jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/parallelScavenge/parallelScavengeHeap.cpp@8a729074feae (annotated)

src/share/vm/gc_implementation/parallelScavenge/parallelScavengeHeap.cpp@8a729074feae (annotated)

src/share/vm/gc_implementation/parallelScavenge/parallelScavengeHeap.cpp

Fri, 16 Mar 2012 16:14:04 +0100

author: nloodin
date: Fri, 16 Mar 2012 16:14:04 +0100
changeset 3665: 8a729074feae
parent 3541: 23c0eb012d6f
child 3711: b632e80fc9dc
permissions: -rw-r--r--

7154517: Build error in hotspot-gc without precompiled headers
Reviewed-by: jcoomes, brutisso

 /*
  * Copyright (c) 2001, 2012, 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 "gc_implementation/parallelScavenge/adjoiningGenerations.hpp"
 #include "gc_implementation/parallelScavenge/adjoiningVirtualSpaces.hpp"
 #include "gc_implementation/parallelScavenge/cardTableExtension.hpp"
 #include "gc_implementation/parallelScavenge/gcTaskManager.hpp"
 #include "gc_implementation/parallelScavenge/generationSizer.hpp"
 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.inline.hpp"
 #include "gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp"
 #include "gc_implementation/parallelScavenge/psMarkSweep.hpp"
 #include "gc_implementation/parallelScavenge/psParallelCompact.hpp"
 #include "gc_implementation/parallelScavenge/psPromotionManager.hpp"
 #include "gc_implementation/parallelScavenge/psScavenge.hpp"
 #include "gc_implementation/parallelScavenge/vmPSOperations.hpp"
 #include "memory/gcLocker.inline.hpp"
 #include "oops/oop.inline.hpp"
 #include "runtime/handles.inline.hpp"
 #include "runtime/java.hpp"
 #include "runtime/vmThread.hpp"
 #include "utilities/vmError.hpp"
 PSYoungGen*  ParallelScavengeHeap::_young_gen = NULL;
 PSOldGen*    ParallelScavengeHeap::_old_gen = NULL;
 PSPermGen*   ParallelScavengeHeap::_perm_gen = NULL;
 PSAdaptiveSizePolicy* ParallelScavengeHeap::_size_policy = NULL;
 PSGCAdaptivePolicyCounters* ParallelScavengeHeap::_gc_policy_counters = NULL;
 ParallelScavengeHeap* ParallelScavengeHeap::_psh = NULL;
 GCTaskManager* ParallelScavengeHeap::_gc_task_manager = NULL;
 static void trace_gen_sizes(const char* const str,
                             size_t pg_min, size_t pg_max,
                             size_t og_min, size_t og_max,
                             size_t yg_min, size_t yg_max)
 {
   if (TracePageSizes) {
     tty->print_cr("%s:  " SIZE_FORMAT "," SIZE_FORMAT " "
                   SIZE_FORMAT "," SIZE_FORMAT " "
                   SIZE_FORMAT "," SIZE_FORMAT " "
                   SIZE_FORMAT,
                   str, pg_min / K, pg_max / K,
                   og_min / K, og_max / K,
                   yg_min / K, yg_max / K,
                   (pg_max + og_max + yg_max) / K);
   }
 }
 jint ParallelScavengeHeap::initialize() {
   CollectedHeap::pre_initialize();
   // Cannot be initialized until after the flags are parsed
   // GenerationSizer flag_parser;
   _collector_policy = new GenerationSizer();
   size_t yg_min_size = _collector_policy->min_young_gen_size();
   size_t yg_max_size = _collector_policy->max_young_gen_size();
   size_t og_min_size = _collector_policy->min_old_gen_size();
   size_t og_max_size = _collector_policy->max_old_gen_size();
   // Why isn't there a min_perm_gen_size()?
   size_t pg_min_size = _collector_policy->perm_gen_size();
   size_t pg_max_size = _collector_policy->max_perm_gen_size();
   trace_gen_sizes("ps heap raw",
                   pg_min_size, pg_max_size,
                   og_min_size, og_max_size,
                   yg_min_size, yg_max_size);
   // The ReservedSpace ctor used below requires that the page size for the perm
   // gen is <= the page size for the rest of the heap (young + old gens).
   const size_t og_page_sz = os::page_size_for_region(yg_min_size + og_min_size,
                                                      yg_max_size + og_max_size,
 );
   const size_t pg_page_sz = MIN2(os::page_size_for_region(pg_min_size,
                                                           pg_max_size, 16),
                                  og_page_sz);
   const size_t pg_align = set_alignment(_perm_gen_alignment,  pg_page_sz);
   const size_t og_align = set_alignment(_old_gen_alignment,   og_page_sz);
   const size_t yg_align = set_alignment(_young_gen_alignment, og_page_sz);
   // Update sizes to reflect the selected page size(s).
