rev 52084 : 8211980: Remove ThreadHeapSampler enable/disable/enabled methods
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   1 /*
   2  * Copyright (c) 2018, 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 #include "precompiled.hpp"
  26 #include "classfile/javaClasses.hpp"
  27 #include "gc/shared/allocTracer.hpp"
  28 #include "gc/shared/collectedHeap.hpp"
  29 #include "gc/shared/memAllocator.hpp"
  30 #include "gc/shared/threadLocalAllocBuffer.inline.hpp"
  31 #include "memory/universe.hpp"
  32 #include "oops/arrayOop.hpp"
  33 #include "oops/oop.inline.hpp"
  34 #include "prims/jvmtiExport.hpp"
  35 #include "runtime/sharedRuntime.hpp"
  36 #include "runtime/handles.inline.hpp"
  37 #include "runtime/thread.inline.hpp"
  38 #include "services/lowMemoryDetector.hpp"
  39 #include "utilities/align.hpp"
  40 #include "utilities/copy.hpp"
  41 
  42 class MemAllocator::Allocation: StackObj {
  43   friend class MemAllocator;
  44 
  45   const MemAllocator& _allocator;
  46   Thread*             _thread;
  47   oop*                _obj_ptr;
  48   bool                _overhead_limit_exceeded;
  49   bool                _allocated_outside_tlab;
  50   size_t              _allocated_tlab_size;
  51   bool                _tlab_end_reset_for_sample;
  52 
  53   bool check_out_of_memory();
  54   void verify_before();
  55   void verify_after();
  56   void notify_allocation();
  57   void notify_allocation_jvmti_allocation_event();
  58   void notify_allocation_jvmti_sampler();
  59   void notify_allocation_low_memory_detector();
  60   void notify_allocation_jfr_sampler();
  61   void notify_allocation_dtrace_sampler();
  62   void check_for_bad_heap_word_value() const;
  63 #ifdef ASSERT
  64   void check_for_valid_allocation_state() const;
  65 #endif
  66 
  67   class PreserveObj;
  68 
  69 public:
  70   Allocation(const MemAllocator& allocator, oop* obj_ptr)
  71     : _allocator(allocator),
  72       _thread(Thread::current()),
  73       _obj_ptr(obj_ptr),
  74       _overhead_limit_exceeded(false),
  75       _allocated_outside_tlab(false),
  76       _allocated_tlab_size(0),
  77       _tlab_end_reset_for_sample(false)
  78   {
  79     verify_before();
  80   }
  81 
  82   ~Allocation() {
  83     if (!check_out_of_memory()) {
  84       verify_after();
  85       notify_allocation();
  86     }
  87   }
  88 
  89   oop obj() const { return *_obj_ptr; }
  90 };
  91 
  92 class MemAllocator::Allocation::PreserveObj: StackObj {
  93   HandleMark _handle_mark;
  94   Handle     _handle;
  95   oop* const _obj_ptr;
  96 
  97 public:
  98   PreserveObj(Thread* thread, oop* obj_ptr)
  99     : _handle_mark(thread),
 100       _handle(thread, *obj_ptr),
 101       _obj_ptr(obj_ptr)
 102   {
 103     *obj_ptr = NULL;
 104   }
 105 
 106   ~PreserveObj() {
 107     *_obj_ptr = _handle();
 108   }
 109 
 110   oop operator()() const {
 111     return _handle();
 112   }
 113 };
 114 
 115 bool MemAllocator::Allocation::check_out_of_memory() {
 116   Thread* THREAD = _thread;
 117   assert(!HAS_PENDING_EXCEPTION, "Unexpected exception, will result in uninitialized storage");
 118 
 119   if (obj() != NULL) {
 120     return false;
 121   }
 122 
 123   const char* message = _overhead_limit_exceeded ? "GC overhead limit exceeded" : "Java heap space";
 124   if (!THREAD->in_retryable_allocation()) {
 125     // -XX:+HeapDumpOnOutOfMemoryError and -XX:OnOutOfMemoryError support
 126     report_java_out_of_memory(message);
 127 
 128     if (JvmtiExport::should_post_resource_exhausted()) {
 129       JvmtiExport::post_resource_exhausted(
 130         JVMTI_RESOURCE_EXHAUSTED_OOM_ERROR | JVMTI_RESOURCE_EXHAUSTED_JAVA_HEAP,
 131         message);
 132     }
 133     oop exception = _overhead_limit_exceeded ?
