1 /*
   2  * Copyright (c) 2012, 2016, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 
  26 #include "precompiled.hpp"
  27 
  28 #include "logging/log.hpp"
  29 #include "memory/metaspace/chunkLevel.hpp"
  30 #include "memory/metaspace/constants.hpp"
  31 #include "memory/metaspace/metachunk.hpp"
  32 #include "memory/metaspace/metaspaceCommon.hpp"
  33 #include "memory/metaspace/virtualSpaceNode.hpp"
  34 
  35 #include "utilities/align.hpp"
  36 #include "utilities/copy.hpp"
  37 #include "utilities/debug.hpp"
  38 
  39 namespace metaspace {
  40 
  41 // Make sure that the Klass alignment also agree.
  42 STATIC_ASSERT(Metachunk::allocation_alignment_bytes == (size_t)KlassAlignmentInBytes);
  43 
  44 void Metachunk::remove_from_list() {
  45   if (_prev != NULL) {
  46     _prev->set_next(_next);
  47   }
  48   if (_next != NULL) {
  49     _next->set_prev(_prev);
  50   }
  51   _prev = _next = NULL;
  52 }
  53 
  54 
  55 // Commit uncommitted section of the chunk.
  56 // Fails if we hit a commit limit.
  57 bool Metachunk::commit_up_to(size_t new_committed_words) {
  58 
  59   // We should hold the expand lock at this point.
  60   assert_lock_strong(MetaspaceExpand_lock);
  61 
  62   assert(new_committed_words <= word_size(), "Sanity.");
  63 
  64   // Note: we may commit more than the area of our own chunk and that is okay.
  65   MetaWord* const commit_top = align_down(base() + committed_words(), constants::commit_granule_words);
  66   MetaWord* const new_commit_top = align_up(base() + new_committed_words, constants::commit_granule_words);
  67 
  68   // Function should only be called if there is someting to commit.
  69   assert(new_commit_top > commit_top, "No need to commit.");
  70 
  71   log_debug(metaspace)("Chunk " PTR_FORMAT ": attempting to move commit line to "
  72                        SIZE_FORMAT " words.", p2i(this), new_committed_words);
  73 
  74   if (!_vsnode->ensure_range_is_committed(commit_top, new_commit_top - commit_top)) {
  75     return false;
  76   }
  77 
  78   // Remember how far we have committed.
  79   _committed_words = new_commit_top - base();
  80   if (_committed_words > word_size()) {
  81     _committed_words = word_size();
  82   }
  83 
  84   return true;
  85 
  86 }
  87 
  88 
  89 // Ensure that chunk is committed up to at least new_committed_words words.
  90 // Fails if we hit a commit limit.
  91 bool Metachunk::ensure_committed(size_t new_committed_words) {
  92 
  93   bool rc = true;
  94 
  95   if (new_committed_words > committed_words()) {
  96     MutexLocker cl(MetaspaceExpand_lock, Mutex::_no_safepoint_check_flag);
  97     rc = commit_up_to(new_committed_words);
  98   }
  99 
 100   return rc;
 101 
 102 }
 103 
 104 bool Metachunk::ensure_committed_locked(size_t new_committed_words) {
 105 
 106   // the .._locked() variant should be called if we own the lock already.
 107   assert_lock_strong(MetaspaceExpand_lock);
 108 
 109   bool rc = true;
 110 
 111   if (new_committed_words > committed_words()) {
 112     rc = commit_up_to(new_committed_words);
 113   }
 114 
 115   return rc;
 116 
 117 }
 118 
 119 // Allocate word_size words from this chunk.
 120 //
 121 // May cause memory to be committed. That may fail if we hit a commit limit. In that case,
 122 //  NULL is returned and p_did_hit_commit_limit will be set to true.
 123 // If the remainder portion of the chunk was too small to hold the allocation,
 124 //  NULL is returned and p_did_hit_commit_limit will be set to false.
 125 MetaWord* Metachunk::allocate(size_t word_size, bool* p_did_hit_commit_limit) {
 126 
 127   size_t request_word_size = align_up(word_size, allocation_alignment_words);
 128 
 129   log_trace(metaspace)("Chunk " PTR_FORMAT ": allocating "
 130                        SIZE_FORMAT " words.", p2i(this), word_size);
 131 
 132   // Space enough left?
 133   if (free_words() < request_word_size) {
 134     *p_did_hit_commit_limit = false;
 135     log_trace(metaspace)("Chunk " PTR_FORMAT ": .. does not fit (remaining space: "
 136                          SIZE_FORMAT " words).", p2i(this), free_words());
 137     return NULL;
 138   }
 139 
 140   // Expand committed region if necessary.
 141   if (ensure_committed(used_words() + request_word_size) == false) {
 142     *p_did_hit_commit_limit = true;
 143     log_trace(metaspace)("Chunk " PTR_FORMAT ": .. failed, we hit a limit.", p2i(this));
 144     return NULL;
 145   }
 146 
 147   MetaWord* const p = top();
 148 
 149   _used_words += request_word_size;
 150 
 151   return p;
 152 
 153 }
 154 
 155 #ifdef ASSERT
 156 
 157 void Metachunk::verify(bool slow) const {
 158 
 159   // Note: only call this on a life Metachunk.
 160   chklvl::check_valid_level(level());
 161 
 162   assert(base() != NULL, "No base ptr");
 163   assert(committed_words() >= used_words(), "Sanity");
 164   assert(word_size() >= committed_words(), "Sanity");
 165 
 166   // Test base pointer
 167   assert(vsnode() != NULL, "No space");
 168   vsnode()->check_pointer(base());
 169   assert(base() != NULL, "Base pointer NULL");
 170 
 171   // Starting address shall be aligned to chunk size.
 172   const size_t required_alignment = word_size() * sizeof(MetaWord);
 173   assert_is_aligned(base(), required_alignment);
 174 
 175   // Used words
 176   assert(used_words() < word_size(), "oob");
 177 
 178   // If we are not a root chunk, we shall have a reference to a tree node
 179   assert(tree_node_ref() != 0 || level() == chklvl::ROOT_CHUNK_LEVEL, "No parent node.");
 180 
 181 }
 182 #endif // ASSERT
 183 
 184 
 185 #ifdef ASSERT
 186 
 187 bool MetachunkList::contains(const Metachunk* c) const {
 188   for (Metachunk* c2 = first(); c2 != NULL; c2 = c2->next()) {
 189     if (c == c2) {
 190       return true;
 191     }
 192   }
 193   return false;
 194 }
 195 
 196 void MetachunkList::verify(bool slow) const {
 197   int num = 0;
 198   for (Metachunk* c = first(); c != NULL; c = c->next()) {
 199     num ++;
 200     if (slow) {
 201       c->verify(false);
 202     }
 203     _num.check(num);
 204   }
 205 }
 206 
 207 #endif // ASSERT
 208 
 209 } // namespace metaspace
 210