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

 /*

  * Copyright 2001-2007 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

  * CA 95054 USA or visit www.sun.com if you need additional information or

  * have any questions.

  *

  */

 # include "incls/_precompiled.incl"

 # include "incls/_collectorPolicy.cpp.incl"

 // CollectorPolicy methods.

 void CollectorPolicy::initialize_flags() {

   if (PermSize > MaxPermSize) {

     MaxPermSize = PermSize;

   }

   PermSize = align_size_down(PermSize, min_alignment());

   MaxPermSize = align_size_up(MaxPermSize, max_alignment());

   MinPermHeapExpansion = align_size_down(MinPermHeapExpansion, min_alignment());

   MaxPermHeapExpansion = align_size_down(MaxPermHeapExpansion, min_alignment());

   MinHeapDeltaBytes = align_size_up(MinHeapDeltaBytes, min_alignment());

   SharedReadOnlySize = align_size_up(SharedReadOnlySize, max_alignment());

   SharedReadWriteSize = align_size_up(SharedReadWriteSize, max_alignment());

   SharedMiscDataSize = align_size_up(SharedMiscDataSize, max_alignment());

   assert(PermSize    % min_alignment() == 0, "permanent space alignment");

   assert(MaxPermSize % max_alignment() == 0, "maximum permanent space alignment");

   assert(SharedReadOnlySize % max_alignment() == 0, "read-only space alignment");

   assert(SharedReadWriteSize % max_alignment() == 0, "read-write space alignment");

   assert(SharedMiscDataSize % max_alignment() == 0, "misc-data space alignment");

   if (PermSize < M) {

     vm_exit_during_initialization("Too small initial permanent heap");

   }

 }

 void CollectorPolicy::initialize_size_info() {

   // User inputs from -mx and ms are aligned

   _initial_heap_byte_size = align_size_up(Arguments::initial_heap_size(),

                                           min_alignment());

   _min_heap_byte_size = align_size_up(Arguments::min_heap_size(),

                                           min_alignment());

   _max_heap_byte_size = align_size_up(MaxHeapSize, max_alignment());

   // Check validity of heap parameters from launcher

   if (_initial_heap_byte_size == 0) {

     _initial_heap_byte_size = NewSize + OldSize;

   } else {

     Universe::check_alignment(_initial_heap_byte_size, min_alignment(),

                             "initial heap");

   }

   if (_min_heap_byte_size == 0) {

     _min_heap_byte_size = NewSize + OldSize;

   } else {

     Universe::check_alignment(_min_heap_byte_size, min_alignment(),

                             "initial heap");

   }

   // Check heap parameter properties

   if (_initial_heap_byte_size < M) {

     vm_exit_during_initialization("Too small initial heap");

   }

   // Check heap parameter properties

   if (_min_heap_byte_size < M) {

     vm_exit_during_initialization("Too small minimum heap");

   }

   if (_initial_heap_byte_size <= NewSize) {

      // make sure there is at least some room in old space

     vm_exit_during_initialization("Too small initial heap for new size specified");

   }

   if (_max_heap_byte_size < _min_heap_byte_size) {

     vm_exit_during_initialization("Incompatible minimum and maximum heap sizes specified");

   }

   if (_initial_heap_byte_size < _min_heap_byte_size) {

     vm_exit_during_initialization("Incompatible minimum and initial heap sizes specified");

   }

   if (_max_heap_byte_size < _initial_heap_byte_size) {

     vm_exit_during_initialization("Incompatible initial and maximum heap sizes specified");

   }

 }

 void CollectorPolicy::initialize_perm_generation(PermGen::Name pgnm) {

   _permanent_generation =

     new PermanentGenerationSpec(pgnm, PermSize, MaxPermSize,

                                 SharedReadOnlySize,

                                 SharedReadWriteSize,

                                 SharedMiscDataSize,

                                 SharedMiscCodeSize);

   if (_permanent_generation == NULL) {

     vm_exit_during_initialization("Unable to allocate gen spec");

