6946417: G1: Java VisualVM does not support G1 properly.

Summary: Added counters for jstat
Reviewed-by: tonyp, jwilhelm, stefank, ysr, johnc

hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp

@@ -1161,6 +1161,7 @@ bool G1CollectedHeap::do_collection(bool explicit_gc,
     TraceTime t(system_gc ? "Full GC (System.gc())" : "Full GC",
                 PrintGC, true, gclog_or_tty);
 
+    TraceCollectorStats tcs(g1mm()->full_collection_counters());
     TraceMemoryManagerStats tms(true /* fullGC */);
 
     double start = os::elapsedTime();
@@ -1339,6 +1340,7 @@ bool G1CollectedHeap::do_collection(bool explicit_gc,
   if (PrintHeapAtGC) {
     Universe::print_heap_after_gc();
   }
+  g1mm()->update_counters();
 
   return true;
 }
@@ -1971,6 +1973,10 @@ jint G1CollectedHeap::initialize() {
 
   init_mutator_alloc_region();
 
+  // Do create of the monitoring and management support so that
+  // values in the heap have been properly initialized.
+  _g1mm = new G1MonitoringSupport(this, &_g1_storage);
+
   return JNI_OK;
 }
 
@@ -3186,6 +3192,7 @@ G1CollectedHeap::do_collection_pause_at_safepoint(double target_pause_time_ms) {
     TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
     TraceTime t(verbose_str, PrintGC && !PrintGCDetails, true, gclog_or_tty);
 
+    TraceCollectorStats tcs(g1mm()->incremental_collection_counters());
     TraceMemoryManagerStats tms(false /* fullGC */);
 
     // If the secondary_free_list is not empty, append it to the
@@ -3425,6 +3432,8 @@ G1CollectedHeap::do_collection_pause_at_safepoint(double target_pause_time_ms) {
   if (PrintHeapAtGC) {
     Universe::print_heap_after_gc();
   }
+  g1mm()->update_counters();
+
   if (G1SummarizeRSetStats &&
       (G1SummarizeRSetStatsPeriod > 0) &&
       (total_collections() % G1SummarizeRSetStatsPeriod == 0)) {
@@ -5338,6 +5347,7 @@ HeapRegion* G1CollectedHeap::new_mutator_alloc_region(size_t word_size,
     if (new_alloc_region != NULL) {
       g1_policy()->update_region_num(true /* next_is_young */);
       set_region_short_lived_locked(new_alloc_region);
+      g1mm()->update_eden_counters();
       return new_alloc_region;
     }
   }

hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp

@@ -28,7 +28,9 @@
 #include "gc_implementation/g1/concurrentMark.hpp"
 #include "gc_implementation/g1/g1AllocRegion.hpp"
 #include "gc_implementation/g1/g1RemSet.hpp"
+#include "gc_implementation/g1/g1MonitoringSupport.hpp"
 #include "gc_implementation/g1/heapRegionSets.hpp"
+#include "gc_implementation/shared/hSpaceCounters.hpp"
 #include "gc_implementation/parNew/parGCAllocBuffer.hpp"
 #include "memory/barrierSet.hpp"
 #include "memory/memRegion.hpp"
@@ -57,6 +59,7 @@ class HeapRegionRemSetIterator;
 class ConcurrentMark;
 class ConcurrentMarkThread;
 class ConcurrentG1Refine;
+class GenerationCounters;
 
 typedef OverflowTaskQueue<StarTask>         RefToScanQueue;
 typedef GenericTaskQueueSet<RefToScanQueue> RefToScanQueueSet;
@@ -236,6 +239,9 @@ private:
   // current collection.
   HeapRegion* _gc_alloc_region_list;
 
+  // Helper for monitoring and management support.
+  G1MonitoringSupport* _g1mm;
+
   // Determines PLAB size for a particular allocation purpose.
   static size_t desired_plab_sz(GCAllocPurpose purpose);
 