 134         Universe::out_of_memory_error_gc_overhead_limit() :
 135         Universe::out_of_memory_error_java_heap();
 136     THROW_OOP_(exception, true);
 137   } else {
 138     THROW_OOP_(Universe::out_of_memory_error_retry(), true);
 139   }
 140 }
 141 
 142 void MemAllocator::Allocation::verify_before() {
 143   // Clear unhandled oops for memory allocation.  Memory allocation might
 144   // not take out a lock if from tlab, so clear here.
 145   Thread* THREAD = _thread;
 146   CHECK_UNHANDLED_OOPS_ONLY(THREAD->clear_unhandled_oops();)
 147   assert(!HAS_PENDING_EXCEPTION, "Should not allocate with exception pending");
 148   debug_only(check_for_valid_allocation_state());
 149   assert(!Universe::heap()->is_gc_active(), "Allocation during gc not allowed");
 150 }
 151 
 152 void MemAllocator::Allocation::verify_after() {
 153   NOT_PRODUCT(check_for_bad_heap_word_value();)
 154 }
 155 
 156 void MemAllocator::Allocation::check_for_bad_heap_word_value() const {
 157   MemRegion obj_range = _allocator.obj_memory_range(obj());
 158   HeapWord* addr = obj_range.start();
 159   size_t size = obj_range.word_size();
 160   if (CheckMemoryInitialization && ZapUnusedHeapArea) {
 161     for (size_t slot = 0; slot < size; slot += 1) {
 162       assert((*(intptr_t*) (addr + slot)) != ((intptr_t) badHeapWordVal),
 163              "Found badHeapWordValue in post-allocation check");
 164     }
 165   }
 166 }
 167 
 168 #ifdef ASSERT
 169 void MemAllocator::Allocation::check_for_valid_allocation_state() const {
 170   // How to choose between a pending exception and a potential
 171   // OutOfMemoryError?  Don't allow pending exceptions.
 172   // This is a VM policy failure, so how do we exhaustively test it?
 173   assert(!_thread->has_pending_exception(),
 174          "shouldn't be allocating with pending exception");
 175   if (StrictSafepointChecks) {
 176     assert(_thread->allow_allocation(),
 177            "Allocation done by thread for which allocation is blocked "
 178            "by No_Allocation_Verifier!");
 179     // Allocation of an oop can always invoke a safepoint,
 180     // hence, the true argument
 181     _thread->check_for_valid_safepoint_state(true);
 182   }
 183 }
 184 #endif
 185 
 186 void MemAllocator::Allocation::notify_allocation_jvmti_sampler() {
 187   // support for JVMTI VMObjectAlloc event (no-op if not enabled)
 188   JvmtiExport::vm_object_alloc_event_collector(obj());
 189 
 190   if (!JvmtiExport::should_post_sampled_object_alloc()) {
 191     // Sampling disabled
 192     return;
 193   }
 194 
 195   if (!_allocated_outside_tlab && _allocated_tlab_size == 0 && !_tlab_end_reset_for_sample) {
 196     // Sample if it's a non-TLAB allocation, or a TLAB allocation that either refills the TLAB
 197     // or expands it due to taking a sampler induced slow path.
 198     return;
 199   }
 200 
 201   if (JvmtiExport::should_post_sampled_object_alloc()) {
 202     // If we want to be sampling, protect the allocated object with a Handle
 203     // before doing the callback. The callback is done in the destructor of
 204     // the JvmtiSampledObjectAllocEventCollector.