   }

 }

 GenRemSet* CollectorPolicy::create_rem_set(MemRegion whole_heap,

                                            int max_covered_regions) {

   switch (rem_set_name()) {

   case GenRemSet::CardTable: {

     if (barrier_set_name() != BarrierSet::CardTableModRef)

       vm_exit_during_initialization("Mismatch between RS and BS.");

     CardTableRS* res = new CardTableRS(whole_heap, max_covered_regions);

     return res;

   }

   default:

     guarantee(false, "unrecognized GenRemSet::Name");

     return NULL;

   }

 }

 // GenCollectorPolicy methods.

 void GenCollectorPolicy::initialize_size_policy(size_t init_eden_size,

                                                 size_t init_promo_size,

                                                 size_t init_survivor_size) {

   double max_gc_minor_pause_sec = ((double) MaxGCMinorPauseMillis)/1000.0;

   _size_policy = new AdaptiveSizePolicy(init_eden_size,

                                         init_promo_size,

                                         init_survivor_size,

                                         max_gc_minor_pause_sec,

                                         GCTimeRatio);

 }

 size_t GenCollectorPolicy::compute_max_alignment() {

   // The card marking array and the offset arrays for old generations are

   // committed in os pages as well. Make sure they are entirely full (to

   // avoid partial page problems), e.g. if 512 bytes heap corresponds to 1

   // byte entry and the os page size is 4096, the maximum heap size should

   // be 512*4096 = 2MB aligned.

   size_t alignment = GenRemSet::max_alignment_constraint(rem_set_name());

   // Parallel GC does its own alignment of the generations to avoid requiring a

   // large page (256M on some platforms) for the permanent generation.  The

   // other collectors should also be updated to do their own alignment and then

   // this use of lcm() should be removed.

   if (UseLargePages && !UseParallelGC) {

       // in presence of large pages we have to make sure that our

       // alignment is large page aware

       alignment = lcm(os::large_page_size(), alignment);

   }

   return alignment;

 }

 void GenCollectorPolicy::initialize_flags() {

   // All sizes must be multiples of the generation granularity.

   set_min_alignment((uintx) Generation::GenGrain);

   set_max_alignment(compute_max_alignment());

   assert(max_alignment() >= min_alignment() &&

          max_alignment() % min_alignment() == 0,

          "invalid alignment constraints");

   CollectorPolicy::initialize_flags();

   // All generational heaps have a youngest gen; handle those flags here.

   // Adjust max size parameters

   if (NewSize > MaxNewSize) {

     MaxNewSize = NewSize;

   }

   NewSize = align_size_down(NewSize, min_alignment());

   MaxNewSize = align_size_down(MaxNewSize, min_alignment());

   // Check validity of heap flags

   assert(NewSize     % min_alignment() == 0, "eden space alignment");

   assert(MaxNewSize  % min_alignment() == 0, "survivor space alignment");

   if (NewSize < 3*min_alignment()) {

      // make sure there room for eden and two survivor spaces

     vm_exit_during_initialization("Too small new size specified");

   }

   if (SurvivorRatio < 1 || NewRatio < 1) {

     vm_exit_during_initialization("Invalid heap ratio specified");

   }

 }

 void TwoGenerationCollectorPolicy::initialize_flags() {

   GenCollectorPolicy::initialize_flags();

   OldSize = align_size_down(OldSize, min_alignment());

   if (NewSize + OldSize > MaxHeapSize) {

     MaxHeapSize = NewSize + OldSize;

   }

   MaxHeapSize = align_size_up(MaxHeapSize, max_alignment());

   always_do_update_barrier = UseConcMarkSweepGC;

   BlockOffsetArrayUseUnallocatedBlock =

       BlockOffsetArrayUseUnallocatedBlock || ParallelGCThreads > 0;

   // Check validity of heap flags

   assert(OldSize     % min_alignment() == 0, "old space alignment");

   assert(MaxHeapSize % max_alignment() == 0, "maximum heap alignment");

 }

 void GenCollectorPolicy::initialize_size_info() {

   CollectorPolicy::initialize_size_info();

   // Minimum sizes of the generations may be different than

   // the initial sizes.

   if (!FLAG_IS_DEFAULT(NewSize)) {

     _min_gen0_size = NewSize;

   } else {

     _min_gen0_size = align_size_down(_min_heap_byte_size / (NewRatio+1),

                                      min_alignment());

     // We bound the minimum size by NewSize below (since it historically

     // would have been NewSize and because the NewRatio calculation could

     // yield a size that is too small) and bound it by MaxNewSize above.

