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src/share/vm/gc_implementation/shared/parGCAllocBuffer.cpp
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rev 7799 : [mq]: 8073466-remove-ratining-functionality-in-pargcallocbuffer
rev 7800 : [mq]: 8073466-kim-fixes
@@ -1,7 +1,7 @@
/*
- * 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
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
@@ -22,71 +22,68 @@
*
*/
#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
// look like it's full of objects when we retire it, so we make
// 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) {
+ // We want to distinguish between unused space in the last buffer and waste
+ // created otherwise. Save the amount of unused space because retire() will
+ // update the pointers we use.
+ size_t unused = pointer_delta(_end, _top);
+
+ // Retire the last allocation buffer.
+ retire();
+
+ stats->add_allocated(_allocated);
+ // Retire() counts the unused space as wasted. So we need to remove it again
+ // before updating the statistics.
+ stats->add_wasted(_wasted - unused);
+ 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() {
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();
}
- }
- }
-}
-
-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));
}
// Compute desired plab size and latch result for later
// use. This should be called once at the end of parallel
// scavenge; it clears the sensor accumulators.
@@ -99,46 +96,39 @@
if (_allocated == 0) {
assert(_unused == 0,
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
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