@@ -550,6 +556,9 @@ protected:
   HeapWord* expand_and_allocate(size_t word_size);
 
 public:
+
+  G1MonitoringSupport* g1mm() { return _g1mm; }
+
   // Expand the garbage-first heap by at least the given size (in bytes!).
   // Returns true if the heap was expanded by the requested amount;
   // false otherwise.

hotspot/src/share/vm/gc_implementation/g1/g1MonitoringSupport.cpp

+/*
+ * Copyright (c) 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
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "gc_implementation/g1/g1MonitoringSupport.hpp"
+#include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
+#include "gc_implementation/g1/g1CollectorPolicy.hpp"
+
+G1MonitoringSupport::G1MonitoringSupport(G1CollectedHeap* g1h,
+                                         VirtualSpace* g1_storage_addr) :
+  _g1h(g1h),
+  _incremental_collection_counters(NULL),
+  _full_collection_counters(NULL),
+  _non_young_collection_counters(NULL),
+  _old_space_counters(NULL),
+  _young_collection_counters(NULL),
+  _eden_counters(NULL),
+  _from_counters(NULL),
+  _to_counters(NULL),
+  _g1_storage_addr(g1_storage_addr)
+{
+  // Counters for GC collections
+  //
+  //  name "collector.0".  In a generational collector this would be the
+  // young generation collection.
+  _incremental_collection_counters =
+    new CollectorCounters("G1 incremental collections", 0);
+  //   name "collector.1".  In a generational collector this would be the
+  // old generation collection.
+  _full_collection_counters =
+    new CollectorCounters("G1 stop-the-world full collections", 1);
+
+  // timer sampling for all counters supporting sampling only update the
+  // used value.  See the take_sample() method.  G1 requires both used and
+  // capacity updated so sampling is not currently used.  It might
+  // be sufficient to update all counters in take_sample() even though
+  // take_sample() only returns "used".  When sampling was used, there
+  // were some anomolous values emitted which may have been the consequence
+  // of not updating all values simultaneously (i.e., see the calculation done
+  // in eden_space_used(), is it possbile that the values used to
+  // calculate either eden_used or survivor_used are being updated by
+  // the collector when the sample is being done?).
+  const bool sampled = false;
+
+  // "Generation" and "Space" counters.
+  //
+  //  name "generation.1" This is logically the old generation in
+  // generational GC terms.  The "1, 1" parameters are for
+  // the n-th generation (=1) with 1 space.
+  // Counters are created from minCapacity, maxCapacity, and capacity
+  _non_young_collection_counters =
+    new GenerationCounters("whole heap", 1, 1, _g1_storage_addr);
+
+  //  name  "generation.1.space.0"
+  // Counters are created from maxCapacity, capacity, initCapacity,
+  // and used.
+  _old_space_counters = new HSpaceCounters("space", 0,
+    _g1h->max_capacity(), _g1h->capacity(), _non_young_collection_counters);
+
+  //   Young collection set
+  //  name "generation.0".  This is logically the young generation.
+  //  The "0, 3" are paremeters for the n-th genertaion (=0) with 3 spaces.
+  // See  _non_young_collection_counters for additional counters
+  _young_collection_counters = new GenerationCounters("young", 0, 3, NULL);
+
+  // Replace "max_heap_byte_size() with maximum young gen size for
+  // g1Collectedheap
+  //  name "generation.0.space.0"
+  // See _old_space_counters for additional counters
+  _eden_counters = new HSpaceCounters("eden", 0,
+    _g1h->max_capacity(), eden_space_committed(),
+    _young_collection_counters);
+
+  //  name "generation.0.space.1"
+  // See _old_space_counters for additional counters
+  // Set the arguments to indicate that this survivor space is not used.
+  _from_counters = new HSpaceCounters("s0", 1, (long) 0, (long) 0,
+    _young_collection_counters);
+
+  //  name "generation.0.space.2"
+  // See _old_space_counters for additional counters
+  _to_counters = new HSpaceCounters("s1", 2,
+    _g1h->max_capacity(),
+    survivor_space_committed(),
+    _young_collection_counters);
+}
+
+size_t G1MonitoringSupport::overall_committed() {
+  return g1h()->capacity();
+}
+
+size_t G1MonitoringSupport::overall_used() {
+  return g1h()->used_unlocked();
+}
+
+size_t G1MonitoringSupport::eden_space_committed() {
+  return MAX2(eden_space_used(), (size_t) HeapRegion::GrainBytes);
+}
+
+size_t G1MonitoringSupport::eden_space_used() {
+  size_t young_list_length = g1h()->young_list()->length();
+  size_t eden_used = young_list_length * HeapRegion::GrainBytes;
+  size_t survivor_used = survivor_space_used();
+  eden_used = subtract_up_to_zero(eden_used, survivor_used);
+  return eden_used;
+}
+
+size_t G1MonitoringSupport::survivor_space_committed() {
+  return MAX2(survivor_space_used(),
+              (size_t) HeapRegion::GrainBytes);
+}
+
+size_t G1MonitoringSupport::survivor_space_used() {
+  size_t survivor_num = g1h()->g1_policy()->recorded_survivor_regions();
+  size_t survivor_used = survivor_num * HeapRegion::GrainBytes;
+  return survivor_used;
+}
+
+size_t G1MonitoringSupport::old_space_committed() {
+  size_t committed = overall_committed();
+  size_t eden_committed = eden_space_committed();
+  size_t survivor_committed = survivor_space_committed();
+  committed = subtract_up_to_zero(committed, eden_committed);
+  committed = subtract_up_to_zero(committed, survivor_committed);
+  committed = MAX2(committed, (size_t) HeapRegion::GrainBytes);
+  return committed;
+}
+
+// See the comment near the top of g1MonitoringSupport.hpp for
+// an explanation of these calculations for "used" and "capacity".
+size_t G1MonitoringSupport::old_space_used() {
+  size_t used = overall_used();
+  size_t eden_used = eden_space_used();
+  size_t survivor_used = survivor_space_used();
+  used = subtract_up_to_zero(used, eden_used);
+  used = subtract_up_to_zero(used, survivor_used);
+  return used;
+}
+
+void G1MonitoringSupport::update_counters() {
+  if (UsePerfData) {
+    eden_counters()->update_capacity(eden_space_committed());
+    eden_counters()->update_used(eden_space_used());
+    to_counters()->update_capacity(survivor_space_committed());
+    to_counters()->update_used(survivor_space_used());
+    old_space_counters()->update_capacity(old_space_committed());
+    old_space_counters()->update_used(old_space_used());
+    non_young_collection_counters()->update_all();
+  }
+}
+
+void G1MonitoringSupport::update_eden_counters() {
+  if (UsePerfData) {
+    eden_counters()->update_capacity(eden_space_committed());
+    eden_counters()->update_used(eden_space_used());
+  }
+}