   //
   // NEEDS_CLEANUP.  The default TwoGenerationCollectorPolicy uses NewRatio; it
   // should check UseAdaptiveSizePolicy.  Changes from generationSizer could
   // move to the common code.
   yg_min_size = align_size_up(yg_min_size, yg_align);
   yg_max_size = align_size_up(yg_max_size, yg_align);
   size_t yg_cur_size =
     align_size_up(_collector_policy->young_gen_size(), yg_align);
   yg_cur_size = MAX2(yg_cur_size, yg_min_size);
   og_min_size = align_size_up(og_min_size, og_align);
   // Align old gen size down to preserve specified heap size.
   assert(og_align == yg_align, "sanity");
   og_max_size = align_size_down(og_max_size, og_align);
   og_max_size = MAX2(og_max_size, og_min_size);
   size_t og_cur_size =
     align_size_down(_collector_policy->old_gen_size(), og_align);
   og_cur_size = MAX2(og_cur_size, og_min_size);
   pg_min_size = align_size_up(pg_min_size, pg_align);
   pg_max_size = align_size_up(pg_max_size, pg_align);
   size_t pg_cur_size = pg_min_size;
   trace_gen_sizes("ps heap rnd",
                   pg_min_size, pg_max_size,
                   og_min_size, og_max_size,
                   yg_min_size, yg_max_size);
   const size_t total_reserved = pg_max_size + og_max_size + yg_max_size;
   char* addr = Universe::preferred_heap_base(total_reserved, Universe::UnscaledNarrowOop);
   // The main part of the heap (old gen + young gen) can often use a larger page
   // size than is needed or wanted for the perm gen.  Use the "compound
   // alignment" ReservedSpace ctor to avoid having to use the same page size for
   // all gens.
   ReservedHeapSpace heap_rs(pg_max_size, pg_align, og_max_size + yg_max_size,
                             og_align, addr);
   if (UseCompressedOops) {
     if (addr != NULL && !heap_rs.is_reserved()) {
       // Failed to reserve at specified address - the requested memory
       // region is taken already, for example, by 'java' launcher.
       // Try again to reserver heap higher.
       addr = Universe::preferred_heap_base(total_reserved, Universe::ZeroBasedNarrowOop);
       ReservedHeapSpace heap_rs0(pg_max_size, pg_align, og_max_size + yg_max_size,
                                  og_align, addr);
       if (addr != NULL && !heap_rs0.is_reserved()) {
         // Failed to reserve at specified address again - give up.
         addr = Universe::preferred_heap_base(total_reserved, Universe::HeapBasedNarrowOop);
         assert(addr == NULL, "");
         ReservedHeapSpace heap_rs1(pg_max_size, pg_align, og_max_size + yg_max_size,
                                    og_align, addr);
         heap_rs = heap_rs1;
       } else {
         heap_rs = heap_rs0;
       }
     }
   }
   os::trace_page_sizes("ps perm", pg_min_size, pg_max_size, pg_page_sz,
                        heap_rs.base(), pg_max_size);
   os::trace_page_sizes("ps main", og_min_size + yg_min_size,
                        og_max_size + yg_max_size, og_page_sz,
                        heap_rs.base() + pg_max_size,
                        heap_rs.size() - pg_max_size);
   if (!heap_rs.is_reserved()) {
     vm_shutdown_during_initialization(
       "Could not reserve enough space for object heap");
     return JNI_ENOMEM;
   }
   _reserved = MemRegion((HeapWord*)heap_rs.base(),
                         (HeapWord*)(heap_rs.base() + heap_rs.size()));
   CardTableExtension* const barrier_set = new CardTableExtension(_reserved, 3);
   _barrier_set = barrier_set;
   oopDesc::set_bs(_barrier_set);
   if (_barrier_set == NULL) {
     vm_shutdown_during_initialization(
       "Could not reserve enough space for barrier set");
     return JNI_ENOMEM;
   }
   // Initial young gen size is 4 Mb
   //
   // XXX - what about flag_parser.young_gen_size()?
   const size_t init_young_size = align_size_up(4 * M, yg_align);
   yg_cur_size = MAX2(MIN2(init_young_size, yg_max_size), yg_cur_size);
   // Split the reserved space into perm gen and the main heap (everything else).
   // The main heap uses a different alignment.
   ReservedSpace perm_rs = heap_rs.first_part(pg_max_size);
   ReservedSpace main_rs = heap_rs.last_part(pg_max_size, og_align);
   // Make up the generations
   // Calculate the maximum size that a generation can grow.  This
   // includes growth into the other generation.  Note that the
   // parameter _max_gen_size is kept as the maximum
   // size of the generation as the boundaries currently stand.
