, "to is sane: %d/%d", to, len);
	#endif

	array->oop_iterate_range(cl, from, to);
	}

	class ShenandoahSATBBufferClosure : public SATBBufferClosure {
	private:
	ShenandoahObjToScanQueue* _queue;
	ShenandoahHeap* _heap;
	ShenandoahMarkingContext* const _mark_context;
	public:
	ShenandoahSATBBufferClosure(ShenandoahObjToScanQueue* q) :
	_queue(q),
	_heap(ShenandoahHeap::heap()),
	_mark_context(_heap->marking_context())
	{
	}

	void do_buffer(void **buffer, size_t size) {
	if (_heap->has_forwarded_objects()) {
	if (ShenandoahStringDedup::is_enabled()) {
	do_buffer_impl<RESOLVE, ENQUEUE_DEDUP>(buffer, size);
	} else {
	do_buffer_impl<RESOLVE, NO_DEDUP>(buffer, size);
	}
	} else {
	if (ShenandoahStringDedup::is_enabled()) {
	do_buffer_impl<NONE, ENQUEUE_DEDUP>(buffer, size);
	} else {
	do_buffer_impl<NONE, NO_DEDUP>(buffer, size);
	}
	}
	}

	template<UpdateRefsMode UPDATE_REFS, StringDedupMode STRING_DEDUP>
	void do_buffer_impl(void **buffer, size_t size) {
	for (size_t i = 0; i < size; ++i) {
	oop p = (oop ) &buffer[i];
	ShenandoahConcurrentMark::mark_through_ref<oop, UPDATE_REFS, STRING_DEDUP>(p, _heap, _queue, _mark_context);
	}
	}
	};

	template<class T, UpdateRefsMode UPDATE_REFS, StringDedupMode STRING_DEDUP>
	inline void ShenandoahConcurrentMark::mark_through_ref(T p, ShenandoahHeap heap, ShenandoahObjToScanQueue* q, ShenandoahMarkingContext* const mark_context) {
	T o = RawAccess<>::oop_load(p);
	if (!CompressedOops::is_null(o)) {
	oop obj = CompressedOops::decode_not_null(o);
	switch (UPDATE_REFS) {
	case NONE:
	break;
	case RESOLVE:
	obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
	break;
	case SIMPLE:
	// We piggy-back reference updating to the marking tasks.
	obj = heap->update_with_forwarded_not_null(p, obj);
	break;
	case CONCURRENT:
	obj = heap->maybe_update_with_forwarded_not_null(p, obj);
	break;
	default:
	ShouldNotReachHere();
	}

	// Note: Only when concurrently updating references can obj become NULL here.
	// It happens when a mutator thread beats us by writing another value. In that
	// case we don't need to do anything else.
	if (UPDATE_REFS != CONCURRENT \|\| !CompressedOops::is_null(obj)) {
	shenandoah_assert_not_forwarded(p, obj);
	shenandoah_assert_not_in_cset_except(p, obj, heap->cancelled_gc());

	if (mark_context->mark(obj)) {
	bool pushed = q->push(ShenandoahMarkTask(obj));
	assert(pushed, "overflow queue should always succeed pushing");

	if ((STRING_DEDUP == ENQUEUE_DEDUP) && ShenandoahStringDedup::is_candidate(obj)) {
	assert(ShenandoahStringDedup::is_enabled(), "Must be enabled");
	ShenandoahStringDedup::enqueue_candidate(obj);
	}
	}

	shenandoah_assert_marked(p, obj);
	}
	}
	}

	#endif // SHARE_GC_SHENANDOAH_SHENANDOAHCONCURRENTMARK_INLINE_HPP