hotspot/src/share/vm/gc_implementation/g1/g1MonitoringSupport.hpp

+/*
+ * Copyright (c) 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
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1MONITORINGSUPPORT_HPP
+#define SHARE_VM_GC_IMPLEMENTATION_G1_G1MONITORINGSUPPORT_HPP
+
+#include "gc_implementation/shared/hSpaceCounters.hpp"
+
+class G1CollectedHeap;
+class G1SpaceMonitoringSupport;
+
+// Class for monitoring logical spaces in G1.
+// G1 defines a set of regions as a young
+// collection (analogous to a young generation).
+// The young collection is a logical generation
+// with no fixed chunk (see space.hpp) reflecting
+// the address space for the generation.  In addition
+// to the young collection there is its complement
+// the non-young collection that is simply the regions
+// not in the young collection.  The non-young collection
+// is treated here as a logical old generation only
+// because the monitoring tools expect a generational
+// heap.  The monitoring tools expect that a Space
+// (see space.hpp) exists that describe the
+// address space of young collection and non-young
+// collection and such a view is provided here.
+//
+// This class provides interfaces to access
+// the value of variables for the young collection
+// that include the "capacity" and "used" of the
+// young collection along with constant values
+// for the minimum and maximum capacities for
+// the logical spaces.  Similarly for the non-young
+// collection.
+//
+// Also provided are counters for G1 concurrent collections
+// and stop-the-world full heap collecitons.
+//
+// Below is a description of how "used" and "capactiy"
+// (or committed) is calculated for the logical spaces.
+//
+// 1) The used space calculation for a pool is not necessarily
+// independent of the others. We can easily get from G1 the overall
+// used space in the entire heap, the number of regions in the young
+// generation (includes both eden and survivors), and the number of
+// survivor regions. So, from that we calculate:
+//
+//  survivor_used = survivor_num * region_size
+//  eden_used     = young_region_num * region_size - survivor_used
+//  old_gen_used  = overall_used - eden_used - survivor_used
+//
+// Note that survivor_used and eden_used are upper bounds. To get the
+// actual value we would have to iterate over the regions and add up
+// ->used(). But that'd be expensive. So, we'll accept some lack of
+// accuracy for those two. But, we have to be careful when calculating
+// old_gen_used, in case we subtract from overall_used more then the
+// actual number and our result goes negative.
+//
+// 2) Calculating the used space is straightforward, as described
+// above. However, how do we calculate the committed space, given that
+// we allocate space for the eden, survivor, and old gen out of the
+// same pool of regions? One way to do this is to use the used value
+// as also the committed value for the eden and survivor spaces and
+// then calculate the old gen committed space as follows:
+//
+//  old_gen_committed = overall_committed - eden_committed - survivor_committed
+//
+// Maybe a better way to do that would be to calculate used for eden
+// and survivor as a sum of ->used() over their regions and then
+// calculate committed as region_num * region_size (i.e., what we use
+// to calculate the used space now). This is something to consider
+// in the future.
+//
+// 3) Another decision that is again not straightforward is what is
+// the max size that each memory pool can grow to. One way to do this
+// would be to use the committed size for the max for the eden and
+// survivors and calculate the old gen max as follows (basically, it's
+// a similar pattern to what we use for the committed space, as
+// described above):
+//
+//  old_gen_max = overall_max - eden_max - survivor_max
+//
+// Unfortunately, the above makes the max of each pool fluctuate over
