--- a/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp Wed Feb 15 16:09:49 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp Fri Feb 17 13:23:29 2012 +0100
@@ -6092,7 +6092,11 @@
_inter_sweep_timer.reset();
_inter_sweep_timer.start();
- update_time_of_last_gc(os::javaTimeMillis());
+ // We need to use a monotonically non-deccreasing time in ms
+ // or we will see time-warp warnings and os::javaTimeMillis()
+ // does not guarantee monotonicity.
+ jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
+ update_time_of_last_gc(now);
// NOTE on abstract state transitions:
// Mutators allocate-live and/or mark the mod-union table dirty
--- a/hotspot/src/share/vm/gc_implementation/g1/collectionSetChooser.cpp Wed Feb 15 16:09:49 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/collectionSetChooser.cpp Fri Feb 17 13:23:29 2012 +0100
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2012, 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
@@ -48,6 +48,8 @@
#ifndef PRODUCT
bool CSetChooserCache::verify() {
+ guarantee(false, "CSetChooserCache::verify(): don't call this any more");
+
int index = _first;
HeapRegion *prev = NULL;
for (int i = 0; i < _occupancy; ++i) {
@@ -75,6 +77,8 @@
#endif // PRODUCT
void CSetChooserCache::insert(HeapRegion *hr) {
+ guarantee(false, "CSetChooserCache::insert(): don't call this any more");
+
assert(!is_full(), "cache should not be empty");
hr->calc_gc_efficiency();
@@ -104,6 +108,9 @@
}
HeapRegion *CSetChooserCache::remove_first() {
+ guarantee(false, "CSetChooserCache::remove_first(): "
+ "don't call this any more");
+
if (_occupancy > 0) {
assert(_cache[_first] != NULL, "cache should have at least one region");
HeapRegion *ret = _cache[_first];
@@ -118,16 +125,35 @@
}
}
-static inline int orderRegions(HeapRegion* hr1, HeapRegion* hr2) {
+// Even though we don't use the GC efficiency in our heuristics as
+// much as we used to, we still order according to GC efficiency. This
+// will cause regions with a lot of live objects and large RSets to
+// end up at the end of the array. Given that we might skip collecting
+// the last few old regions, if after a few mixed GCs the remaining
+// have reclaimable bytes under a certain threshold, the hope is that
+// the ones we'll skip are ones with both large RSets and a lot of
+// live objects, not the ones with just a lot of live objects if we
+// ordered according to the amount of reclaimable bytes per region.
+static int orderRegions(HeapRegion* hr1, HeapRegion* hr2) {
if (hr1 == NULL) {
- if (hr2 == NULL) return 0;
- else return 1;
+ if (hr2 == NULL) {
+ return 0;
+ } else {
+ return 1;
+ }
} else if (hr2 == NULL) {
return -1;
}
- if (hr2->gc_efficiency() < hr1->gc_efficiency()) return -1;
- else if (hr1->gc_efficiency() < hr2->gc_efficiency()) return 1;
- else return 0;
+
+ double gc_eff1 = hr1->gc_efficiency();
+ double gc_eff2 = hr2->gc_efficiency();
+ if (gc_eff1 > gc_eff2) {
+ return -1;
+ } if (gc_eff1 < gc_eff2) {
+ return 1;
+ } else {
+ return 0;
+ }
}
static int orderRegions(HeapRegion** hr1p, HeapRegion** hr2p) {
@@ -151,51 +177,61 @@
//
_markedRegions((ResourceObj::set_allocation_type((address)&_markedRegions,
ResourceObj::C_HEAP),
- 100),
- true),
- _curMarkedIndex(0),
- _numMarkedRegions(0),
- _unmarked_age_1_returned_as_new(false),
- _first_par_unreserved_idx(0)
-{}
-
-
+ 100), true /* C_Heap */),
+ _curr_index(0), _length(0),
+ _regionLiveThresholdBytes(0), _remainingReclaimableBytes(0),
+ _first_par_unreserved_idx(0) {
+ _regionLiveThresholdBytes =
+ HeapRegion::GrainBytes * (size_t) G1OldCSetRegionLiveThresholdPercent / 100;
+}
#ifndef PRODUCT
bool CollectionSetChooser::verify() {
+ guarantee(_length >= 0, err_msg("_length: %d", _length));
+ guarantee(0 <= _curr_index && _curr_index <= _length,
+ err_msg("_curr_index: %d _length: %d", _curr_index, _length));
int index = 0;
- guarantee(_curMarkedIndex <= _numMarkedRegions,
- "_curMarkedIndex should be within bounds");
- while (index < _curMarkedIndex) {
- guarantee(_markedRegions.at(index++) == NULL,
- "all entries before _curMarkedIndex should be NULL");
+ size_t sum_of_reclaimable_bytes = 0;
+ while (index < _curr_index) {
+ guarantee(_markedRegions.at(index) == NULL,
+ "all entries before _curr_index should be NULL");
+ index += 1;
}
HeapRegion *prev = NULL;
- while (index < _numMarkedRegions) {
+ while (index < _length) {
HeapRegion *curr = _markedRegions.at(index++);
guarantee(curr != NULL, "Regions in _markedRegions array cannot be NULL");
int si = curr->sort_index();
guarantee(!curr->is_young(), "should not be young!");
+ guarantee(!curr->isHumongous(), "should not be humongous!");
guarantee(si > -1 && si == (index-1), "sort index invariant");
if (prev != NULL) {
- guarantee(orderRegions(prev, curr) != 1, "regions should be sorted");
+ guarantee(orderRegions(prev, curr) != 1,
+ err_msg("GC eff prev: %1.4f GC eff curr: %1.4f",
+ prev->gc_efficiency(), curr->gc_efficiency()));
}
+ sum_of_reclaimable_bytes += curr->reclaimable_bytes();
prev = curr;
}
- return _cache.verify();
+ guarantee(sum_of_reclaimable_bytes == _remainingReclaimableBytes,
+ err_msg("reclaimable bytes inconsistent, "
+ "remaining: "SIZE_FORMAT" sum: "SIZE_FORMAT,
+ _remainingReclaimableBytes, sum_of_reclaimable_bytes));
+ return true;
}
#endif
-void
-CollectionSetChooser::fillCache() {
- while (!_cache.is_full() && (_curMarkedIndex < _numMarkedRegions)) {
- HeapRegion* hr = _markedRegions.at(_curMarkedIndex);
+void CollectionSetChooser::fillCache() {
+ guarantee(false, "fillCache: don't call this any more");
+
+ while (!_cache.is_full() && (_curr_index < _length)) {
+ HeapRegion* hr = _markedRegions.at(_curr_index);
assert(hr != NULL,
err_msg("Unexpected NULL hr in _markedRegions at index %d",
- _curMarkedIndex));
- _curMarkedIndex += 1;
+ _curr_index));
+ _curr_index += 1;
assert(!hr->is_young(), "should not be young!");
- assert(hr->sort_index() == _curMarkedIndex-1, "sort_index invariant");
+ assert(hr->sort_index() == _curr_index-1, "sort_index invariant");
_markedRegions.at_put(hr->sort_index(), NULL);
_cache.insert(hr);
assert(!_cache.is_empty(), "cache should not be empty");
@@ -203,9 +239,7 @@
assert(verify(), "cache should be consistent");
}
-void
-CollectionSetChooser::sortMarkedHeapRegions() {
- guarantee(_cache.is_empty(), "cache should be empty");
+void CollectionSetChooser::sortMarkedHeapRegions() {
// First trim any unused portion of the top in the parallel case.
