--- a/hotspot/src/share/vm/gc_implementation/g1/g1Allocator.cpp Tue Mar 03 12:19:35 2015 +0100
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1Allocator.cpp Tue Mar 03 13:25:23 2015 +0000
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, 2015, 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
@@ -120,7 +120,7 @@
if (word_sz * 100 < gclab_word_size * ParallelGCBufferWastePct) {
G1ParGCAllocBuffer* alloc_buf = alloc_buffer(dest, context);
add_to_alloc_buffer_waste(alloc_buf->words_remaining());
- alloc_buf->retire(false /* end_of_gc */, false /* retain */);
+ alloc_buf->retire();
HeapWord* buf = _g1h->par_allocate_during_gc(dest, gclab_word_size, context);
if (buf == NULL) {
@@ -154,9 +154,7 @@
G1ParGCAllocBuffer* const buf = _alloc_buffers[state];
if (buf != NULL) {
add_to_alloc_buffer_waste(buf->words_remaining());
- buf->flush_stats_and_retire(_g1h->alloc_buffer_stats(state),
- true /* end_of_gc */,
- false /* retain */);
+ buf->flush_and_retire_stats(_g1h->alloc_buffer_stats(state));
}
}
}
--- a/hotspot/src/share/vm/gc_implementation/g1/g1Allocator.hpp Tue Mar 03 12:19:35 2015 +0100
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1Allocator.hpp Tue Mar 03 13:25:23 2015 +0000
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, 2015, 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
@@ -159,11 +159,11 @@
_retired = false;
}
- virtual void retire(bool end_of_gc, bool retain) {
+ virtual void retire() {
if (_retired) {
return;
}
- ParGCAllocBuffer::retire(end_of_gc, retain);
+ ParGCAllocBuffer::retire();
_retired = true;
}
};
--- a/hotspot/src/share/vm/gc_implementation/parNew/parNewGeneration.cpp Tue Mar 03 12:19:35 2015 +0100
+++ b/hotspot/src/share/vm/gc_implementation/parNew/parNewGeneration.cpp Tue Mar 03 13:25:23 2015 +0000
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2001, 2014, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2015, 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
@@ -232,7 +232,7 @@
if (word_sz * 100 <
ParallelGCBufferWastePct * plab->word_sz()) {
// Is small enough; abandon this buffer and start a new one.
- plab->retire(false, false);
+ plab->retire();
size_t buf_size = plab->word_sz();
HeapWord* buf_space = sp->par_allocate(buf_size);
if (buf_space == NULL) {
@@ -463,10 +463,7 @@
// Flush stats related to To-space PLAB activity and
// retire the last buffer.
- par_scan_state.to_space_alloc_buffer()->
- flush_stats_and_retire(_gen.plab_stats(),
- true /* end_of_gc */,
- false /* retain */);
+ par_scan_state.to_space_alloc_buffer()->flush_and_retire_stats(_gen.plab_stats());
// Every thread has its own age table. We need to merge
// them all into one.
--- a/hotspot/src/share/vm/gc_implementation/shared/parGCAllocBuffer.cpp Tue Mar 03 12:19:35 2015 +0100
+++ b/hotspot/src/share/vm/gc_implementation/shared/parGCAllocBuffer.cpp Tue Mar 03 13:25:23 2015 +0000
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2001, 2014, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2015, 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
@@ -24,27 +24,30 @@
#include "precompiled.hpp"
#include "gc_implementation/shared/parGCAllocBuffer.hpp"
-#include "memory/sharedHeap.hpp"
+#include "memory/threadLocalAllocBuffer.hpp"
#include "oops/arrayOop.hpp"
#include "oops/oop.inline.hpp"
-#include "utilities/globalDefinitions.hpp"
-PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
+size_t ParGCAllocBuffer::min_size() {
+ // Make sure that we return something that is larger than AlignmentReserve
+ return align_object_size(MAX2(MinTLABSize / HeapWordSize, (uintx)oopDesc::header_size())) + AlignmentReserve;
+}
+
+size_t ParGCAllocBuffer::max_size() {
+ return ThreadLocalAllocBuffer::max_size();
+}
ParGCAllocBuffer::ParGCAllocBuffer(size_t desired_plab_sz_) :
_word_sz(desired_plab_sz_), _bottom(NULL), _top(NULL),
- _end(NULL), _hard_end(NULL),
- _retained(false), _retained_filler(),
- _allocated(0), _wasted(0)
+ _end(NULL), _hard_end(NULL), _allocated(0), _wasted(0)
{
- assert (min_size() > AlignmentReserve, "Inconsistency!");
- // arrayOopDesc::header_size depends on command line initialization.
