1 /*

     2  * Copyright (c) 2015, 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 "gc/cms/jvmFlagConstraintsCMS.hpp"

    27 #include "gc/cms/concurrentMarkSweepGeneration.inline.hpp"

    28 #include "gc/shared/cardTableRS.hpp"

    29 #include "gc/shared/collectedHeap.hpp"

    30 #include "gc/shared/genCollectedHeap.hpp"

    31 #include "gc/shared/jvmFlagConstraintsGC.hpp"

    32 #include "memory/universe.hpp"

    33 #include "runtime/globals_extension.hpp"

    34 #include "utilities/globalDefinitions.hpp"

    35 

    36 static JVMFlag::Error ParallelGCThreadsAndCMSWorkQueueDrainThreshold(uint threads, uintx threshold, bool verbose) {

    37   // CMSWorkQueueDrainThreshold is verified to be less than max_juint

    38   if (UseConcMarkSweepGC && (threads > (uint)(max_jint / (uint)threshold))) {

    39     JVMFlag::printError(verbose,

    40                         "ParallelGCThreads (" UINT32_FORMAT ") or CMSWorkQueueDrainThreshold ("

    41                         UINTX_FORMAT ") is too large\n",

    42                         threads, threshold);

    43     return JVMFlag::VIOLATES_CONSTRAINT;

    44   }

    45   return JVMFlag::SUCCESS;

    46 }

    47 

    48 JVMFlag::Error ParallelGCThreadsConstraintFuncCMS(uint value, bool verbose) {

    49   // To avoid overflow at ParScanClosure::do_oop_work.

    50   if (UseConcMarkSweepGC && (value > (max_jint / 10))) {

    51     JVMFlag::printError(verbose,

    52                         "ParallelGCThreads (" UINT32_FORMAT ") must be "

    53                         "less than or equal to " UINT32_FORMAT " for CMS GC\n",

    54                         value, (max_jint / 10));

    55     return JVMFlag::VIOLATES_CONSTRAINT;

    56   }

    57   return ParallelGCThreadsAndCMSWorkQueueDrainThreshold(value, CMSWorkQueueDrainThreshold, verbose);

    58 }

    59 JVMFlag::Error ParGCStridesPerThreadConstraintFunc(uintx value, bool verbose) {

    60   if (UseConcMarkSweepGC && (value > ((uintx)max_jint / (uintx)ParallelGCThreads))) {

    61     JVMFlag::printError(verbose,

    62                         "ParGCStridesPerThread (" UINTX_FORMAT ") must be "

    63                         "less than or equal to ergonomic maximum (" UINTX_FORMAT ")\n",

    64                         value, ((uintx)max_jint / (uintx)ParallelGCThreads));

    65     return JVMFlag::VIOLATES_CONSTRAINT;

    66   }

    67   return JVMFlag::SUCCESS;

    68 }

    69 

    70 JVMFlag::Error ParGCCardsPerStrideChunkConstraintFunc(intx value, bool verbose) {

    71   if (UseConcMarkSweepGC) {

    72     // ParGCCardsPerStrideChunk should be compared with card table size.

    73     size_t heap_size = CMSHeap::heap()->reserved_region().word_size();

    74     CardTableRS* ct = GenCollectedHeap::heap()->rem_set();

    75     size_t card_table_size = ct->cards_required(heap_size) - 1; // Valid card table size

    76 

    77     if ((size_t)value > card_table_size) {

    78       JVMFlag::printError(verbose,

    79                           "ParGCCardsPerStrideChunk (" INTX_FORMAT ") is too large for the heap size and "

    80                           "must be less than or equal to card table size (" SIZE_FORMAT ")\n",

    81                           value, card_table_size);

    82       return JVMFlag::VIOLATES_CONSTRAINT;

    83     }

    84 

    85     // ParGCCardsPerStrideChunk is used with n_strides(ParallelGCThreads*ParGCStridesPerThread)

    86     // from CardTableRS::process_stride(). Note that ParGCStridesPerThread is already checked

    87     // not to make an overflow with ParallelGCThreads from its constraint function.

