src/hotspot/share/gc/shenandoah/shenandoahCodeRoots.cpp - platform/libcore - Git at Google

 /*
  * Copyright (c) 2017, 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.
  *
  */

 #include "precompiled.hpp"
 #include "code/codeCache.hpp"
 #include "code/nmethod.hpp"
 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
 #include "gc/shenandoah/shenandoahCodeRoots.hpp"
 #include "gc/shenandoah/shenandoahUtils.hpp"
 #include "memory/resourceArea.hpp"

 ShenandoahParallelCodeCacheIterator::ShenandoahParallelCodeCacheIterator(const GrowableArray<CodeHeap*>* heaps) {
   _length = heaps->length();
   _iters = NEW_C_HEAP_ARRAY(ShenandoahParallelCodeHeapIterator, _length, mtGC);
   for (int h = 0; h < _length; h++) {
     _iters[h] = ShenandoahParallelCodeHeapIterator(heaps->at(h));
   }
 }

 ShenandoahParallelCodeCacheIterator::~ShenandoahParallelCodeCacheIterator() {
   FREE_C_HEAP_ARRAY(ParallelCodeHeapIterator, _iters);
 }

 void ShenandoahParallelCodeCacheIterator::parallel_blobs_do(CodeBlobClosure* f) {
   for (int c = 0; c < _length; c++) {
     _iters[c].parallel_blobs_do(f);
   }
 }

 ShenandoahParallelCodeHeapIterator::ShenandoahParallelCodeHeapIterator(CodeHeap* heap) :
         _heap(heap), _claimed_idx(0), _finished(false) {
 }

 void ShenandoahParallelCodeHeapIterator::parallel_blobs_do(CodeBlobClosure* f) {
   assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint");

   /*
    * Parallel code heap walk.
    *
    * This code makes all threads scan all code heaps, but only one thread would execute the
    * closure on given blob. This is achieved by recording the "claimed" blocks: if a thread
    * had claimed the block, it can process all blobs in it. Others have to fast-forward to
    * next attempt without processing.
    *
    * Late threads would return immediately if iterator is finished.
    */

   if (_finished) {
     return;
   }

   int stride = 256; // educated guess
   int stride_mask = stride - 1;
   assert (is_power_of_2(stride), "sanity");

   int count = 0;
   bool process_block = true;

   for (CodeBlob *cb = CodeCache::first_blob(_heap); cb != NULL; cb = CodeCache::next_blob(_heap, cb)) {
     int current = count++;
     if ((current & stride_mask) == 0) {
       process_block = (current >= _claimed_idx) &&
                       (Atomic::cmpxchg(current + stride, &_claimed_idx, current) == current);
     }
     if (process_block) {
       if (cb->is_alive()) {
         f->do_code_blob(cb);
 #ifdef ASSERT
         if (cb->is_nmethod())
           Universe::heap()->verify_nmethod((nmethod*)cb);
 #endif
       }
     }
   }

   _finished = true;
 }

 class ShenandoahNMethodOopDetector : public OopClosure {
 private:
   ResourceMark rm; // For growable array allocation below.
   GrowableArray<oop*> _oops;

 public:
   ShenandoahNMethodOopDetector() : _oops(10) {};

   void do_oop(oop* o) {
     _oops.append(o);
   }
   void do_oop(narrowOop* o) {
     fatal("NMethods should not have compressed oops embedded.");
   }

   GrowableArray<oop*>* oops() {
     return &_oops;
   }

   bool has_oops() {
     return !_oops.is_empty();
   }
 };

 GrowableArray<ShenandoahNMethod*>* ShenandoahCodeRoots::_recorded_nms;
 ShenandoahLock                     ShenandoahCodeRoots::_recorded_nms_lock;

 void ShenandoahCodeRoots::initialize() {
   _recorded_nms = new (ResourceObj::C_HEAP, mtGC) GrowableArray<ShenandoahNMethod*>(100, true, mtGC);
 }

 void ShenandoahCodeRoots::add_nmethod(nmethod* nm) {
   switch (ShenandoahCodeRootsStyle) {
     case 0:
     case 1:
       break;
     case 2: {
       assert_locked_or_safepoint(CodeCache_lock);
       ShenandoahLocker locker(CodeCache_lock->owned_by_self() ? NULL : &_recorded_nms_lock);