+// time and, even though this is allowed according to the spec, it
+// broke several assumptions in the M&M framework (there were cases
+// where used would reach a value greater than max). So, for max we
+// use -1, which means "undefined" according to the spec.
+//
+// 4) Now, there is a very subtle issue with all the above. The
+// framework will call get_memory_usage() on the three pools
+// asynchronously. As a result, each call might get a different value
+// for, say, survivor_num which will yield inconsistent values for
+// eden_used, survivor_used, and old_gen_used (as survivor_num is used
+// in the calculation of all three). This would normally be
+// ok. However, it's possible that this might cause the sum of
+// eden_used, survivor_used, and old_gen_used to go over the max heap
+// size and this seems to sometimes cause JConsole (and maybe other
+// clients) to get confused. There's not a really an easy / clean
+// solution to this problem, due to the asynchrounous nature of the
+// framework.
+
+class G1MonitoringSupport : public CHeapObj {
+  G1CollectedHeap* _g1h;
+  VirtualSpace* _g1_storage_addr;
+
+  // jstat performance counters
+  //  incremental collections both fully and partially young
+  CollectorCounters*   _incremental_collection_counters;
+  //  full stop-the-world collections
+  CollectorCounters*   _full_collection_counters;
+  //  young collection set counters.  The _eden_counters,
+  // _from_counters, and _to_counters are associated with
+  // this "generational" counter.
+  GenerationCounters*  _young_collection_counters;
+  //  non-young collection set counters. The _old_space_counters
+  // below are associated with this "generational" counter.
+  GenerationCounters*  _non_young_collection_counters;
+  // Counters for the capacity and used for
+  //   the whole heap
+  HSpaceCounters*      _old_space_counters;
+  //   the young collection
+  HSpaceCounters*      _eden_counters;
+  //   the survivor collection (only one, _to_counters, is actively used)
+  HSpaceCounters*      _from_counters;
+  HSpaceCounters*      _to_counters;
+
+  // It returns x - y if x > y, 0 otherwise.
+  // As described in the comment above, some of the inputs to the
+  // calculations we have to do are obtained concurrently and hence
+  // may be inconsistent with each other. So, this provides a
+  // defensive way of performing the subtraction and avoids the value
+  // going negative (which would mean a very large result, given that
+  // the parameter are size_t).
+  static size_t subtract_up_to_zero(size_t x, size_t y) {
+    if (x > y) {
+      return x - y;
+    } else {
+      return 0;
+    }
+  }
+
+ public:
+  G1MonitoringSupport(G1CollectedHeap* g1h, VirtualSpace* g1_storage_addr);
+
+  G1CollectedHeap* g1h() { return _g1h; }
+  VirtualSpace* g1_storage_addr() { return _g1_storage_addr; }
+
+  // Performance Counter accessors
+  void update_counters();
+  void update_eden_counters();
+
+  CollectorCounters* incremental_collection_counters() {
+    return _incremental_collection_counters;
+  }
+  CollectorCounters* full_collection_counters() {
+    return _full_collection_counters;
+  }
+  GenerationCounters* non_young_collection_counters() {
+    return _non_young_collection_counters;
+  }
+  HSpaceCounters*      old_space_counters() { return _old_space_counters; }
+  HSpaceCounters*      eden_counters() { return _eden_counters; }
+  HSpaceCounters*      from_counters() { return _from_counters; }
+  HSpaceCounters*      to_counters() { return _to_counters; }
+
+  // Monitoring support used by
+  //   MemoryService
+  //   jstat counters
+  size_t overall_committed();
+  size_t overall_used();
+
+  size_t eden_space_committed();
+  size_t eden_space_used();
+
+  size_t survivor_space_committed();
+  size_t survivor_space_used();
+
+  size_t old_space_committed();
+  size_t old_space_used();
+};
+
+#endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1MONITORINGSUPPORT_HPP

