Mercurial > hg > truffle
diff src/share/vm/memory/metaspace.cpp @ 12902:bdfbb1fb19ca
8026391: The Metachunk header wastes memory
Reviewed-by: coleenp, jmasa
author | stefank |
---|---|
date | Tue, 15 Oct 2013 14:28:51 +0200 |
parents | a6414751d537 |
children | 94c0343b1887 |
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--- a/src/share/vm/memory/metaspace.cpp Tue Oct 15 07:10:09 2013 -0700 +++ b/src/share/vm/memory/metaspace.cpp Tue Oct 15 14:28:51 2013 +0200 @@ -30,7 +30,6 @@ #include "memory/filemap.hpp" #include "memory/freeList.hpp" #include "memory/gcLocker.hpp" -#include "memory/metablock.hpp" #include "memory/metachunk.hpp" #include "memory/metaspace.hpp" #include "memory/metaspaceShared.hpp" @@ -49,8 +48,8 @@ typedef BinaryTreeDictionary<Metablock, FreeList> BlockTreeDictionary; typedef BinaryTreeDictionary<Metachunk, FreeList> ChunkTreeDictionary; -// Define this macro to enable slow integrity checking of -// the free chunk lists + +// Set this constant to enable slow integrity checking of the free chunk lists const bool metaspace_slow_verify = false; // Parameters for stress mode testing @@ -92,24 +91,9 @@ uint MetaspaceGC::_shrink_factor = 0; bool MetaspaceGC::_should_concurrent_collect = false; -// Blocks of space for metadata are allocated out of Metachunks. -// -// Metachunk are allocated out of MetadataVirtualspaces and once -// allocated there is no explicit link between a Metachunk and -// the MetadataVirtualspaces from which it was allocated. -// -// Each SpaceManager maintains a -// list of the chunks it is using and the current chunk. The current -// chunk is the chunk from which allocations are done. Space freed in -// a chunk is placed on the free list of blocks (BlockFreelist) and -// reused from there. - typedef class FreeList<Metachunk> ChunkList; // Manages the global free lists of chunks. -// Has three lists of free chunks, and a total size and -// count that includes all three - class ChunkManager : public CHeapObj<mtInternal> { // Free list of chunks of different sizes. @@ -119,7 +103,6 @@ // HumongousChunk ChunkList _free_chunks[NumberOfFreeLists]; - // HumongousChunk ChunkTreeDictionary _humongous_dictionary; @@ -230,7 +213,6 @@ // to the allocation of a quantum of metadata). class BlockFreelist VALUE_OBJ_CLASS_SPEC { BlockTreeDictionary* _dictionary; - static Metablock* initialize_free_chunk(MetaWord* p, size_t word_size); // Only allocate and split from freelist if the size of the allocation // is at least 1/4th the size of the available block. @@ -258,6 +240,7 @@ void print_on(outputStream* st) const; }; +// A VirtualSpaceList node. class VirtualSpaceNode : public CHeapObj<mtClass> { friend class VirtualSpaceList; @@ -414,13 +397,13 @@ Metachunk* chunk = first_chunk(); Metachunk* invalid_chunk = (Metachunk*) top(); while (chunk < invalid_chunk ) { - assert(chunk->is_free(), "Should be marked free"); - MetaWord* next = ((MetaWord*)chunk) + chunk->word_size(); - chunk_manager->remove_chunk(chunk); - assert(chunk->next() == NULL && - chunk->prev() == NULL, - "Was not removed from its list"); - chunk = (Metachunk*) next; + assert(chunk->is_tagged_free(), "Should be tagged free"); + MetaWord* next = ((MetaWord*)chunk) + chunk->word_size(); + chunk_manager->remove_chunk(chunk); + assert(chunk->next() == NULL && + chunk->prev() == NULL, + "Was not removed from its list"); + chunk = (Metachunk*) next; } } @@ -434,7 +417,7 @@ // Don't count the chunks on the free lists. Those are // still part of the VirtualSpaceNode but not currently // counted. - if (!chunk->is_free()) { + if (!chunk->is_tagged_free()) { count++; } chunk = (Metachunk*) next; @@ -753,14 +736,11 @@ #endif size_t get_raw_word_size(size_t word_size) { - // If only the dictionary is going to be used (i.e., no - // indexed free list), then there is a minimum size requirement. - // MinChunkSize is a placeholder for the real minimum size JJJ size_t byte_size = word_size * BytesPerWord; - size_t raw_bytes_size = MAX2(byte_size, - Metablock::min_block_byte_size()); - raw_bytes_size = ARENA_ALIGN(raw_bytes_size); + size_t raw_bytes_size = MAX2(byte_size, sizeof(Metablock)); + raw_bytes_size = align_size_up(raw_bytes_size, Metachunk::object_alignment()); + size_t raw_word_size = raw_bytes_size / BytesPerWord; assert(raw_word_size * BytesPerWord == raw_bytes_size, "Size problem"); @@ -813,17 +793,8 @@ } } -Metablock* BlockFreelist::initialize_free_chunk(MetaWord* p, size_t word_size) { - Metablock* block = (Metablock*) p; - block->set_word_size(word_size); - block->set_prev(NULL); - block->set_next(NULL); - - return block; -} - void BlockFreelist::return_block(MetaWord* p, size_t word_size) { - Metablock* free_chunk = initialize_free_chunk(p, word_size); + Metablock* free_chunk = ::new (p) Metablock(word_size); if (dictionary() == NULL) { _dictionary = new BlockTreeDictionary(); } @@ -1069,7 +1040,7 @@ } // Chunk is being removed from the chunks free list. - dec_free_chunks_total(chunk->capacity_word_size()); + dec_free_chunks_total(chunk->word_size()); } // Walk the list of VirtualSpaceNodes and delete @@ -1760,7 +1731,7 @@ chunk->set_next(free_list->head()); free_list->set_head(chunk); // chunk is being returned to the chunk free list - inc_free_chunks_total(chunk->capacity_word_size()); + inc_free_chunks_total(chunk->word_size()); slow_locked_verify(); } @@ -1822,7 +1793,7 @@ } // Chunk is being removed from the chunks free list. - dec_free_chunks_total(chunk->capacity_word_size()); + dec_free_chunks_total(chunk->word_size()); // Remove it from the links to this freelist chunk->set_next(NULL); @@ -1830,7 +1801,7 @@ #ifdef ASSERT // Chunk is no longer on any freelist. Setting to false make container_count_slow() // work. - chunk->set_is_free(false); + chunk->set_is_tagged_free(false); #endif chunk->container()->inc_container_count(); @@ -1962,7 +1933,7 @@ for (ChunkIndex i = ZeroIndex; i < NumberOfInUseLists; i = next_chunk_index(i)) { Metachunk* chunk = chunks_in_use(i); while (chunk != NULL) { - sum += chunk->capacity_word_size(); + sum += chunk->word_size(); chunk = chunk->next(); } } @@ -2210,7 +2181,7 @@ // Capture the next link before it is changed // by the call to return_chunk_at_head(); Metachunk* next = cur->next(); - cur->set_is_free(true); + DEBUG_ONLY(cur->set_is_tagged_free(true);) list->return_chunk_at_head(cur); cur = next; } @@ -2282,7 +2253,7 @@ while (humongous_chunks != NULL) { #ifdef ASSERT - humongous_chunks->set_is_free(true); + humongous_chunks->set_is_tagged_free(true); #endif if (TraceMetadataChunkAllocation && Verbose) { gclog_or_tty->print(PTR_FORMAT " (" SIZE_FORMAT ") ", @@ -2545,7 +2516,7 @@ curr->print_on(out); curr_total += curr->word_size(); used += curr->used_word_size(); - capacity += curr->capacity_word_size(); + capacity += curr->word_size(); waste += curr->free_word_size() + curr->overhead();; } } @@ -3396,7 +3367,7 @@ } -Metablock* Metaspace::allocate(ClassLoaderData* loader_data, size_t word_size, +MetaWord* Metaspace::allocate(ClassLoaderData* loader_data, size_t word_size, bool read_only, MetaspaceObj::Type type, TRAPS) { if (HAS_PENDING_EXCEPTION) { assert(false, "Should not allocate with exception pending"); @@ -3415,10 +3386,14 @@ MetaWord* result = space->allocate(word_size, NonClassType); if (result == NULL) { report_out_of_shared_space(read_only ? SharedReadOnly : SharedReadWrite); - } else { - space->record_allocation(result, type, space->vsm()->get_raw_word_size(word_size)); } - return Metablock::initialize(result, word_size); + + space->record_allocation(result, type, space->vsm()->get_raw_word_size(word_size)); + + // Zero initialize. + Copy::fill_to_aligned_words((HeapWord*)result, word_size, 0); + + return result; } MetadataType mdtype = (type == MetaspaceObj::ClassType) ? ClassType : NonClassType; @@ -3443,7 +3418,10 @@ return NULL; } - return Metablock::initialize(result, word_size); + // Zero initialize. + Copy::fill_to_aligned_words((HeapWord*)result, word_size, 0); + + return result; } void Metaspace::report_metadata_oome(ClassLoaderData* loader_data, size_t word_size, MetadataType mdtype, TRAPS) {