       ShenandoahNMethodOopDetector detector;
       nm->oops_do(&detector);

       if (detector.has_oops()) {
         ShenandoahNMethod* nmr = new ShenandoahNMethod(nm, detector.oops());
         nmr->assert_alive_and_correct();
         int idx = _recorded_nms->find(nm, ShenandoahNMethod::find_with_nmethod);
         if (idx != -1) {
           ShenandoahNMethod* old = _recorded_nms->at(idx);
           _recorded_nms->at_put(idx, nmr);
           delete old;
         } else {
           _recorded_nms->append(nmr);
         }
       }
       break;
     }
     default:
       ShouldNotReachHere();
   }
 };

 void ShenandoahCodeRoots::remove_nmethod(nmethod* nm) {
   switch (ShenandoahCodeRootsStyle) {
     case 0:
     case 1: {
       break;
     }
     case 2: {
       assert_locked_or_safepoint(CodeCache_lock);
       ShenandoahLocker locker(CodeCache_lock->owned_by_self() ? NULL : &_recorded_nms_lock);

       ShenandoahNMethodOopDetector detector;
       nm->oops_do(&detector, /* allow_zombie = */ true);

       if (detector.has_oops()) {
         int idx = _recorded_nms->find(nm, ShenandoahNMethod::find_with_nmethod);
         assert(idx != -1, "nmethod " PTR_FORMAT " should be registered", p2i(nm));
         ShenandoahNMethod* old = _recorded_nms->at(idx);
         old->assert_same_oops(detector.oops());
         _recorded_nms->delete_at(idx);
         delete old;
       }
       break;
     }
     default:
       ShouldNotReachHere();
   }
 }

 ShenandoahCodeRootsIterator::ShenandoahCodeRootsIterator() :
         _heap(ShenandoahHeap::heap()),
         _par_iterator(CodeCache::heaps()),
         _claimed(0) {
   assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint");
   assert(!Thread::current()->is_Worker_thread(), "Should not be acquired by workers");
   switch (ShenandoahCodeRootsStyle) {
     case 0:
     case 1: {
       // No need to do anything here
       break;
     }
     case 2: {
       CodeCache_lock->lock_without_safepoint_check();
       break;
     }
     default:
       ShouldNotReachHere();
   }
 }

 ShenandoahCodeRootsIterator::~ShenandoahCodeRootsIterator() {
   switch (ShenandoahCodeRootsStyle) {
     case 0:
     case 1: {
       // No need to do anything here
       break;
     }
     case 2: {
       CodeCache_lock->unlock();
       break;
     }
     default:
       ShouldNotReachHere();
   }
 }

 template<bool CSET_FILTER>
 void ShenandoahCodeRootsIterator::dispatch_parallel_blobs_do(CodeBlobClosure *f) {
   switch (ShenandoahCodeRootsStyle) {
     case 0: {
       if (_seq_claimed.try_set()) {
         CodeCache::blobs_do(f);
       }
       break;
     }
     case 1: {
       _par_iterator.parallel_blobs_do(f);
       break;
     }
     case 2: {
       ShenandoahCodeRootsIterator::fast_parallel_blobs_do<CSET_FILTER>(f);
       break;
     }
     default:
       ShouldNotReachHere();
   }
 }

 void ShenandoahAllCodeRootsIterator::possibly_parallel_blobs_do(CodeBlobClosure *f) {
   ShenandoahCodeRootsIterator::dispatch_parallel_blobs_do<false>(f);
 }

 void ShenandoahCsetCodeRootsIterator::possibly_parallel_blobs_do(CodeBlobClosure *f) {
   ShenandoahCodeRootsIterator::dispatch_parallel_blobs_do<true>(f);
 }

 template <bool CSET_FILTER>
 void ShenandoahCodeRootsIterator::fast_parallel_blobs_do(CodeBlobClosure *f) {
   assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint");

   size_t stride = 256; // educated guess

   GrowableArray<ShenandoahNMethod*>* list = ShenandoahCodeRoots::_recorded_nms;

   size_t max = (size_t)list->length();
   while (_claimed < max) {
     size_t cur = Atomic::add(stride, &_claimed) - stride;
     size_t start = cur;
     size_t end = MIN2(cur + stride, max);
     if (start >= max) break;

     for (size_t idx = start; idx < end; idx++) {
       ShenandoahNMethod* nmr = list->at((int) idx);
       nmr->assert_alive_and_correct();

       if (CSET_FILTER && !nmr->has_cset_oops(_heap)) {
         continue;
       }

       f->do_code_blob(nmr->nm());
     }
   }
 }

 ShenandoahNMethod::ShenandoahNMethod(nmethod* nm, GrowableArray<oop*>* oops) {
   _nm = nm;
   _oops = NEW_C_HEAP_ARRAY(oop*, oops->length(), mtGC);
   _oops_count = oops->length();
   for (int c = 0; c < _oops_count; c++) {
     _oops[c] = oops->at(c);
   }
 }

