Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright (c) 2001, 2011, 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

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  */

 #include "precompiled.hpp"

 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"

 #include "gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp"

 #include "gc_implementation/parallelScavenge/psMarkSweepDecorator.hpp"

 #include "gc_implementation/parallelScavenge/psOldGen.hpp"

 #include "gc_implementation/shared/spaceDecorator.hpp"

 #include "memory/cardTableModRefBS.hpp"

 #include "memory/gcLocker.inline.hpp"

 #include "oops/oop.inline.hpp"

 #include "runtime/java.hpp"

 inline const char* PSOldGen::select_name() {

   return UseParallelOldGC ? "ParOldGen" : "PSOldGen";

 }

 PSOldGen::PSOldGen(ReservedSpace rs, size_t alignment,

                    size_t initial_size, size_t min_size, size_t max_size,

                    const char* perf_data_name, int level):

   _name(select_name()), _init_gen_size(initial_size), _min_gen_size(min_size),

   _max_gen_size(max_size)

 {

   initialize(rs, alignment, perf_data_name, level);

 }

 PSOldGen::PSOldGen(size_t initial_size,

                    size_t min_size, size_t max_size,

                    const char* perf_data_name, int level):

   _name(select_name()), _init_gen_size(initial_size), _min_gen_size(min_size),

   _max_gen_size(max_size)

 {}

 void PSOldGen::initialize(ReservedSpace rs, size_t alignment,

                           const char* perf_data_name, int level) {

   initialize_virtual_space(rs, alignment);

   initialize_work(perf_data_name, level);

   // The old gen can grow to gen_size_limit().  _reserve reflects only

   // the current maximum that can be committed.

   assert(_reserved.byte_size() <= gen_size_limit(), "Consistency check");

 }

 void PSOldGen::initialize_virtual_space(ReservedSpace rs, size_t alignment) {

   _virtual_space = new PSVirtualSpace(rs, alignment);

   if (!_virtual_space->expand_by(_init_gen_size)) {

     vm_exit_during_initialization("Could not reserve enough space for "

                                   "object heap");

   }

 }

 void PSOldGen::initialize_work(const char* perf_data_name, int level) {

   //

   // Basic memory initialization

   //

   MemRegion limit_reserved((HeapWord*)virtual_space()->low_boundary(),

     heap_word_size(_max_gen_size));

   assert(limit_reserved.byte_size() == _max_gen_size,

     "word vs bytes confusion");

   //

   // Object start stuff

   //

   start_array()->initialize(limit_reserved);

   _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),

                         (HeapWord*)virtual_space()->high_boundary());

   //

   // Card table stuff

   //

   MemRegion cmr((HeapWord*)virtual_space()->low(),

                 (HeapWord*)virtual_space()->high());

   if (ZapUnusedHeapArea) {

     // Mangle newly committed space immediately rather than

     // waiting for the initialization of the space even though

     // mangling is related to spaces.  Doing it here eliminates

     // the need to carry along information that a complete mangling

     // (bottom to end) needs to be done.

     SpaceMangler::mangle_region(cmr);

   }

   Universe::heap()->barrier_set()->resize_covered_region(cmr);

   CardTableModRefBS* _ct = (CardTableModRefBS*)Universe::heap()->barrier_set();

   assert (_ct->kind() == BarrierSet::CardTableModRef, "Sanity");

   // Verify that the start and end of this generation is the start of a card.

   // If this wasn't true, a single card could span more than one generation,

   // which would cause problems when we commit/uncommit memory, and when we

   // clear and dirty cards.

   guarantee(_ct->is_card_aligned(_reserved.start()), "generation must be card aligned");

   if (_reserved.end() != Universe::heap()->reserved_region().end()) {

     // Don't check at the very end of the heap as we'll assert that we're probing off

     // the end if we try.

     guarantee(_ct->is_card_aligned(_reserved.end()), "generation must be card aligned");

   }

   //

   // ObjectSpace stuff

   //

   _object_space = new MutableSpace(virtual_space()->alignment());

   if (_object_space == NULL)

     vm_exit_during_initialization("Could not allocate an old gen space");

   object_space()->initialize(cmr,

                              SpaceDecorator::Clear,

                              SpaceDecorator::Mangle);