    88     uintx n_strides = ParallelGCThreads * ParGCStridesPerThread;

    89     uintx ergo_max = max_uintx / n_strides;

    90     if ((uintx)value > ergo_max) {

    91       JVMFlag::printError(verbose,

    92                           "ParGCCardsPerStrideChunk (" INTX_FORMAT ") must be "

    93                           "less than or equal to ergonomic maximum (" UINTX_FORMAT ")\n",

    94                           value, ergo_max);

    95       return JVMFlag::VIOLATES_CONSTRAINT;

    96     }

    97   }

    98   return JVMFlag::SUCCESS;

    99 }

   100 

   101 JVMFlag::Error CMSOldPLABMinConstraintFunc(size_t value, bool verbose) {

   102   JVMFlag::Error status = JVMFlag::SUCCESS;

   103 

   104   if (UseConcMarkSweepGC) {

   105     if (value > CMSOldPLABMax) {

   106       JVMFlag::printError(verbose,

   107                           "CMSOldPLABMin (" SIZE_FORMAT ") must be "

   108                           "less than or equal to CMSOldPLABMax (" SIZE_FORMAT ")\n",

   109                           value, CMSOldPLABMax);

   110       return JVMFlag::VIOLATES_CONSTRAINT;

   111     }

   112     status = MaxPLABSizeBounds("CMSOldPLABMin", value, verbose);

   113   }

   114   return status;

   115 }

   116 

   117 JVMFlag::Error CMSOldPLABMaxConstraintFunc(size_t value, bool verbose) {

   118   JVMFlag::Error status = JVMFlag::SUCCESS;

   119 

   120   if (UseConcMarkSweepGC) {

   121     status = MaxPLABSizeBounds("CMSOldPLABMax", value, verbose);

   122   }

   123   return status;

   124 }

   125 

   126 static JVMFlag::Error CMSReservedAreaConstraintFunc(const char* name, size_t value, bool verbose) {

   127   if (UseConcMarkSweepGC) {

   128     ConcurrentMarkSweepGeneration* cms = CMSHeap::heap()->old_gen();

   129     const size_t ergo_max = cms->cmsSpace()->max_flag_size_for_task_size();

   130     if (value > ergo_max) {

   131       JVMFlag::printError(verbose,

   132                           "%s (" SIZE_FORMAT ") must be "

   133                           "less than or equal to ergonomic maximum (" SIZE_FORMAT ") "

   134                           "which is based on the maximum size of the old generation of the Java heap\n",

   135                           name, value, ergo_max);

   136       return JVMFlag::VIOLATES_CONSTRAINT;

   137     }

   138   }

   139   return JVMFlag::SUCCESS;

   140 }

   141 

   142 JVMFlag::Error CMSRescanMultipleConstraintFunc(size_t value, bool verbose) {

   143   JVMFlag::Error status = CMSReservedAreaConstraintFunc("CMSRescanMultiple", value, verbose);

   144 

   145   if (status == JVMFlag::SUCCESS && UseConcMarkSweepGC) {

   146     // CMSParRemarkTask::do_dirty_card_rescan_tasks requires CompactibleFreeListSpace::rescan_task_size()

   147     // to be aligned to CardTable::card_size * BitsPerWord.

   148     // Note that rescan_task_size() will be aligned if CMSRescanMultiple is a multiple of 'HeapWordSize'

   149     // because rescan_task_size() is CardTable::card_size / HeapWordSize * BitsPerWord.

   150     if (value % HeapWordSize != 0) {

   151       JVMFlag::printError(verbose,

   152                           "CMSRescanMultiple (" SIZE_FORMAT ") must be "

   153                           "a multiple of %d\n",

   154                           value, HeapWordSize);

   155       status = JVMFlag::VIOLATES_CONSTRAINT;

   156     }

   157   }

   158   return status;

   159 }

   160 

   161 JVMFlag::Error CMSConcMarkMultipleConstraintFunc(size_t value, bool verbose) {

   162   return CMSReservedAreaConstraintFunc("CMSConcMarkMultiple", value, verbose);