if (_first_par_unreserved_idx > 0) {
if (G1PrintParCleanupStats) {
@@ -217,43 +251,78 @@
_markedRegions.trunc_to(_first_par_unreserved_idx);
}
_markedRegions.sort(orderRegions);
- assert(_numMarkedRegions <= _markedRegions.length(), "Requirement");
- assert(_numMarkedRegions == 0
- || _markedRegions.at(_numMarkedRegions-1) != NULL,
- "Testing _numMarkedRegions");
- assert(_numMarkedRegions == _markedRegions.length()
- || _markedRegions.at(_numMarkedRegions) == NULL,
- "Testing _numMarkedRegions");
+ assert(_length <= _markedRegions.length(), "Requirement");
+ assert(_length == 0 || _markedRegions.at(_length - 1) != NULL,
+ "Testing _length");
+ assert(_length == _markedRegions.length() ||
+ _markedRegions.at(_length) == NULL, "Testing _length");
if (G1PrintParCleanupStats) {
- gclog_or_tty->print_cr(" Sorted %d marked regions.", _numMarkedRegions);
+ gclog_or_tty->print_cr(" Sorted %d marked regions.", _length);
}
- for (int i = 0; i < _numMarkedRegions; i++) {
+ for (int i = 0; i < _length; i++) {
assert(_markedRegions.at(i) != NULL, "Should be true by sorting!");
_markedRegions.at(i)->set_sort_index(i);
}
if (G1PrintRegionLivenessInfo) {
G1PrintRegionLivenessInfoClosure cl(gclog_or_tty, "Post-Sorting");
- for (int i = 0; i < _numMarkedRegions; ++i) {
+ for (int i = 0; i < _length; ++i) {
HeapRegion* r = _markedRegions.at(i);
cl.doHeapRegion(r);
}
}
- assert(verify(), "should now be sorted");
+ assert(verify(), "CSet chooser verification");
}
-void
-CollectionSetChooser::addMarkedHeapRegion(HeapRegion* hr) {
+size_t CollectionSetChooser::calcMinOldCSetLength() {
+ // The min old CSet region bound is based on the maximum desired
+ // number of mixed GCs after a cycle. I.e., even if some old regions
+ // look expensive, we should add them to the CSet anyway to make
+ // sure we go through the available old regions in no more than the
+ // maximum desired number of mixed GCs.
+ //
+ // The calculation is based on the number of marked regions we added
+ // to the CSet chooser in the first place, not how many remain, so
+ // that the result is the same during all mixed GCs that follow a cycle.
+
+ const size_t region_num = (size_t) _length;
+ const size_t gc_num = (size_t) G1MaxMixedGCNum;
+ size_t result = region_num / gc_num;
+ // emulate ceiling
+ if (result * gc_num < region_num) {
+ result += 1;
+ }
+ return result;
+}
+
+size_t CollectionSetChooser::calcMaxOldCSetLength() {
+ // The max old CSet region bound is based on the threshold expressed
+ // as a percentage of the heap size. I.e., it should bound the
+ // number of old regions added to the CSet irrespective of how many
+ // of them are available.
+
+ G1CollectedHeap* g1h = G1CollectedHeap::heap();
+ const size_t region_num = g1h->n_regions();
+ const size_t perc = (size_t) G1OldCSetRegionThresholdPercent;
+ size_t result = region_num * perc / 100;
+ // emulate ceiling
+ if (100 * result < region_num * perc) {
+ result += 1;
+ }
+ return result;
+}
+
+void CollectionSetChooser::addMarkedHeapRegion(HeapRegion* hr) {
assert(!hr->isHumongous(),
"Humongous regions shouldn't be added to the collection set");
assert(!hr->is_young(), "should not be young!");
_markedRegions.append(hr);
- _numMarkedRegions++;
+ _length++;
+ _remainingReclaimableBytes += hr->reclaimable_bytes();
hr->calc_gc_efficiency();
}
-void
-CollectionSetChooser::
-prepareForAddMarkedHeapRegionsPar(size_t n_regions, size_t chunkSize) {
+void CollectionSetChooser::prepareForAddMarkedHeapRegionsPar(size_t n_regions,
+ size_t chunkSize) {
_first_par_unreserved_idx = 0;
int n_threads = ParallelGCThreads;
if (UseDynamicNumberOfGCThreads) {
@@ -274,8 +343,7 @@
_markedRegions.at_put_grow((int)(aligned_n_regions + max_waste - 1), NULL);
}
-jint
-CollectionSetChooser::getParMarkedHeapRegionChunk(jint n_regions) {
+jint CollectionSetChooser::getParMarkedHeapRegionChunk(jint n_regions) {
// Don't do this assert because this can be called at a point
// where the loop up stream will not execute again but might
// try to claim more chunks (loop test has not been done yet).
@@ -287,83 +355,37 @@
return res - n_regions;
}
-void
-CollectionSetChooser::setMarkedHeapRegion(jint index, HeapRegion* hr) {
+void CollectionSetChooser::setMarkedHeapRegion(jint index, HeapRegion* hr) {
assert(_markedRegions.at(index) == NULL, "precondition");
assert(!hr->is_young(), "should not be young!");
_markedRegions.at_put(index, hr);
hr->calc_gc_efficiency();
}
-void
-CollectionSetChooser::incNumMarkedHeapRegions(jint inc_by) {
- (void)Atomic::add(inc_by, &_numMarkedRegions);
-}
-
-void
-CollectionSetChooser::clearMarkedHeapRegions(){
- for (int i = 0; i < _markedRegions.length(); i++) {
- HeapRegion* r = _markedRegions.at(i);
- if (r != NULL) r->set_sort_index(-1);
+void CollectionSetChooser::updateTotals(jint region_num,
+ size_t reclaimable_bytes) {
+ // Only take the lock if we actually need to update the totals.
+ if (region_num > 0) {
+ assert(reclaimable_bytes > 0, "invariant");
+ // We could have just used atomics instead of taking the
+ // lock. However, we currently don't have an atomic add for size_t.
+ MutexLockerEx x(ParGCRareEvent_lock, Mutex::_no_safepoint_check_flag);
+ _length += (int) region_num;
+ _remainingReclaimableBytes += reclaimable_bytes;
+ } else {
+ assert(reclaimable_bytes == 0, "invariant");
}
- _markedRegions.clear();
- _curMarkedIndex = 0;
- _numMarkedRegions = 0;
- _cache.clear();
-};
-
-void
-CollectionSetChooser::updateAfterFullCollection() {
- clearMarkedHeapRegions();
}
-// if time_remaining < 0.0, then this method should try to return
-// a region, whether it fits within the remaining time or not
-HeapRegion*
-CollectionSetChooser::getNextMarkedRegion(double time_remaining,
- double avg_prediction) {
- G1CollectedHeap* g1h = G1CollectedHeap::heap();
- G1CollectorPolicy* g1p = g1h->g1_policy();
- fillCache();
- if (_cache.is_empty()) {
- assert(_curMarkedIndex == _numMarkedRegions,
- "if cache is empty, list should also be empty");
- ergo_verbose0(ErgoCSetConstruction,
- "stop adding old regions to CSet",
- ergo_format_reason("cache is empty"));
- return NULL;
- }
-
- HeapRegion *hr = _cache.get_first();
- assert(hr != NULL, "if cache not empty, first entry should be non-null");
- double predicted_time = g1h->predict_region_elapsed_time_ms(hr, false);
-
- if (g1p->adaptive_young_list_length()) {
- if (time_remaining - predicted_time < 0.0) {
- g1h->check_if_region_is_too_expensive(predicted_time);
- ergo_verbose2(ErgoCSetConstruction,
- "stop adding old regions to CSet",
- ergo_format_reason("predicted old region time higher than remaining time")
- ergo_format_ms("predicted old region time")
- ergo_format_ms("remaining time"),
- predicted_time, time_remaining);
- return NULL;
- }
- } else {
- double threshold = 2.0 * avg_prediction;
- if (predicted_time > threshold) {
- ergo_verbose2(ErgoCSetConstruction,
- "stop adding old regions to CSet",
- ergo_format_reason("predicted old region time higher than threshold")
- ergo_format_ms("predicted old region time")
- ergo_format_ms("threshold"),
- predicted_time, threshold);
- return NULL;
+void CollectionSetChooser::clearMarkedHeapRegions() {
+ for (int i = 0; i < _markedRegions.length(); i++) {
+ HeapRegion* r = _markedRegions.at(i);
+ if (r != NULL) {
+ r->set_sort_index(-1);
}
}
-
- HeapRegion *hr2 = _cache.remove_first();
- assert(hr == hr2, "cache contents should not have changed");
-
- return hr;
-}
+ _markedRegions.clear();
+ _curr_index = 0;
+ _length = 0;
+ _remainingReclaimableBytes = 0;
+};
--- a/hotspot/src/share/vm/gc_implementation/g1/collectionSetChooser.hpp Wed Feb 15 16:09:49 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/collectionSetChooser.hpp Fri Feb 17 13:23:29 2012 +0100
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2012, 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
@@ -28,28 +28,6 @@
#include "gc_implementation/g1/heapRegion.hpp"
#include "utilities/growableArray.hpp"
-// We need to sort heap regions by collection desirability.