 ShenandoahNMethod::~ShenandoahNMethod() {
   if (_oops != NULL) {
     FREE_C_HEAP_ARRAY(oop*, _oops);
   }
 }

 bool ShenandoahNMethod::has_cset_oops(ShenandoahHeap *heap) {
   for (int c = 0; c < _oops_count; c++) {
     oop o = RawAccess<>::oop_load(_oops[c]);
     if (heap->in_collection_set(o)) {
       return true;
     }
   }
   return false;
 }

 #ifdef ASSERT
 void ShenandoahNMethod::assert_alive_and_correct() {
   assert(_nm->is_alive(), "only alive nmethods here");
   assert(_oops_count > 0, "should have filtered nmethods without oops before");
   ShenandoahHeap* heap = ShenandoahHeap::heap();
   for (int c = 0; c < _oops_count; c++) {
     oop *loc = _oops[c];
     assert(_nm->code_contains((address) loc) || _nm->oops_contains(loc), "nmethod should contain the oop*");
     oop o = RawAccess<>::oop_load(loc);
     shenandoah_assert_correct_except(loc, o,
              o == NULL ||
              heap->is_full_gc_move_in_progress() ||
              (VMThread::vm_operation() != NULL) && (VMThread::vm_operation()->type() == VM_Operation::VMOp_HeapWalkOperation)
     );
   }
 }

 void ShenandoahNMethod::assert_same_oops(GrowableArray<oop*>* oops) {
   assert(_oops_count == oops->length(), "should have the same number of oop*");
   for (int c = 0; c < _oops_count; c++) {
     assert(_oops[c] == oops->at(c), "should be the same oop*");
   }
 }
 #endif
	/*
	* Copyright (c) 2017, 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.
	*
	*/

	#include "precompiled.hpp"
	#include "code/codeCache.hpp"
	#include "code/nmethod.hpp"
	#include "gc/shenandoah/shenandoahHeap.inline.hpp"
	#include "gc/shenandoah/shenandoahCodeRoots.hpp"
	#include "gc/shenandoah/shenandoahUtils.hpp"
	#include "memory/resourceArea.hpp"

	ShenandoahParallelCodeCacheIterator::ShenandoahParallelCodeCacheIterator(const GrowableArray<CodeHeap> heaps) {
	_length = heaps->length();
	_iters = NEW_C_HEAP_ARRAY(ShenandoahParallelCodeHeapIterator, _length, mtGC);
	for (int h = 0; h < _length; h++) {
	_iters[h] = ShenandoahParallelCodeHeapIterator(heaps->at(h));
	}
	}

	ShenandoahParallelCodeCacheIterator::~ShenandoahParallelCodeCacheIterator() {
	FREE_C_HEAP_ARRAY(ParallelCodeHeapIterator, _iters);
	}

	void ShenandoahParallelCodeCacheIterator::parallel_blobs_do(CodeBlobClosure* f) {
	for (int c = 0; c < _length; c++) {
	_iters[c].parallel_blobs_do(f);
	}
	}

	ShenandoahParallelCodeHeapIterator::ShenandoahParallelCodeHeapIterator(CodeHeap* heap) :
	_heap(heap), _claimed_idx(0), _finished(false) {
	}

	void ShenandoahParallelCodeHeapIterator::parallel_blobs_do(CodeBlobClosure* f) {
	assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint");

