5b42f3ce0d
Consistently use _g1h member names for cached G1CollectedHeap* variables. Reviewed-by: sangheki, sjohanss
275 lines
11 KiB
C++
275 lines
11 KiB
C++
/*
|
|
* Copyright (c) 2011, 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
|
|
* or visit www.oracle.com if you need additional information or have any
|
|
* questions.
|
|
*
|
|
*/
|
|
|
|
#ifndef SHARE_VM_GC_G1_G1MONITORINGSUPPORT_HPP
|
|
#define SHARE_VM_GC_G1_G1MONITORINGSUPPORT_HPP
|
|
|
|
#include "gc/shared/generationCounters.hpp"
|
|
|
|
class CollectorCounters;
|
|
class G1CollectedHeap;
|
|
class HSpaceCounters;
|
|
|
|
// Class for monitoring logical spaces in G1. It provides data for
|
|
// both G1's jstat counters as well as G1's memory pools.
|
|
//
|
|
// G1 splits the heap into heap regions and each heap region belongs
|
|
// to one of the following categories:
|
|
//
|
|
// * eden : regions that have been allocated since the last GC
|
|
// * survivors : regions with objects that survived the last few GCs
|
|
// * old : long-lived non-humongous regions
|
|
// * humongous : humongous regions
|
|
// * free : free regions
|
|
//
|
|
// The combination of eden and survivor regions form the equivalent of
|
|
// the young generation in the other GCs. The combination of old and
|
|
// humongous regions form the equivalent of the old generation in the
|
|
// other GCs. Free regions do not have a good equivalent in the other
|
|
// GCs given that they can be allocated as any of the other region types.
|
|
//
|
|
// The monitoring tools expect the heap to contain a number of
|
|
// generations (young, old, perm) and each generation to contain a
|
|
// number of spaces (young: eden, survivors, old). Given that G1 does
|
|
// not maintain those spaces physically (e.g., the set of
|
|
// non-contiguous eden regions can be considered as a "logical"
|
|
// space), we'll provide the illusion that those generations and
|
|
// spaces exist. In reality, each generation and space refers to a set
|
|
// of heap regions that are potentially non-contiguous.
|
|
//
|
|
// This class provides interfaces to access the min, current, and max
|
|
// capacity and current occupancy for each of G1's logical spaces and
|
|
// generations we expose to the monitoring tools. Also provided are
|
|
// counters for G1 concurrent collections and stop-the-world full heap
|
|
// collections.
|
|
//
|
|
// Below is a description of how the various sizes are calculated.
|
|
//
|
|
// * Current Capacity
|
|
//
|
|
// - heap_capacity = current heap capacity (e.g., current committed size)
|
|
// - young_gen_capacity = current max young gen target capacity
|
|
// (i.e., young gen target capacity + max allowed expansion capacity)
|
|
// - survivor_capacity = current survivor region capacity
|
|
// - eden_capacity = young_gen_capacity - survivor_capacity
|
|
// - old_capacity = heap_capacity - young_gen_capacity
|
|
//
|
|
// What we do in the above is to distribute the free regions among
|
|
// eden_capacity and old_capacity.
|
|
//
|
|
// * Occupancy
|
|
//
|
|
// - young_gen_used = current young region capacity
|
|
// - survivor_used = survivor_capacity
|
|
// - eden_used = young_gen_used - survivor_used
|
|
// - old_used = overall_used - young_gen_used
|
|
//
|
|
// Unfortunately, we currently only keep track of the number of
|
|
// currently allocated young and survivor regions + the overall used
|
|
// bytes in the heap, so the above can be a little inaccurate.
|
|
//
|
|
// * Min Capacity
|
|
//
|
|
// We set this to 0 for all spaces.
|
|
//
|
|
// * Max Capacity
|
|
//
|
|
// For jstat, we set the max capacity of all spaces to heap_capacity,
|
|
// given that we don't always have a reasonable upper bound on how big
|
|
// each space can grow. For the memory pools, we make the max
|
|
// capacity undefined with the exception of the old memory pool for
|
|
// which we make the max capacity same as the max heap capacity.
|
|
//
|
|
// If we had more accurate occupancy / capacity information per
|
|
// region set the above calculations would be greatly simplified and
|
|
// be made more accurate.
|
|
//
|
|
// We update all the above synchronously and we store the results in
|
|
// fields so that we just read said fields when needed. A subtle point
|
|
// is that all the above sizes need to be recalculated when the old
|
|
// gen changes capacity (after a GC or after a humongous allocation)
|
|
// but only the eden occupancy changes when a new eden region is
|
|
// allocated. So, in the latter case we have minimal recalculation to
|
|
// do which is important as we want to keep the eden region allocation
|
|
// path as low-overhead as possible.
|
|
|
|
class G1MonitoringSupport : public CHeapObj<mtGC> {
|
|
friend class VMStructs;
|
|
|
|
G1CollectedHeap* _g1h;
|
|
|
|
// jstat performance counters
|
|
// incremental collections both young and mixed
|
|
CollectorCounters* _incremental_collection_counters;
|
|
// full stop-the-world collections
|
|
CollectorCounters* _full_collection_counters;
|
|
// stop-the-world phases in G1
|
|
CollectorCounters* _conc_collection_counters;
|
|
// young collection set counters. The _eden_counters,
|
|
// _from_counters, and _to_counters are associated with
|
|
// this "generational" counter.