-// This sorting is currently done in two "stages". An initial sort is
-// done following a cleanup pause as soon as all of the marked but
-// non-empty regions have been identified and the completely empty
-// ones reclaimed.
-// This gives us a global sort on a GC efficiency metric
-// based on predictive data available at that time. However,
-// any of these regions that are collected will only be collected
-// during a future GC pause, by which time it is possible that newer
-// data might allow us to revise and/or refine the earlier
-// pause predictions, leading to changes in expected gc efficiency
-// order. To somewhat mitigate this obsolescence, more so in the
-// case of regions towards the end of the list, which will be
-// picked later, these pre-sorted regions from the _markedRegions
-// array are not used as is, but a small prefix thereof is
-// insertion-sorted again into a small cache, based on more
-// recent remembered set information. Regions are then drawn
-// from this cache to construct the collection set at each
-// incremental GC.
-// This scheme and/or its implementation may be subject to
-// revision in the future.
-
class CSetChooserCache VALUE_OBJ_CLASS_SPEC {
private:
enum {
@@ -103,24 +81,82 @@
class CollectionSetChooser: public CHeapObj {
GrowableArray<HeapRegion*> _markedRegions;
- int _curMarkedIndex;
- int _numMarkedRegions;
- CSetChooserCache _cache;
+
+ // The index of the next candidate old region to be considered for
+ // addition to the CSet.
+ int _curr_index;
+
+ // The number of candidate old regions added to the CSet chooser.
+ int _length;
- // True iff last collection pause ran of out new "age 0" regions, and
- // returned an "age 1" region.
- bool _unmarked_age_1_returned_as_new;
+ CSetChooserCache _cache;
+ jint _first_par_unreserved_idx;
- jint _first_par_unreserved_idx;
+ // If a region has more live bytes than this threshold, it will not
+ // be added to the CSet chooser and will not be a candidate for
+ // collection.
+ size_t _regionLiveThresholdBytes;
+
+ // The sum of reclaimable bytes over all the regions in the CSet chooser.
+ size_t _remainingReclaimableBytes;
public:
- HeapRegion* getNextMarkedRegion(double time_so_far, double avg_prediction);
+ // Return the current candidate region to be considered for
+ // collection without removing it from the CSet chooser.
+ HeapRegion* peek() {
+ HeapRegion* res = NULL;
+ if (_curr_index < _length) {
+ res = _markedRegions.at(_curr_index);
+ assert(res != NULL,
+ err_msg("Unexpected NULL hr in _markedRegions at index %d",
+ _curr_index));
+ }
+ return res;
+ }
+
+ // Remove the given region from the CSet chooser and move to the
+ // next one. The given region should be the current candidate region
+ // in the CSet chooser.
+ void remove_and_move_to_next(HeapRegion* hr) {
+ assert(hr != NULL, "pre-condition");
+ assert(_curr_index < _length, "pre-condition");
+ assert(_markedRegions.at(_curr_index) == hr, "pre-condition");
+ hr->set_sort_index(-1);
+ _markedRegions.at_put(_curr_index, NULL);
+ assert(hr->reclaimable_bytes() <= _remainingReclaimableBytes,
+ err_msg("remaining reclaimable bytes inconsistent "
+ "from region: "SIZE_FORMAT" remaining: "SIZE_FORMAT,
+ hr->reclaimable_bytes(), _remainingReclaimableBytes));
+ _remainingReclaimableBytes -= hr->reclaimable_bytes();
+ _curr_index += 1;
+ }
CollectionSetChooser();
void sortMarkedHeapRegions();
void fillCache();
+
+ // Determine whether to add the given region to the CSet chooser or
+ // not. Currently, we skip humongous regions (we never add them to
+ // the CSet, we only reclaim them during cleanup) and regions whose
+ // live bytes are over the threshold.
+ bool shouldAdd(HeapRegion* hr) {
+ assert(hr->is_marked(), "pre-condition");
+ assert(!hr->is_young(), "should never consider young regions");
+ return !hr->isHumongous() &&
+ hr->live_bytes() < _regionLiveThresholdBytes;
+ }
+
+ // Calculate the minimum number of old regions we'll add to the CSet
+ // during a mixed GC.
+ size_t calcMinOldCSetLength();
+
+ // Calculate the maximum number of old regions we'll add to the CSet
+ // during a mixed GC.
+ size_t calcMaxOldCSetLength();
+
+ // Serial version.
void addMarkedHeapRegion(HeapRegion *hr);
// Must be called before calls to getParMarkedHeapRegionChunk.
@@ -133,14 +169,21 @@
// Set the marked array entry at index to hr. Careful to claim the index
// first if in parallel.
void setMarkedHeapRegion(jint index, HeapRegion* hr);
- // Atomically increment the number of claimed regions by "inc_by".
- void incNumMarkedHeapRegions(jint inc_by);
+ // Atomically increment the number of added regions by region_num
+ // and the amount of reclaimable bytes by reclaimable_bytes.
+ void updateTotals(jint region_num, size_t reclaimable_bytes);
void clearMarkedHeapRegions();
- void updateAfterFullCollection();
+ // Return the number of candidate regions that remain to be collected.
+ size_t remainingRegions() { return _length - _curr_index; }
- bool unmarked_age_1_returned_as_new() { return _unmarked_age_1_returned_as_new; }
+ // Determine whether the CSet chooser has more candidate regions or not.
+ bool isEmpty() { return remainingRegions() == 0; }
+
+ // Return the reclaimable bytes that remain to be collected on
+ // all the candidate regions in the CSet chooser.
+ size_t remainingReclaimableBytes () { return _remainingReclaimableBytes; }
// Returns true if the used portion of "_markedRegions" is properly
// sorted, otherwise asserts false.
@@ -148,9 +191,17 @@
bool verify(void);
bool regionProperlyOrdered(HeapRegion* r) {
int si = r->sort_index();
- return (si == -1) ||
- (si > -1 && _markedRegions.at(si) == r) ||
- (si < -1 && _cache.region_in_cache(r));
+ if (si > -1) {
+ guarantee(_curr_index <= si && si < _length,
+ err_msg("curr: %d sort index: %d: length: %d",
+ _curr_index, si, _length));
+ guarantee(_markedRegions.at(si) == r,
+ err_msg("sort index: %d at: "PTR_FORMAT" r: "PTR_FORMAT,
+ si, _markedRegions.at(si), r));
+ } else {
+ guarantee(si == -1, err_msg("sort index: %d", si));
+ }
+ return true;
}
#endif
--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp Wed Feb 15 16:09:49 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp Fri Feb 17 13:23:29 2012 +0100
@@ -958,7 +958,7 @@
should_try_gc = false;
} else {
// Read the GC count while still holding the Heap_lock.
