Mercurial > hg > graal-compiler
annotate src/share/vm/runtime/sweeper.cpp @ 1644:2a47bd84841f
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Reviewed-by: kvn
| author | never |
|---|---|
| date | Thu, 08 Jul 2010 14:29:44 -0700 |
| parents | ff38d05ea86f |
| children | 8d5934a77f10 |
| rev | line source |
|---|---|
| 0 | 1 /* |
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2 * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved. |
| 0 | 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 * | |
|
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
| 0 | 22 * |
| 23 */ | |
| 24 | |
| 25 # include "incls/_precompiled.incl" | |
| 26 # include "incls/_sweeper.cpp.incl" | |
| 27 | |
| 28 long NMethodSweeper::_traversals = 0; // No. of stack traversals performed | |
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29 nmethod* NMethodSweeper::_current = NULL; // Current nmethod |
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30 int NMethodSweeper::_seen = 0 ; // No. of nmethods we have currently processed in current pass of CodeCache |
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31 |
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32 volatile int NMethodSweeper::_invocations = 0; // No. of invocations left until we are completed with this pass |
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33 volatile int NMethodSweeper::_sweep_started = 0; // Whether a sweep is in progress. |
| 0 | 34 |
| 35 jint NMethodSweeper::_locked_seen = 0; | |
| 36 jint NMethodSweeper::_not_entrant_seen_on_stack = 0; | |
| 37 bool NMethodSweeper::_rescan = false; | |
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38 bool NMethodSweeper::_do_sweep = false; |
| 1202 | 39 bool NMethodSweeper::_was_full = false; |
| 40 jint NMethodSweeper::_advise_to_sweep = 0; | |
| 41 jlong NMethodSweeper::_last_was_full = 0; | |
| 42 uint NMethodSweeper::_highest_marked = 0; | |
| 43 long NMethodSweeper::_was_full_traversal = 0; | |
| 0 | 44 |
| 989 | 45 class MarkActivationClosure: public CodeBlobClosure { |
| 46 public: | |
| 47 virtual void do_code_blob(CodeBlob* cb) { | |
| 48 // If we see an activation belonging to a non_entrant nmethod, we mark it. | |
| 49 if (cb->is_nmethod() && ((nmethod*)cb)->is_not_entrant()) { | |
| 50 ((nmethod*)cb)->mark_as_seen_on_stack(); | |
| 51 } | |
| 52 } | |
| 53 }; | |
| 54 static MarkActivationClosure mark_activation_closure; | |
| 55 | |
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56 void NMethodSweeper::scan_stacks() { |
| 0 | 57 assert(SafepointSynchronize::is_at_safepoint(), "must be executed at a safepoint"); |
| 58 if (!MethodFlushing) return; | |
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59 _do_sweep = true; |
| 0 | 60 |
| 61 // No need to synchronize access, since this is always executed at a | |
| 62 // safepoint. If we aren't in the middle of scan and a rescan | |
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63 // hasn't been requested then just return. If UseCodeCacheFlushing is on and |
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64 // code cache flushing is in progress, don't skip sweeping to help make progress |
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65 // clearing space in the code cache. |
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66 if ((_current == NULL && !_rescan) && !(UseCodeCacheFlushing && !CompileBroker::should_compile_new_jobs())) { |
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67 _do_sweep = false; |
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68 return; |
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69 } |
| 0 | 70 |
| 71 // Make sure CompiledIC_lock in unlocked, since we might update some | |
| 72 // inline caches. If it is, we just bail-out and try later. | |
| 73 if (CompiledIC_lock->is_locked() || Patching_lock->is_locked()) return; | |
| 74 | |
| 75 // Check for restart | |
| 76 assert(CodeCache::find_blob_unsafe(_current) == _current, "Sweeper nmethod cached state invalid"); | |
| 77 if (_current == NULL) { | |
| 78 _seen = 0; | |
| 79 _invocations = NmethodSweepFraction; | |
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80 _current = CodeCache::first_nmethod(); |
| 0 | 81 _traversals += 1; |
| 82 if (PrintMethodFlushing) { | |
| 83 tty->print_cr("### Sweep: stack traversal %d", _traversals); | |
| 84 } | |
| 989 | 85 Threads::nmethods_do(&mark_activation_closure); |
| 0 | 86 |
| 87 // reset the flags since we started a scan from the beginning. | |
| 88 _rescan = false; | |
| 89 _locked_seen = 0; | |
| 90 _not_entrant_seen_on_stack = 0; | |
| 91 } | |
| 92 | |
| 1202 | 93 if (UseCodeCacheFlushing) { |
| 94 if (!CodeCache::needs_flushing()) { | |
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95 // scan_stacks() runs during a safepoint, no race with setters |
| 1202 | 96 _advise_to_sweep = 0; |
| 97 } | |
| 98 | |
| 99 if (was_full()) { | |
| 100 // There was some progress so attempt to restart the compiler | |
| 101 jlong now = os::javaTimeMillis(); | |
| 102 jlong max_interval = (jlong)MinCodeCacheFlushingInterval * (jlong)1000; | |
| 103 jlong curr_interval = now - _last_was_full; | |
| 104 if ((!CodeCache::needs_flushing()) && (curr_interval > max_interval)) { | |
| 105 CompileBroker::set_should_compile_new_jobs(CompileBroker::run_compilation); | |