hotspot/src/share/vm/gc_implementation/shared/generationCounters.cpp

 /*
- * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2002, 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
@@ -51,15 +51,18 @@ GenerationCounters::GenerationCounters(const char* name,
 
     cname = PerfDataManager::counter_name(_name_space, "minCapacity");
     PerfDataManager::create_constant(SUN_GC, cname, PerfData::U_Bytes,
+                                     _virtual_space == NULL ? 0 :
                                      _virtual_space->committed_size(), CHECK);
 
     cname = PerfDataManager::counter_name(_name_space, "maxCapacity");
     PerfDataManager::create_constant(SUN_GC, cname, PerfData::U_Bytes,
+                                     _virtual_space == NULL ? 0 :
                                      _virtual_space->reserved_size(), CHECK);
 
     cname = PerfDataManager::counter_name(_name_space, "capacity");
     _current_size = PerfDataManager::create_variable(SUN_GC, cname,
-                                      PerfData::U_Bytes,
+                                     PerfData::U_Bytes,
+                                     _virtual_space == NULL ? 0 :
                                      _virtual_space->committed_size(), CHECK);
   }
 }

hotspot/src/share/vm/gc_implementation/shared/generationCounters.hpp

 /*
- * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2002, 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
@@ -61,10 +61,11 @@ class GenerationCounters: public CHeapObj {
   }
 
   virtual void update_all() {
-    _current_size->set_value(_virtual_space->committed_size());
+    _current_size->set_value(_virtual_space == NULL ? 0 :
+                             _virtual_space->committed_size());
   }
 
   const char* name_space() const        { return _name_space; }
-};
 