- FillerHeaderSize = align_object_size(arrayOopDesc::header_size(T_INT));
- AlignmentReserve = oopDesc::header_size() > MinObjAlignment ? FillerHeaderSize : 0;
+ // ArrayOopDesc::header_size depends on command line initialization.
+ AlignmentReserve = oopDesc::header_size() > MinObjAlignment ? align_object_size(arrayOopDesc::header_size(T_INT)) : 0;
+ assert(min_size() > AlignmentReserve,
+ err_msg("Minimum PLAB size " SIZE_FORMAT" must be larger than alignment reserve " SIZE_FORMAT" "
+ "to be able to contain objects", min_size(), AlignmentReserve));
}
-size_t ParGCAllocBuffer::FillerHeaderSize;
-
// If the minimum object size is greater than MinObjAlignment, we can
// end up with a shard at the end of the buffer that's smaller than
// the smallest object. We can't allow that because the buffer must
@@ -52,39 +55,33 @@
// sure we have enough space for a filler int array object.
size_t ParGCAllocBuffer::AlignmentReserve;
-void ParGCAllocBuffer::retire(bool end_of_gc, bool retain) {
- assert(!retain || end_of_gc, "Can only retain at GC end.");
- if (_retained) {
- // If the buffer had been retained shorten the previous filler object.
- assert(_retained_filler.end() <= _top, "INVARIANT");
- CollectedHeap::fill_with_object(_retained_filler);
- // Wasted space book-keeping, otherwise (normally) done in invalidate()
- _wasted += _retained_filler.word_size();
- _retained = false;
- }
- assert(!end_of_gc || !_retained, "At this point, end_of_gc ==> !_retained.");
+void ParGCAllocBuffer::flush_and_retire_stats(PLABStats* stats) {
+ // Retire the last allocation buffer.
+ size_t unused = retire_internal();
+
+ // Now flush the statistics.
+ stats->add_allocated(_allocated);
+ stats->add_wasted(_wasted);
+ stats->add_unused(unused);
+
+ // Since we have flushed the stats we need to clear the _allocated and _wasted
+ // fields in case somebody retains an instance of this over GCs. Not doing so
+ // will artifically inflate the values in the statistics.
+ _allocated = 0;
+ _wasted = 0;
+}
+
+void ParGCAllocBuffer::retire() {
+ _wasted += retire_internal();
+}
+
+size_t ParGCAllocBuffer::retire_internal() {
+ size_t result = 0;
if (_top < _hard_end) {
CollectedHeap::fill_with_object(_top, _hard_end);
- if (!retain) {
- invalidate();
- } else {
- // Is there wasted space we'd like to retain for the next GC?
- if (pointer_delta(_end, _top) > FillerHeaderSize) {
- _retained = true;
- _retained_filler = MemRegion(_top, FillerHeaderSize);
- _top = _top + FillerHeaderSize;
- } else {
- invalidate();
- }
- }
+ result += invalidate();
}
-}
-
-void ParGCAllocBuffer::flush_stats(PLABStats* stats) {
- assert(ResizePLAB, "Wasted work");
- stats->add_allocated(_allocated);
- stats->add_wasted(_wasted);
- stats->add_unused(pointer_delta(_end, _top));
+ return result;
}
// Compute desired plab size and latch result for later
@@ -101,44 +98,37 @@
err_msg("Inconsistency in PLAB stats: "
"_allocated: "SIZE_FORMAT", "
"_wasted: "SIZE_FORMAT", "
- "_unused: "SIZE_FORMAT", "
- "_used : "SIZE_FORMAT,
- _allocated, _wasted, _unused, _used));
+ "_unused: "SIZE_FORMAT,
+ _allocated, _wasted, _unused));
_allocated = 1;
}
- double wasted_frac = (double)_unused/(double)_allocated;
- size_t target_refills = (size_t)((wasted_frac*TargetSurvivorRatio)/
- TargetPLABWastePct);
+ double wasted_frac = (double)_unused / (double)_allocated;
+ size_t target_refills = (size_t)((wasted_frac * TargetSurvivorRatio) / TargetPLABWastePct);
if (target_refills == 0) {
target_refills = 1;
}
- _used = _allocated - _wasted - _unused;
- size_t plab_sz = _used/(target_refills*no_of_gc_workers);