| 106 set_was_full(false); | |
| 107 | |
| 108 // Update the _last_was_full time so we can tell how fast the | |
| 109 // code cache is filling up | |
| 110 _last_was_full = os::javaTimeMillis(); | |
| 111 | |
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112 log_sweep("restart_compiler"); |
| 1202 | 113 } |
| 114 } | |
| 115 } | |
| 0 | 116 } |
| 117 | |
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118 void NMethodSweeper::possibly_sweep() { |
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119 assert(JavaThread::current()->thread_state() == _thread_in_vm, "must run in vm mode"); |
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120 if ((!MethodFlushing) || (!_do_sweep)) return; |
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121 |
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122 if (_invocations > 0) { |
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123 // Only one thread at a time will sweep |
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124 jint old = Atomic::cmpxchg( 1, &_sweep_started, 0 ); |
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125 if (old != 0) { |
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126 return; |
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127 } |
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128 if (_invocations > 0) { |
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129 sweep_code_cache(); |
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130 _invocations--; |
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131 } |
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132 _sweep_started = 0; |
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133 } |
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134 } |
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135 |
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136 void NMethodSweeper::sweep_code_cache() { |
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137 #ifdef ASSERT |
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138 jlong sweep_start; |
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139 if (PrintMethodFlushing) { |
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140 sweep_start = os::javaTimeMillis(); |
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141 } |
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142 #endif |
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143 if (PrintMethodFlushing && Verbose) { |
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144 tty->print_cr("### Sweep at %d out of %d. Invocations left: %d", _seen, CodeCache::nof_nmethods(), _invocations); |
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145 } |
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146 |
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147 // We want to visit all nmethods after NmethodSweepFraction |
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148 // invocations so divide the remaining number of nmethods by the |
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149 // remaining number of invocations. This is only an estimate since |
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150 // the number of nmethods changes during the sweep so the final |
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151 // stage must iterate until it there are no more nmethods. |
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152 int todo = (CodeCache::nof_nmethods() - _seen) / _invocations; |
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153 |
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154 assert(!SafepointSynchronize::is_at_safepoint(), "should not be in safepoint when we get here"); |
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155 assert(!CodeCache_lock->owned_by_self(), "just checking"); |
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156 |
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157 { |
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158 MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag); |
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159 |
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160 // The last invocation iterates until there are no more nmethods |
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161 for (int i = 0; (i < todo || _invocations == 1) && _current != NULL; i++) { |
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162 |
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163 // Since we will give up the CodeCache_lock, always skip ahead |
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164 // to the next nmethod. Other blobs can be deleted by other |
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165 // threads but nmethods are only reclaimed by the sweeper. |
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166 nmethod* next = CodeCache::next_nmethod(_current); |
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167 |
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168 // Now ready to process nmethod and give up CodeCache_lock |
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169 { |
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170 MutexUnlockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag); |
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171 process_nmethod(_current); |