|
|
GenerationCounters* _young_collection_counters;
|
|
// old collection set counters. The _old_space_counters
|
|
// below are associated with this "generational" counter.
|
|
GenerationCounters* _old_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;
|
|
|
|
// When it's appropriate to recalculate the various sizes (at the
|
|
// end of a GC, when a new eden region is allocated, etc.) we store
|
|
// them here so that we can easily report them when needed and not
|
|
// have to recalculate them every time.
|
|
|
|
size_t _overall_reserved;
|
|
size_t _overall_committed;
|
|
size_t _overall_used;
|
|
|
|
uint _young_region_num;
|
|
size_t _young_gen_committed;
|
|
size_t _eden_committed;
|
|
size_t _eden_used;
|
|
size_t _survivor_committed;
|
|
size_t _survivor_used;
|
|
|
|
size_t _old_committed;
|
|
size_t _old_used;
|
|
|
|
// 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;
|
|
}
|
|
}
|
|
|
|
// Recalculate all the sizes.
|
|
void recalculate_sizes();
|
|
// Recalculate only what's necessary when a new eden region is allocated.
|
|
void recalculate_eden_size();
|
|
|
|
public:
|
|
G1MonitoringSupport(G1CollectedHeap* g1h);
|
|
|
|
// Unfortunately, the jstat tool assumes that no space has 0
|
|
// capacity. In our case, given that each space is logical, it's
|
|
// possible that no regions will be allocated to it, hence to have 0
|
|
// capacity (e.g., if there are no survivor regions, the survivor
|
|
// space has 0 capacity). The way we deal with this is to always pad
|
|
// each capacity value we report to jstat by a very small amount to
|
|
// make sure that it's never zero. Given that we sometimes have to
|
|
// report a capacity of a generation that contains several spaces
|
|
// (e.g., young gen includes one eden, two survivor spaces), the
|
|
// mult parameter is provided in order to adding the appropriate
|
|
// padding multiple times so that the capacities add up correctly.
|
|
static size_t pad_capacity(size_t size_bytes, size_t mult = 1) {
|
|
return size_bytes + MinObjAlignmentInBytes * mult;
|
|
}
|
|
|
|
// Recalculate all the sizes from scratch and update all the jstat
|
|
// counters accordingly.
|
|
void update_sizes();
|
|
// Recalculate only what's necessary when a new eden region is
|
|
// allocated and update any jstat counters that need to be updated.
|
|
void update_eden_size();
|
|
|
|
CollectorCounters* incremental_collection_counters() {
|
|
return _incremental_collection_counters;
|
|
}
|
|
CollectorCounters* full_collection_counters() {
|
|
return _full_collection_counters;
|
|
}
|
|
CollectorCounters* conc_collection_counters() {
|
|
return _conc_collection_counters;
|
|
}
|
|
GenerationCounters* young_collection_counters() {
|
|
return _young_collection_counters;
|
|
}
|
|
GenerationCounters* old_collection_counters() {
|
|
return _old_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
|
|
// Tracing
|
|
|
|
size_t overall_reserved() { return _overall_reserved; }
|
|
size_t overall_committed() { return _overall_committed; }
|
|
size_t overall_used() { return _overall_used; }
|
|
|
|
size_t young_gen_committed() { return _young_gen_committed; }
|
|
size_t young_gen_max() { return overall_reserved(); }
|
|
size_t eden_space_committed() { return _eden_committed; }
|
|
size_t eden_space_used() { return _eden_used; }
|
|
size_t survivor_space_committed() { return _survivor_committed; }
|
|
size_t survivor_space_used() { return _survivor_used; }
|
|
|
|
size_t old_gen_committed() { return old_space_committed(); }
|
|
size_t old_gen_max() { return overall_reserved(); }
|
|
size_t old_space_committed() { return _old_committed; }
|
|
size_t old_space_used() { return _old_used; }
|
|
};
|
|
|
|
class G1GenerationCounters: public GenerationCounters {
|
|
protected:
|
|
G1MonitoringSupport* _g1mm;
|
|
|
|
public:
|
|
G1GenerationCounters(G1MonitoringSupport* g1mm,
|
|
const char* name, int ordinal, int spaces,
|
|
size_t min_capacity, size_t max_capacity,
|
|
size_t curr_capacity);
|
|
};
|
|
|
|
class G1YoungGenerationCounters: public G1GenerationCounters {
|
|
public:
|
|
G1YoungGenerationCounters(G1MonitoringSupport* g1mm, const char* name);
|
|
virtual void update_all();
|
|
};
|
|
|
|
class G1OldGenerationCounters: public G1GenerationCounters {
|
|
public:
|
|
G1OldGenerationCounters(G1MonitoringSupport* g1mm, const char* name);
|
|
virtual void update_all();
|
|
};
|
|
|
|
#endif // SHARE_VM_GC_G1_G1MONITORINGSUPPORT_HPP
|