Mercurial > hg > graal-compiler
diff src/share/vm/memory/heap.cpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
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children | 82db0859acbe |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/memory/heap.cpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,482 @@ +/* + * Copyright 1997-2006 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, + * CA 95054 USA or visit www.sun.com if you need additional information or + * have any questions. + * + */ + +# include "incls/_precompiled.incl" +# include "incls/_heap.cpp.incl" + + +size_t CodeHeap::header_size() { + return sizeof(HeapBlock); +} + + +// Implementation of Heap + +CodeHeap::CodeHeap() { + _number_of_committed_segments = 0; + _number_of_reserved_segments = 0; + _segment_size = 0; + _log2_segment_size = 0; + _next_segment = 0; + _freelist = NULL; + _free_segments = 0; +} + + +void CodeHeap::mark_segmap_as_free(size_t beg, size_t end) { + assert(0 <= beg && beg < _number_of_committed_segments, "interval begin out of bounds"); + assert(beg < end && end <= _number_of_committed_segments, "interval end out of bounds"); + // setup _segmap pointers for faster indexing + address p = (address)_segmap.low() + beg; + address q = (address)_segmap.low() + end; + // initialize interval + while (p < q) *p++ = 0xFF; +} + + +void CodeHeap::mark_segmap_as_used(size_t beg, size_t end) { + assert(0 <= beg && beg < _number_of_committed_segments, "interval begin out of bounds"); + assert(beg < end && end <= _number_of_committed_segments, "interval end out of bounds"); + // setup _segmap pointers for faster indexing + address p = (address)_segmap.low() + beg; + address q = (address)_segmap.low() + end; + // initialize interval + int i = 0; + while (p < q) { + *p++ = i++; + if (i == 0xFF) i = 1; + } +} + + +static size_t align_to_page_size(size_t size) { + const size_t alignment = (size_t)os::vm_page_size(); + assert(is_power_of_2(alignment), "no kidding ???"); + return (size + alignment - 1) & ~(alignment - 1); +} + + +static size_t align_to_allocation_size(size_t size) { + const size_t alignment = (size_t)os::vm_allocation_granularity(); + assert(is_power_of_2(alignment), "no kidding ???"); + return (size + alignment - 1) & ~(alignment - 1); +} + + +void CodeHeap::on_code_mapping(char* base, size_t size) { +#ifdef LINUX + extern void linux_wrap_code(char* base, size_t size); + linux_wrap_code(base, size); +#endif +} + + +bool CodeHeap::reserve(size_t reserved_size, size_t committed_size, + size_t segment_size) { + assert(reserved_size >= committed_size, "reserved < committed"); + assert(segment_size >= sizeof(FreeBlock), "segment size is too small"); + assert(is_power_of_2(segment_size), "segment_size must be a power of 2"); + + _segment_size = segment_size; + _log2_segment_size = exact_log2(segment_size); + + // Reserve and initialize space for _memory. + const size_t page_size = os::page_size_for_region(committed_size, + reserved_size, 8); + const size_t granularity = os::vm_allocation_granularity(); + const size_t r_align = MAX2(page_size, granularity); + const size_t r_size = align_size_up(reserved_size, r_align); + const size_t c_size = align_size_up(committed_size, page_size); + + const size_t rs_align = page_size == (size_t) os::vm_page_size() ? 0 : + MAX2(page_size, granularity); + ReservedSpace rs(r_size, rs_align, false); + os::trace_page_sizes("code heap", committed_size, reserved_size, page_size, + rs.base(), rs.size()); + if (!_memory.initialize(rs, c_size)) { + return false; + } + + 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()); + assert(_number_of_reserved_segments >= _number_of_committed_segments, "just checking"); + + // reserve space for _segmap + if (!_segmap.initialize(align_to_page_size(_number_of_reserved_segments), align_to_page_size(_number_of_committed_segments))) { + return false; + } + assert(_segmap.committed_size() >= (size_t) _number_of_committed_segments, "could not commit enough space for segment map"); + assert(_segmap.reserved_size() >= (size_t) _number_of_reserved_segments , "could not reserve enough space for segment map"); + assert(_segmap.reserved_size() >= _segmap.committed_size() , "just checking"); + + // initialize remaining instance variables + clear(); + return true; +} + + +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(); + if (dm > 0) { + char* base = _memory.low() + _memory.committed_size(); + 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"); + 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) { + if (!_segmap.expand_by(ds)) return false; + } + assert(_segmap.committed_size() >= (size_t) _number_of_committed_segments, "just checking"); + // initialize additional segmap entries + mark_segmap_as_free(i, _number_of_committed_segments); + } + 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); +} + + +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"); + + // First check if we can satify request from freelist + debug_only(verify()); + HeapBlock* block = search_freelist(length); + debug_only(if (VerifyCodeCacheOften) verify()); + if (block != NULL) { + assert(block->length() >= length && block->length() < length + CodeCacheMinBlockLength, "sanity check"); + assert(!block->free(), "must be marked free"); +#ifdef ASSERT + memset((void *)block->allocated_space(), badCodeHeapNewVal, size); +#endif + return block->allocated_space(); + } + + if (length < CodeCacheMinBlockLength) { + length = CodeCacheMinBlockLength; + } + if (_next_segment + length <= _number_of_committed_segments) { + mark_segmap_as_used(_next_segment, _next_segment + length); + HeapBlock* b = block_at(_next_segment); + b->initialize(length); + _next_segment += length; +#ifdef ASSERT + memset((void *)b->allocated_space(), badCodeHeapNewVal, size); +#endif + return b->allocated_space(); + } else { + return NULL; + } +} + + +void CodeHeap::deallocate(void* p) { + assert(p == find_start(p), "illegal deallocation"); + // Find start of HeapBlock + HeapBlock* b = (((HeapBlock *)p) - 1); + assert(b->allocated_space() == p, "sanity check"); +#ifdef ASSERT + memset((void *)b->allocated_space(), + badCodeHeapFreeVal, + size(b->length()) - sizeof(HeapBlock)); +#endif + add_to_freelist(b); + + debug_only(if (VerifyCodeCacheOften) verify()); +} + + +void* CodeHeap::find_start(void* p) const { + if (!contains(p)) { + return NULL; + } + size_t i = segment_for(p); + address b = (address)_segmap.low(); + if (b[i] == 0xFF) { + return NULL; + } + while (b[i] > 0) i -= (int)b[i]; + HeapBlock* h = block_at(i); + if (h->free()) { + return NULL; + } + return h->allocated_space(); +} + + +size_t CodeHeap::alignment_unit() const { + // this will be a power of two + return _segment_size; +} + + +size_t CodeHeap::alignment_offset() const { + // The lowest address in any allocated block will be + // equal to alignment_offset (mod alignment_unit). + return sizeof(HeapBlock) & (_segment_size - 1); +} + +// Finds the next free heapblock. If the current one is free, that it returned +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); + assert(b == NULL || !b->free(), "must be in use or at end of heap"); + return (b == NULL) ? NULL : b->allocated_space(); +} + +// Returns the first used HeapBlock +HeapBlock* CodeHeap::first_block() const { + if (_next_segment > 0) + return block_at(0); + return NULL; +} + +HeapBlock *CodeHeap::block_start(void *q) const { + HeapBlock* b = (HeapBlock*)find_start(q); + if (b == NULL) return NULL; + return b - 1; +} + +// Returns the next Heap block an offset into one +HeapBlock* CodeHeap::next_block(HeapBlock *b) const { + if (b == NULL) return NULL; + size_t i = segment_for(b) + b->length(); + if (i < _next_segment) + return block_at(i); + return NULL; +} + + +// Returns current capacity +size_t CodeHeap::capacity() const { + return _memory.committed_size(); +} + +size_t CodeHeap::max_capacity() const { + return _memory.reserved_size(); +} + +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; +} + +// Free list management + +FreeBlock *CodeHeap::following_block(FreeBlock *b) { + return (FreeBlock*)(((address)b) + _segment_size * b->length()); +} + +// Inserts block b after a +void CodeHeap::insert_after(FreeBlock* a, FreeBlock* b) { + assert(a != NULL && b != NULL, "must be real pointers"); + + // Link b into the list after a + b->set_link(a->link()); + a->set_link(b); + + // See if we can merge blocks + merge_right(b); // Try to make b bigger + merge_right(a); // Try to make a include b +} + +// Try to merge this block with the following block +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"); + // Update block a to include the following block + a->set_length(a->length() + a->link()->length()); + a->set_link(a->link()->link()); + // Update find_start map + size_t beg = segment_for(a); + mark_segmap_as_used(beg, beg + a->length()); + } +} + +void CodeHeap::add_to_freelist(HeapBlock *a) { + FreeBlock* b = (FreeBlock*)a; + assert(b != _freelist, "cannot be removed twice"); + + // Mark as free and update free space count + _free_segments += b->length(); + b->set_free(); + + // First element in list? + if (_freelist == NULL) { + _freelist = b; + b->set_link(NULL); + return; + } + + // Scan for right place to put into list. List + // is sorted by increasing addresseses + 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); + } else { + insert_after(prev, b); + } +} + +// 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 *best_block = NULL; + FreeBlock *best_prev = NULL; + size_t best_length = 0; + + // Search for smallest block which is bigger than length + FreeBlock *prev = NULL; + FreeBlock *cur = _freelist; + while(cur != NULL) { + size_t l = cur->length(); + if (l >= length && (best_block == NULL || best_length > l)) { + // 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 (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 (best_length < length + CodeCacheMinBlockLength) { + length = best_length; + if (best_prev == NULL) { + assert(_freelist == best_block, "sanity check"); + _freelist = _freelist->link(); + } else { + // Unmap element + 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 + size_t beg = segment_for(best_block); + mark_segmap_as_used(beg, beg + length); + best_block->set_length(length); + } + + best_block->set_used(); + _free_segments -= length; + return best_block; +} + +//---------------------------------------------------------------------------- +// Non-product code + +#ifndef PRODUCT + +void CodeHeap::print() { + tty->print_cr("The Heap"); +} + +#endif + +void CodeHeap::verify() { + // 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 == _free_segments, "wrong freelist"); + + // 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"); +}