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172 } |
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173 _seen++; |
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174 _current = next; |
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175 } |
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176 } |
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177 |
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178 assert(_invocations > 1 || _current == NULL, "must have scanned the whole cache"); |
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179 |
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180 if (_current == NULL && !_rescan && (_locked_seen || _not_entrant_seen_on_stack)) { |
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181 // we've completed a scan without making progress but there were |
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182 // nmethods we were unable to process either because they were |
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183 // locked or were still on stack. We don't have to aggresively |
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184 // clean them up so just stop scanning. We could scan once more |
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185 // but that complicates the control logic and it's unlikely to |
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186 // matter much. |
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187 if (PrintMethodFlushing) { |
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188 tty->print_cr("### Couldn't make progress on some nmethods so stopping sweep"); |
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189 } |
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190 } |
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191 |
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192 #ifdef ASSERT |
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193 if(PrintMethodFlushing) { |
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194 jlong sweep_end = os::javaTimeMillis(); |
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195 tty->print_cr("### sweeper: sweep time(%d): " INT64_FORMAT, _invocations, sweep_end - sweep_start); |
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196 } |
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197 #endif |
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198 |
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199 if (_invocations == 1) { |
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200 log_sweep("finished"); |
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201 } |
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202 } |
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203 |
| 0 | 204 |
| 205 void NMethodSweeper::process_nmethod(nmethod *nm) { | |
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206 assert(!CodeCache_lock->owned_by_self(), "just checking"); |
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207 |
| 0 | 208 // Skip methods that are currently referenced by the VM |
| 209 if (nm->is_locked_by_vm()) { | |
| 210 // But still remember to clean-up inline caches for alive nmethods | |
| 211 if (nm->is_alive()) { | |
| 212 // Clean-up all inline caches that points to zombie/non-reentrant methods | |
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213 MutexLocker cl(CompiledIC_lock); |
| 0 | 214 nm->cleanup_inline_caches(); |
| 215 } else { | |
| 216 _locked_seen++; | |
| 217 } | |
| 218 return; | |
| 219 } | |
| 220 | |
| 221 if (nm->is_zombie()) { | |
| 222 // If it is first time, we see nmethod then we mark it. Otherwise, | |
| 223 // we reclame it. When we have seen a zombie method twice, we know that | |
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224 // there are no inline caches that refer to it. |
| 0 | 225 if (nm->is_marked_for_reclamation()) { |
| 226 assert(!nm->is_locked_by_vm(), "must not flush locked nmethods"); | |
| 941 | 227 if (PrintMethodFlushing && Verbose) { |
| 1202 | 228 tty->print_cr("### Nmethod %3d/" PTR_FORMAT " (marked for reclamation) being flushed", nm->compile_id(), nm); |
| 941 | 229 } |
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230 MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag); |
| 0 | 231 nm->flush(); |
| 232 } else { | |
| 941 | 233 if (PrintMethodFlushing && Verbose) { |
| 1202 | 234 tty->print_cr("### Nmethod %3d/" PTR_FORMAT " (zombie) being marked for reclamation", nm->compile_id(), nm); |
| 941 | 235 } |
| 0 | 236 nm->mark_for_reclamation(); |
| 237 _rescan = true; | |
| 238 } | |
| 239 } else if (nm->is_not_entrant()) { | |
| 240 // If there is no current activations of this method on the | |
| 241 // stack we can safely convert it to a zombie method | |
| 242 if (nm->can_not_entrant_be_converted()) { | |
| 941 | 243 if (PrintMethodFlushing && Verbose) { |
| 1202 | 244 tty->print_cr("### Nmethod %3d/" PTR_FORMAT " (not entrant) being made zombie", nm->compile_id(), nm); |
| 941 | 245 } |
| 0 | 246 nm->make_zombie(); |
| 247 _rescan = true; | |
| 248 } else { | |
| 249 // Still alive, clean up its inline caches | |
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250 MutexLocker cl(CompiledIC_lock); |
| 0 | 251 nm->cleanup_inline_caches(); |