- gc_count_before = SharedHeap::heap()->total_collections();
+ gc_count_before = total_collections();
should_try_gc = true;
}
}
@@ -976,7 +976,7 @@
// failed to allocate. No point in trying to allocate
// further. We'll just return NULL.
MutexLockerEx x(Heap_lock);
- *gc_count_before_ret = SharedHeap::heap()->total_collections();
+ *gc_count_before_ret = total_collections();
return NULL;
}
} else {
@@ -1031,7 +1031,8 @@
// the check before we do the actual allocation. The reason for doing it
// before the allocation is that we avoid having to keep track of the newly
// allocated memory while we do a GC.
- if (g1_policy()->need_to_start_conc_mark("concurrent humongous allocation", word_size)) {
+ if (g1_policy()->need_to_start_conc_mark("concurrent humongous allocation",
+ word_size)) {
collect(GCCause::_g1_humongous_allocation);
}
@@ -1059,7 +1060,7 @@
should_try_gc = false;
} else {
// Read the GC count while still holding the Heap_lock.
- gc_count_before = SharedHeap::heap()->total_collections();
+ gc_count_before = total_collections();
should_try_gc = true;
}
}
@@ -1081,7 +1082,7 @@
// failed to allocate. No point in trying to allocate
// further. We'll just return NULL.
MutexLockerEx x(Heap_lock);
- *gc_count_before_ret = SharedHeap::heap()->total_collections();
+ *gc_count_before_ret = total_collections();
return NULL;
}
} else {
@@ -2311,10 +2312,12 @@
}
bool G1CollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) {
- return
- ((cause == GCCause::_gc_locker && GCLockerInvokesConcurrent) ||
- (cause == GCCause::_java_lang_system_gc && ExplicitGCInvokesConcurrent) ||
- cause == GCCause::_g1_humongous_allocation);
+ switch (cause) {
+ case GCCause::_gc_locker: return GCLockerInvokesConcurrent;
+ case GCCause::_java_lang_system_gc: return ExplicitGCInvokesConcurrent;
+ case GCCause::_g1_humongous_allocation: return true;
+ default: return false;
+ }
}
#ifndef PRODUCT
@@ -2408,47 +2411,66 @@
}
void G1CollectedHeap::collect(GCCause::Cause cause) {
- // The caller doesn't have the Heap_lock
- assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
+ assert_heap_not_locked();
unsigned int gc_count_before;
unsigned int full_gc_count_before;
- {
- MutexLocker ml(Heap_lock);
-
- // Read the GC count while holding the Heap_lock
- gc_count_before = SharedHeap::heap()->total_collections();
- full_gc_count_before = SharedHeap::heap()->total_full_collections();
- }
-
- if (should_do_concurrent_full_gc(cause)) {
- // Schedule an initial-mark evacuation pause that will start a
- // concurrent cycle. We're setting word_size to 0 which means that
- // we are not requesting a post-GC allocation.
- VM_G1IncCollectionPause op(gc_count_before,
- 0, /* word_size */
- true, /* should_initiate_conc_mark */
- g1_policy()->max_pause_time_ms(),
- cause);
- VMThread::execute(&op);
- } else {
- if (cause == GCCause::_gc_locker
- DEBUG_ONLY(|| cause == GCCause::_scavenge_alot)) {
-
- // Schedule a standard evacuation pause. We're setting word_size
- // to 0 which means that we are not requesting a post-GC allocation.
+ bool retry_gc;
+
+ do {
+ retry_gc = false;
+
+ {
+ MutexLocker ml(Heap_lock);
+
+ // Read the GC count while holding the Heap_lock
+ gc_count_before = total_collections();
+ full_gc_count_before = total_full_collections();
+ }
+
+ if (should_do_concurrent_full_gc(cause)) {
+ // Schedule an initial-mark evacuation pause that will start a
+ // concurrent cycle. We're setting word_size to 0 which means that
+ // we are not requesting a post-GC allocation.
VM_G1IncCollectionPause op(gc_count_before,
0, /* word_size */
- false, /* should_initiate_conc_mark */
+ true, /* should_initiate_conc_mark */
g1_policy()->max_pause_time_ms(),
cause);
VMThread::execute(&op);
+ if (!op.pause_succeeded()) {
+ // Another GC got scheduled and prevented us from scheduling
+ // the initial-mark GC. It's unlikely that the GC that
+ // pre-empted us was also an initial-mark GC. So, we'll retry
+ // the initial-mark GC.
+
+ if (full_gc_count_before == total_full_collections()) {
+ retry_gc = true;
+ } else {
+ // A Full GC happened while we were trying to schedule the
+ // initial-mark GC. No point in starting a new cycle given
+ // that the whole heap was collected anyway.
+ }
+ }
} else {
- // Schedule a Full GC.
- VM_G1CollectFull op(gc_count_before, full_gc_count_before, cause);
- VMThread::execute(&op);
+ if (cause == GCCause::_gc_locker
+ DEBUG_ONLY(|| cause == GCCause::_scavenge_alot)) {
+
+ // Schedule a standard evacuation pause. We're setting word_size
+ // to 0 which means that we are not requesting a post-GC allocation.
+ VM_G1IncCollectionPause op(gc_count_before,
+ 0, /* word_size */
+ false, /* should_initiate_conc_mark */
+ g1_policy()->max_pause_time_ms(),
+ cause);
+ VMThread::execute(&op);
+ } else {
+ // Schedule a Full GC.
+ VM_G1CollectFull op(gc_count_before, full_gc_count_before, cause);
+ VMThread::execute(&op);
+ }
}
- }
+ } while (retry_gc);
}
bool G1CollectedHeap::is_in(const void* p) const {
@@ -3149,12 +3171,12 @@
// We apply the relevant closures to all the oops in the
// system dictionary, the string table and the code cache.
- const int so = SharedHeap::SO_AllClasses | SharedHeap::SO_Strings | SharedHeap::SO_CodeCache;
+ const int so = SO_AllClasses | SO_Strings | SO_CodeCache;
process_strong_roots(true, // activate StrongRootsScope
true, // we set "collecting perm gen" to true,
// so we don't reset the dirty cards in the perm gen.
- SharedHeap::ScanningOption(so), // roots scanning options
+ ScanningOption(so), // roots scanning options
&rootsCl,
&blobsCl,
&rootsCl);
@@ -3425,16 +3447,6 @@
}
}
-double G1CollectedHeap::predict_region_elapsed_time_ms(HeapRegion *hr,
- bool young) {
- return _g1_policy->predict_region_elapsed_time_ms(hr, young);
-}
-
-void G1CollectedHeap::check_if_region_is_too_expensive(double
- predicted_time_ms) {
- _g1_policy->check_if_region_is_too_expensive(predicted_time_ms);
-}
-
size_t G1CollectedHeap::pending_card_num() {
size_t extra_cards = 0;
JavaThread *curr = Threads::first();
@@ -3706,12 +3718,12 @@
g1_policy()->print_collection_set(g1_policy()->inc_cset_head(), gclog_or_tty);
#endif // YOUNG_LIST_VERBOSE
- g1_policy()->choose_collection_set(target_pause_time_ms);
+ g1_policy()->finalize_cset(target_pause_time_ms);
_cm->note_start_of_gc();
// We should not verify the per-thread SATB buffers given that
// we have not filtered them yet (we'll do so during the
- // GC). We also call this after choose_collection_set() to
+ // GC). We also call this after finalize_cset() to
// ensure that the CSet has been finalized.