 205     PreserveObj obj_h(_thread, _obj_ptr);
 206     JvmtiSampledObjectAllocEventCollector collector;
 207     size_t size_in_bytes = _allocator._word_size * HeapWordSize;
 208     ThreadLocalAllocBuffer& tlab = _thread->tlab();
 209     size_t bytes_since_last = _allocated_outside_tlab ? 0 : tlab.bytes_since_last_sample_point();
 210     _thread->heap_sampler().check_for_sampling(obj_h(), size_in_bytes, bytes_since_last);
 211   }
 212 
 213   if (_tlab_end_reset_for_sample || _allocated_tlab_size != 0) {
 214     _thread->tlab().set_sample_end();
 215   }
 216 }
 217 
 218 void MemAllocator::Allocation::notify_allocation_low_memory_detector() {
 219   // support low memory notifications (no-op if not enabled)
 220   LowMemoryDetector::detect_low_memory_for_collected_pools();
 221 }
 222 
 223 void MemAllocator::Allocation::notify_allocation_jfr_sampler() {
 224   HeapWord* mem = (HeapWord*)obj();
 225   size_t size_in_bytes = _allocator._word_size * HeapWordSize;
 226 
 227   if (_allocated_outside_tlab) {
 228     AllocTracer::send_allocation_outside_tlab(_allocator._klass, mem, size_in_bytes, _thread);
 229   } else if (_allocated_tlab_size != 0) {
 230     // TLAB was refilled
 231     AllocTracer::send_allocation_in_new_tlab(_allocator._klass, mem, _allocated_tlab_size * HeapWordSize,
 232                                              size_in_bytes, _thread);
 233   }
 234 }
 235 
 236 void MemAllocator::Allocation::notify_allocation_dtrace_sampler() {
 237   if (DTraceAllocProbes) {
 238     // support for Dtrace object alloc event (no-op most of the time)
 239     Klass* klass = _allocator._klass;
 240     size_t word_size = _allocator._word_size;
 241     if (klass != NULL && klass->name() != NULL) {
 242       SharedRuntime::dtrace_object_alloc(obj(), (int)word_size);
 243     }
 244   }
 245 }
 246 
 247 void MemAllocator::Allocation::notify_allocation() {
 248   notify_allocation_low_memory_detector();
 249   notify_allocation_jfr_sampler();
 250   notify_allocation_dtrace_sampler();
 251   notify_allocation_jvmti_sampler();
 252 }
 253 
 254 HeapWord* MemAllocator::allocate_outside_tlab(Allocation& allocation) const {
 255   allocation._allocated_outside_tlab = true;
 256   HeapWord* mem = _heap->mem_allocate(_word_size, &allocation._overhead_limit_exceeded);
 257   if (mem == NULL) {
 258     return mem;
 259   }
 260 
 261   NOT_PRODUCT(_heap->check_for_non_bad_heap_word_value(mem, _word_size));
 262   size_t size_in_bytes = _word_size * HeapWordSize;
 263   _thread->incr_allocated_bytes(size_in_bytes);
 264 
 265   return mem;
 266 }
 267 
 268 HeapWord* MemAllocator::allocate_inside_tlab(Allocation& allocation) const {
 269   assert(UseTLAB, "should use UseTLAB");
 270 
 271   // Try allocating from an existing TLAB.
 272   HeapWord* mem = _thread->tlab().allocate(_word_size);
 273   if (mem != NULL) {
 274     return mem;
 275   }
 276 
 277   // Try refilling the TLAB and allocating the object in it.
 278   return allocate_inside_tlab_slow(allocation);
 279 }
 280 
 281 HeapWord* MemAllocator::allocate_inside_tlab_slow(Allocation& allocation) const {
 282   HeapWord* mem = NULL;
 283   ThreadLocalAllocBuffer& tlab = _thread->tlab();
 284 
 285   if (JvmtiExport::should_post_sampled_object_alloc()) {
 286     // Try to allocate the sampled object from TLAB, it is possible a sample
 287     // point was put and the TLAB still has space.
 288     tlab.set_back_allocation_end();
 289     mem = tlab.allocate(_word_size);
 290     if (mem != NULL) {
 291       allocation._tlab_end_reset_for_sample = true;
 292       return mem;
 293     }
 294   }
 295 
 296   // Retain tlab and allocate object in shared space if
 297   // the amount free in the tlab is too large to discard.
 298   if (tlab.free() > tlab.refill_waste_limit()) {
 299     tlab.record_slow_allocation(_word_size);
 300     return NULL;
 301   }
 302 
 303   // Discard tlab and allocate a new one.
 304   // To minimize fragmentation, the last TLAB may be smaller than the rest.
 305   size_t new_tlab_size = tlab.compute_size(_word_size);
 306 
 307   tlab.retire_before_allocation();
 308 
 309   if (new_tlab_size == 0) {
 310     return NULL;
 311   }
 312 
 313   // Allocate a new TLAB requesting new_tlab_size. Any size
 314   // between minimal and new_tlab_size is accepted.
 315   size_t min_tlab_size = ThreadLocalAllocBuffer::compute_min_size(_word_size);
 316   mem = _heap->allocate_new_tlab(min_tlab_size, new_tlab_size, &allocation._allocated_tlab_size);
 317   if (mem == NULL) {
 318     assert(allocation._allocated_tlab_size == 0,
 319            "Allocation failed, but actual size was updated. min: " SIZE_FORMAT
 320            ", desired: " SIZE_FORMAT ", actual: " SIZE_FORMAT,
 321            min_tlab_size, new_tlab_size, allocation._allocated_tlab_size);
 322     return NULL;
 323   }
 324   assert(allocation._allocated_tlab_size != 0, "Allocation succeeded but actual size not updated. mem at: "
 325          PTR_FORMAT " min: " SIZE_FORMAT ", desired: " SIZE_FORMAT,
 326          p2i(mem), min_tlab_size, new_tlab_size);
 327 
 328   if (ZeroTLAB) {
 329     // ..and clear it.