| 252 // we coudn't transition this nmethod so don't immediately | |
| 253 // request a rescan. If this method stays on the stack for a | |
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254 // long time we don't want to keep rescanning the code cache. |
| 0 | 255 _not_entrant_seen_on_stack++; |
| 256 } | |
| 257 } else if (nm->is_unloaded()) { | |
| 258 // Unloaded code, just make it a zombie | |
| 941 | 259 if (PrintMethodFlushing && Verbose) |
| 1202 | 260 tty->print_cr("### Nmethod %3d/" PTR_FORMAT " (unloaded) being made zombie", nm->compile_id(), nm); |
| 941 | 261 if (nm->is_osr_method()) { |
| 0 | 262 // No inline caches will ever point to osr methods, so we can just remove it |
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263 MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag); |
| 0 | 264 nm->flush(); |
| 265 } else { | |
| 266 nm->make_zombie(); | |
| 267 _rescan = true; | |
| 268 } | |
| 269 } else { | |
| 270 assert(nm->is_alive(), "should be alive"); | |
| 1202 | 271 |
| 272 if (UseCodeCacheFlushing) { | |
| 273 if ((nm->method()->code() != nm) && !(nm->is_locked_by_vm()) && !(nm->is_osr_method()) && | |
| 274 (_traversals > _was_full_traversal+2) && (((uint)nm->compile_id()) < _highest_marked) && | |
| 275 CodeCache::needs_flushing()) { | |
| 276 // This method has not been called since the forced cleanup happened | |
| 277 nm->make_not_entrant(); | |
| 278 } | |
| 279 } | |
| 280 | |
| 0 | 281 // Clean-up all inline caches that points to zombie/non-reentrant methods |
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282 MutexLocker cl(CompiledIC_lock); |
| 0 | 283 nm->cleanup_inline_caches(); |
| 284 } | |
| 285 } | |
| 1202 | 286 |
| 287 // Code cache unloading: when compilers notice the code cache is getting full, | |
| 288 // they will call a vm op that comes here. This code attempts to speculatively | |
| 289 // unload the oldest half of the nmethods (based on the compile job id) by | |
| 290 // saving the old code in a list in the CodeCache. Then | |
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291 // execution resumes. If a method so marked is not called by the second sweeper |
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292 // stack traversal after the current one, the nmethod will be marked non-entrant and |
| 1202 | 293 // got rid of by normal sweeping. If the method is called, the methodOop's |
| 294 // _code field is restored and the methodOop/nmethod | |
| 295 // go back to their normal state. | |
| 296 void NMethodSweeper::handle_full_code_cache(bool is_full) { | |
| 297 // Only the first one to notice can advise us to start early cleaning | |
| 298 if (!is_full){ | |
| 299 jint old = Atomic::cmpxchg( 1, &_advise_to_sweep, 0 ); | |
| 300 if (old != 0) { | |
| 301 return; | |
| 302 } | |
| 303 } | |
| 304 | |
| 305 if (is_full) { | |
| 306 // Since code cache is full, immediately stop new compiles | |
| 307 bool did_set = CompileBroker::set_should_compile_new_jobs(CompileBroker::stop_compilation); | |
| 308 if (!did_set) { | |
| 309 // only the first to notice can start the cleaning, | |
| 310 // others will go back and block | |
| 311 return; | |
| 312 } | |
| 313 set_was_full(true); | |
| 314 | |
| 315 // If we run out within MinCodeCacheFlushingInterval of the last unload time, give up | |
| 316 jlong now = os::javaTimeMillis(); | |
| 317 jlong max_interval = (jlong)MinCodeCacheFlushingInterval * (jlong)1000; | |
| 318 jlong curr_interval = now - _last_was_full; | |
| 319 if (curr_interval < max_interval) { | |
| 320 _rescan = true; | |
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321 log_sweep("disable_compiler", "flushing_interval='" UINT64_FORMAT "'", |
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322 curr_interval/1000); |
| 1202 | 323 return; |
| 324 } | |
| 325 } | |
| 326 | |
| 327 VM_HandleFullCodeCache op(is_full); | |
| 328 VMThread::execute(&op); | |
| 329 | |
| 330 // rescan again as soon as possible | |
| 331 _rescan = true; | |
| 332 } | |
| 333 | |
| 334 void NMethodSweeper::speculative_disconnect_nmethods(bool is_full) { | |
| 335 // If there was a race in detecting full code cache, only run | |
| 336 // one vm op for it or keep the compiler shut off | |
| 337 | |
| 338 debug_only(jlong start = os::javaTimeMillis();) | |
| 339 | |
| 340 if ((!was_full()) && (is_full)) { | |
| 341 if (!CodeCache::needs_flushing()) { | |
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342 log_sweep("restart_compiler"); |
| 1202 | 343 CompileBroker::set_should_compile_new_jobs(CompileBroker::run_compilation); |
| 344 return; | |
| 345 } | |
| 346 } | |
| 347 | |
| 348 // Traverse the code cache trying to dump the oldest nmethods | |
| 349 uint curr_max_comp_id = CompileBroker::get_compilation_id(); | |
| 350 uint flush_target = ((curr_max_comp_id - _highest_marked) >> 1) + _highest_marked; | |
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351 log_sweep("start_cleaning"); |
| 1202 | 352 |
| 353 nmethod* nm = CodeCache::alive_nmethod(CodeCache::first()); | |
| 354 jint disconnected = 0; | |
| 355 jint made_not_entrant = 0; | |
| 356 while ((nm != NULL)){ | |
| 357 uint curr_comp_id = nm->compile_id(); | |
| 358 | |
| 359 // OSR methods cannot be flushed like this. Also, don't flush native methods | |
| 360 // since they are part of the JDK in most cases | |