	/*
	* Parallel code heap walk.
	*
	* This code makes all threads scan all code heaps, but only one thread would execute the
	* closure on given blob. This is achieved by recording the "claimed" blocks: if a thread
	* had claimed the block, it can process all blobs in it. Others have to fast-forward to
	* next attempt without processing.
	*
	* Late threads would return immediately if iterator is finished.
	*/

	if (_finished) {
	return;
	}

	int stride = 256; // educated guess
	int stride_mask = stride - 1;
	assert (is_power_of_2(stride), "sanity");

	int count = 0;
	bool process_block = true;

	for (CodeBlob *cb = CodeCache::first_blob(_heap); cb != NULL; cb = CodeCache::next_blob(_heap, cb)) {
	int current = count++;
	if ((current & stride_mask) == 0) {
	process_block = (current >= _claimed_idx) &&
	(Atomic::cmpxchg(current + stride, &_claimed_idx, current) == current);
	}
	if (process_block) {
	if (cb->is_alive()) {
	f->do_code_blob(cb);
	#ifdef ASSERT
	if (cb->is_nmethod())
	Universe::heap()->verify_nmethod((nmethod*)cb);
	#endif
	}
	}
	}

	_finished = true;
	}

	class ShenandoahNMethodOopDetector : public OopClosure {
	private:
	ResourceMark rm; // For growable array allocation below.
	GrowableArray<oop*> _oops;

	public:
	ShenandoahNMethodOopDetector() : _oops(10) {};

	void do_oop(oop* o) {
	_oops.append(o);
	}
	void do_oop(narrowOop* o) {
	fatal("NMethods should not have compressed oops embedded.");
	}

	GrowableArray<oop> oops() {
	return &_oops;
	}

	bool has_oops() {
	return !_oops.is_empty();
	}
	};

	GrowableArray<ShenandoahNMethod> ShenandoahCodeRoots::_recorded_nms;
	ShenandoahLock ShenandoahCodeRoots::_recorded_nms_lock;

	void ShenandoahCodeRoots::initialize() {
	_recorded_nms = new (ResourceObj::C_HEAP, mtGC) GrowableArray<ShenandoahNMethod*>(100, true, mtGC);
	}

	void ShenandoahCodeRoots::add_nmethod(nmethod* nm) {
	switch (ShenandoahCodeRootsStyle) {
	case 0:
	case 1:
	break;
	case 2: {
	assert_locked_or_safepoint(CodeCache_lock);
	ShenandoahLocker locker(CodeCache_lock->owned_by_self() ? NULL : &_recorded_nms_lock);

	ShenandoahNMethodOopDetector detector;
	nm->oops_do(&detector);

	if (detector.has_oops()) {
	ShenandoahNMethod* nmr = new ShenandoahNMethod(nm, detector.oops());
	nmr->assert_alive_and_correct();
	int idx = _recorded_nms->find(nm, ShenandoahNMethod::find_with_nmethod);
	if (idx != -1) {
	ShenandoahNMethod* old = _recorded_nms->at(idx);
	_recorded_nms->at_put(idx, nmr);
	delete old;
	} else {
	_recorded_nms->append(nmr);
	}
	}
	break;
	}
	default:
	ShouldNotReachHere();
	}
	};

	void ShenandoahCodeRoots::remove_nmethod(nmethod* nm) {
	switch (ShenandoahCodeRootsStyle) {
	case 0:
	case 1: {
	break;
	}
	case 2: {
	assert_locked_or_safepoint(CodeCache_lock);
	ShenandoahLocker locker(CodeCache_lock->owned_by_self() ? NULL : &_recorded_nms_lock);

	ShenandoahNMethodOopDetector detector;
	nm->oops_do(&detector, /* allow_zombie = */ true);

	if (detector.has_oops()) {
	int idx = _recorded_nms->find(nm, ShenandoahNMethod::find_with_nmethod);
	assert(idx != -1, "nmethod " PTR_FORMAT " should be registered", p2i(nm));
	ShenandoahNMethod* old = _recorded_nms->at(idx);
	old->assert_same_oops(detector.oops());
	_recorded_nms->delete_at(idx);
	delete old;
	}
	break;
	}
	default:
	ShouldNotReachHere();
	}
	}

	ShenandoahCodeRootsIterator::ShenandoahCodeRootsIterator() :
	_heap(ShenandoahHeap::heap()),
	_par_iterator(CodeCache::heaps()),
	_claimed(0) {
	assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint");
	assert(!Thread::current()->is_Worker_thread(), "Should not be acquired by workers");
	switch (ShenandoahCodeRootsStyle) {
	case 0:
	case 1: {
	// No need to do anything here
	break;
	}
	case 2: {
	CodeCache_lock->lock_without_safepoint_check();
	break;
	}
	default:
	ShouldNotReachHere();
	}
	}