   // _max_gen_size is still used as that value.
   double max_gc_pause_sec = ((double) MaxGCPauseMillis)/1000.0;
   double max_gc_minor_pause_sec = ((double) MaxGCMinorPauseMillis)/1000.0;
   _gens = new AdjoiningGenerations(main_rs,
                                    og_cur_size,
                                    og_min_size,
                                    og_max_size,
                                    yg_cur_size,
                                    yg_min_size,
                                    yg_max_size,
                                    yg_align);
   _old_gen = _gens->old_gen();
   _young_gen = _gens->young_gen();
   const size_t eden_capacity = _young_gen->eden_space()->capacity_in_bytes();
   const size_t old_capacity = _old_gen->capacity_in_bytes();
   const size_t initial_promo_size = MIN2(eden_capacity, old_capacity);
   _size_policy =
     new PSAdaptiveSizePolicy(eden_capacity,
                              initial_promo_size,
                              young_gen()->to_space()->capacity_in_bytes(),
                              intra_heap_alignment(),
                              max_gc_pause_sec,
                              max_gc_minor_pause_sec,
                              GCTimeRatio
                              );
   _perm_gen = new PSPermGen(perm_rs,
                             pg_align,
                             pg_cur_size,
                             pg_cur_size,
                             pg_max_size,
                             "perm", 2);
   assert(!UseAdaptiveGCBoundary ||
     (old_gen()->virtual_space()->high_boundary() ==
      young_gen()->virtual_space()->low_boundary()),
     "Boundaries must meet");
   // initialize the policy counters - 2 collectors, 3 generations
   _gc_policy_counters =
     new PSGCAdaptivePolicyCounters("ParScav:MSC", 2, 3, _size_policy);
   _psh = this;
   // Set up the GCTaskManager
   _gc_task_manager = GCTaskManager::create(ParallelGCThreads);
   if (UseParallelOldGC && !PSParallelCompact::initialize()) {
     return JNI_ENOMEM;
   }
   return JNI_OK;
 }
 void ParallelScavengeHeap::post_initialize() {
   // Need to init the tenuring threshold
   PSScavenge::initialize();
   if (UseParallelOldGC) {
     PSParallelCompact::post_initialize();
   } else {
     PSMarkSweep::initialize();
   }
   PSPromotionManager::initialize();
 }
 void ParallelScavengeHeap::update_counters() {
   young_gen()->update_counters();
   old_gen()->update_counters();
   perm_gen()->update_counters();
 }
 size_t ParallelScavengeHeap::capacity() const {
   size_t value = young_gen()->capacity_in_bytes() + old_gen()->capacity_in_bytes();
   return value;
 }
 size_t ParallelScavengeHeap::used() const {
   size_t value = young_gen()->used_in_bytes() + old_gen()->used_in_bytes();
   return value;
 }
 bool ParallelScavengeHeap::is_maximal_no_gc() const {
   return old_gen()->is_maximal_no_gc() && young_gen()->is_maximal_no_gc();
 }
 size_t ParallelScavengeHeap::permanent_capacity() const {
   return perm_gen()->capacity_in_bytes();
 }
 size_t ParallelScavengeHeap::permanent_used() const {
   return perm_gen()->used_in_bytes();
 }
 size_t ParallelScavengeHeap::max_capacity() const {
   size_t estimated = reserved_region().byte_size();
   estimated -= perm_gen()->reserved().byte_size();
   if (UseAdaptiveSizePolicy) {
     estimated -= _size_policy->max_survivor_size(young_gen()->max_size());
   } else {
     estimated -= young_gen()->to_space()->capacity_in_bytes();
   }
   return MAX2(estimated, capacity());
 }
 bool ParallelScavengeHeap::is_in(const void* p) const {
   if (young_gen()->is_in(p)) {
     return true;
   }
   if (old_gen()->is_in(p)) {
     return true;
   }
   if (perm_gen()->is_in(p)) {
     return true;
   }
   return false;
 }
 bool ParallelScavengeHeap::is_in_reserved(const void* p) const {
   if (young_gen()->is_in_reserved(p)) {
     return true;
   }
   if (old_gen()->is_in_reserved(p)) {
     return true;
   }
   if (perm_gen()->is_in_reserved(p)) {
     return true;
   }
   return false;
 }
 bool ParallelScavengeHeap::is_scavengable(const void* addr) {
   return is_in_young((oop)addr);
 }
 #ifdef ASSERT
 // Don't implement this by using is_in_young().  This method is used
 // in some cases to check that is_in_young() is correct.
 bool ParallelScavengeHeap::is_in_partial_collection(const void *p) {
   assert(is_in_reserved(p) || p == NULL,
     "Does not work if address is non-null and outside of the heap");
   // The order of the generations is perm (low addr), old, young (high addr)
   return p >= old_gen()->reserved().end();
 }
 #endif
 // There are two levels of allocation policy here.
 //
 // When an allocation request fails, the requesting thread must invoke a VM
 // operation, transfer control to the VM thread, and await the results of a
 // garbage collection. That is quite expensive, and we should avoid doing it
 // multiple times if possible.