+};
 #endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_GENERATIONCOUNTERS_HPP

hotspot/src/share/vm/gc_implementation/shared/hSpaceCounters.cpp

+/*
+ * Copyright (c) 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
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "gc_implementation/shared/hSpaceCounters.hpp"
+#include "memory/generation.hpp"
+#include "memory/resourceArea.hpp"
+
+HSpaceCounters::HSpaceCounters(const char* name,
+                               int ordinal,
+                               size_t max_size,
+                               size_t initial_capacity,
+                               GenerationCounters* gc) {
+
+  if (UsePerfData) {
+    EXCEPTION_MARK;
+    ResourceMark rm;
+
+    const char* cns =
+      PerfDataManager::name_space(gc->name_space(), "space", ordinal);
+
+    _name_space = NEW_C_HEAP_ARRAY(char, strlen(cns)+1);
+    strcpy(_name_space, cns);
+
+    const char* cname = PerfDataManager::counter_name(_name_space, "name");
+    PerfDataManager::create_string_constant(SUN_GC, cname, name, CHECK);
+
+    cname = PerfDataManager::counter_name(_name_space, "maxCapacity");
+    PerfDataManager::create_constant(SUN_GC, cname, PerfData::U_Bytes,
+                                     (jlong)max_size, CHECK);
+
+    cname = PerfDataManager::counter_name(_name_space, "capacity");
+    _capacity = PerfDataManager::create_variable(SUN_GC, cname,
+                                                 PerfData::U_Bytes,
+                                                 initial_capacity, CHECK);
+
+    cname = PerfDataManager::counter_name(_name_space, "used");
+    _used = PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes,
+                                             (jlong) 0, CHECK);
+
+    cname = PerfDataManager::counter_name(_name_space, "initCapacity");
+    PerfDataManager::create_constant(SUN_GC, cname, PerfData::U_Bytes,
+                                     initial_capacity, CHECK);
+  }
+}

hotspot/src/share/vm/gc_implementation/shared/hSpaceCounters.hpp

+/*
+ * Copyright (c) 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
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_VM_GC_IMPLEMENTATION_SHARED_HSPACECOUNTERS_HPP
+#define SHARE_VM_GC_IMPLEMENTATION_SHARED_HSPACECOUNTERS_HPP
+
+#ifndef SERIALGC
+#include "gc_implementation/shared/generationCounters.hpp"
+#include "memory/generation.hpp"
+#include "runtime/perfData.hpp"
+#endif
+
+// A HSpaceCounter is a holder class for performance counters
+// that track a collections (logical spaces) in a heap;
+
+class HeapSpaceUsedHelper;
+class G1SpaceMonitoringSupport;
+
+class HSpaceCounters: public CHeapObj {
+  friend class VMStructs;
+
+ private:
+  PerfVariable*        _capacity;
+  PerfVariable*        _used;
+
+  // Constant PerfData types don't need to retain a reference.
+  // However, it's a good idea to document them here.
+
+  char*             _name_space;
+
+ public:
+
+  HSpaceCounters(const char* name, int ordinal, size_t max_size,
+                 size_t initial_capacity, GenerationCounters* gc);
+
+  ~HSpaceCounters() {
+    if (_name_space != NULL) FREE_C_HEAP_ARRAY(char, _name_space);
+  }
+
+  inline void update_capacity(size_t v) {
+    _capacity->set_value(v);
+  }
+
+  inline void update_used(size_t v) {
+    _used->set_value(v);
+  }
+
+  debug_only(
+    // for security reasons, we do not allow arbitrary reads from
+    // the counters as they may live in shared memory.
+    jlong used() {
+      return _used->get_value();
+    }
+    jlong capacity() {
+      return _used->get_value();
+    }
+  )
+
+  inline void update_all(size_t capacity, size_t used) {
+    update_capacity(capacity);
+    update_used(used);
+  }
+
+  const char* name_space() const        { return _name_space; }
+};
+#endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_HSPACECOUNTERS_HPP