     // This is not always best.  The NewSize calculated by CMS (which has

     // a fixed minimum of 16m) can sometimes be "too" large.  Consider

     // the case where -Xmx32m.  The CMS calculated NewSize would be about

     // half the entire heap which seems too large.  But the counter

     // example is seen when the client defaults for NewRatio are used.

     // An initial young generation size of 640k was observed

     // with -Xmx128m -XX:MaxNewSize=32m when NewSize was not used

     // as a lower bound as with

     // _min_gen0_size = MIN2(_min_gen0_size, MaxNewSize);

     // and 640k seemed too small a young generation.

     _min_gen0_size = MIN2(MAX2(_min_gen0_size, NewSize), MaxNewSize);

   }

   // Parameters are valid, compute area sizes.

   size_t max_new_size = align_size_down(_max_heap_byte_size / (NewRatio+1),

                                         min_alignment());

   max_new_size = MIN2(MAX2(max_new_size, _min_gen0_size), MaxNewSize);

   // desired_new_size is used to set the initial size.  The

   // initial size must be greater than the minimum size.

   size_t desired_new_size =

     align_size_down(_initial_heap_byte_size / (NewRatio+1),

                   min_alignment());

   size_t new_size = MIN2(MAX2(desired_new_size, _min_gen0_size), max_new_size);

   _initial_gen0_size = new_size;

   _max_gen0_size = max_new_size;

 }

 void TwoGenerationCollectorPolicy::initialize_size_info() {

   GenCollectorPolicy::initialize_size_info();

   // Minimum sizes of the generations may be different than

   // the initial sizes.  An inconsistently is permitted here

   // in the total size that can be specified explicitly by

   // command line specification of OldSize and NewSize and

   // also a command line specification of -Xms.  Issue a warning

   // but allow the values to pass.

   if (!FLAG_IS_DEFAULT(OldSize)) {

     _min_gen1_size = OldSize;

     // The generation minimums and the overall heap mimimum should

     // be within one heap alignment.

     if ((_min_gen1_size + _min_gen0_size + max_alignment()) <

          _min_heap_byte_size) {

       warning("Inconsistency between minimum heap size and minimum "

         "generation sizes: using min heap = " SIZE_FORMAT,

         _min_heap_byte_size);

     }

   } else {

     _min_gen1_size = _min_heap_byte_size - _min_gen0_size;

   }

   _initial_gen1_size = _initial_heap_byte_size - _initial_gen0_size;

   _max_gen1_size = _max_heap_byte_size - _max_gen0_size;

 }

 HeapWord* GenCollectorPolicy::mem_allocate_work(size_t size,

                                         bool is_tlab,

                                         bool* gc_overhead_limit_was_exceeded) {

   GenCollectedHeap *gch = GenCollectedHeap::heap();

   debug_only(gch->check_for_valid_allocation_state());

   assert(gch->no_gc_in_progress(), "Allocation during gc not allowed");

   HeapWord* result = NULL;

   // Loop until the allocation is satisified,

   // or unsatisfied after GC.

   for (int try_count = 1; /* return or throw */; try_count += 1) {

     HandleMark hm; // discard any handles allocated in each iteration

     // First allocation attempt is lock-free.

     Generation *gen0 = gch->get_gen(0);

     assert(gen0->supports_inline_contig_alloc(),

       "Otherwise, must do alloc within heap lock");

     if (gen0->should_allocate(size, is_tlab)) {

       result = gen0->par_allocate(size, is_tlab);

       if (result != NULL) {

         assert(gch->is_in_reserved(result), "result not in heap");

         return result;

       }

     }

     unsigned int gc_count_before;  // read inside the Heap_lock locked region

     {

       MutexLocker ml(Heap_lock);

       if (PrintGC && Verbose) {

         gclog_or_tty->print_cr("TwoGenerationCollectorPolicy::mem_allocate_work:"

                       " attempting locked slow path allocation");

       }

       // Note that only large objects get a shot at being

       // allocated in later generations.

       bool first_only = ! should_try_older_generation_allocation(size);

       result = gch->attempt_allocation(size, is_tlab, first_only);

       if (result != NULL) {

         assert(gch->is_in_reserved(result), "result not in heap");

         return result;

       }

       // There are NULL's returned for different circumstances below.