_cm->verify_no_cset_oops(true /* verify_stacks */,
true /* verify_enqueued_buffers */,
@@ -4734,7 +4746,7 @@
void
G1CollectedHeap::
g1_process_strong_roots(bool collecting_perm_gen,
- SharedHeap::ScanningOption so,
+ ScanningOption so,
OopClosure* scan_non_heap_roots,
OopsInHeapRegionClosure* scan_rs,
OopsInGenClosure* scan_perm,
--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp Wed Feb 15 16:09:49 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp Fri Feb 17 13:23:29 2012 +0100
@@ -770,7 +770,7 @@
// the "i" of the calling parallel worker thread's work(i) function.
// In the sequential case this param will be ignored.
void g1_process_strong_roots(bool collecting_perm_gen,
- SharedHeap::ScanningOption so,
+ ScanningOption so,
OopClosure* scan_non_heap_roots,
OopsInHeapRegionClosure* scan_rs,
OopsInGenClosure* scan_perm,
@@ -1182,6 +1182,12 @@
bool free_regions_coming() { return _free_regions_coming; }
void wait_while_free_regions_coming();
+ // Determine whether the given region is one that we are using as an
+ // old GC alloc region.
+ bool is_old_gc_alloc_region(HeapRegion* hr) {
+ return hr == _retained_old_gc_alloc_region;
+ }
+
// Perform a collection of the heap; intended for use in implementing
// "System.gc". This probably implies as full a collection as the
// "CollectedHeap" supports.
@@ -1662,8 +1668,6 @@
public:
void stop_conc_gc_threads();
- double predict_region_elapsed_time_ms(HeapRegion* hr, bool young);
- void check_if_region_is_too_expensive(double predicted_time_ms);
size_t pending_card_num();
size_t max_pending_card_num();
size_t cards_scanned();
--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp Wed Feb 15 16:09:49 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp Fri Feb 17 13:23:29 2012 +0100
@@ -206,7 +206,6 @@
_initiate_conc_mark_if_possible(false),
_during_initial_mark_pause(false),
- _should_revert_to_young_gcs(false),
_last_young_gc(false),
_last_gc_was_young(false),
@@ -295,9 +294,6 @@
_par_last_gc_worker_times_ms = new double[_parallel_gc_threads];
_par_last_gc_worker_other_times_ms = new double[_parallel_gc_threads];
- // start conservatively
- _expensive_region_limit_ms = 0.5 * (double) MaxGCPauseMillis;
-
int index;
if (ParallelGCThreads == 0)
index = 0;
@@ -629,16 +625,9 @@
// possible to maximize how many old regions we can add to it.
}
} else {
- if (gcs_are_young()) {
- young_list_target_length = _young_list_fixed_length;
- } else {
- // A bit arbitrary: during mixed GCs we allocate half
- // the young regions to try to add old regions to the CSet.
- young_list_target_length = _young_list_fixed_length / 2;
- // We choose to accept that we might go under the desired min
- // length given that we intentionally ask for a smaller young gen.
- desired_min_length = absolute_min_length;
- }
+ // The user asked for a fixed young gen so we'll fix the young gen
+ // whether the next GC is young or mixed.
+ young_list_target_length = _young_list_fixed_length;
}
// Make sure we don't go over the desired max length, nor under the
@@ -872,7 +861,6 @@
// transitions and make sure we start with young GCs after the Full GC.
set_gcs_are_young(true);
_last_young_gc = false;
- _should_revert_to_young_gcs = false;
clear_initiate_conc_mark_if_possible();
clear_during_initial_mark_pause();
_known_garbage_bytes = 0;
@@ -889,7 +877,7 @@
// Reset survivors SurvRateGroup.
_survivor_surv_rate_group->reset();
update_young_list_target_length();
- _collectionSetChooser->updateAfterFullCollection();
+ _collectionSetChooser->clearMarkedHeapRegions();
}
void G1CollectorPolicy::record_stop_world_start() {
@@ -1000,7 +988,6 @@
}
void G1CollectorPolicy::record_concurrent_mark_cleanup_completed() {
- _should_revert_to_young_gcs = false;
_last_young_gc = true;
_in_marking_window = false;
}
@@ -1205,9 +1192,7 @@
last_pause_included_initial_mark = during_initial_mark_pause();
if (last_pause_included_initial_mark) {
record_concurrent_mark_init_end(0.0);
- }
-
- if (!_last_young_gc && need_to_start_conc_mark("end of GC")) {
+ } else if (!_last_young_gc && need_to_start_conc_mark("end of GC")) {
// Note: this might have already been set, if during the last
// pause we decided to start a cycle but at the beginning of
// this pause we decided to postpone it. That's OK.
@@ -1492,12 +1477,14 @@
}
if (_last_young_gc) {
+ // This is supposed to to be the "last young GC" before we start
+ // doing mixed GCs. Here we decide whether to start mixed GCs or not.
+
if (!last_pause_included_initial_mark) {
- ergo_verbose2(ErgoMixedGCs,
- "start mixed GCs",
- ergo_format_byte_perc("known garbage"),
- _known_garbage_bytes, _known_garbage_ratio * 100.0);
- set_gcs_are_young(false);
+ if (next_gc_should_be_mixed("start mixed GCs",
+ "do not start mixed GCs")) {
+ set_gcs_are_young(false);
+ }
} else {
ergo_verbose0(ErgoMixedGCs,
"do not start mixed GCs",
@@ -1507,39 +1494,14 @@
}
if (!_last_gc_was_young) {
- if (_should_revert_to_young_gcs) {
- ergo_verbose2(ErgoMixedGCs,
- "end mixed GCs",
- ergo_format_reason("mixed GCs end requested")
- ergo_format_byte_perc("known garbage"),
- _known_garbage_bytes, _known_garbage_ratio * 100.0);
- set_gcs_are_young(true);
- } else if (_known_garbage_ratio < 0.05) {
- ergo_verbose3(ErgoMixedGCs,
- "end mixed GCs",
- ergo_format_reason("known garbage percent lower than threshold")
- ergo_format_byte_perc("known garbage")
- ergo_format_perc("threshold"),
- _known_garbage_bytes, _known_garbage_ratio * 100.0,
- 0.05 * 100.0);
- set_gcs_are_young(true);
- } else if (adaptive_young_list_length() &&
- (get_gc_eff_factor() * cur_efficiency < predict_young_gc_eff())) {
- ergo_verbose5(ErgoMixedGCs,
- "end mixed GCs",
- ergo_format_reason("current GC efficiency lower than "
- "predicted young GC efficiency")
- ergo_format_double("GC efficiency factor")
- ergo_format_double("current GC efficiency")
- ergo_format_double("predicted young GC efficiency")
- ergo_format_byte_perc("known garbage"),
- get_gc_eff_factor(), cur_efficiency,
- predict_young_gc_eff(),
- _known_garbage_bytes, _known_garbage_ratio * 100.0);
+ // This is a mixed GC. Here we decide whether to continue doing
+ // mixed GCs or not.