	ShenandoahCodeRootsIterator::~ShenandoahCodeRootsIterator() {
	switch (ShenandoahCodeRootsStyle) {
	case 0:
	case 1: {
	// No need to do anything here
	break;
	}
	case 2: {
	CodeCache_lock->unlock();
	break;
	}
	default:
	ShouldNotReachHere();
	}
	}

	template<bool CSET_FILTER>
	void ShenandoahCodeRootsIterator::dispatch_parallel_blobs_do(CodeBlobClosure *f) {
	switch (ShenandoahCodeRootsStyle) {
	case 0: {
	if (_seq_claimed.try_set()) {
	CodeCache::blobs_do(f);
	}
	break;
	}
	case 1: {
	_par_iterator.parallel_blobs_do(f);
	break;
	}
	case 2: {
	ShenandoahCodeRootsIterator::fast_parallel_blobs_do<CSET_FILTER>(f);
	break;
	}
	default:
	ShouldNotReachHere();
	}
	}

	void ShenandoahAllCodeRootsIterator::possibly_parallel_blobs_do(CodeBlobClosure *f) {
	ShenandoahCodeRootsIterator::dispatch_parallel_blobs_do<false>(f);
	}

	void ShenandoahCsetCodeRootsIterator::possibly_parallel_blobs_do(CodeBlobClosure *f) {
	ShenandoahCodeRootsIterator::dispatch_parallel_blobs_do<true>(f);
	}

	template <bool CSET_FILTER>
	void ShenandoahCodeRootsIterator::fast_parallel_blobs_do(CodeBlobClosure *f) {
	assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint");

	size_t stride = 256; // educated guess

	GrowableArray<ShenandoahNMethod> list = ShenandoahCodeRoots::_recorded_nms;

	size_t max = (size_t)list->length();
	while (_claimed < max) {
	size_t cur = Atomic::add(stride, &_claimed) - stride;
	size_t start = cur;
	size_t end = MIN2(cur + stride, max);
	if (start >= max) break;

	for (size_t idx = start; idx < end; idx++) {
	ShenandoahNMethod* nmr = list->at((int) idx);
	nmr->assert_alive_and_correct();

	if (CSET_FILTER && !nmr->has_cset_oops(_heap)) {
	continue;
	}

	f->do_code_blob(nmr->nm());
	}
	}
	}

	ShenandoahNMethod::ShenandoahNMethod(nmethod* nm, GrowableArray<oop> oops) {
	_nm = nm;
	_oops = NEW_C_HEAP_ARRAY(oop*, oops->length(), mtGC);
	_oops_count = oops->length();
	for (int c = 0; c < _oops_count; c++) {
	_oops[c] = oops->at(c);
	}
	}

	ShenandoahNMethod::~ShenandoahNMethod() {
	if (_oops != NULL) {
	FREE_C_HEAP_ARRAY(oop*, _oops);
	}
	}

	bool ShenandoahNMethod::has_cset_oops(ShenandoahHeap *heap) {
	for (int c = 0; c < _oops_count; c++) {
	oop o = RawAccess<>::oop_load(_oops[c]);
	if (heap->in_collection_set(o)) {
	return true;
	}
	}
	return false;
	}

	#ifdef ASSERT
	void ShenandoahNMethod::assert_alive_and_correct() {
	assert(_nm->is_alive(), "only alive nmethods here");
	assert(_oops_count > 0, "should have filtered nmethods without oops before");
	ShenandoahHeap* heap = ShenandoahHeap::heap();
	for (int c = 0; c < _oops_count; c++) {
	oop *loc = _oops[c];
	assert(_nm->code_contains((address) loc) \|\| _nm->oops_contains(loc), "nmethod should contain the oop*");
	oop o = RawAccess<>::oop_load(loc);
	shenandoah_assert_correct_except(loc, o,
	o == NULL \|\|
	heap->is_full_gc_move_in_progress() \|\|
	(VMThread::vm_operation() != NULL) && (VMThread::vm_operation()->type() == VM_Operation::VMOp_HeapWalkOperation)
	);
	}
	}

	void ShenandoahNMethod::assert_same_oops(GrowableArray<oop> oops) {
	assert(_oops_count == oops->length(), "should have the same number of oop*");
	for (int c = 0; c < _oops_count; c++) {
	assert(_oops[c] == oops->at(c), "should be the same oop*");
	}
	}
	#endif