   _object_mark_sweep = new PSMarkSweepDecorator(_object_space, start_array(), MarkSweepDeadRatio);

   if (_object_mark_sweep == NULL)

     vm_exit_during_initialization("Could not complete allocation of old generation");

   // Update the start_array

   start_array()->set_covered_region(cmr);

   // Generation Counters, generation 'level', 1 subspace

   _gen_counters = new PSGenerationCounters(perf_data_name, level, 1,

                                            virtual_space());

   _space_counters = new SpaceCounters(perf_data_name, 0,

                                       virtual_space()->reserved_size(),

                                       _object_space, _gen_counters);

 }

 // Assume that the generation has been allocated if its

 // reserved size is not 0.

 bool  PSOldGen::is_allocated() {

   return virtual_space()->reserved_size() != 0;

 }

 void PSOldGen::precompact() {

   ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();

   assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");

   // Reset start array first.

   start_array()->reset();

   object_mark_sweep()->precompact();

   // Now compact the young gen

   heap->young_gen()->precompact();

 }

 void PSOldGen::adjust_pointers() {

   object_mark_sweep()->adjust_pointers();

 }

 void PSOldGen::compact() {

   object_mark_sweep()->compact(ZapUnusedHeapArea);

 }

 size_t PSOldGen::contiguous_available() const {

   return object_space()->free_in_bytes() + virtual_space()->uncommitted_size();

 }

 // Allocation. We report all successful allocations to the size policy

 // Note that the perm gen does not use this method, and should not!

 HeapWord* PSOldGen::allocate(size_t word_size, bool is_tlab) {

   assert_locked_or_safepoint(Heap_lock);

   HeapWord* res = allocate_noexpand(word_size, is_tlab);

   if (res == NULL) {

     res = expand_and_allocate(word_size, is_tlab);

   }

   // Allocations in the old generation need to be reported

   if (res != NULL) {

     ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();

     heap->size_policy()->tenured_allocation(word_size);

   }

   return res;

 }

 HeapWord* PSOldGen::expand_and_allocate(size_t word_size, bool is_tlab) {

   assert(!is_tlab, "TLAB's are not supported in PSOldGen");

   expand(word_size*HeapWordSize);

   if (GCExpandToAllocateDelayMillis > 0) {

     os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false);

   }

   return allocate_noexpand(word_size, is_tlab);

 }

 HeapWord* PSOldGen::expand_and_cas_allocate(size_t word_size) {

   expand(word_size*HeapWordSize);

   if (GCExpandToAllocateDelayMillis > 0) {

     os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false);

   }

   return cas_allocate_noexpand(word_size);

 }

 void PSOldGen::expand(size_t bytes) {

   if (bytes == 0) {

     return;

   }

   MutexLocker x(ExpandHeap_lock);

   const size_t alignment = virtual_space()->alignment();

   size_t aligned_bytes  = align_size_up(bytes, alignment);

   size_t aligned_expand_bytes = align_size_up(MinHeapDeltaBytes, alignment);

   if (aligned_bytes == 0){

     // The alignment caused the number of bytes to wrap.  An expand_by(0) will

     // return true with the implication that and expansion was done when it

     // was not.  A call to expand implies a best effort to expand by "bytes"

     // but not a guarantee.  Align down to give a best effort.  This is likely

     // the most that the generation can expand since it has some capacity to

     // start with.

     aligned_bytes = align_size_down(bytes, alignment);

   }

   bool success = false;

   if (aligned_expand_bytes > aligned_bytes) {

     success = expand_by(aligned_expand_bytes);

   }

   if (!success) {

     success = expand_by(aligned_bytes);

   }

   if (!success) {

     success = expand_to_reserved();

   }

   if (PrintGC && Verbose) {

     if (success && GC_locker::is_active()) {

       gclog_or_tty->print_cr("Garbage collection disabled, expanded heap instead");

     }

   }

 }

 bool PSOldGen::expand_by(size_t bytes) {

   assert_lock_strong(ExpandHeap_lock);

   assert_locked_or_safepoint(Heap_lock);

   if (bytes == 0) {

     return true;  // That's what virtual_space()->expand_by(0) would return

   }

   bool result = virtual_space()->expand_by(bytes);

   if (result) {

     if (ZapUnusedHeapArea) {

       // We need to mangle the newly expanded area. The memregion spans

       // end -> new_end, we assume that top -> end is already mangled.