+
+ if (!next_gc_should_be_mixed("continue mixed GCs",
+ "do not continue mixed GCs")) {
set_gcs_are_young(true);
}
}
- _should_revert_to_young_gcs = false;
if (_last_gc_was_young && !_during_marking) {
_young_gc_eff_seq->add(cur_efficiency);
@@ -1648,15 +1610,6 @@
_pending_cards_seq->add((double) _pending_cards);
_rs_lengths_seq->add((double) _max_rs_lengths);
-
- double expensive_region_limit_ms =
- (double) MaxGCPauseMillis - predict_constant_other_time_ms();
- if (expensive_region_limit_ms < 0.0) {
- // this means that the other time was predicted to be longer than
- // than the max pause time
- expensive_region_limit_ms = (double) MaxGCPauseMillis;
- }
- _expensive_region_limit_ms = expensive_region_limit_ms;
}
_in_marking_window = new_in_marking_window;
@@ -1838,13 +1791,11 @@
if (hr->is_marked())
bytes_to_copy = hr->max_live_bytes();
else {
- guarantee( hr->is_young() && hr->age_in_surv_rate_group() != -1,
- "invariant" );
+ assert(hr->is_young() && hr->age_in_surv_rate_group() != -1, "invariant");
int age = hr->age_in_surv_rate_group();
double yg_surv_rate = predict_yg_surv_rate(age, hr->surv_rate_group());
bytes_to_copy = (size_t) ((double) hr->used() * yg_surv_rate);
}
-
return bytes_to_copy;
}
@@ -1860,22 +1811,6 @@
_recorded_rs_lengths = rs_lengths;
}
-void G1CollectorPolicy::check_if_region_is_too_expensive(double
- predicted_time_ms) {
- // I don't think we need to do this when in young GC mode since
- // marking will be initiated next time we hit the soft limit anyway...
- if (predicted_time_ms > _expensive_region_limit_ms) {
- ergo_verbose2(ErgoMixedGCs,
- "request mixed GCs end",
- ergo_format_reason("predicted region time higher than threshold")
- ergo_format_ms("predicted region time")
- ergo_format_ms("threshold"),
- predicted_time_ms, _expensive_region_limit_ms);
- // no point in doing another mixed GC
- _should_revert_to_young_gcs = true;
- }
-}
-
void G1CollectorPolicy::update_recent_gc_times(double end_time_sec,
double elapsed_ms) {
_recent_gc_times_ms->add(elapsed_ms);
@@ -2274,12 +2209,12 @@
}
class KnownGarbageClosure: public HeapRegionClosure {
+ G1CollectedHeap* _g1h;
CollectionSetChooser* _hrSorted;
public:
KnownGarbageClosure(CollectionSetChooser* hrSorted) :
- _hrSorted(hrSorted)
- {}
+ _g1h(G1CollectedHeap::heap()), _hrSorted(hrSorted) { }
bool doHeapRegion(HeapRegion* r) {
// We only include humongous regions in collection
@@ -2288,11 +2223,10 @@
// Do we have any marking information for this region?
if (r->is_marked()) {
- // We don't include humongous regions in collection
- // sets because we collect them immediately at the end of a marking
- // cycle. We also don't include young regions because we *must*
- // include them in the next collection pause.
- if (!r->isHumongous() && !r->is_young()) {
+ // We will skip any region that's currently used as an old GC
+ // alloc region (we should not consider those for collection
+ // before we fill them up).
+ if (_hrSorted->shouldAdd(r) && !_g1h->is_old_gc_alloc_region(r)) {
_hrSorted->addMarkedHeapRegion(r);
}
}
@@ -2301,8 +2235,10 @@
};
class ParKnownGarbageHRClosure: public HeapRegionClosure {
+ G1CollectedHeap* _g1h;
CollectionSetChooser* _hrSorted;
jint _marked_regions_added;
+ size_t _reclaimable_bytes_added;
jint _chunk_size;
jint _cur_chunk_idx;
jint _cur_chunk_end; // Cur chunk [_cur_chunk_idx, _cur_chunk_end)
@@ -2320,6 +2256,7 @@
assert(_cur_chunk_idx < _cur_chunk_end, "postcondition");
_hrSorted->setMarkedHeapRegion(_cur_chunk_idx, r);
_marked_regions_added++;
+ _reclaimable_bytes_added += r->reclaimable_bytes();
_cur_chunk_idx++;
}
@@ -2327,10 +2264,10 @@
ParKnownGarbageHRClosure(CollectionSetChooser* hrSorted,
jint chunk_size,
int worker) :
- _hrSorted(hrSorted), _chunk_size(chunk_size), _worker(worker),
- _marked_regions_added(0), _cur_chunk_idx(0), _cur_chunk_end(0),
- _invokes(0)
- {}
+ _g1h(G1CollectedHeap::heap()),
+ _hrSorted(hrSorted), _chunk_size(chunk_size), _worker(worker),
+ _marked_regions_added(0), _reclaimable_bytes_added(0),
+ _cur_chunk_idx(0), _cur_chunk_end(0), _invokes(0) { }
bool doHeapRegion(HeapRegion* r) {
// We only include humongous regions in collection
@@ -2340,17 +2277,17 @@
// Do we have any marking information for this region?
if (r->is_marked()) {
- // We don't include humongous regions in collection
- // sets because we collect them immediately at the end of a marking
- // cycle.
- // We also do not include young regions in collection sets
- if (!r->isHumongous() && !r->is_young()) {
+ // We will skip any region that's currently used as an old GC
+ // alloc region (we should not consider those for collection
+ // before we fill them up).
+ if (_hrSorted->shouldAdd(r) && !_g1h->is_old_gc_alloc_region(r)) {
add_region(r);
}
}
return false;
}
jint marked_regions_added() { return _marked_regions_added; }
+ size_t reclaimable_bytes_added() { return _reclaimable_bytes_added; }
int invokes() { return _invokes; }
};
@@ -2362,8 +2299,7 @@
ParKnownGarbageTask(CollectionSetChooser* hrSorted, jint chunk_size) :
AbstractGangTask("ParKnownGarbageTask"),
_hrSorted(hrSorted), _chunk_size(chunk_size),
- _g1(G1CollectedHeap::heap())
- {}
+ _g1(G1CollectedHeap::heap()) { }
void work(uint worker_id) {
ParKnownGarbageHRClosure parKnownGarbageCl(_hrSorted,
@@ -2374,7 +2310,9 @@
_g1->workers()->active_workers(),
HeapRegion::InitialClaimValue);
jint regions_added = parKnownGarbageCl.marked_regions_added();
- _hrSorted->incNumMarkedHeapRegions(regions_added);
+ size_t reclaimable_bytes_added =
+ parKnownGarbageCl.reclaimable_bytes_added();
+ _hrSorted->updateTotals(regions_added, reclaimable_bytes_added);
if (G1PrintParCleanupStats) {
gclog_or_tty->print_cr(" Thread %d called %d times, added %d regions to list.",
worker_id, parKnownGarbageCl.invokes(), regions_added);
@@ -2658,7 +2596,43 @@
}
#endif // !PRODUCT
-void G1CollectorPolicy::choose_collection_set(double target_pause_time_ms) {
+bool G1CollectorPolicy::next_gc_should_be_mixed(const char* true_action_str,
+ const char* false_action_str) {
+ CollectionSetChooser* cset_chooser = _collectionSetChooser;
+ if (cset_chooser->isEmpty()) {
+ ergo_verbose0(ErgoMixedGCs,
+ false_action_str,
+ ergo_format_reason("candidate old regions not available"));
+ return false;
+ }
+ size_t reclaimable_bytes = cset_chooser->remainingReclaimableBytes();
+ size_t capacity_bytes = _g1->capacity();
+ double perc = (double) reclaimable_bytes * 100.0 / (double) capacity_bytes;
+ double threshold = (double) G1OldReclaimableThresholdPercent;
+ if (perc < threshold) {
+ ergo_verbose4(ErgoMixedGCs,
+ false_action_str,
+ ergo_format_reason("reclaimable percentage lower than threshold")
+ ergo_format_region("candidate old regions")
+ ergo_format_byte_perc("reclaimable")
+ ergo_format_perc("threshold"),
+ cset_chooser->remainingRegions(),
+ reclaimable_bytes, perc, threshold);
+ return false;
+ }
+
+ ergo_verbose4(ErgoMixedGCs,
+ true_action_str,
+ ergo_format_reason("candidate old regions available")
+ ergo_format_region("candidate old regions")
+ ergo_format_byte_perc("reclaimable")
+ ergo_format_perc("threshold"),
+ cset_chooser->remainingRegions(),
+ reclaimable_bytes, perc, threshold);
+ return true;
+}
+
+void G1CollectorPolicy::finalize_cset(double target_pause_time_ms) {
// Set this here - in case we're not doing young collections.
double non_young_start_time_sec = os::elapsedTime();
@@ -2672,7 +2646,6 @@
double base_time_ms = predict_base_elapsed_time_ms(_pending_cards);
double predicted_pause_time_ms = base_time_ms;
-
double time_remaining_ms = target_pause_time_ms - base_time_ms;
ergo_verbose3(ErgoCSetConstruction | ErgoHigh,
@@ -2682,22 +2655,6 @@
ergo_format_ms("target pause time"),
base_time_ms, time_remaining_ms, target_pause_time_ms);
- // the 10% and 50% values are arbitrary...