 //
 // To accomplish this, we have a basic allocation policy, and also a
 // failed allocation policy.
 //
 // The basic allocation policy controls how you allocate memory without
 // attempting garbage collection. It is okay to grab locks and
 // expand the heap, if that can be done without coming to a safepoint.
 // It is likely that the basic allocation policy will not be very
 // aggressive.
 //
 // The failed allocation policy is invoked from the VM thread after
 // the basic allocation policy is unable to satisfy a mem_allocate
 // request. This policy needs to cover the entire range of collection,
 // heap expansion, and out-of-memory conditions. It should make every
 // attempt to allocate the requested memory.
 // Basic allocation policy. Should never be called at a safepoint, or
 // from the VM thread.
 //
 // This method must handle cases where many mem_allocate requests fail
 // simultaneously. When that happens, only one VM operation will succeed,
 // and the rest will not be executed. For that reason, this method loops
 // during failed allocation attempts. If the java heap becomes exhausted,
 // we rely on the size_policy object to force a bail out.
 HeapWord* ParallelScavengeHeap::mem_allocate(
                                      size_t size,
                                      bool* gc_overhead_limit_was_exceeded) {
   assert(!SafepointSynchronize::is_at_safepoint(), "should not be at safepoint");
   assert(Thread::current() != (Thread*)VMThread::vm_thread(), "should not be in vm thread");
   assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
   // In general gc_overhead_limit_was_exceeded should be false so
   // set it so here and reset it to true only if the gc time
   // limit is being exceeded as checked below.
   *gc_overhead_limit_was_exceeded = false;
   HeapWord* result = young_gen()->allocate(size);
   uint loop_count = 0;
   uint gc_count = 0;
   while (result == NULL) {
     // We don't want to have multiple collections for a single filled generation.
     // To prevent this, each thread tracks the total_collections() value, and if
     // the count has changed, does not do a new collection.
     //
     // The collection count must be read only while holding the heap lock. VM
     // operations also hold the heap lock during collections. There is a lock
     // contention case where thread A blocks waiting on the Heap_lock, while
     // thread B is holding it doing a collection. When thread A gets the lock,
     // the collection count has already changed. To prevent duplicate collections,
     // The policy MUST attempt allocations during the same period it reads the
     // total_collections() value!
     {
       MutexLocker ml(Heap_lock);
       gc_count = Universe::heap()->total_collections();
       result = young_gen()->allocate(size);
       if (result != NULL) {
         return result;
       }
       // If certain conditions hold, try allocating from the old gen.
       result = mem_allocate_old_gen(size);
       if (result != NULL) {
         return result;
       }
       // Failed to allocate without a gc.
       if (GC_locker::is_active_and_needs_gc()) {
         // If this thread is not in a jni critical section, we stall
         // the requestor until the critical section has cleared and
         // GC allowed. When the critical section clears, a GC is
         // initiated by the last thread exiting the critical section; so
         // we retry the allocation sequence from the beginning of the loop,
         // rather than causing more, now probably unnecessary, GC attempts.
         JavaThread* jthr = JavaThread::current();
         if (!jthr->in_critical()) {
           MutexUnlocker mul(Heap_lock);
           GC_locker::stall_until_clear();
           continue;
         } else {
           if (CheckJNICalls) {
             fatal("Possible deadlock due to allocating while"
                   " in jni critical section");
           }
           return NULL;
         }
       }
     }
     if (result == NULL) {
       // Generate a VM operation
       VM_ParallelGCFailedAllocation op(size, gc_count);
       VMThread::execute(&op);
       // Did the VM operation execute? If so, return the result directly.
       // This prevents us from looping until time out on requests that can
       // not be satisfied.
       if (op.prologue_succeeded()) {
         assert(Universe::heap()->is_in_or_null(op.result()),
           "result not in heap");
         // If GC was locked out during VM operation then retry allocation
         // and/or stall as necessary.
         if (op.gc_locked()) {
           assert(op.result() == NULL, "must be NULL if gc_locked() is true");
           continue;  // retry and/or stall as necessary
         }
         // Exit the loop if the gc time limit has been exceeded.