- if (PrintPLAB) gclog_or_tty->print(" (plab_sz = " SIZE_FORMAT " ", plab_sz);
+ size_t used = _allocated - _wasted - _unused;
+ size_t recent_plab_sz = used / (target_refills * no_of_gc_workers);
// Take historical weighted average
- _filter.sample(plab_sz);
+ _filter.sample(recent_plab_sz);
// Clip from above and below, and align to object boundary
- plab_sz = MAX2(min_size(), (size_t)_filter.average());
- plab_sz = MIN2(max_size(), plab_sz);
- plab_sz = align_object_size(plab_sz);
+ size_t new_plab_sz = MAX2(min_size(), (size_t)_filter.average());
+ new_plab_sz = MIN2(max_size(), new_plab_sz);
+ new_plab_sz = align_object_size(new_plab_sz);
// Latch the result
- if (PrintPLAB) gclog_or_tty->print(" desired_plab_sz = " SIZE_FORMAT ") ", plab_sz);
- _desired_plab_sz = plab_sz;
- // Now clear the accumulators for next round:
- // note this needs to be fixed in the case where we
- // are retaining across scavenges. FIX ME !!! XXX
- _allocated = 0;
- _wasted = 0;
- _unused = 0;
+ if (PrintPLAB) {
+ gclog_or_tty->print(" (plab_sz = " SIZE_FORMAT" desired_plab_sz = " SIZE_FORMAT") ", recent_plab_sz, new_plab_sz);
+ }
+ _desired_plab_sz = new_plab_sz;
+
+ reset();
}
#ifndef PRODUCT
void ParGCAllocBuffer::print() {
- gclog_or_tty->print("parGCAllocBuffer: _bottom: " PTR_FORMAT " _top: " PTR_FORMAT
- " _end: " PTR_FORMAT " _hard_end: " PTR_FORMAT " _retained: %c"
- " _retained_filler: [" PTR_FORMAT "," PTR_FORMAT ")\n",
- _bottom, _top, _end, _hard_end,
- "FT"[_retained], _retained_filler.start(), _retained_filler.end());
+ gclog_or_tty->print_cr("parGCAllocBuffer: _bottom: " PTR_FORMAT " _top: " PTR_FORMAT
+ " _end: " PTR_FORMAT " _hard_end: " PTR_FORMAT ")",
+ p2i(_bottom), p2i(_top), p2i(_end), p2i(_hard_end));
}
#endif // !PRODUCT
--- a/hotspot/src/share/vm/gc_implementation/shared/parGCAllocBuffer.hpp Tue Mar 03 12:19:35 2015 +0100
+++ b/hotspot/src/share/vm/gc_implementation/shared/parGCAllocBuffer.hpp Tue Mar 03 13:25:23 2015 +0000
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2001, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2015, 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
@@ -24,37 +24,43 @@
#ifndef SHARE_VM_GC_IMPLEMENTATION_PARNEW_PARGCALLOCBUFFER_HPP
#define SHARE_VM_GC_IMPLEMENTATION_PARNEW_PARGCALLOCBUFFER_HPP
-#include "gc_interface/collectedHeap.hpp"
+
+#include "gc_implementation/shared/gcUtil.hpp"
#include "memory/allocation.hpp"
-#include "memory/blockOffsetTable.hpp"
-#include "memory/threadLocalAllocBuffer.hpp"
+#include "runtime/atomic.hpp"
#include "utilities/globalDefinitions.hpp"
-// Forward decl.
-
+// Forward declarations.
class PLABStats;
// A per-thread allocation buffer used during GC.
class ParGCAllocBuffer: public CHeapObj<mtGC> {
protected:
- char head[32];
- size_t _word_sz; // in HeapWord units
+ char head[32];
+ size_t _word_sz; // In HeapWord units
HeapWord* _bottom;
HeapWord* _top;
- HeapWord* _end; // last allocatable address + 1
- HeapWord* _hard_end; // _end + AlignmentReserve
- bool _retained; // whether we hold a _retained_filler
- MemRegion _retained_filler;
+ HeapWord* _end; // Last allocatable address + 1
+ HeapWord* _hard_end; // _end + AlignmentReserve
// In support of ergonomic sizing of PLAB's
size_t _allocated; // in HeapWord units
size_t _wasted; // in HeapWord units
- char tail[32];
- static size_t FillerHeaderSize;
+ char tail[32];
static size_t AlignmentReserve;
- // Flush the stats supporting ergonomic sizing of PLAB's
- // Should not be called directly
- void flush_stats(PLABStats* stats);
+ // Force future allocations to fail and queries for contains()
+ // to return false. Returns the amount of unused space in this PLAB.