   163 }

   164 

   165 JVMFlag::Error CMSPrecleanDenominatorConstraintFunc(uintx value, bool verbose) {

   166   if (UseConcMarkSweepGC && (value <= CMSPrecleanNumerator)) {

   167     JVMFlag::printError(verbose,

   168                         "CMSPrecleanDenominator (" UINTX_FORMAT ") must be "

   169                         "strickly greater than CMSPrecleanNumerator (" UINTX_FORMAT ")\n",

   170                         value, CMSPrecleanNumerator);

   171     return JVMFlag::VIOLATES_CONSTRAINT;

   172   }

   173   return JVMFlag::SUCCESS;

   174 }

   175 

   176 JVMFlag::Error CMSPrecleanNumeratorConstraintFunc(uintx value, bool verbose) {

   177   if (UseConcMarkSweepGC && (value >= CMSPrecleanDenominator)) {

   178     JVMFlag::printError(verbose,

   179                         "CMSPrecleanNumerator (" UINTX_FORMAT ") must be "

   180                         "less than CMSPrecleanDenominator (" UINTX_FORMAT ")\n",

   181                         value, CMSPrecleanDenominator);

   182     return JVMFlag::VIOLATES_CONSTRAINT;

   183   }

   184   return JVMFlag::SUCCESS;

   185 }

   186 

   187 JVMFlag::Error CMSSamplingGrainConstraintFunc(uintx value, bool verbose) {

   188   if (UseConcMarkSweepGC) {

   189     size_t max_capacity = CMSHeap::heap()->young_gen()->max_capacity();

   190     if (value > max_uintx - max_capacity) {

   191     JVMFlag::printError(verbose,

   192                         "CMSSamplingGrain (" UINTX_FORMAT ") must be "

   193                         "less than or equal to ergonomic maximum (" SIZE_FORMAT ")\n",

   194                         value, max_uintx - max_capacity);

   195     return JVMFlag::VIOLATES_CONSTRAINT;

   196     }

   197   }

   198   return JVMFlag::SUCCESS;

   199 }

   200 

   201 JVMFlag::Error CMSWorkQueueDrainThresholdConstraintFunc(uintx value, bool verbose) {

   202   if (UseConcMarkSweepGC) {

   203     return ParallelGCThreadsAndCMSWorkQueueDrainThreshold(ParallelGCThreads, value, verbose);

   204   }

   205   return JVMFlag::SUCCESS;

   206 }

   207 

   208 JVMFlag::Error CMSBitMapYieldQuantumConstraintFunc(size_t value, bool verbose) {

   209   // Skip for current default value.

   210   if (UseConcMarkSweepGC && FLAG_IS_CMDLINE(CMSBitMapYieldQuantum)) {

   211     // CMSBitMapYieldQuantum should be compared with mark bitmap size.

   212     ConcurrentMarkSweepGeneration* cms = CMSHeap::heap()->old_gen();

   213     size_t bitmap_size = cms->collector()->markBitMap()->sizeInWords();

   214 

   215     if (value > bitmap_size) {

   216       JVMFlag::printError(verbose,

   217                           "CMSBitMapYieldQuantum (" SIZE_FORMAT ") must "

   218                           "be less than or equal to bitmap size (" SIZE_FORMAT ") "

   219                           "whose size corresponds to the size of old generation of the Java heap\n",

   220                           value, bitmap_size);

   221       return JVMFlag::VIOLATES_CONSTRAINT;

   222     }

   223   }

   224   return JVMFlag::SUCCESS;

   225 }

   226 

   227 JVMFlag::Error OldPLABSizeConstraintFuncCMS(size_t value, bool verbose) {

   228   if (value == 0) {

   229     JVMFlag::printError(verbose,

   230                         "OldPLABSize (" SIZE_FORMAT ") must be greater than 0",

   231                         value);

   232     return JVMFlag::VIOLATES_CONSTRAINT;

   233   }

   234   // For CMS, OldPLABSize is the number of free blocks of a given size that are used when

   235   // replenishing the local per-worker free list caches.

   236   // For more details, please refer to Arguments::set_cms_and_parnew_gc_flags().

   237   return MaxPLABSizeBounds("OldPLABSize", value, verbose);

   238 }