         // The allocation must have failed above ("result" guarding
         // this path is NULL) and the most recent collection has exceeded the
         // gc overhead limit (although enough may have been collected to
         // satisfy the allocation).  Exit the loop so that an out-of-memory
         // will be thrown (return a NULL ignoring the contents of
         // op.result()),
         // but clear gc_overhead_limit_exceeded so that the next collection
         // starts with a clean slate (i.e., forgets about previous overhead
         // excesses).  Fill op.result() with a filler object so that the
         // heap remains parsable.
         const bool limit_exceeded = size_policy()->gc_overhead_limit_exceeded();
         const bool softrefs_clear = collector_policy()->all_soft_refs_clear();
         assert(!limit_exceeded || softrefs_clear, "Should have been cleared");
         if (limit_exceeded && softrefs_clear) {
           *gc_overhead_limit_was_exceeded = true;
           size_policy()->set_gc_overhead_limit_exceeded(false);
           if (PrintGCDetails && Verbose) {
             gclog_or_tty->print_cr("ParallelScavengeHeap::mem_allocate: "
               "return NULL because gc_overhead_limit_exceeded is set");
           }
           if (op.result() != NULL) {
             CollectedHeap::fill_with_object(op.result(), size);
           }
           return NULL;
         }
         return op.result();
       }
     }
     // The policy object will prevent us from looping forever. If the
     // time spent in gc crosses a threshold, we will bail out.
     loop_count++;
     if ((result == NULL) && (QueuedAllocationWarningCount > 0) &&
         (loop_count % QueuedAllocationWarningCount == 0)) {
       warning("ParallelScavengeHeap::mem_allocate retries %d times \n\t"
               " size=%d", loop_count, size);
     }
   }
   return result;
 }
 // A "death march" is a series of ultra-slow allocations in which a full gc is
 // done before each allocation, and after the full gc the allocation still
 // cannot be satisfied from the young gen.  This routine detects that condition;
 // it should be called after a full gc has been done and the allocation
 // attempted from the young gen. The parameter 'addr' should be the result of
 // that young gen allocation attempt.
 void
 ParallelScavengeHeap::death_march_check(HeapWord* const addr, size_t size) {
   if (addr != NULL) {
     _death_march_count = 0;  // death march has ended
   } else if (_death_march_count == 0) {
     if (should_alloc_in_eden(size)) {
       _death_march_count = 1;    // death march has started
     }
   }
 }
 HeapWord* ParallelScavengeHeap::mem_allocate_old_gen(size_t size) {
   if (!should_alloc_in_eden(size) || GC_locker::is_active_and_needs_gc()) {
     // Size is too big for eden, or gc is locked out.
     return old_gen()->allocate(size);
   }
   // If a "death march" is in progress, allocate from the old gen a limited
   // number of times before doing a GC.
   if (_death_march_count > 0) {
     if (_death_march_count < 64) {
       ++_death_march_count;
       return old_gen()->allocate(size);
     } else {
       _death_march_count = 0;
     }
   }
   return NULL;
 }
 // Failed allocation policy. Must be called from the VM thread, and
 // only at a safepoint! Note that this method has policy for allocation
 // flow, and NOT collection policy. So we do not check for gc collection
 // time over limit here, that is the responsibility of the heap specific
 // collection methods. This method decides where to attempt allocations,
 // and when to attempt collections, but no collection specific policy.
 HeapWord* ParallelScavengeHeap::failed_mem_allocate(size_t size) {
   assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
   assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
   assert(!Universe::heap()->is_gc_active(), "not reentrant");
   assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
   // We assume that allocation in eden will fail unless we collect.
   // First level allocation failure, scavenge and allocate in young gen.
   GCCauseSetter gccs(this, GCCause::_allocation_failure);
   const bool invoked_full_gc = PSScavenge::invoke();
   HeapWord* result = young_gen()->allocate(size);
   // Second level allocation failure.
   //   Mark sweep and allocate in young generation.
   if (result == NULL && !invoked_full_gc) {
     invoke_full_gc(false);
     result = young_gen()->allocate(size);
   }
   death_march_check(result, size);
   // Third level allocation failure.
   //   After mark sweep and young generation allocation failure,
   //   allocate in old generation.
   if (result == NULL) {
     result = old_gen()->allocate(size);
   }
   // Fourth level allocation failure. We're running out of memory.
   //   More complete mark sweep and allocate in young generation.
   if (result == NULL) {
     invoke_full_gc(true);
     result = young_gen()->allocate(size);
   }
   // Fifth level allocation failure.
   //   After more complete mark sweep, allocate in old generation.
   if (result == NULL) {
     result = old_gen()->allocate(size);
   }
   return result;
 }
 //
 // This is the policy loop for allocating in the permanent generation.
 // If the initial allocation fails, we create a vm operation which will
 // cause a collection.
 HeapWord* ParallelScavengeHeap::permanent_mem_allocate(size_t size) {
   assert(!SafepointSynchronize::is_at_safepoint(), "should not be at safepoint");
   assert(Thread::current() != (Thread*)VMThread::vm_thread(), "should not be in vm thread");
   assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
   HeapWord* result;
   uint loop_count = 0;
   uint gc_count = 0;
   uint full_gc_count = 0;
   do {
     // We don't want to have multiple collections for a single filled generation.
     // To prevent this, each thread tracks the total_collections() value, and if
     // the count has changed, does not do a new collection.