 330     Copy::zero_to_words(mem, allocation._allocated_tlab_size);
 331   } else {
 332     // ...and zap just allocated object.
 333 #ifdef ASSERT
 334     // Skip mangling the space corresponding to the object header to
 335     // ensure that the returned space is not considered parsable by
 336     // any concurrent GC thread.
 337     size_t hdr_size = oopDesc::header_size();
 338     Copy::fill_to_words(mem + hdr_size, allocation._allocated_tlab_size - hdr_size, badHeapWordVal);
 339 #endif // ASSERT
 340   }
 341 
 342   tlab.fill(mem, mem + _word_size, allocation._allocated_tlab_size);
 343   return mem;
 344 }
 345 
 346 HeapWord* MemAllocator::mem_allocate(Allocation& allocation) const {
 347   if (UseTLAB) {
 348     HeapWord* result = allocate_inside_tlab(allocation);
 349     if (result != NULL) {
 350       return result;
 351     }
 352   }
 353 
 354   return allocate_outside_tlab(allocation);
 355 }
 356 
 357 oop MemAllocator::allocate() const {
 358   oop obj = NULL;
 359   {
 360     Allocation allocation(*this, &obj);
 361     HeapWord* mem = mem_allocate(allocation);
 362     if (mem != NULL) {
 363       obj = initialize(mem);
 364     }
 365   }
 366   return obj;
 367 }
 368 
 369 void MemAllocator::mem_clear(HeapWord* mem) const {
 370   assert(mem != NULL, "cannot initialize NULL object");
 371   const size_t hs = oopDesc::header_size();
 372   assert(_word_size >= hs, "unexpected object size");
 373   oopDesc::set_klass_gap(mem, 0);
 374   Copy::fill_to_aligned_words(mem + hs, _word_size - hs);
 375 }
 376 
 377 oop MemAllocator::finish(HeapWord* mem) const {
 378   assert(mem != NULL, "NULL object pointer");
 379   if (UseBiasedLocking) {
 380     oopDesc::set_mark_raw(mem, _klass->prototype_header());
 381   } else {
 382     // May be bootstrapping
 383     oopDesc::set_mark_raw(mem, markOopDesc::prototype());
 384   }
 385   // Need a release store to ensure array/class length, mark word, and
 386   // object zeroing are visible before setting the klass non-NULL, for
 387   // concurrent collectors.
 388   oopDesc::release_set_klass(mem, _klass);
 389   return oop(mem);
 390 }
 391 
 392 oop ObjAllocator::initialize(HeapWord* mem) const {
 393   mem_clear(mem);
 394   return finish(mem);
 395 }
 396 
 397 MemRegion ObjArrayAllocator::obj_memory_range(oop obj) const {
 398   if (_do_zero) {
 399     return MemAllocator::obj_memory_range(obj);
 400   }
 401   ArrayKlass* array_klass = ArrayKlass::cast(_klass);
 402   const size_t hs = arrayOopDesc::header_size(array_klass->element_type());
 403   return MemRegion(((HeapWord*)obj) + hs, _word_size - hs);
 404 }
 405 
 406 oop ObjArrayAllocator::initialize(HeapWord* mem) const {
 407   // Set array length before setting the _klass field because a
 408   // non-NULL klass field indicates that the object is parsable by
 409   // concurrent GC.
 410   assert(_length >= 0, "length should be non-negative");
 411   if (_do_zero) {
 412     mem_clear(mem);
 413   }
 414   arrayOopDesc::set_length(mem, _length);
 415   return finish(mem);
 416 }
 417 
 418 oop ClassAllocator::initialize(HeapWord* mem) const {
 419   // Set oop_size field before setting the _klass field because a
 420   // non-NULL _klass field indicates that the object is parsable by
 421   // concurrent GC.
 422   assert(_word_size > 0, "oop_size must be positive.");
 423   mem_clear(mem);
 424   java_lang_Class::set_oop_size(mem, (int)_word_size);
 425   return finish(mem);
 426 }
--- EOF ---