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src/share/vm/gc_implementation/shared/parGCAllocBuffer.hpp
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rev 7799 : imported patch 8073466-remove-ratining-functionality-in-pargcallocbuffer
@@ -1,7 +1,7 @@
/*
- * 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
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
@@ -22,56 +22,44 @@
*
*/
#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
+ size_t _word_sz; // In HeapWord units
HeapWord* _bottom;
HeapWord* _top;
- HeapWord* _end; // last allocatable address + 1
+ HeapWord* _end; // Last allocatable address + 1
HeapWord* _hard_end; // _end + AlignmentReserve
- bool _retained; // whether we hold a _retained_filler
- MemRegion _retained_filler;
// 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;
static size_t AlignmentReserve;
- // Flush the stats supporting ergonomic sizing of PLAB's
- // Should not be called directly
- void flush_stats(PLABStats* stats);
-
public:
// Initializes the buffer to be empty, but with the given "word_sz".
// Must get initialized with "set_buf" for an allocation to succeed.
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 const size_t min_size();
+ // Maximum PLAB size.
+ static const 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
// allocated block. If the allocation request cannot be satisfied,
// return NULL.
@@ -126,66 +114,49 @@
assert(_end >= _top, "Negative buffer");
// In support of ergonomic sizing
_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);
-
- // 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);
- }
+ // Flush allocation statistics into the given PLABStats supporting ergonomic
+ // sizing of PLAB's and retire the current buffer.
+ void flush_and_retire_stats(PLABStats* stats);
// 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 update
+ // statistics.
+ 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)
{ }
static const size_t min_size() {
@@ -198,13 +169,13 @@
size_t desired_plab_sz() {
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);
}
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