hotspot/src/share/vm/services/g1MemoryPool.cpp

 /*
- * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 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
@@ -34,10 +34,10 @@ G1MemoryPoolSuper::G1MemoryPoolSuper(G1CollectedHeap* g1h,
                                      size_t init_size,
                                      bool support_usage_threshold) :
   _g1h(g1h), CollectedMemoryPool(name,
-                                 MemoryPool::Heap,
-                                 init_size,
-                                 undefined_max(),
-                                 support_usage_threshold) {
+                                   MemoryPool::Heap,
+                                   init_size,
+                                   undefined_max(),
+                                   support_usage_threshold) {
   assert(UseG1GC, "sanity");
 }
 
@@ -48,44 +48,27 @@ size_t G1MemoryPoolSuper::eden_space_committed(G1CollectedHeap* g1h) {
 
 // See the comment at the top of g1MemoryPool.hpp
 size_t G1MemoryPoolSuper::eden_space_used(G1CollectedHeap* g1h) {
-  size_t young_list_length = g1h->young_list()->length();
-  size_t eden_used = young_list_length * HeapRegion::GrainBytes;
-  size_t survivor_used = survivor_space_used(g1h);
-  eden_used = subtract_up_to_zero(eden_used, survivor_used);
-  return eden_used;
+  return g1h->g1mm()->eden_space_used();
 }
 
 // See the comment at the top of g1MemoryPool.hpp
 size_t G1MemoryPoolSuper::survivor_space_committed(G1CollectedHeap* g1h) {
-  return MAX2(survivor_space_used(g1h), (size_t) HeapRegion::GrainBytes);
+  return g1h->g1mm()->survivor_space_committed();
 }
 
 // See the comment at the top of g1MemoryPool.hpp
 size_t G1MemoryPoolSuper::survivor_space_used(G1CollectedHeap* g1h) {
-  size_t survivor_num = g1h->g1_policy()->recorded_survivor_regions();
-  size_t survivor_used = survivor_num * HeapRegion::GrainBytes;
-  return survivor_used;
+  return g1h->g1mm()->survivor_space_used();
 }
 
 // See the comment at the top of g1MemoryPool.hpp
 size_t G1MemoryPoolSuper::old_space_committed(G1CollectedHeap* g1h) {
-  size_t committed = overall_committed(g1h);
-  size_t eden_committed = eden_space_committed(g1h);
-  size_t survivor_committed = survivor_space_committed(g1h);
-  committed = subtract_up_to_zero(committed, eden_committed);
-  committed = subtract_up_to_zero(committed, survivor_committed);
-  committed = MAX2(committed, (size_t) HeapRegion::GrainBytes);
-  return committed;
+  return g1h->g1mm()->old_space_committed();
 }
 
 // See the comment at the top of g1MemoryPool.hpp
 size_t G1MemoryPoolSuper::old_space_used(G1CollectedHeap* g1h) {
-  size_t used = overall_used(g1h);
-  size_t eden_used = eden_space_used(g1h);
-  size_t survivor_used = survivor_space_used(g1h);
-  used = subtract_up_to_zero(used, eden_used);
-  used = subtract_up_to_zero(used, survivor_used);
-  return used;
+  return g1h->g1mm()->old_space_used();
 }
 
 G1EdenPool::G1EdenPool(G1CollectedHeap* g1h) :