     //
     // The collection count must be read only while holding the heap lock. VM
     // operations also hold the heap lock during collections. There is a lock
     // contention case where thread A blocks waiting on the Heap_lock, while
     // thread B is holding it doing a collection. When thread A gets the lock,
     // the collection count has already changed. To prevent duplicate collections,
     // The policy MUST attempt allocations during the same period it reads the
     // total_collections() value!
     {
       MutexLocker ml(Heap_lock);
       gc_count      = Universe::heap()->total_collections();
       full_gc_count = Universe::heap()->total_full_collections();
       result = perm_gen()->allocate_permanent(size);
       if (result != NULL) {
         return result;
       }
       if (GC_locker::is_active_and_needs_gc()) {
         // If this thread is not in a jni critical section, we stall
         // the requestor until the critical section has cleared and
         // GC allowed. When the critical section clears, a GC is
         // initiated by the last thread exiting the critical section; so
         // we retry the allocation sequence from the beginning of the loop,
         // rather than causing more, now probably unnecessary, GC attempts.
         JavaThread* jthr = JavaThread::current();
         if (!jthr->in_critical()) {
           MutexUnlocker mul(Heap_lock);
           GC_locker::stall_until_clear();
           continue;
         } else {
           if (CheckJNICalls) {
             fatal("Possible deadlock due to allocating while"
                   " in jni critical section");
           }
           return NULL;
         }
       }
     }
     if (result == NULL) {
       // Exit the loop if the gc time limit has been exceeded.
       // The allocation must have failed above (result must be NULL),
       // and the most recent collection must have exceeded the
       // gc time limit.  Exit the loop so that an out-of-memory
       // will be thrown (returning a NULL will do that), but
       // clear gc_overhead_limit_exceeded so that the next collection
       // will succeeded if the applications decides to handle the
       // out-of-memory and tries to go on.
       const bool limit_exceeded = size_policy()->gc_overhead_limit_exceeded();
       if (limit_exceeded) {
         size_policy()->set_gc_overhead_limit_exceeded(false);
         if (PrintGCDetails && Verbose) {
           gclog_or_tty->print_cr("ParallelScavengeHeap::permanent_mem_allocate:"
             " return NULL because gc_overhead_limit_exceeded is set");
         }
         assert(result == NULL, "Allocation did not fail");
         return NULL;
       }
       // Generate a VM operation
       VM_ParallelGCFailedPermanentAllocation op(size, gc_count, full_gc_count);
       VMThread::execute(&op);
       // Did the VM operation execute? If so, return the result directly.
       // This prevents us from looping until time out on requests that can
       // not be satisfied.
       if (op.prologue_succeeded()) {
         assert(Universe::heap()->is_in_permanent_or_null(op.result()),
           "result not in heap");
         // If GC was locked out during VM operation then retry allocation
         // and/or stall as necessary.
         if (op.gc_locked()) {
           assert(op.result() == NULL, "must be NULL if gc_locked() is true");
           continue;  // retry and/or stall as necessary
         }
         // If a NULL results is being returned, an out-of-memory
         // will be thrown now.  Clear the gc_overhead_limit_exceeded
         // flag to avoid the following situation.
         //      gc_overhead_limit_exceeded is set during a collection
         //      the collection fails to return enough space and an OOM is thrown
         //      a subsequent GC prematurely throws an out-of-memory because
         //        the gc_overhead_limit_exceeded counts did not start
         //        again from 0.
         if (op.result() == NULL) {
           size_policy()->reset_gc_overhead_limit_count();
         }
         return op.result();
       }
     }
     // The policy object will prevent us from looping forever. If the
     // time spent in gc crosses a threshold, we will bail out.
     loop_count++;
     if ((QueuedAllocationWarningCount > 0) &&
         (loop_count % QueuedAllocationWarningCount == 0)) {
       warning("ParallelScavengeHeap::permanent_mem_allocate retries %d times \n\t"
               " size=%d", loop_count, size);
     }
   } while (result == NULL);
   return result;
 }
 //
 // This is the policy code for permanent allocations which have failed
 // and require a collection. Note that just as in failed_mem_allocate,
 // we do not set collection policy, only where & when to allocate and
 // collect.
 HeapWord* ParallelScavengeHeap::failed_permanent_mem_allocate(size_t size) {
   assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
   assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
   assert(!Universe::heap()->is_gc_active(), "not reentrant");
   assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
   assert(size > perm_gen()->free_in_words(), "Allocation should fail");
   // We assume (and assert!) that an allocation at this point will fail
   // unless we collect.
   // First level allocation failure.  Mark-sweep and allocate in perm gen.
