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 /*

  * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * 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/nmethod.hpp"

 #include "gc_implementation/g1/g1CodeCacheRemSet.hpp"

 #include "memory/iterator.hpp"

 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC

 G1CodeRootChunk::G1CodeRootChunk() : _top(NULL), _next(NULL), _prev(NULL) {

   _top = bottom();

 }

 void G1CodeRootChunk::reset() {

   _next = _prev = NULL;

   _top = bottom();

 }

 void G1CodeRootChunk::nmethods_do(CodeBlobClosure* cl) {

   nmethod** cur = bottom();

   while (cur != _top) {

     cl->do_code_blob(*cur);

     cur++;

   }

 }

 FreeList<G1CodeRootChunk> G1CodeRootSet::_free_list;

 size_t G1CodeRootSet::_num_chunks_handed_out = 0;

 G1CodeRootChunk* G1CodeRootSet::new_chunk() {

   G1CodeRootChunk* result = _free_list.get_chunk_at_head();

   if (result == NULL) {

     result = new G1CodeRootChunk();

   }

   G1CodeRootSet::_num_chunks_handed_out++;

   result->reset();

   return result;

 }

 void G1CodeRootSet::free_chunk(G1CodeRootChunk* chunk) {

   _free_list.return_chunk_at_head(chunk);

   G1CodeRootSet::_num_chunks_handed_out--;

 }

 void G1CodeRootSet::free_all_chunks(FreeList<G1CodeRootChunk>* list) {

   G1CodeRootSet::_num_chunks_handed_out -= list->count();

   _free_list.prepend(list);

 }

 void G1CodeRootSet::purge_chunks(size_t keep_ratio) {

   size_t keep = G1CodeRootSet::_num_chunks_handed_out * keep_ratio / 100;

   if (keep >= (size_t)_free_list.count()) {

     return;

   }

   FreeList<G1CodeRootChunk> temp;

   temp.initialize();

   temp.set_size(G1CodeRootChunk::word_size());

   _free_list.getFirstNChunksFromList((size_t)_free_list.count() - keep, &temp);

   G1CodeRootChunk* cur = temp.get_chunk_at_head();

   while (cur != NULL) {

     delete cur;

     cur = temp.get_chunk_at_head();

   }

 }

 size_t G1CodeRootSet::static_mem_size() {

   return sizeof(_free_list) + sizeof(_num_chunks_handed_out);

 }

 size_t G1CodeRootSet::fl_mem_size() {

   return _free_list.count() * _free_list.size();

 }

 void G1CodeRootSet::initialize() {

   _free_list.initialize();

   _free_list.set_size(G1CodeRootChunk::word_size());

 }

 G1CodeRootSet::G1CodeRootSet() : _list(), _length(0) {

   _list.initialize();

   _list.set_size(G1CodeRootChunk::word_size());

 }

 G1CodeRootSet::~G1CodeRootSet() {

   clear();

 }

 void G1CodeRootSet::add(nmethod* method) {

   if (!contains(method)) {

     // Try to add the nmethod. If there is not enough space, get a new chunk.

     if (_list.head() == NULL || _list.head()->is_full()) {

       G1CodeRootChunk* cur = new_chunk();

       _list.return_chunk_at_head(cur);

     }

     bool result = _list.head()->add(method);

     guarantee(result, err_msg("Not able to add nmethod "PTR_FORMAT" to newly allocated chunk.", method));

     _length++;

   }

 }

 void G1CodeRootSet::remove(nmethod* method) {

   G1CodeRootChunk* found = find(method);

   if (found != NULL) {

     bool result = found->remove(method);

     guarantee(result, err_msg("could not find nmethod "PTR_FORMAT" during removal although we previously found it", method));

     // eventually free completely emptied chunk

     if (found->is_empty()) {

       _list.remove_chunk(found);

       free(found);

     }

     _length--;

   }

   assert(!contains(method), err_msg(PTR_FORMAT" still contains nmethod "PTR_FORMAT, this, method));

 }

 nmethod* G1CodeRootSet::pop() {

   do {

     G1CodeRootChunk* cur = _list.head();

     if (cur == NULL) {

       assert(_length == 0, "when there are no chunks, there should be no elements");

       return NULL;

     }

     nmethod* result = cur->pop();

     if (result != NULL) {

       _length--;

       return result;

     } else {

       free(_list.get_chunk_at_head());

     }

   } while (true);

 }

 G1CodeRootChunk* G1CodeRootSet::find(nmethod* method) {

   G1CodeRootChunk* cur = _list.head();

   while (cur != NULL) {

     if (cur->contains(method)) {

       return cur;

     }

     cur = (G1CodeRootChunk*)cur->next();

   }

   return NULL;

 }

 void G1CodeRootSet::free(G1CodeRootChunk* chunk) {

   free_chunk(chunk);

 }

 bool G1CodeRootSet::contains(nmethod* method) {

   return find(method) != NULL;

 }

 void G1CodeRootSet::clear() {

   free_all_chunks(&_list);

   _length = 0;

 }

 void G1CodeRootSet::nmethods_do(CodeBlobClosure* blk) const {

   G1CodeRootChunk* cur = _list.head();

   while (cur != NULL) {

     cur->nmethods_do(blk);

     cur = (G1CodeRootChunk*)cur->next();

   }

 }

 size_t G1CodeRootSet::mem_size() {

   return sizeof(this) + _list.count() * _list.size();

