Mercurial > hg > graal-compiler
diff src/share/vm/memory/heap.cpp @ 14726:92aa6797d639
Backed out merge changeset: b51e29501f30
Backed out merge revision to its first parent (8f483e200405)
author | Doug Simon <doug.simon@oracle.com> |
---|---|
date | Mon, 24 Mar 2014 21:30:43 +0100 |
parents | b51e29501f30 |
children |
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--- a/src/share/vm/memory/heap.cpp Fri Mar 21 16:36:59 2014 -0700 +++ b/src/share/vm/memory/heap.cpp Mon Mar 24 21:30:43 2014 +0100 @@ -43,7 +43,6 @@ _next_segment = 0; _freelist = NULL; _freelist_segments = 0; - _freelist_length = 0; } @@ -54,7 +53,7 @@ address p = (address)_segmap.low() + beg; address q = (address)_segmap.low() + end; // initialize interval - while (p < q) *p++ = free_sentinel; + while (p < q) *p++ = 0xFF; } @@ -68,7 +67,7 @@ int i = 0; while (p < q) { *p++ = i++; - if (i == free_sentinel) i = 1; + if (i == 0xFF) i = 1; } } @@ -140,6 +139,11 @@ } +void CodeHeap::release() { + Unimplemented(); +} + + bool CodeHeap::expand_by(size_t size) { // expand _memory space size_t dm = align_to_page_size(_memory.committed_size() + size) - _memory.committed_size(); @@ -153,8 +157,8 @@ 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(); - if ((ds > 0) && !_segmap.expand_by(ds)) { - return false; + if (ds > 0) { + if (!_segmap.expand_by(ds)) return false; } assert(_segmap.committed_size() >= (size_t) _number_of_committed_segments, "just checking"); // initialize additional segmap entries @@ -163,6 +167,12 @@ return true; } + +void CodeHeap::shrink_by(size_t size) { + Unimplemented(); +} + + void CodeHeap::clear() { _next_segment = 0; mark_segmap_as_free(0, _number_of_committed_segments); @@ -170,23 +180,26 @@ void* CodeHeap::allocate(size_t instance_size, bool is_critical) { - size_t number_of_segments = size_to_segments(instance_size + header_size()); + 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 satisfy request from freelist - NOT_PRODUCT(verify()); + debug_only(verify()); HeapBlock* block = search_freelist(number_of_segments, is_critical); - NOT_PRODUCT(verify()); - + debug_only(if (VerifyCodeCacheOften) verify()); if (block != NULL) { assert(block->length() >= number_of_segments && block->length() < number_of_segments + CodeCacheMinBlockLength, "sanity check"); assert(!block->free(), "must be marked free"); - DEBUG_ONLY(memset((void*)block->allocated_space(), badCodeHeapNewVal, instance_size)); +#ifdef ASSERT + memset((void *)block->allocated_space(), badCodeHeapNewVal, instance_size); +#endif return block->allocated_space(); } // Ensure minimum size for allocation to the heap. - number_of_segments = MAX2((int)CodeCacheMinBlockLength, (int)number_of_segments); + if (number_of_segments < CodeCacheMinBlockLength) { + number_of_segments = CodeCacheMinBlockLength; + } if (!is_critical) { // Make sure the allocation fits in the unallocated heap without using @@ -202,7 +215,9 @@ HeapBlock* b = block_at(_next_segment); b->initialize(number_of_segments); _next_segment += number_of_segments; - DEBUG_ONLY(memset((void *)b->allocated_space(), badCodeHeapNewVal, instance_size)); +#ifdef ASSERT + memset((void *)b->allocated_space(), badCodeHeapNewVal, instance_size); +#endif return b->allocated_space(); } else { return NULL; @@ -215,56 +230,28 @@ // Find start of HeapBlock HeapBlock* b = (((HeapBlock *)p) - 1); assert(b->allocated_space() == p, "sanity check"); - DEBUG_ONLY(memset((void *)b->allocated_space(), badCodeHeapFreeVal, - segments_to_size(b->length()) - sizeof(HeapBlock))); +#ifdef ASSERT + memset((void *)b->allocated_space(), + badCodeHeapFreeVal, + segments_to_size(b->length()) - sizeof(HeapBlock)); +#endif add_to_freelist(b); - NOT_PRODUCT(verify()); + + debug_only(if (VerifyCodeCacheOften) verify()); } -/** - * Uses segment map to find the the start (header) of a nmethod. This works as follows: - * The memory of the code cache is divided into 'segments'. The size of a segment is - * determined by -XX:CodeCacheSegmentSize=XX. Allocation in the code cache can only - * happen at segment boundaries. A pointer in the code cache can be mapped to a segment - * by calling segment_for(addr). Each time memory is requested from the code cache, - * the segmap is updated accordingly. See the following example, which illustrates the - * state of code cache and the segment map: (seg -> segment, nm ->nmethod) - * - * code cache segmap - * ----------- --------- - * seg 1 | nm 1 | -> | 0 | - * seg 2 | nm 1 | -> | 1 | - * ... | nm 1 | -> | .. | - * seg m | nm 2 | -> | 0 | - * seg m+1 | nm 2 | -> | 1 | - * ... | nm 2 | -> | 2 | - * ... | nm 2 | -> | .. | - * ... | nm 2 | -> | 0xFE | - * seg m+n | nm 2 | -> | 1 | - * ... | nm 2 | -> | | - * - * A value of '0' in the segmap indicates that this segment contains the beginning of - * an nmethod. Let's walk through a simple example: If we want to find the start of - * an nmethod that falls into seg 2, we read the value of the segmap[2]. The value - * is an offset that points to the segment that contains the start of the nmethod. - * Another example: If we want to get the start of nm 2, and we happen to get a pointer - * that points to seg m+n, we first read seg[n+m], which returns '1'. So we have to - * do one more read of the segmap[m+n-1] to finally get the segment header. - */ + void* CodeHeap::find_start(void* p) const { if (!contains(p)) { return NULL; } - size_t seg_idx = segment_for(p); - address seg_map = (address)_segmap.low(); - if (is_segment_unused(seg_map[seg_idx])) { + size_t i = segment_for(p); + address b = (address)_segmap.low(); + if (b[i] == 0xFF) { return NULL; } - while (seg_map[seg_idx] > 0) { - seg_idx -= (int)seg_map[seg_idx]; - } - - HeapBlock* h = block_at(seg_idx); + while (b[i] > 0) i -= (int)b[i]; + HeapBlock* h = block_at(i); if (h->free()) { return NULL; } @@ -285,7 +272,7 @@ } // Finds the next free heapblock. If the current one is free, that it returned -void* CodeHeap::next_free(HeapBlock* b) const { +void* CodeHeap::next_free(HeapBlock *b) const { // Since free blocks are merged, there is max. on free block // between two used ones if (b != NULL && b->free()) b = next_block(b); @@ -300,7 +287,7 @@ return NULL; } -HeapBlock* CodeHeap::block_start(void* q) const { +HeapBlock *CodeHeap::block_start(void *q) const { HeapBlock* b = (HeapBlock*)find_start(q); if (b == NULL) return NULL; return b - 1; @@ -325,10 +312,6 @@ return _memory.reserved_size(); } -int CodeHeap::allocated_segments() const { - return (int)_next_segment; -} - size_t CodeHeap::allocated_capacity() const { // size of used heap - size on freelist return segments_to_size(_next_segment - _freelist_segments); @@ -342,7 +325,7 @@ // Free list management -FreeBlock* CodeHeap::following_block(FreeBlock *b) { +FreeBlock *CodeHeap::following_block(FreeBlock *b) { return (FreeBlock*)(((address)b) + _segment_size * b->length()); } @@ -360,7 +343,7 @@ } // Try to merge this block with the following block -bool CodeHeap::merge_right(FreeBlock* a) { +void CodeHeap::merge_right(FreeBlock *a) { assert(a->free(), "must be a free block"); if (following_block(a) == a->link()) { assert(a->link() != NULL && a->link()->free(), "must be free too"); @@ -370,20 +353,13 @@ // Update find_start map size_t beg = segment_for(a); mark_segmap_as_used(beg, beg + a->length()); - _freelist_length--; - return true; } - return false; } - -void CodeHeap::add_to_freelist(HeapBlock* a) { +void CodeHeap::add_to_freelist(HeapBlock *a) { FreeBlock* b = (FreeBlock*)a; - _freelist_length++; - assert(b != _freelist, "cannot be removed twice"); - // Mark as free and update free space count _freelist_segments += b->length(); b->set_free(); @@ -395,96 +371,95 @@ return; } - // Since the freelist is ordered (smaller addresses -> larger addresses) and the - // element we want to insert into the freelist has a smaller address than the first - // element, we can simply add 'b' as the first element and we are done. - if (b < _freelist) { + // Scan for right place to put into list. List + // is sorted by increasing addresses + FreeBlock* prev = NULL; + FreeBlock* cur = _freelist; + while(cur != NULL && cur < b) { + assert(prev == NULL || prev < cur, "must be ordered"); + prev = cur; + cur = cur->link(); + } + + assert( (prev == NULL && b < _freelist) || + (prev < b && (cur == NULL || b < cur)), "list must be ordered"); + + if (prev == NULL) { // Insert first in list b->set_link(_freelist); _freelist = b; merge_right(_freelist); - return; + } else { + insert_after(prev, b); } - - // Scan for right place to put into list. List - // is sorted by increasing addresses - FreeBlock* prev = _freelist; - FreeBlock* cur = _freelist->link(); - while(cur != NULL && cur < b) { - assert(prev < cur, "Freelist must be ordered"); - prev = cur; - cur = cur->link(); - } - assert((prev < b) && (cur == NULL || b < cur), "free-list must be ordered"); - insert_after(prev, b); } -/** - * Search freelist for an entry on the list with the best fit. - * @return NULL, if no one was found - */ +// 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, bool is_critical) { - FreeBlock* found_block = NULL; - FreeBlock* found_prev = NULL; - size_t found_length = 0; + FreeBlock *best_block = NULL; + FreeBlock *best_prev = NULL; + size_t best_length = 0; - FreeBlock* prev = NULL; - FreeBlock* cur = _freelist; - const size_t critical_boundary = (size_t)high_boundary() - CodeCacheMinimumFreeSpace; - - // Search for first block that fits + // Search for smallest block which is bigger than length + FreeBlock *prev = NULL; + FreeBlock *cur = _freelist; while(cur != NULL) { - if (cur->length() >= length) { + 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. - // Make sure the end of the allocation doesn't cross into the last part of the code heap. - if (!is_critical && (((size_t)cur + length) > critical_boundary)) { - // The freelist is sorted by address - if one fails, all consecutive will also fail. - break; + 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 block, its previous element, and its length - found_block = cur; - found_prev = prev; - found_length = found_block->length(); - break; + // Remember best block, its previous element, and its length + best_block = cur; + best_prev = prev; + best_length = best_block->length(); } + // Next element in list prev = cur; cur = cur->link(); } - if (found_block == NULL) { + if (best_block == NULL) { // None found return NULL; } + assert((best_prev == NULL && _freelist == best_block ) || + (best_prev != NULL && best_prev->link() == best_block), "sanity check"); + // Exact (or at least good enough) fit. Remove from list. // Don't leave anything on the freelist smaller than CodeCacheMinBlockLength. - if (found_length - length < CodeCacheMinBlockLength) { - _freelist_length--; - length = found_length; - if (found_prev == NULL) { - assert(_freelist == found_block, "sanity check"); + if (best_length < length + CodeCacheMinBlockLength) { + length = best_length; + if (best_prev == NULL) { + assert(_freelist == best_block, "sanity check"); _freelist = _freelist->link(); } else { - assert((found_prev->link() == found_block), "sanity check"); // Unmap element - found_prev->set_link(found_block->link()); + best_prev->set_link(best_block->link()); } } else { // Truncate block and return a pointer to the following block + best_block->set_length(best_length - length); + best_block = following_block(best_block); // Set used bit and length on new block - found_block->set_length(found_length - length); - found_block = following_block(found_block); - - size_t beg = segment_for(found_block); + size_t beg = segment_for(best_block); mark_segmap_as_used(beg, beg + length); - found_block->set_length(length); + best_block->set_length(length); } - found_block->set_used(); + best_block->set_used(); _freelist_segments -= length; - return found_block; + return best_block; } //---------------------------------------------------------------------------- @@ -496,34 +471,33 @@ tty->print_cr("The Heap"); } +#endif + void CodeHeap::verify() { - if (VerifyCodeCache) { - size_t len = 0; - int count = 0; - for(FreeBlock* b = _freelist; b != NULL; b = b->link()) { - len += b->length(); - count++; - // Check if we have merged all free blocks - assert(merge_right(b) == false, "Missed merging opportunity"); - } - // Verify that freelist contains the right amount of free space - assert(len == _freelist_segments, "wrong freelist"); + // Count the number of blocks on the freelist, and the amount of space + // represented. + int count = 0; + size_t len = 0; + for(FreeBlock* b = _freelist; b != NULL; b = b->link()) { + len += b->length(); + count++; + } + + // Verify that freelist contains the right amount of free space + // guarantee(len == _freelist_segments, "wrong freelist"); - for(HeapBlock* h = first_block(); h != NULL; h = next_block(h)) { - if (h->free()) count--; - } - // Verify that the freelist contains the same number of blocks - // than free blocks found on the full list. - assert(count == 0, "missing free blocks"); + // Verify that the number of free blocks is not out of hand. + static int free_block_threshold = 10000; + if (count > free_block_threshold) { + warning("CodeHeap: # of free blocks > %d", free_block_threshold); + // Double the warning limit + free_block_threshold *= 2; + } - // Verify that the number of free blocks is not out of hand. - static int free_block_threshold = 10000; - if (count > free_block_threshold) { - warning("CodeHeap: # of free blocks > %d", free_block_threshold); - // Double the warning limit - free_block_threshold *= 2; - } + // Verify that the freelist contains the same number of free blocks that is + // found on the full list. + for(HeapBlock *h = first_block(); h != NULL; h = next_block(h)) { + if (h->free()) count--; } + // guarantee(count == 0, "missing free blocks"); } - -#endif