   GCCauseSetter gccs(this, GCCause::_allocation_failure);
   invoke_full_gc(false);
   HeapWord* result = perm_gen()->allocate_permanent(size);
   // Second level allocation failure. We're running out of memory.
   if (result == NULL) {
     invoke_full_gc(true);
     result = perm_gen()->allocate_permanent(size);
   }
   return result;
 }
 void ParallelScavengeHeap::ensure_parsability(bool retire_tlabs) {
   CollectedHeap::ensure_parsability(retire_tlabs);
   young_gen()->eden_space()->ensure_parsability();
 }
 size_t ParallelScavengeHeap::unsafe_max_alloc() {
   return young_gen()->eden_space()->free_in_bytes();
 }
 size_t ParallelScavengeHeap::tlab_capacity(Thread* thr) const {
   return young_gen()->eden_space()->tlab_capacity(thr);
 }
 size_t ParallelScavengeHeap::unsafe_max_tlab_alloc(Thread* thr) const {
   return young_gen()->eden_space()->unsafe_max_tlab_alloc(thr);
 }
 HeapWord* ParallelScavengeHeap::allocate_new_tlab(size_t size) {
   return young_gen()->allocate(size);
 }
 void ParallelScavengeHeap::accumulate_statistics_all_tlabs() {
   CollectedHeap::accumulate_statistics_all_tlabs();
 }
 void ParallelScavengeHeap::resize_all_tlabs() {
   CollectedHeap::resize_all_tlabs();
 }
 bool ParallelScavengeHeap::can_elide_initializing_store_barrier(oop new_obj) {
   // We don't need barriers for stores to objects in the
   // young gen and, a fortiori, for initializing stores to
   // objects therein.
   return is_in_young(new_obj);
 }
 // This method is used by System.gc() and JVMTI.
 void ParallelScavengeHeap::collect(GCCause::Cause cause) {
   assert(!Heap_lock->owned_by_self(),
     "this thread should not own the Heap_lock");
   unsigned int gc_count      = 0;
   unsigned int full_gc_count = 0;
   {
     MutexLocker ml(Heap_lock);
     // This value is guarded by the Heap_lock
     gc_count      = Universe::heap()->total_collections();
     full_gc_count = Universe::heap()->total_full_collections();
   }
   VM_ParallelGCSystemGC op(gc_count, full_gc_count, cause);
   VMThread::execute(&op);
 }
 // This interface assumes that it's being called by the
 // vm thread. It collects the heap assuming that the
 // heap lock is already held and that we are executing in
 // the context of the vm thread.
 void ParallelScavengeHeap::collect_as_vm_thread(GCCause::Cause cause) {
   assert(Thread::current()->is_VM_thread(), "Precondition#1");
   assert(Heap_lock->is_locked(), "Precondition#2");
   GCCauseSetter gcs(this, cause);
   switch (cause) {
     case GCCause::_heap_inspection:
     case GCCause::_heap_dump: {
       HandleMark hm;
       invoke_full_gc(false);
       break;
     }
     default: // XXX FIX ME
       ShouldNotReachHere();
   }
 }
 void ParallelScavengeHeap::oop_iterate(OopClosure* cl) {
   Unimplemented();
 }
 void ParallelScavengeHeap::object_iterate(ObjectClosure* cl) {
   young_gen()->object_iterate(cl);
   old_gen()->object_iterate(cl);
   perm_gen()->object_iterate(cl);
 }
 void ParallelScavengeHeap::permanent_oop_iterate(OopClosure* cl) {
   Unimplemented();
 }
 void ParallelScavengeHeap::permanent_object_iterate(ObjectClosure* cl) {
   perm_gen()->object_iterate(cl);
 }
 HeapWord* ParallelScavengeHeap::block_start(const void* addr) const {
   if (young_gen()->is_in_reserved(addr)) {
     assert(young_gen()->is_in(addr),
            "addr should be in allocated part of young gen");
     // called from os::print_location by find or VMError
     if (Debugging || VMError::fatal_error_in_progress())  return NULL;
     Unimplemented();
   } else if (old_gen()->is_in_reserved(addr)) {
     assert(old_gen()->is_in(addr),
            "addr should be in allocated part of old gen");
     return old_gen()->start_array()->object_start((HeapWord*)addr);
   } else if (perm_gen()->is_in_reserved(addr)) {
     assert(perm_gen()->is_in(addr),
            "addr should be in allocated part of perm gen");
     return perm_gen()->start_array()->object_start((HeapWord*)addr);
   }
   return 0;
 }
 size_t ParallelScavengeHeap::block_size(const HeapWord* addr) const {
   return oop(addr)->size();
 }
 bool ParallelScavengeHeap::block_is_obj(const HeapWord* addr) const {
   return block_start(addr) == addr;
 }
 jlong ParallelScavengeHeap::millis_since_last_gc() {
   return UseParallelOldGC ?