+ size_t invalidate() {
+ _end = _hard_end;
+ size_t remaining = pointer_delta(_end, _top); // Calculate remaining space.
+ _top = _end; // Force future allocations to fail.
+ _bottom = _end; // Force future contains() queries to return false.
+ return remaining;
+ }
+
+ // Fill in remaining space with a dummy object and invalidate the PLAB. Returns
+ // the amount of remaining space.
+ size_t retire_internal();
public:
// Initializes the buffer to be empty, but with the given "word_sz".
@@ -62,14 +68,10 @@
ParGCAllocBuffer(size_t word_sz);
virtual ~ParGCAllocBuffer() {}
- static const size_t min_size() {
- // Make sure that we return something that is larger than AlignmentReserve
- return align_object_size(MAX2(MinTLABSize / HeapWordSize, (uintx)oopDesc::header_size())) + AlignmentReserve;
- }
-
- static const size_t max_size() {
- return ThreadLocalAllocBuffer::max_size();
- }
+ // Minimum PLAB size.
+ static size_t min_size();
+ // Maximum PLAB size.
+ static size_t max_size();
// If an allocation of the given "word_sz" can be satisfied within the
// buffer, do the allocation, returning a pointer to the start of the
@@ -128,62 +130,37 @@
_allocated += word_sz();
}
- // Flush the stats supporting ergonomic sizing of PLAB's
- // and retire the current buffer.
- void flush_stats_and_retire(PLABStats* stats, bool end_of_gc, bool retain) {
- // We flush the stats first in order to get a reading of
- // unused space in the last buffer.
- if (ResizePLAB) {
- flush_stats(stats);
+ // Flush allocation statistics into the given PLABStats supporting ergonomic
+ // sizing of PLAB's and retire the current buffer. To be called at the end of
+ // GC.
+ void flush_and_retire_stats(PLABStats* stats);
- // Since we have flushed the stats we need to clear
- // the _allocated and _wasted fields. Not doing so
- // will artifically inflate the values in the stats
- // to which we add them.
- // The next time we flush these values, we will add
- // what we have just flushed in addition to the size
- // of the buffers allocated between now and then.
- _allocated = 0;
- _wasted = 0;
- }
- // Retire the last allocation buffer.
- retire(end_of_gc, retain);
- }
-
- // Force future allocations to fail and queries for contains()
- // to return false
- void invalidate() {
- assert(!_retained, "Shouldn't retain an invalidated buffer.");
- _end = _hard_end;
- _wasted += pointer_delta(_end, _top); // unused space
- _top = _end; // force future allocations to fail
- _bottom = _end; // force future contains() queries to return false
- }
-
- // Fills in the unallocated portion of the buffer with a garbage object.
- // If "end_of_gc" is TRUE, is after the last use in the GC. IF "retain"
- // is true, attempt to re-use the unused portion in the next GC.
- virtual void retire(bool end_of_gc, bool retain);
+ // Fills in the unallocated portion of the buffer with a garbage object and updates
+ // statistics. To be called during GC.
+ virtual void retire();
void print() PRODUCT_RETURN;
};
-// PLAB stats book-keeping
+// PLAB book-keeping.
class PLABStats VALUE_OBJ_CLASS_SPEC {
- size_t _allocated; // total allocated
+ size_t _allocated; // Total allocated
size_t _wasted; // of which wasted (internal fragmentation)
size_t _unused; // Unused in last buffer
- size_t _used; // derived = allocated - wasted - unused
- size_t _desired_plab_sz;// output of filter (below), suitably trimmed and quantized
+ size_t _desired_plab_sz;// Output of filter (below), suitably trimmed and quantized
AdaptiveWeightedAverage
- _filter; // integrator with decay
+ _filter; // Integrator with decay
+ void reset() {
+ _allocated = 0;
+ _wasted = 0;
+ _unused = 0;
+ }
public:
PLABStats(size_t desired_plab_sz_, unsigned wt) :
_allocated(0),
_wasted(0),
_unused(0),
- _used(0),
_desired_plab_sz(desired_plab_sz_),
_filter(wt)
{ }
@@ -200,9 +177,9 @@
return _desired_plab_sz;
}
+ // Updates the current desired PLAB size. Computes the new desired PLAB size,
+ // updates _desired_plab_sz and clears sensor accumulators.
void adjust_desired_plab_sz(uint no_of_gc_workers);
- // filter computation, latches output to
- // _desired_plab_sz, clears sensor accumulators
void add_allocated(size_t v) {
Atomic::add_ptr(v, &_allocated);