1.1 --- a/src/share/vm/memory/metaspace.cpp Wed Jun 03 14:22:57 2015 +0200
1.2 +++ b/src/share/vm/memory/metaspace.cpp Tue Jun 02 10:09:08 2015 -0400
1.3 @@ -622,8 +622,7 @@
1.4 Metachunk* _chunks_in_use[NumberOfInUseLists];
1.5 Metachunk* _current_chunk;
1.6
1.7 - // Number of small chunks to allocate to a manager
1.8 - // If class space manager, small chunks are unlimited
1.9 + // Maximum number of small chunks to allocate to a SpaceManager
1.10 static uint const _small_chunk_limit;
1.11
1.12 // Sum of all space in allocated chunks
1.13 @@ -737,6 +736,8 @@
1.14 // Block allocation and deallocation.
1.15 // Allocates a block from the current chunk
1.16 MetaWord* allocate(size_t word_size);
1.17 + // Allocates a block from a small chunk
1.18 + MetaWord* get_small_chunk_and_allocate(size_t word_size);
1.19
1.20 // Helper for allocations
1.21 MetaWord* allocate_work(size_t word_size);
1.22 @@ -2031,9 +2032,8 @@
1.23 size_t SpaceManager::calc_chunk_size(size_t word_size) {
1.24
1.25 // Decide between a small chunk and a medium chunk. Up to
1.26 - // _small_chunk_limit small chunks can be allocated but
1.27 - // once a medium chunk has been allocated, no more small
1.28 - // chunks will be allocated.
1.29 + // _small_chunk_limit small chunks can be allocated.
1.30 + // After that a medium chunk is preferred.
1.31 size_t chunk_word_size;
1.32 if (chunks_in_use(MediumIndex) == NULL &&
1.33 sum_count_in_chunks_in_use(SmallIndex) < _small_chunk_limit) {
1.34 @@ -2101,7 +2101,7 @@
1.35 word_size, words_used, words_left);
1.36 }
1.37
1.38 - // Get another chunk out of the virtual space
1.39 + // Get another chunk
1.40 size_t grow_chunks_by_words = calc_chunk_size(word_size);
1.41 Metachunk* next = get_new_chunk(word_size, grow_chunks_by_words);
1.42
1.43 @@ -2432,6 +2432,43 @@
1.44 return next;
1.45 }
1.46
1.47 +/*
1.48 + * The policy is to allocate up to _small_chunk_limit small chunks
1.49 + * after which only medium chunks are allocated. This is done to
1.50 + * reduce fragmentation. In some cases, this can result in a lot
1.51 + * of small chunks being allocated to the point where it's not
1.52 + * possible to expand. If this happens, there may be no medium chunks
1.53 + * available and OOME would be thrown. Instead of doing that,
1.54 + * if the allocation request size fits in a small chunk, an attempt
1.55 + * will be made to allocate a small chunk.
1.56 + */
1.57 +MetaWord* SpaceManager::get_small_chunk_and_allocate(size_t word_size) {
1.58 + if (word_size + Metachunk::overhead() > small_chunk_size()) {
1.59 + return NULL;
1.60 + }
1.61 +
1.62 + MutexLockerEx cl(lock(), Mutex::_no_safepoint_check_flag);
1.63 + MutexLockerEx cl1(expand_lock(), Mutex::_no_safepoint_check_flag);
1.64 +
1.65 + Metachunk* chunk = chunk_manager()->chunk_freelist_allocate(small_chunk_size());
1.66 +
1.67 + MetaWord* mem = NULL;
1.68 +
1.69 + if (chunk != NULL) {
1.70 + // Add chunk to the in-use chunk list and do an allocation from it.
1.71 + // Add to this manager's list of chunks in use.
1.72 + add_chunk(chunk, false);
1.73 + mem = chunk->allocate(word_size);
1.74 +
1.75 + inc_used_metrics(word_size);
1.76 +
1.77 + // Track metaspace memory usage statistic.
1.78 + track_metaspace_memory_usage();
1.79 + }
1.80 +
1.81 + return mem;
1.82 +}
1.83 +
1.84 MetaWord* SpaceManager::allocate(size_t word_size) {
1.85 MutexLockerEx cl(lock(), Mutex::_no_safepoint_check_flag);
1.86
1.87 @@ -3511,7 +3548,18 @@
1.88 }
1.89
1.90 if (result == NULL) {
1.91 - report_metadata_oome(loader_data, word_size, type, mdtype, CHECK_NULL);
1.92 + SpaceManager* sm;
1.93 + if (is_class_space_allocation(mdtype)) {
1.94 + sm = loader_data->metaspace_non_null()->class_vsm();
1.95 + } else {
1.96 + sm = loader_data->metaspace_non_null()->vsm();
1.97 + }
1.98 +
1.99 + result = sm->get_small_chunk_and_allocate(word_size);
1.100 +
1.101 + if (result == NULL) {
1.102 + report_metadata_oome(loader_data, word_size, type, mdtype, CHECK_NULL);
1.103 + }
1.104 }
1.105
1.106 // Zero initialize.