       // Do the mangling before post_resize() is called because

       // the space is available for allocation after post_resize();

       HeapWord* const virtual_space_high = (HeapWord*) virtual_space()->high();

       assert(object_space()->end() < virtual_space_high,

         "Should be true before post_resize()");

       MemRegion mangle_region(object_space()->end(), virtual_space_high);

       // Note that the object space has not yet been updated to

       // coincede with the new underlying virtual space.

       SpaceMangler::mangle_region(mangle_region);

     }

     post_resize();

     if (UsePerfData) {

       _space_counters->update_capacity();

       _gen_counters->update_all();

     }

   }

   if (result && Verbose && PrintGC) {

     size_t new_mem_size = virtual_space()->committed_size();

     size_t old_mem_size = new_mem_size - bytes;

     gclog_or_tty->print_cr("Expanding %s from " SIZE_FORMAT "K by "

                                        SIZE_FORMAT "K to "

                                        SIZE_FORMAT "K",

                     name(), old_mem_size/K, bytes/K, new_mem_size/K);

   }

   return result;

 }

 bool PSOldGen::expand_to_reserved() {

   assert_lock_strong(ExpandHeap_lock);

   assert_locked_or_safepoint(Heap_lock);

   bool result = true;

   const size_t remaining_bytes = virtual_space()->uncommitted_size();

   if (remaining_bytes > 0) {

     result = expand_by(remaining_bytes);

     DEBUG_ONLY(if (!result) warning("grow to reserve failed"));

   }

   return result;

 }

 void PSOldGen::shrink(size_t bytes) {

   assert_lock_strong(ExpandHeap_lock);

   assert_locked_or_safepoint(Heap_lock);

   size_t size = align_size_down(bytes, virtual_space()->alignment());

   if (size > 0) {

     assert_lock_strong(ExpandHeap_lock);

     virtual_space()->shrink_by(bytes);

     post_resize();

     if (Verbose && PrintGC) {

       size_t new_mem_size = virtual_space()->committed_size();

       size_t old_mem_size = new_mem_size + bytes;

       gclog_or_tty->print_cr("Shrinking %s from " SIZE_FORMAT "K by "

                                          SIZE_FORMAT "K to "

                                          SIZE_FORMAT "K",

                       name(), old_mem_size/K, bytes/K, new_mem_size/K);

     }

   }

 }

 void PSOldGen::resize(size_t desired_free_space) {

   const size_t alignment = virtual_space()->alignment();

   const size_t size_before = virtual_space()->committed_size();

   size_t new_size = used_in_bytes() + desired_free_space;

   if (new_size < used_in_bytes()) {

     // Overflowed the addition.

     new_size = gen_size_limit();

   }

   // Adjust according to our min and max

   new_size = MAX2(MIN2(new_size, gen_size_limit()), min_gen_size());

   assert(gen_size_limit() >= reserved().byte_size(), "max new size problem?");

   new_size = align_size_up(new_size, alignment);

   const size_t current_size = capacity_in_bytes();

   if (PrintAdaptiveSizePolicy && Verbose) {

     gclog_or_tty->print_cr("AdaptiveSizePolicy::old generation size: "

       "desired free: " SIZE_FORMAT " used: " SIZE_FORMAT

       " new size: " SIZE_FORMAT " current size " SIZE_FORMAT

       " gen limits: " SIZE_FORMAT " / " SIZE_FORMAT,

       desired_free_space, used_in_bytes(), new_size, current_size,

       gen_size_limit(), min_gen_size());

   }

   if (new_size == current_size) {

     // No change requested

     return;

   }

   if (new_size > current_size) {

     size_t change_bytes = new_size - current_size;

     expand(change_bytes);

   } else {

     size_t change_bytes = current_size - new_size;

     // shrink doesn't grab this lock, expand does. Is that right?