| 361 if (nm->is_in_use() && (!nm->is_osr_method()) && (!nm->is_locked_by_vm()) && | |
| 362 (!nm->is_native_method()) && ((curr_comp_id < flush_target))) { | |
| 363 | |
| 364 if ((nm->method()->code() == nm)) { | |
| 365 // This method has not been previously considered for | |
| 366 // unloading or it was restored already | |
| 367 CodeCache::speculatively_disconnect(nm); | |
| 368 disconnected++; | |
| 369 } else if (nm->is_speculatively_disconnected()) { | |
| 370 // This method was previously considered for preemptive unloading and was not called since then | |
| 371 nm->method()->invocation_counter()->decay(); | |
| 372 nm->method()->backedge_counter()->decay(); | |
| 373 nm->make_not_entrant(); | |
| 374 made_not_entrant++; | |
| 375 } | |
| 376 | |
| 377 if (curr_comp_id > _highest_marked) { | |
| 378 _highest_marked = curr_comp_id; | |
| 379 } | |
| 380 } | |
| 381 nm = CodeCache::alive_nmethod(CodeCache::next(nm)); | |
| 382 } | |
| 383 | |
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384 log_sweep("stop_cleaning", |
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385 "disconnected='" UINT32_FORMAT "' made_not_entrant='" UINT32_FORMAT "'", |
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386 disconnected, made_not_entrant); |
| 1202 | 387 |
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388 // Shut off compiler. Sweeper will start over with a new stack scan and |
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389 // traversal cycle and turn it back on if it clears enough space. |
| 1202 | 390 if (was_full()) { |
| 391 _last_was_full = os::javaTimeMillis(); | |
| 392 CompileBroker::set_should_compile_new_jobs(CompileBroker::stop_compilation); | |
| 393 } | |
| 394 | |
| 395 // After two more traversals the sweeper will get rid of unrestored nmethods | |
| 396 _was_full_traversal = _traversals; | |
| 397 #ifdef ASSERT | |
| 398 jlong end = os::javaTimeMillis(); | |
| 399 if(PrintMethodFlushing && Verbose) { | |
| 400 tty->print_cr("### sweeper: unload time: " INT64_FORMAT, end-start); | |
| 401 } | |
| 402 #endif | |
| 403 } | |
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404 |
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405 |
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406 // Print out some state information about the current sweep and the |
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407 // state of the code cache if it's requested. |
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408 void NMethodSweeper::log_sweep(const char* msg, const char* format, ...) { |
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409 if (PrintMethodFlushing) { |
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410 ttyLocker ttyl; |
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411 tty->print("### sweeper: %s ", msg); |
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412 if (format != NULL) { |
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413 va_list ap; |
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414 va_start(ap, format); |
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415 tty->vprint(format, ap); |
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416 va_end(ap); |
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417 } |
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418 tty->print_cr(" total_blobs='" UINT32_FORMAT "' nmethods='" UINT32_FORMAT "'" |
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419 " adapters='" UINT32_FORMAT "' free_code_cache='" SIZE_FORMAT "'", |
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420 CodeCache::nof_blobs(), CodeCache::nof_nmethods(), CodeCache::nof_adapters(), CodeCache::unallocated_capacity()); |
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421 } |
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422 |
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423 if (LogCompilation && (xtty != NULL)) { |
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424 ttyLocker ttyl; |
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425 xtty->begin_elem("sweeper state='%s' traversals=`" INTX_FORMAT "' ", msg, (intx)traversal_count()); |
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426 if (format != NULL) { |
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427 va_list ap; |
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428 va_start(ap, format); |
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429 xtty->vprint(format, ap); |
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430 va_end(ap); |
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431 } |
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432 xtty->print(" total_blobs='" UINT32_FORMAT "' nmethods='" UINT32_FORMAT "'" |
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433 " adapters='" UINT32_FORMAT "' free_code_cache='" SIZE_FORMAT "'", |
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434 CodeCache::nof_blobs(), CodeCache::nof_nmethods(), CodeCache::nof_adapters(), CodeCache::unallocated_capacity()); |
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435 xtty->stamp(); |
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436 xtty->end_elem(); |
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437 } |
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438 } |