src/hotspot/share/gc/shenandoah/shenandoahArguments.cpp

@@ -1,7 +1,8 @@
  /*
   * Copyright (c) 2018, 2022, Red Hat, Inc. All rights reserved.
+  * Copyright Amazon.com Inc. 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.

@@ -25,11 +26,13 @@
  #include "precompiled.hpp"
  #include "gc/shared/gcArguments.hpp"
  #include "gc/shared/tlab_globals.hpp"
  #include "gc/shared/workerPolicy.hpp"
  #include "gc/shenandoah/shenandoahArguments.hpp"
+ #include "gc/shenandoah/shenandoahCardTable.hpp"
  #include "gc/shenandoah/shenandoahCollectorPolicy.hpp"
+ #include "gc/shenandoah/shenandoahGenerationalHeap.hpp"
  #include "gc/shenandoah/shenandoahHeap.inline.hpp"
  #include "gc/shenandoah/shenandoahHeapRegion.hpp"
  #include "runtime/globals_extension.hpp"
  #include "runtime/java.hpp"
  #include "utilities/defaultStream.hpp"

@@ -46,12 +49,12 @@
  
    FLAG_SET_DEFAULT(ShenandoahGCHeuristics,           "passive");
  
    FLAG_SET_DEFAULT(ShenandoahSATBBarrier,            false);
    FLAG_SET_DEFAULT(ShenandoahLoadRefBarrier,         false);
-   FLAG_SET_DEFAULT(ShenandoahIUBarrier,              false);
    FLAG_SET_DEFAULT(ShenandoahCASBarrier,             false);
+   FLAG_SET_DEFAULT(ShenandoahCardBarrier,            false);
    FLAG_SET_DEFAULT(ShenandoahCloneBarrier,           false);
  
    FLAG_SET_DEFAULT(ShenandoahVerifyOptoBarriers,     false);
  #endif
    if (UseLargePages) {

@@ -67,10 +70,17 @@
    // storage allocation code NUMA-aware.
    if (FLAG_IS_DEFAULT(UseNUMA)) {
      FLAG_SET_DEFAULT(UseNUMA, true);
    }
  
+   // We use this as the time period for tracking minimum mutator utilization (MMU).
+   // In generational mode, the MMU is used as a signal to adjust the size of the
+   // young generation.
+   if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
+     FLAG_SET_DEFAULT(GCPauseIntervalMillis, 5000);
+   }
+ 
    // Set up default number of concurrent threads. We want to have cycles complete fast
    // enough, but we also do not want to steal too much CPU from the concurrently running
    // application. Using 1/4 of available threads for concurrent GC seems a good
    // compromise here.
    bool ergo_conc = FLAG_IS_DEFAULT(ConcGCThreads);

@@ -111,10 +121,20 @@
        // User settings error, report and ask user to rectify.
        vm_exit_during_initialization("Shenandoah expects ConcGCThreads <= ParallelGCThreads, check -XX:ParallelGCThreads, -XX:ConcGCThreads");
      }
    }
  
+   // Disable support for dynamic number of GC threads. We do not let the runtime
+   // heuristics to misjudge how many threads we need during the heavy concurrent phase
+   // or a GC pause.
+   if (UseDynamicNumberOfGCThreads) {
+     if (FLAG_IS_CMDLINE(UseDynamicNumberOfGCThreads)) {
+       warning("Shenandoah does not support UseDynamicNumberOfGCThreads, disabling");
+     }
+     FLAG_SET_DEFAULT(UseDynamicNumberOfGCThreads, false);
+   }
+ 
    if (ShenandoahRegionSampling && FLAG_IS_DEFAULT(PerfDataMemorySize)) {
      // When sampling is enabled, max out the PerfData memory to get more
      // Shenandoah data in, including Matrix.
      FLAG_SET_DEFAULT(PerfDataMemorySize, 2048*K);
    }

@@ -130,11 +150,10 @@
  #ifdef ASSERT
    // C2 barrier verification is only reliable when all default barriers are enabled
    if (ShenandoahVerifyOptoBarriers &&
            (!FLAG_IS_DEFAULT(ShenandoahSATBBarrier)            ||
             !FLAG_IS_DEFAULT(ShenandoahLoadRefBarrier)         ||
-            !FLAG_IS_DEFAULT(ShenandoahIUBarrier)              ||
             !FLAG_IS_DEFAULT(ShenandoahCASBarrier)             ||
             !FLAG_IS_DEFAULT(ShenandoahCloneBarrier)
            )) {
      warning("Unusual barrier configuration, disabling C2 barrier verification");
      FLAG_SET_DEFAULT(ShenandoahVerifyOptoBarriers, false);

@@ -165,10 +184,15 @@
    // With Shenandoah, GC cycles are much less frequent, so we need we need sizing policy
    // to converge faster over smaller number of resizing decisions.
    if (FLAG_IS_DEFAULT(TLABAllocationWeight)) {
      FLAG_SET_DEFAULT(TLABAllocationWeight, 90);
    }
+ 
+   if (GCCardSizeInBytes < ShenandoahMinCardSizeInBytes) {
+     vm_exit_during_initialization(
+       err_msg("GCCardSizeInBytes ( %u ) must be >= %u\n", GCCardSizeInBytes, (unsigned int) ShenandoahMinCardSizeInBytes));
+   }
  }
  
  size_t ShenandoahArguments::conservative_max_heap_alignment() {
    size_t align = ShenandoahMaxRegionSize;
    if (UseLargePages) {

@@ -176,10 +200,12 @@
    }
    return align;
  }
  
  void ShenandoahArguments::initialize_alignments() {
+   CardTable::initialize_card_size();
+ 
    // Need to setup sizes early to get correct alignments.
    MaxHeapSize = ShenandoahHeapRegion::setup_sizes(MaxHeapSize);
  
    // This is expected by our algorithm for ShenandoahHeap::heap_region_containing().
    size_t align = ShenandoahHeapRegion::region_size_bytes();

@@ -189,7 +215,12 @@
    SpaceAlignment = align;
    HeapAlignment = align;
  }
  
  CollectedHeap* ShenandoahArguments::create_heap() {
-   return new ShenandoahHeap(new ShenandoahCollectorPolicy());
+   if (strcmp(ShenandoahGCMode, "generational") != 0) {
+     // Not generational
+     return new ShenandoahHeap(new ShenandoahCollectorPolicy());
+   } else {
+     return new ShenandoahGenerationalHeap(new ShenandoahCollectorPolicy());
+   }
  }