     MutexLocker x(ExpandHeap_lock);

     shrink(change_bytes);

   }

   if (PrintAdaptiveSizePolicy) {

     ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();

     assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");

     gclog_or_tty->print_cr("AdaptiveSizePolicy::old generation size: "

                   "collection: %d "

                   "(" SIZE_FORMAT ") -> (" SIZE_FORMAT ") ",

                   heap->total_collections(),

                   size_before, virtual_space()->committed_size());

   }

 }

 // NOTE! We need to be careful about resizing. During a GC, multiple

 // allocators may be active during heap expansion. If we allow the

 // heap resizing to become visible before we have correctly resized

 // all heap related data structures, we may cause program failures.

 void PSOldGen::post_resize() {

   // First construct a memregion representing the new size

   MemRegion new_memregion((HeapWord*)virtual_space()->low(),

     (HeapWord*)virtual_space()->high());

   size_t new_word_size = new_memregion.word_size();

   start_array()->set_covered_region(new_memregion);

   Universe::heap()->barrier_set()->resize_covered_region(new_memregion);

   // ALWAYS do this last!!

   object_space()->initialize(new_memregion,

                              SpaceDecorator::DontClear,

                              SpaceDecorator::DontMangle);

   assert(new_word_size == heap_word_size(object_space()->capacity_in_bytes()),

     "Sanity");

 }

 size_t PSOldGen::gen_size_limit() {

   return _max_gen_size;

 }

 void PSOldGen::reset_after_change() {

   ShouldNotReachHere();

   return;

 }

 size_t PSOldGen::available_for_expansion() {

   ShouldNotReachHere();

   return 0;

 }

 size_t PSOldGen::available_for_contraction() {

   ShouldNotReachHere();

   return 0;

 }

 void PSOldGen::print() const { print_on(tty);}

 void PSOldGen::print_on(outputStream* st) const {

   st->print(" %-15s", name());

   if (PrintGCDetails && Verbose) {

     st->print(" total " SIZE_FORMAT ", used " SIZE_FORMAT,

                 capacity_in_bytes(), used_in_bytes());

   } else {

     st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K",

                 capacity_in_bytes()/K, used_in_bytes()/K);

   }

   st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT ")",

                 virtual_space()->low_boundary(),

                 virtual_space()->high(),

                 virtual_space()->high_boundary());

   st->print("  object"); object_space()->print_on(st);

 }

 void PSOldGen::print_used_change(size_t prev_used) const {

   gclog_or_tty->print(" [%s:", name());

   gclog_or_tty->print(" "  SIZE_FORMAT "K"

                       "->" SIZE_FORMAT "K"

                       "("  SIZE_FORMAT "K)",

                       prev_used / K, used_in_bytes() / K,

                       capacity_in_bytes() / K);

   gclog_or_tty->print("]");

 }

 void PSOldGen::update_counters() {

   if (UsePerfData) {

     _space_counters->update_all();

     _gen_counters->update_all();

   }

 }

 #ifndef PRODUCT

 void PSOldGen::space_invariants() {

   assert(object_space()->end() == (HeapWord*) virtual_space()->high(),

     "Space invariant");

   assert(object_space()->bottom() == (HeapWord*) virtual_space()->low(),

     "Space invariant");

   assert(virtual_space()->low_boundary() <= virtual_space()->low(),

     "Space invariant");

   assert(virtual_space()->high_boundary() >= virtual_space()->high(),

     "Space invariant");

   assert(virtual_space()->low_boundary() == (char*) _reserved.start(),

     "Space invariant");

   assert(virtual_space()->high_boundary() == (char*) _reserved.end(),

     "Space invariant");

   assert(virtual_space()->committed_size() <= virtual_space()->reserved_size(),

     "Space invariant");

 }

 #endif

 void PSOldGen::verify(bool allow_dirty) {

   object_space()->verify(allow_dirty);

 }

 class VerifyObjectStartArrayClosure : public ObjectClosure {

   PSOldGen* _gen;

   ObjectStartArray* _start_array;

  public:

   VerifyObjectStartArrayClosure(PSOldGen* gen, ObjectStartArray* start_array) :

     _gen(gen), _start_array(start_array) { }

   virtual void do_object(oop obj) {

     HeapWord* test_addr = (HeapWord*)obj + 1;

     guarantee(_start_array->object_start(test_addr) == (HeapWord*)obj, "ObjectStartArray cannot find start of object");

     guarantee(_start_array->is_block_allocated((HeapWord*)obj), "ObjectStartArray missing block allocation");

   }

 };

 void PSOldGen::verify_object_start_array() {

   VerifyObjectStartArrayClosure check( this, &_start_array );

   object_iterate(&check);

 }

 #ifndef PRODUCT

 void PSOldGen::record_spaces_top() {

   assert(ZapUnusedHeapArea, "Not mangling unused space");

   object_space()->set_top_for_allocations();

 }

 #endif