       // 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;

       if (GC_locker::is_active_and_needs_gc()) {

         if (is_tlab) {

           return NULL;  // Caller will retry allocating individual object

         }

         if (!gch->is_maximal_no_gc()) {

           // Try and expand heap to satisfy request

           result = expand_heap_and_allocate(size, is_tlab);

           // result could be null if we are out of space

           if (result != NULL) {

             return result;

           }

         }

         // 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);

           // Wait for JNI critical section to be exited

           GC_locker::stall_until_clear();

           continue;

         } else {

           if (CheckJNICalls) {

             fatal("Possible deadlock due to allocating while"

                   " in jni critical section");

           }

           return NULL;

         }

       }

       // Read the gc count while the heap lock is held.

       gc_count_before = Universe::heap()->total_collections();

     }

     // Allocation has failed and a collection is about

     // to be done.  If the gc time limit was exceeded the

     // last time a collection was done, return NULL so

     // that an out-of-memory will be thrown.  Clear

     // gc_time_limit_exceeded so that subsequent attempts

     // at a collection will be made.

     if (size_policy()->gc_time_limit_exceeded()) {

       *gc_overhead_limit_was_exceeded = true;

       size_policy()->set_gc_time_limit_exceeded(false);

       return NULL;

     }

     VM_GenCollectForAllocation op(size,

                                   is_tlab,

                                   gc_count_before);

     VMThread::execute(&op);

     if (op.prologue_succeeded()) {

       result = op.result();

       if (op.gc_locked()) {

          assert(result == NULL, "must be NULL if gc_locked() is true");

          continue;  // retry and/or stall as necessary

       }

       assert(result == NULL || gch->is_in_reserved(result),

              "result not in heap");

       return result;

     }

     // Give a warning if we seem to be looping forever.

     if ((QueuedAllocationWarningCount > 0) &&

         (try_count % QueuedAllocationWarningCount == 0)) {

           warning("TwoGenerationCollectorPolicy::mem_allocate_work retries %d times \n\t"

                   " size=%d %s", try_count, size, is_tlab ? "(TLAB)" : "");

     }

   }

 }

 HeapWord* GenCollectorPolicy::expand_heap_and_allocate(size_t size,

                                                        bool   is_tlab) {

   GenCollectedHeap *gch = GenCollectedHeap::heap();

   HeapWord* result = NULL;

   for (int i = number_of_generations() - 1; i >= 0 && result == NULL; i--) {

     Generation *gen = gch->get_gen(i);

     if (gen->should_allocate(size, is_tlab)) {

       result = gen->expand_and_allocate(size, is_tlab);

     }

   }

   assert(result == NULL || gch->is_in_reserved(result), "result not in heap");

   return result;

 }

 HeapWord* GenCollectorPolicy::satisfy_failed_allocation(size_t size,

                                                         bool   is_tlab) {

   GenCollectedHeap *gch = GenCollectedHeap::heap();

   GCCauseSetter x(gch, GCCause::_allocation_failure);

   HeapWord* result = NULL;

   assert(size != 0, "Precondition violated");

   if (GC_locker::is_active_and_needs_gc()) {

     // GC locker is active; instead of a collection we will attempt

     // to expand the heap, if there's room for expansion.

     if (!gch->is_maximal_no_gc()) {

       result = expand_heap_and_allocate(size, is_tlab);

     }

     return result;   // could be null if we are out of space

   } else if (!gch->incremental_collection_will_fail()) {

     // The gc_prologues have not executed yet.  The value

     // for incremental_collection_will_fail() is the remanent

     // of the last collection.

