| /* |
| * Copyright (c) 1997, 2015, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #include "precompiled.hpp" |
| #include "memory/heap.hpp" |
| #include "oops/oop.inline.hpp" |
| #include "runtime/os.hpp" |
| #include "services/memTracker.hpp" |
| #include "utilities/align.hpp" |
| |
| size_t CodeHeap::header_size() { |
| return sizeof(HeapBlock); |
| } |
| |
| |
| // Implementation of Heap |
| |
| CodeHeap::CodeHeap(const char* name, const int code_blob_type) |
| : _code_blob_type(code_blob_type) { |
| _name = name; |
| _number_of_committed_segments = 0; |
| _number_of_reserved_segments = 0; |
| _segment_size = 0; |
| _log2_segment_size = 0; |
| _next_segment = 0; |
| _freelist = NULL; |
| _freelist_segments = 0; |
| _freelist_length = 0; |
| _max_allocated_capacity = 0; |
| _blob_count = 0; |
| _nmethod_count = 0; |
| _adapter_count = 0; |
| _full_count = 0; |
| } |
| |
| |
| void CodeHeap::mark_segmap_as_free(size_t beg, size_t end) { |
| assert( 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++ = free_sentinel; |
| } |
| |
| |
| void CodeHeap::mark_segmap_as_used(size_t beg, size_t end) { |
| assert( 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 == free_sentinel) 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); |
| } |
| |
| |
| 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(ReservedSpace rs, size_t committed_size, size_t segment_size) { |
| assert(rs.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. |
| size_t page_size = os::vm_page_size(); |
| if (os::can_execute_large_page_memory()) { |
| const size_t min_pages = 8; |
| page_size = MIN2(os::page_size_for_region_aligned(committed_size, min_pages), |
| os::page_size_for_region_aligned(rs.size(), min_pages)); |
| } |
| |
| const size_t granularity = os::vm_allocation_granularity(); |
| const size_t c_size = align_up(committed_size, page_size); |
| |
| os::trace_page_sizes(_name, committed_size, rs.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 = 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"); |
| const size_t reserved_segments_alignment = MAX2((size_t)os::vm_page_size(), granularity); |
| const size_t reserved_segments_size = align_up(_number_of_reserved_segments, reserved_segments_alignment); |
| const size_t committed_segments_size = align_to_page_size(_number_of_committed_segments); |
| |
| // reserve space for _segmap |
| if (!_segmap.initialize(reserved_segments_size, committed_segments_size)) { |
| return false; |
| } |
| |
| MemTracker::record_virtual_memory_type((address)_segmap.low_boundary(), mtCode); |
| |
| 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; |
| } |
| |
| |
| 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) { |
| // Use at least the available uncommitted space if 'size' is larger |
| if (_memory.uncommitted_size() != 0 && dm > _memory.uncommitted_size()) { |
| dm = _memory.uncommitted_size(); |
| } |
| 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 = 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(); |
| if ((ds > 0) && !_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::clear() { |
| _next_segment = 0; |
| mark_segmap_as_free(0, _number_of_committed_segments); |
| } |
| |
| |
| void* CodeHeap::allocate(size_t instance_size) { |
| size_t number_of_segments = size_to_segments(instance_size + header_size()); |
| 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()); |
| HeapBlock* block = search_freelist(number_of_segments); |
| NOT_PRODUCT(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"); |
| guarantee((char*) block >= _memory.low_boundary() && (char*) block < _memory.high(), |
| "The newly allocated block " INTPTR_FORMAT " is not within the heap " |
| "starting with " INTPTR_FORMAT " and ending with " INTPTR_FORMAT, |
| p2i(block), p2i(_memory.low_boundary()), p2i(_memory.high())); |
| DEBUG_ONLY(memset((void*)block->allocated_space(), badCodeHeapNewVal, instance_size)); |
| _max_allocated_capacity = MAX2(_max_allocated_capacity, allocated_capacity()); |
| _blob_count++; |
| return block->allocated_space(); |
| } |
| |
| // Ensure minimum size for allocation to the heap. |
| number_of_segments = MAX2((int)CodeCacheMinBlockLength, (int)number_of_segments); |
| |
| 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(number_of_segments); |
| _next_segment += number_of_segments; |