- double threshold = 0.10 * target_pause_time_ms;
- if (time_remaining_ms < threshold) {
- double prev_time_remaining_ms = time_remaining_ms;
- time_remaining_ms = 0.50 * target_pause_time_ms;
- ergo_verbose3(ErgoCSetConstruction,
- "adjust remaining time",
- ergo_format_reason("remaining time lower than threshold")
- ergo_format_ms("remaining time")
- ergo_format_ms("threshold")
- ergo_format_ms("adjusted remaining time"),
- prev_time_remaining_ms, threshold, time_remaining_ms);
- }
-
- size_t expansion_bytes = _g1->expansion_regions() * HeapRegion::GrainBytes;
-
HeapRegion* hr;
double young_start_time_sec = os::elapsedTime();
@@ -2752,78 +2709,97 @@
non_young_start_time_sec = young_end_time_sec;
if (!gcs_are_young()) {
- bool should_continue = true;
- NumberSeq seq;
- double avg_prediction = 100000000000000000.0; // something very large
-
- double prev_predicted_pause_time_ms = predicted_pause_time_ms;
- do {
- // Note that add_old_region_to_cset() increments the
- // _old_cset_region_length field and cset_region_length() returns the
- // sum of _eden_cset_region_length, _survivor_cset_region_length, and
- // _old_cset_region_length. So, as old regions are added to the
- // CSet, _old_cset_region_length will be incremented and
- // cset_region_length(), which is used below, will always reflect
- // the the total number of regions added up to this point to the CSet.
-
- hr = _collectionSetChooser->getNextMarkedRegion(time_remaining_ms,
- avg_prediction);
- if (hr != NULL) {
- _g1->old_set_remove(hr);
- double predicted_time_ms = predict_region_elapsed_time_ms(hr, false);
- time_remaining_ms -= predicted_time_ms;
- predicted_pause_time_ms += predicted_time_ms;
- add_old_region_to_cset(hr);
- seq.add(predicted_time_ms);
- avg_prediction = seq.avg() + seq.sd();
+ CollectionSetChooser* cset_chooser = _collectionSetChooser;
+ assert(cset_chooser->verify(), "CSet Chooser verification - pre");
+ const size_t min_old_cset_length = cset_chooser->calcMinOldCSetLength();
+ const size_t max_old_cset_length = cset_chooser->calcMaxOldCSetLength();
+
+ size_t expensive_region_num = 0;
+ bool check_time_remaining = adaptive_young_list_length();
+ HeapRegion* hr = cset_chooser->peek();
+ while (hr != NULL) {
+ if (old_cset_region_length() >= max_old_cset_length) {
+ // Added maximum number of old regions to the CSet.
+ ergo_verbose2(ErgoCSetConstruction,
+ "finish adding old regions to CSet",
+ ergo_format_reason("old CSet region num reached max")
+ ergo_format_region("old")
+ ergo_format_region("max"),
+ old_cset_region_length(), max_old_cset_length);
+ break;
}
- should_continue = true;
- if (hr == NULL) {
- // No need for an ergo verbose message here,
- // getNextMarkRegion() does this when it returns NULL.
- should_continue = false;
+ double predicted_time_ms = predict_region_elapsed_time_ms(hr, false);
+ if (check_time_remaining) {
+ if (predicted_time_ms > time_remaining_ms) {
+ // Too expensive for the current CSet.
+
+ if (old_cset_region_length() >= min_old_cset_length) {
+ // We have added the minimum number of old regions to the CSet,
+ // we are done with this CSet.
+ ergo_verbose4(ErgoCSetConstruction,
+ "finish adding old regions to CSet",
+ ergo_format_reason("predicted time is too high")
+ ergo_format_ms("predicted time")
+ ergo_format_ms("remaining time")
+ ergo_format_region("old")
+ ergo_format_region("min"),
+ predicted_time_ms, time_remaining_ms,
+ old_cset_region_length(), min_old_cset_length);
+ break;
+ }
+
+ // We'll add it anyway given that we haven't reached the
+ // minimum number of old regions.
+ expensive_region_num += 1;
+ }
} else {
- if (adaptive_young_list_length()) {
- if (time_remaining_ms < 0.0) {
- ergo_verbose1(ErgoCSetConstruction,
- "stop adding old regions to CSet",
- ergo_format_reason("remaining time is lower than 0")
- ergo_format_ms("remaining time"),
- time_remaining_ms);
- should_continue = false;
- }
- } else {
- if (cset_region_length() >= _young_list_fixed_length) {
- ergo_verbose2(ErgoCSetConstruction,
- "stop adding old regions to CSet",
- ergo_format_reason("CSet length reached target")
- ergo_format_region("CSet")
- ergo_format_region("young target"),
- cset_region_length(), _young_list_fixed_length);
- should_continue = false;
- }
+ if (old_cset_region_length() >= min_old_cset_length) {
+ // In the non-auto-tuning case, we'll finish adding regions
+ // to the CSet if we reach the minimum.
+ ergo_verbose2(ErgoCSetConstruction,
+ "finish adding old regions to CSet",
+ ergo_format_reason("old CSet region num reached min")
+ ergo_format_region("old")
+ ergo_format_region("min"),
+ old_cset_region_length(), min_old_cset_length);
+ break;
}
}
- } while (should_continue);
-
- if (!adaptive_young_list_length() &&
- cset_region_length() < _young_list_fixed_length) {
- ergo_verbose2(ErgoCSetConstruction,
- "request mixed GCs end",
- ergo_format_reason("CSet length lower than target")
- ergo_format_region("CSet")
- ergo_format_region("young target"),
- cset_region_length(), _young_list_fixed_length);
- _should_revert_to_young_gcs = true;
+
+ // We will add this region to the CSet.
+ time_remaining_ms -= predicted_time_ms;
+ predicted_pause_time_ms += predicted_time_ms;
+ cset_chooser->remove_and_move_to_next(hr);
+ _g1->old_set_remove(hr);
+ add_old_region_to_cset(hr);
+
+ hr = cset_chooser->peek();
+ }
+ if (hr == NULL) {
+ ergo_verbose0(ErgoCSetConstruction,
+ "finish adding old regions to CSet",
+ ergo_format_reason("candidate old regions not available"));
}
- ergo_verbose2(ErgoCSetConstruction | ErgoHigh,
- "add old regions to CSet",
- ergo_format_region("old")
- ergo_format_ms("predicted old region time"),
- old_cset_region_length(),
- predicted_pause_time_ms - prev_predicted_pause_time_ms);
+ if (expensive_region_num > 0) {
+ // We print the information once here at the end, predicated on
+ // whether we added any apparently expensive regions or not, to
+ // avoid generating output per region.