     // Do an incremental collection.

     gch->do_collection(false            /* full */,

                        false            /* clear_all_soft_refs */,

                        size             /* size */,

                        is_tlab          /* is_tlab */,

                        number_of_generations() - 1 /* max_level */);

   } else {

     // Try a full collection; see delta for bug id 6266275

     // for the original code and why this has been simplified

     // with from-space allocation criteria modified and

     // such allocation moved out of the safepoint path.

     gch->do_collection(true             /* full */,

                        false            /* clear_all_soft_refs */,

                        size             /* size */,

                        is_tlab          /* is_tlab */,

                        number_of_generations() - 1 /* max_level */);

   }

   result = gch->attempt_allocation(size, is_tlab, false /*first_only*/);

   if (result != NULL) {

     assert(gch->is_in_reserved(result), "result not in heap");

     return result;

   }

   // OK, collection failed, try expansion.

   result = expand_heap_and_allocate(size, is_tlab);

   if (result != NULL) {

     return result;

   }

   // If we reach this point, we're really out of memory. Try every trick

   // we can to reclaim memory. Force collection of soft references. Force

   // a complete compaction of the heap. Any additional methods for finding

   // free memory should be here, especially if they are expensive. If this

   // attempt fails, an OOM exception will be thrown.

   {

     IntFlagSetting flag_change(MarkSweepAlwaysCompactCount, 1); // Make sure the heap is fully compacted

     gch->do_collection(true             /* full */,

                        true             /* clear_all_soft_refs */,

                        size             /* size */,

                        is_tlab          /* is_tlab */,

                        number_of_generations() - 1 /* max_level */);

   }

   result = gch->attempt_allocation(size, is_tlab, false /* first_only */);

   if (result != NULL) {

     assert(gch->is_in_reserved(result), "result not in heap");

     return result;

   }

   // What else?  We might try synchronous finalization later.  If the total

   // space available is large enough for the allocation, then a more

   // complete compaction phase than we've tried so far might be

   // appropriate.

   return NULL;

 }

 size_t GenCollectorPolicy::large_typearray_limit() {

   return FastAllocateSizeLimit;

 }

 // Return true if any of the following is true:

 // . the allocation won't fit into the current young gen heap

 // . gc locker is occupied (jni critical section)

 // . heap memory is tight -- the most recent previous collection

 //   was a full collection because a partial collection (would

 //   have) failed and is likely to fail again

 bool GenCollectorPolicy::should_try_older_generation_allocation(

         size_t word_size) const {

   GenCollectedHeap* gch = GenCollectedHeap::heap();

   size_t gen0_capacity = gch->get_gen(0)->capacity_before_gc();

   return    (word_size > heap_word_size(gen0_capacity))

          || (GC_locker::is_active_and_needs_gc())

          || (   gch->last_incremental_collection_failed()

              && gch->incremental_collection_will_fail());

 }

 //

 // MarkSweepPolicy methods

 //

 MarkSweepPolicy::MarkSweepPolicy() {

   initialize_all();

 }

 void MarkSweepPolicy::initialize_generations() {

   initialize_perm_generation(PermGen::MarkSweepCompact);

   _generations = new GenerationSpecPtr[number_of_generations()];

   if (_generations == NULL)

     vm_exit_during_initialization("Unable to allocate gen spec");

   if (UseParNewGC && ParallelGCThreads > 0) {

     _generations[0] = new GenerationSpec(Generation::ParNew, _initial_gen0_size, _max_gen0_size);

   } else {

     _generations[0] = new GenerationSpec(Generation::DefNew, _initial_gen0_size, _max_gen0_size);

   }

   _generations[1] = new GenerationSpec(Generation::MarkSweepCompact, _initial_gen1_size, _max_gen1_size);

   if (_generations[0] == NULL || _generations[1] == NULL)

     vm_exit_during_initialization("Unable to allocate gen spec");

 }

 void MarkSweepPolicy::initialize_gc_policy_counters() {

   // initialize the policy counters - 2 collectors, 3 generations

   if (UseParNewGC && ParallelGCThreads > 0) {

     _gc_policy_counters = new GCPolicyCounters("ParNew:MSC", 2, 3);

   }

   else {

     _gc_policy_counters = new GCPolicyCounters("Copy:MSC", 2, 3);

   }

 }