/*

 * Copyright (c) 2015, 2018, 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/cms/jvmFlagConstraintsCMS.hpp"

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

#include "gc/shared/cardTableRS.hpp"

#include "gc/shared/collectedHeap.hpp"

#include "gc/shared/genCollectedHeap.hpp"

#include "gc/shared/jvmFlagConstraintsGC.hpp"

#include "memory/universe.hpp"

#include "runtime/globals_extension.hpp"

#include "utilities/globalDefinitions.hpp"

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

  // CMSWorkQueueDrainThreshold is verified to be less than max_juint

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

    JVMFlag::printError(verbose,

                        "ParallelGCThreads (" UINT32_FORMAT ") or CMSWorkQueueDrainThreshold ("

                        UINTX_FORMAT ") is too large\n",

                        threads, threshold);

    return JVMFlag::VIOLATES_CONSTRAINT;

  }

  return JVMFlag::SUCCESS;

}

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

  // To avoid overflow at ParScanClosure::do_oop_work.

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

    JVMFlag::printError(verbose,

                        "ParallelGCThreads (" UINT32_FORMAT ") must be "

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

                        value, (max_jint / 10));

    return JVMFlag::VIOLATES_CONSTRAINT;

  }

  return ParallelGCThreadsAndCMSWorkQueueDrainThreshold(value, CMSWorkQueueDrainThreshold, verbose);

}

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

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

    JVMFlag::printError(verbose,

                        "ParGCStridesPerThread (" UINTX_FORMAT ") must be "

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

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

    return JVMFlag::VIOLATES_CONSTRAINT;

  }

  return JVMFlag::SUCCESS;

}

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

  if (UseConcMarkSweepGC) {

    // ParGCCardsPerStrideChunk should be compared with card table size.

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

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

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

    if ((size_t)value > card_table_size) {

      JVMFlag::printError(verbose,

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

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

                          value, card_table_size);

      return JVMFlag::VIOLATES_CONSTRAINT;

    }

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

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

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

    uintx n_strides = ParallelGCThreads * ParGCStridesPerThread;

    uintx ergo_max = max_uintx / n_strides;

    if ((uintx)value > ergo_max) {

      JVMFlag::printError(verbose,

                          "ParGCCardsPerStrideChunk (" INTX_FORMAT ") must be "

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

                          value, ergo_max);

      return JVMFlag::VIOLATES_CONSTRAINT;

    }

  }

  return JVMFlag::SUCCESS;

}

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

  JVMFlag::Error status = JVMFlag::SUCCESS;

  if (UseConcMarkSweepGC) {

    if (value > CMSOldPLABMax) {

      JVMFlag::printError(verbose,

                          "CMSOldPLABMin (" SIZE_FORMAT ") must be "

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

                          value, CMSOldPLABMax);

      return JVMFlag::VIOLATES_CONSTRAINT;

    }

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

  }

  return status;

}

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

  JVMFlag::Error status = JVMFlag::SUCCESS;

  if (UseConcMarkSweepGC) {

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

  }

  return status;

}

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

  if (UseConcMarkSweepGC) {

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

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

    if (value > ergo_max) {

      JVMFlag::printError(verbose,

                          "%s (" SIZE_FORMAT ") must be "

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

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

                          name, value, ergo_max);

      return JVMFlag::VIOLATES_CONSTRAINT;

    }

  }

  return JVMFlag::SUCCESS;

}

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

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

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

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

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

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

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

    if (value % HeapWordSize != 0) {

      JVMFlag::printError(verbose,

                          "CMSRescanMultiple (" SIZE_FORMAT ") must be "

                          value, HeapWordSize);

      status = JVMFlag::VIOLATES_CONSTRAINT;

    }

  }

  return status;

}

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

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

}

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

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

    JVMFlag::printError(verbose,

                        "CMSPrecleanDenominator (" UINTX_FORMAT ") must be "

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

                        value, CMSPrecleanNumerator);

    return JVMFlag::VIOLATES_CONSTRAINT;

  }

  return JVMFlag::SUCCESS;

}

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

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

    JVMFlag::printError(verbose,

                        "CMSPrecleanNumerator (" UINTX_FORMAT ") must be "

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

                        value, CMSPrecleanDenominator);

    return JVMFlag::VIOLATES_CONSTRAINT;

  }

  return JVMFlag::SUCCESS;

}

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

  if (UseConcMarkSweepGC) {

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

    if (value > max_uintx - max_capacity) {

    JVMFlag::printError(verbose,

                        "CMSSamplingGrain (" UINTX_FORMAT ") must be "

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

                        value, max_uintx - max_capacity);

    return JVMFlag::VIOLATES_CONSTRAINT;

    }

  }

  return JVMFlag::SUCCESS;

}

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

  if (UseConcMarkSweepGC) {

    return ParallelGCThreadsAndCMSWorkQueueDrainThreshold(ParallelGCThreads, value, verbose);

  }

  return JVMFlag::SUCCESS;

}

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

  // Skip for current default value.

  if (UseConcMarkSweepGC && FLAG_IS_CMDLINE(CMSBitMapYieldQuantum)) {

    // CMSBitMapYieldQuantum should be compared with mark bitmap size.

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

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

    if (value > bitmap_size) {

      JVMFlag::printError(verbose,

                          "CMSBitMapYieldQuantum (" SIZE_FORMAT ") must "

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

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

                          value, bitmap_size);

      return JVMFlag::VIOLATES_CONSTRAINT;

    }

  }

  return JVMFlag::SUCCESS;

}

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

  if (value == 0) {

    JVMFlag::printError(verbose,

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

                        value);

    return JVMFlag::VIOLATES_CONSTRAINT;

  }

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

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

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

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

}