| guarantee((char*) b >= _memory.low_boundary() && (char*) block < _memory.high(), |
| "The newly allocated block " INTPTR_FORMAT " is not within the heap " |
| "starting with " INTPTR_FORMAT " and ending with " INTPTR_FORMAT, |
| p2i(b), p2i(_memory.low_boundary()), p2i(_memory.high())); |
| DEBUG_ONLY(memset((void *)b->allocated_space(), badCodeHeapNewVal, instance_size)); |
| _max_allocated_capacity = MAX2(_max_allocated_capacity, allocated_capacity()); |
| _blob_count++; |
| 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"); |
| guarantee((char*) b >= _memory.low_boundary() && (char*) b < _memory.high(), |
| "The block to be deallocated " INTPTR_FORMAT " is not within the heap " |
| "starting with " INTPTR_FORMAT " and ending with " INTPTR_FORMAT, |
| p2i(b), p2i(_memory.low_boundary()), p2i(_memory.high())); |
| DEBUG_ONLY(memset((void *)b->allocated_space(), badCodeHeapFreeVal, |
| segments_to_size(b->length()) - sizeof(HeapBlock))); |
| add_to_freelist(b); |
| NOT_PRODUCT(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])) { |
| return NULL; |
| } |
| while (seg_map[seg_idx] > 0) { |
| seg_idx -= (int)seg_map[seg_idx]; |
| } |
| |
| HeapBlock* h = block_at(seg_idx); |
| if (h->free()) { |
| return NULL; |
| } |
| return h->allocated_space(); |
| } |
| |
| CodeBlob* CodeHeap::find_blob_unsafe(void* start) const { |
| CodeBlob* result = (CodeBlob*)CodeHeap::find_start(start); |
| if (result != NULL && result->blob_contains((address)start)) { |
| return result; |
| } |
| return NULL; |
| } |
| |
| 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); |
| } |
| |
| // Returns the current block if available and used. |
| // If not, it returns the subsequent block (if available), NULL otherwise. |
| // Free blocks are merged, therefore there is at most one free block |
| // between two used ones. As a result, the subsequent block (if available) is |
| // guaranteed to be used. |
| void* CodeHeap::next_used(HeapBlock* b) const { |
| 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(); |
| } |
| |
| 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); |
| } |
| |
| // 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 |
| |
| 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 |
| bool 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()); |
| _freelist_length--; |
| return true; |
| } |
| return false; |
| } |
| |
| |
| 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(); |
| |
| // First element in list? |
| if (_freelist == NULL) { |
| _freelist = b; |
| b->set_link(NULL); |
| 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) { |
| // Insert first in list |
| b->set_link(_freelist); |
| _freelist = b; |
| merge_right(_freelist); |
| return; |
| } |
| |
| // 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 |
| */ |
| FreeBlock* CodeHeap::search_freelist(size_t length) { |
| FreeBlock* found_block = NULL; |
| FreeBlock* found_prev = NULL; |
| size_t found_length = 0; |
| |
| FreeBlock* prev = NULL; |
| FreeBlock* cur = _freelist; |
| |
| // Search for first block that fits |
| while(cur != NULL) { |
| if (cur->length() >= length) { |
| // Remember block, its previous element, and its length |
| found_block = cur; |
| found_prev = prev; |
| found_length = found_block->length(); |
| |
| break; |
| } |
| // Next element in list |
| prev = cur; |
| cur = cur->link(); |
| } |
| |
| if (found_block == NULL) { |
| // None found |
| return NULL; |
| } |
| |
| // 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"); |
| _freelist = _freelist->link(); |
| } else { |
| assert((found_prev->link() == found_block), "sanity check"); |
| // Unmap element |
| found_prev->set_link(found_block->link()); |
| } |
| } else { |
| // Truncate block and return a pointer to the following 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); |
| mark_segmap_as_used(beg, beg + length); |
| found_block->set_length(length); |
| } |
| |
| found_block->set_used(); |
| _freelist_segments -= length; |
| return found_block; |
| } |
| |
| //---------------------------------------------------------------------------- |
| // Non-product code |
| |
| #ifndef PRODUCT |
| |
| void CodeHeap::print() { |
| tty->print_cr("The Heap"); |
| } |
| |
| 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"); |
| |
| 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; |
| } |
| } |
| } |
| |
| #endif |