 }

 #ifndef PRODUCT

 void G1CodeRootSet::test() {

   initialize();

   assert(_free_list.count() == 0, "Free List must be empty");

   assert(_num_chunks_handed_out == 0, "No elements must have been handed out yet");

   // The number of chunks that we allocate for purge testing.

   size_t const num_chunks = 10;

   {

     G1CodeRootSet set1;

     assert(set1.is_empty(), "Code root set must be initially empty but is not.");

     set1.add((nmethod*)1);

     assert(_num_chunks_handed_out == 1,

            err_msg("Must have allocated and handed out one chunk, but handed out "

                    SIZE_FORMAT" chunks", _num_chunks_handed_out));

     assert(set1.length() == 1, err_msg("Added exactly one element, but set contains "

                                        SIZE_FORMAT" elements", set1.length()));

     // G1CodeRootChunk::word_size() is larger than G1CodeRootChunk::num_entries which

     // we cannot access.

     for (uint i = 0; i < G1CodeRootChunk::word_size() + 1; i++) {

       set1.add((nmethod*)1);

     }

     assert(_num_chunks_handed_out == 1,

            err_msg("Duplicate detection must have prevented allocation of further "

                    "chunks but contains "SIZE_FORMAT, _num_chunks_handed_out));

     assert(set1.length() == 1,

            err_msg("Duplicate detection should not have increased the set size but "

                    "is "SIZE_FORMAT, set1.length()));

     size_t num_total_after_add = G1CodeRootChunk::word_size() + 1;

     for (size_t i = 0; i < num_total_after_add - 1; i++) {

       set1.add((nmethod*)(2 + i));

     }

     assert(_num_chunks_handed_out > 1,

            "After adding more code roots, more than one chunks should have been handed out");

     assert(set1.length() == num_total_after_add,

            err_msg("After adding in total "SIZE_FORMAT" distinct code roots, they "

                    "need to be in the set, but there are only "SIZE_FORMAT,

                    num_total_after_add, set1.length()));

     size_t num_popped = 0;

     while (set1.pop() != NULL) {

       num_popped++;

     }

     assert(num_popped == num_total_after_add,

            err_msg("Managed to pop "SIZE_FORMAT" code roots, but only "SIZE_FORMAT" "

                    "were added", num_popped, num_total_after_add));

     assert(_num_chunks_handed_out == 0,

            err_msg("After popping all elements, all chunks must have been returned "

                    "but are still "SIZE_FORMAT, _num_chunks_handed_out));

     purge_chunks(0);

     assert(_free_list.count() == 0,

            err_msg("After purging everything, the free list must be empty but still "

                    "contains "SIZE_FORMAT" chunks", _free_list.count()));

     // Add some more handed out chunks.

     size_t i = 0;

     while (_num_chunks_handed_out < num_chunks) {

       set1.add((nmethod*)i);

       i++;

     }

     {

       // Generate chunks on the free list.

       G1CodeRootSet set2;

       size_t i = 0;

       while (_num_chunks_handed_out < num_chunks * 2) {

         set2.add((nmethod*)i);

         i++;

       }

       // Exit of the scope of the set2 object will call the destructor that generates

       // num_chunks elements on the free list.

     }

     assert(_num_chunks_handed_out == num_chunks,

            err_msg("Deletion of the second set must have resulted in giving back "

                    "those, but there is still "SIZE_FORMAT" handed out, expecting "

                    SIZE_FORMAT, _num_chunks_handed_out, num_chunks));

     assert((size_t)_free_list.count() == num_chunks,

            err_msg("After freeing "SIZE_FORMAT" chunks, they must be on the free list "

                    "but there are only "SIZE_FORMAT, num_chunks, _free_list.count()));

     size_t const test_percentage = 50;

     purge_chunks(test_percentage);

     assert(_num_chunks_handed_out == num_chunks,

            err_msg("Purging must not hand out chunks but there are "SIZE_FORMAT,

                    _num_chunks_handed_out));

     assert((size_t)_free_list.count() == (ssize_t)(num_chunks * test_percentage / 100),

            err_msg("Must have purged "SIZE_FORMAT" percent of "SIZE_FORMAT" chunks"

                    "but there are "SSIZE_FORMAT, test_percentage, num_chunks,

                    _free_list.count()));

     // Purge the remainder of the chunks on the free list.

     purge_chunks(0);

     assert(_free_list.count() == 0, "Free List must be empty");

     assert(_num_chunks_handed_out == num_chunks,

            err_msg("Expected to be "SIZE_FORMAT" chunks handed out from the first set "

                    "but there are "SIZE_FORMAT, num_chunks, _num_chunks_handed_out));

     // Exit of the scope of the set1 object will call the destructor that generates

     // num_chunks additional elements on the free list.

   }

   assert(_num_chunks_handed_out == 0,

          err_msg("Deletion of the only set must have resulted in no chunks handed "

                  "out, but there is still "SIZE_FORMAT" handed out", _num_chunks_handed_out));

   assert((size_t)_free_list.count() == num_chunks,

          err_msg("After freeing "SIZE_FORMAT" chunks, they must be on the free list "

                  "but there are only "SSIZE_FORMAT, num_chunks, _free_list.count()));

   // Restore initial state.

   purge_chunks(0);

   assert(_free_list.count() == 0, "Free List must be empty");

   assert(_num_chunks_handed_out == 0, "No elements must have been handed out yet");

 }

 void TestCodeCacheRemSet_test() {

   G1CodeRootSet::test();

 }

 #endif