     PSParallelCompact::millis_since_last_gc() :
     PSMarkSweep::millis_since_last_gc();
 }
 void ParallelScavengeHeap::prepare_for_verify() {
   ensure_parsability(false);  // no need to retire TLABs for verification
 }
 void ParallelScavengeHeap::print_on(outputStream* st) const {
   young_gen()->print_on(st);
   old_gen()->print_on(st);
   perm_gen()->print_on(st);
 }
 void ParallelScavengeHeap::gc_threads_do(ThreadClosure* tc) const {
   PSScavenge::gc_task_manager()->threads_do(tc);
 }
 void ParallelScavengeHeap::print_gc_threads_on(outputStream* st) const {
   PSScavenge::gc_task_manager()->print_threads_on(st);
 }
 void ParallelScavengeHeap::print_tracing_info() const {
   if (TraceGen0Time) {
     double time = PSScavenge::accumulated_time()->seconds();
     tty->print_cr("[Accumulated GC generation 0 time %3.7f secs]", time);
   }
   if (TraceGen1Time) {
     double time = PSMarkSweep::accumulated_time()->seconds();
     tty->print_cr("[Accumulated GC generation 1 time %3.7f secs]", time);
   }
 }
 void ParallelScavengeHeap::verify(bool allow_dirty, bool silent, VerifyOption option /* ignored */) {
   // Why do we need the total_collections()-filter below?
   if (total_collections() > 0) {
     if (!silent) {
       gclog_or_tty->print("permanent ");
     }
     perm_gen()->verify(allow_dirty);
     if (!silent) {
       gclog_or_tty->print("tenured ");
     }
     old_gen()->verify(allow_dirty);
     if (!silent) {
       gclog_or_tty->print("eden ");
     }
     young_gen()->verify(allow_dirty);
   }
 }
 void ParallelScavengeHeap::print_heap_change(size_t prev_used) {
   if (PrintGCDetails && Verbose) {
     gclog_or_tty->print(" "  SIZE_FORMAT
                         "->" SIZE_FORMAT
                         "("  SIZE_FORMAT ")",
                         prev_used, used(), capacity());
   } else {
     gclog_or_tty->print(" "  SIZE_FORMAT "K"
                         "->" SIZE_FORMAT "K"
                         "("  SIZE_FORMAT "K)",
                         prev_used / K, used() / K, capacity() / K);
   }
 }
 ParallelScavengeHeap* ParallelScavengeHeap::heap() {
   assert(_psh != NULL, "Uninitialized access to ParallelScavengeHeap::heap()");
   assert(_psh->kind() == CollectedHeap::ParallelScavengeHeap, "not a parallel scavenge heap");
   return _psh;
 }
 // Before delegating the resize to the young generation,
 // the reserved space for the young and old generations
 // may be changed to accomodate the desired resize.
 void ParallelScavengeHeap::resize_young_gen(size_t eden_size,
     size_t survivor_size) {
   if (UseAdaptiveGCBoundary) {
     if (size_policy()->bytes_absorbed_from_eden() != 0) {
       size_policy()->reset_bytes_absorbed_from_eden();
       return;  // The generation changed size already.
     }
     gens()->adjust_boundary_for_young_gen_needs(eden_size, survivor_size);
   }
   // Delegate the resize to the generation.
   _young_gen->resize(eden_size, survivor_size);
 }
 // Before delegating the resize to the old generation,
 // the reserved space for the young and old generations
 // may be changed to accomodate the desired resize.
 void ParallelScavengeHeap::resize_old_gen(size_t desired_free_space) {
   if (UseAdaptiveGCBoundary) {
     if (size_policy()->bytes_absorbed_from_eden() != 0) {
       size_policy()->reset_bytes_absorbed_from_eden();
       return;  // The generation changed size already.
     }
     gens()->adjust_boundary_for_old_gen_needs(desired_free_space);
   }
   // Delegate the resize to the generation.
   _old_gen->resize(desired_free_space);
 }
 ParallelScavengeHeap::ParStrongRootsScope::ParStrongRootsScope() {
   // nothing particular
 }
 ParallelScavengeHeap::ParStrongRootsScope::~ParStrongRootsScope() {
   // nothing particular
 }
 #ifndef PRODUCT
 void ParallelScavengeHeap::record_gen_tops_before_GC() {
   if (ZapUnusedHeapArea) {
     young_gen()->record_spaces_top();
     old_gen()->record_spaces_top();
     perm_gen()->record_spaces_top();
   }
 }
 void ParallelScavengeHeap::gen_mangle_unused_area() {
   if (ZapUnusedHeapArea) {
     young_gen()->eden_space()->mangle_unused_area();
     young_gen()->to_space()->mangle_unused_area();
     young_gen()->from_space()->mangle_unused_area();
     old_gen()->object_space()->mangle_unused_area();
     perm_gen()->object_space()->mangle_unused_area();
   }
 }
 #endif

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/parallelScavenge/parallelScavengeHeap.cpp@8a729074feae (annotated)

src/share/vm/gc_implementation/parallelScavenge/parallelScavengeHeap.cpp