Mercurial > hg > graal-compiler
diff src/share/vm/memory/heap.cpp @ 10114:a7fb14888912
8006952: Slow VM due to excessive code cache freelist iteration
Summary: Remove continous free block requirement
Reviewed-by: kvn
author | neliasso |
---|---|
date | Thu, 11 Apr 2013 13:57:44 +0200 |
parents | cc32ccaaf47f |
children | 836a62f43af9 740e263c80c6 |
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--- a/src/share/vm/memory/heap.cpp Tue Apr 16 10:04:01 2013 -0700 +++ b/src/share/vm/memory/heap.cpp Thu Apr 11 13:57:44 2013 +0200 @@ -42,7 +42,7 @@ _log2_segment_size = 0; _next_segment = 0; _freelist = NULL; - _free_segments = 0; + _freelist_segments = 0; } @@ -115,8 +115,8 @@ } on_code_mapping(_memory.low(), _memory.committed_size()); - _number_of_committed_segments = number_of_segments(_memory.committed_size()); - _number_of_reserved_segments = number_of_segments(_memory.reserved_size()); + _number_of_committed_segments = size_to_segments(_memory.committed_size()); + _number_of_reserved_segments = size_to_segments(_memory.reserved_size()); assert(_number_of_reserved_segments >= _number_of_committed_segments, "just checking"); // reserve space for _segmap @@ -149,8 +149,8 @@ if (!_memory.expand_by(dm)) return false; on_code_mapping(base, dm); size_t i = _number_of_committed_segments; - _number_of_committed_segments = number_of_segments(_memory.committed_size()); - assert(_number_of_reserved_segments == number_of_segments(_memory.reserved_size()), "number of reserved segments should not change"); + _number_of_committed_segments = size_to_segments(_memory.committed_size()); + assert(_number_of_reserved_segments == size_to_segments(_memory.reserved_size()), "number of reserved segments should not change"); assert(_number_of_reserved_segments >= _number_of_committed_segments, "just checking"); // expand _segmap space size_t ds = align_to_page_size(_number_of_committed_segments) - _segmap.committed_size(); @@ -176,33 +176,44 @@ } -void* CodeHeap::allocate(size_t size) { - size_t length = number_of_segments(size + sizeof(HeapBlock)); - assert(length *_segment_size >= sizeof(FreeBlock), "not enough room for FreeList"); +void* CodeHeap::allocate(size_t instance_size, bool is_critical) { + size_t number_of_segments = size_to_segments(instance_size + sizeof(HeapBlock)); + assert(segments_to_size(number_of_segments) >= sizeof(FreeBlock), "not enough room for FreeList"); // First check if we can satify request from freelist debug_only(verify()); - HeapBlock* block = search_freelist(length); + HeapBlock* block = search_freelist(number_of_segments, is_critical); debug_only(if (VerifyCodeCacheOften) verify()); if (block != NULL) { - assert(block->length() >= length && block->length() < length + CodeCacheMinBlockLength, "sanity check"); + assert(block->length() >= number_of_segments && block->length() < number_of_segments + CodeCacheMinBlockLength, "sanity check"); assert(!block->free(), "must be marked free"); #ifdef ASSERT - memset((void *)block->allocated_space(), badCodeHeapNewVal, size); + memset((void *)block->allocated_space(), badCodeHeapNewVal, instance_size); #endif return block->allocated_space(); } - if (length < CodeCacheMinBlockLength) { - length = CodeCacheMinBlockLength; + // Ensure minimum size for allocation to the heap. + if (number_of_segments < CodeCacheMinBlockLength) { + number_of_segments = CodeCacheMinBlockLength; } - if (_next_segment + length <= _number_of_committed_segments) { - mark_segmap_as_used(_next_segment, _next_segment + length); + + if (!is_critical) { + // Make sure the allocation fits in the unallocated heap without using + // the CodeCacheMimimumFreeSpace that is reserved for critical allocations. + if (segments_to_size(number_of_segments) > (heap_unallocated_capacity() - CodeCacheMinimumFreeSpace)) { + // Fail allocation + return NULL; + } + } + + if (_next_segment + number_of_segments <= _number_of_committed_segments) { + mark_segmap_as_used(_next_segment, _next_segment + number_of_segments); HeapBlock* b = block_at(_next_segment); - b->initialize(length); - _next_segment += length; + b->initialize(number_of_segments); + _next_segment += number_of_segments; #ifdef ASSERT - memset((void *)b->allocated_space(), badCodeHeapNewVal, size); + memset((void *)b->allocated_space(), badCodeHeapNewVal, instance_size); #endif return b->allocated_space(); } else { @@ -219,7 +230,7 @@ #ifdef ASSERT memset((void *)b->allocated_space(), badCodeHeapFreeVal, - size(b->length()) - sizeof(HeapBlock)); + segments_to_size(b->length()) - sizeof(HeapBlock)); #endif add_to_freelist(b); @@ -299,32 +310,14 @@ } size_t CodeHeap::allocated_capacity() const { - // Start with the committed size in _memory; - size_t l = _memory.committed_size(); - - // Subtract the committed, but unused, segments - l -= size(_number_of_committed_segments - _next_segment); - - // Subtract the size of the freelist - l -= size(_free_segments); - - return l; + // size of used heap - size on freelist + return segments_to_size(_next_segment - _freelist_segments); } -size_t CodeHeap::largest_free_block() const { - // First check unused space excluding free blocks. - size_t free_sz = size(_free_segments); - size_t unused = max_capacity() - allocated_capacity() - free_sz; - if (unused >= free_sz) - return unused; - - // Now check largest free block. - size_t len = 0; - for (FreeBlock* b = _freelist; b != NULL; b = b->link()) { - if (b->length() > len) - len = b->length(); - } - return MAX2(unused, size(len)); +// Returns size of the unallocated heap block +size_t CodeHeap::heap_unallocated_capacity() const { + // Total number of segments - number currently used + return segments_to_size(_number_of_reserved_segments - _next_segment); } // Free list management @@ -365,7 +358,7 @@ assert(b != _freelist, "cannot be removed twice"); // Mark as free and update free space count - _free_segments += b->length(); + _freelist_segments += b->length(); b->set_free(); // First element in list? @@ -400,7 +393,7 @@ // Search freelist for an entry on the list with the best fit // Return NULL if no one was found -FreeBlock* CodeHeap::search_freelist(size_t length) { +FreeBlock* CodeHeap::search_freelist(size_t length, bool is_critical) { FreeBlock *best_block = NULL; FreeBlock *best_prev = NULL; size_t best_length = 0; @@ -411,6 +404,16 @@ while(cur != NULL) { size_t l = cur->length(); if (l >= length && (best_block == NULL || best_length > l)) { + + // Non critical allocations are not allowed to use the last part of the code heap. + if (!is_critical) { + // Make sure the end of the allocation doesn't cross into the last part of the code heap + if (((size_t)cur + length) > ((size_t)high_boundary() - CodeCacheMinimumFreeSpace)) { + // the freelist is sorted by address - if one fails, all consecutive will also fail. + break; + } + } + // Remember best block, its previous element, and its length best_block = cur; best_prev = prev; @@ -452,7 +455,7 @@ } best_block->set_used(); - _free_segments -= length; + _freelist_segments -= length; return best_block; } @@ -478,7 +481,7 @@ } // Verify that freelist contains the right amount of free space - // guarantee(len == _free_segments, "wrong freelist"); + // guarantee(len == _freelist_segments, "wrong freelist"); // Verify that the number of free blocks is not out of hand. static int free_block_threshold = 10000;