--- /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");
+}