hotspot/src/share/vm/services/g1MemoryPool.hpp

 /*
- * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 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
@@ -46,68 +46,9 @@ class G1CollectedHeap;
 // get, as this does affect the performance and behavior of G1. Which
 // is why we introduce the three memory pools implemented here.
 //
-// The above approach inroduces a couple of challenging issues in the
-// implementation of the three memory pools:
+// See comments in g1MonitoringSupport.hpp for additional details
+// on this model.
 //
-// 1) The used space calculation for a pool is not necessarily
-// independent of the others. We can easily get from G1 the overall
-// used space in the entire heap, the number of regions in the young
-// generation (includes both eden and survivors), and the number of
-// survivor regions. So, from that we calculate:
-//
-//  survivor_used = survivor_num * region_size
-//  eden_used     = young_region_num * region_size - survivor_used
-//  old_gen_used  = overall_used - eden_used - survivor_used
-//
-// Note that survivor_used and eden_used are upper bounds. To get the
-// actual value we would have to iterate over the regions and add up
-// ->used(). But that'd be expensive. So, we'll accept some lack of
-// accuracy for those two. But, we have to be careful when calculating
-// old_gen_used, in case we subtract from overall_used more then the
-// actual number and our result goes negative.
-//
-// 2) Calculating the used space is straightforward, as described
-// above. However, how do we calculate the committed space, given that
-// we allocate space for the eden, survivor, and old gen out of the
-// same pool of regions? One way to do this is to use the used value
-// as also the committed value for the eden and survivor spaces and
-// then calculate the old gen committed space as follows:
-//
-//  old_gen_committed = overall_committed - eden_committed - survivor_committed
-//
-// Maybe a better way to do that would be to calculate used for eden
-// and survivor as a sum of ->used() over their regions and then
-// calculate committed as region_num * region_size (i.e., what we use
-// to calculate the used space now). This is something to consider
-// in the future.
-//
-// 3) Another decision that is again not straightforward is what is
-// the max size that each memory pool can grow to. One way to do this
-// would be to use the committed size for the max for the eden and
-// survivors and calculate the old gen max as follows (basically, it's
-// a similar pattern to what we use for the committed space, as
-// described above):
-//
-//  old_gen_max = overall_max - eden_max - survivor_max
-//
-// Unfortunately, the above makes the max of each pool fluctuate over
-// time and, even though this is allowed according to the spec, it
-// broke several assumptions in the M&M framework (there were cases
-// where used would reach a value greater than max). So, for max we
-// use -1, which means "undefined" according to the spec.
-//
-// 4) Now, there is a very subtle issue with all the above. The
-// framework will call get_memory_usage() on the three pools
-// asynchronously. As a result, each call might get a different value
-// for, say, survivor_num which will yield inconsistent values for
-// eden_used, survivor_used, and old_gen_used (as survivor_num is used
-// in the calculation of all three). This would normally be
-// ok. However, it's possible that this might cause the sum of
-// eden_used, survivor_used, and old_gen_used to go over the max heap
-// size and this seems to sometimes cause JConsole (and maybe other
-// clients) to get confused. There's not a really an easy / clean
-// solution to this problem, due to the asynchrounous nature of the
-// framework.
 
 
 // This class is shared by the three G1 memory pool classes
@@ -116,22 +57,6 @@ class G1CollectedHeap;
 // (see comment above), we put the calculations in this class so that
 // we can easily share them among the subclasses.
 class G1MemoryPoolSuper : public CollectedMemoryPool {
-private:
-  // It returns x - y if x > y, 0 otherwise.
-  // As described in the comment above, some of the inputs to the
-  // calculations we have to do are obtained concurrently and hence
-  // may be inconsistent with each other. So, this provides a
-  // defensive way of performing the subtraction and avoids the value
-  // going negative (which would mean a very large result, given that
-  // the parameter are size_t).
-  static size_t subtract_up_to_zero(size_t x, size_t y) {
-    if (x > y) {
-      return x - y;
-    } else {
-      return 0;
-    }
-  }
-
 protected:
   G1CollectedHeap* _g1h;
 
@@ -148,13 +73,6 @@ protected:
     return (size_t) -1;
   }
 
-  static size_t overall_committed(G1CollectedHeap* g1h) {
-    return g1h->capacity();
-  }
-  static size_t overall_used(G1CollectedHeap* g1h) {
-    return g1h->used_unlocked();
-  }
-
   static size_t eden_space_committed(G1CollectedHeap* g1h);
   static size_t eden_space_used(G1CollectedHeap* g1h);