+ ergo_verbose4(ErgoCSetConstruction,
+ "added expensive regions to CSet",
+ ergo_format_reason("old CSet region num not reached min")
+ ergo_format_region("old")
+ ergo_format_region("expensive")
+ ergo_format_region("min")
+ ergo_format_ms("remaining time"),
+ old_cset_region_length(),
+ expensive_region_num,
+ min_old_cset_length,
+ time_remaining_ms);
+ }
+
+ assert(cset_chooser->verify(), "CSet Chooser verification - post");
}
stop_incremental_cset_building();
--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp Wed Feb 15 16:09:49 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp Fri Feb 17 13:23:29 2012 +0100
@@ -312,16 +312,13 @@
double _recorded_non_young_free_cset_time_ms;
double _sigma;
- double _expensive_region_limit_ms;
size_t _rs_lengths_prediction;
size_t _known_garbage_bytes;
double _known_garbage_ratio;
- double sigma() {
- return _sigma;
- }
+ double sigma() { return _sigma; }
// A function that prevents us putting too much stock in small sample
// sets. Returns a number between 2.0 and 1.0, depending on the number
@@ -491,8 +488,6 @@
get_new_prediction(_non_young_other_cost_per_region_ms_seq);
}
- void check_if_region_is_too_expensive(double predicted_time_ms);
-
double predict_young_collection_elapsed_time_ms(size_t adjustment);
double predict_base_elapsed_time_ms(size_t pending_cards);
double predict_base_elapsed_time_ms(size_t pending_cards,
@@ -707,7 +702,6 @@
// initial-mark work.
volatile bool _during_initial_mark_pause;
- bool _should_revert_to_young_gcs;
bool _last_young_gc;
// This set of variables tracks the collector efficiency, in order to
@@ -946,10 +940,17 @@
return _bytes_copied_during_gc;
}
+ // Determine whether the next GC should be mixed. Called to determine
+ // whether to start mixed GCs or whether to carry on doing mixed
+ // GCs. The two action strings are used in the ergo output when the
+ // method returns true or false.
+ bool next_gc_should_be_mixed(const char* true_action_str,
+ const char* false_action_str);
+
// Choose a new collection set. Marks the chosen regions as being
// "in_collection_set", and links them together. The head and number of
// the collection set are available via access methods.
- void choose_collection_set(double target_pause_time_ms);
+ void finalize_cset(double target_pause_time_ms);
// The head of the list (via "next_in_collection_set()") representing the
// current collection set.
--- a/hotspot/src/share/vm/gc_implementation/g1/g1ErgoVerbose.hpp Wed Feb 15 16:09:49 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1ErgoVerbose.hpp Fri Feb 17 13:23:29 2012 +0100
@@ -131,8 +131,8 @@
", " _name_ ": "SIZE_FORMAT" bytes (%1.2f %%)"
// Generates the format string
-#define ergo_format(_action_, _extra_format_) \
- " %1.3f: [G1Ergonomics (%s) " _action_ _extra_format_ "]"
+#define ergo_format(_extra_format_) \
+ " %1.3f: [G1Ergonomics (%s) %s" _extra_format_ "]"
// Conditionally, prints an ergonomic decision record. _extra_format_
// is the format string for the optional items we'd like to print
@@ -145,20 +145,21 @@
// them to the print method. For convenience, we have wrapper macros
// below which take a specific number of arguments and set the rest to
// a default value.
-#define ergo_verbose_common(_tag_, _action_, _extra_format_, \
+#define ergo_verbose_common(_tag_, _action_, _extra_format_, \
_arg0_, _arg1_, _arg2_, _arg3_, _arg4_, _arg5_) \
- do { \
- if (G1ErgoVerbose::enabled((_tag_))) { \
- gclog_or_tty->print_cr(ergo_format(_action_, _extra_format_), \
- os::elapsedTime(), \
- G1ErgoVerbose::to_string((_tag_)), \
- (_arg0_), (_arg1_), (_arg2_), \
- (_arg3_), (_arg4_), (_arg5_)); \
- } \
+ do { \
+ if (G1ErgoVerbose::enabled((_tag_))) { \
+ gclog_or_tty->print_cr(ergo_format(_extra_format_), \
+ os::elapsedTime(), \
+ G1ErgoVerbose::to_string((_tag_)), \
+ (_action_), \
+ (_arg0_), (_arg1_), (_arg2_), \
+ (_arg3_), (_arg4_), (_arg5_)); \
+ } \
} while (0)
-#define ergo_verbose(_tag_, _action_) \
+#define ergo_verbose(_tag_, _action_) \
ergo_verbose_common(_tag_, _action_, "", 0, 0, 0, 0, 0, 0)
#define ergo_verbose0(_tag_, _action_, _extra_format_) \
--- a/hotspot/src/share/vm/gc_implementation/g1/g1_globals.hpp Wed Feb 15 16:09:49 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1_globals.hpp Fri Feb 17 13:23:29 2012 +0100
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2012, 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
@@ -297,7 +297,23 @@
\
develop(uintx, G1DefaultMaxNewGenPercent, 80, \
"Percentage (0-100) of the heap size to use as maximum " \
- "young gen size.")
+ "young gen size.") \
+ \
+ develop(uintx, G1OldCSetRegionLiveThresholdPercent, 95, \
+ "Threshold for regions to be added to the collection set. " \
+ "Regions with more live bytes that this will not be collected.") \
+ \
+ develop(uintx, G1OldReclaimableThresholdPercent, 1, \
+ "Threshold for the remaining old reclaimable bytes, expressed " \
+ "as a percentage of the heap size. If the old reclaimable bytes " \
+ "are under this we will not collect them with more mixed GCs.") \
+ \
+ develop(uintx, G1MaxMixedGCNum, 4, \
+ "The maximum desired number of mixed GCs after a marking cycle.") \
+ \
+ develop(uintx, G1OldCSetRegionThresholdPercent, 10, \
+ "An upper bound for the number of old CSet regions expressed " \
+ "as a percentage of the heap size.")
G1_FLAGS(DECLARE_DEVELOPER_FLAG, DECLARE_PD_DEVELOPER_FLAG, DECLARE_PRODUCT_FLAG, DECLARE_PD_PRODUCT_FLAG, DECLARE_DIAGNOSTIC_FLAG, DECLARE_EXPERIMENTAL_FLAG, DECLARE_NOTPRODUCT_FLAG, DECLARE_MANAGEABLE_FLAG, DECLARE_PRODUCT_RW_FLAG)
--- a/hotspot/src/share/vm/gc_implementation/g1/heapRegion.cpp Wed Feb 15 16:09:49 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/heapRegion.cpp Fri Feb 17 13:23:29 2012 +0100
@@ -387,13 +387,12 @@
ct_bs->clear(MemRegion(bottom(), end()));
}
-// <PREDICTION>
void HeapRegion::calc_gc_efficiency() {
G1CollectedHeap* g1h = G1CollectedHeap::heap();
- _gc_efficiency = (double) garbage_bytes() /
- g1h->predict_region_elapsed_time_ms(this, false);
+ G1CollectorPolicy* g1p = g1h->g1_policy();
+ _gc_efficiency = (double) reclaimable_bytes() /
+ g1p->predict_region_elapsed_time_ms(this, false);
}
-// </PREDICTION>
void HeapRegion::set_startsHumongous(HeapWord* new_top, HeapWord* new_end) {
assert(!isHumongous(), "sanity / pre-condition");
--- a/hotspot/src/share/vm/gc_implementation/g1/heapRegion.hpp Wed Feb 15 16:09:49 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/heapRegion.hpp Fri Feb 17 13:23:29 2012 +0100
@@ -415,6 +415,16 @@
return used_at_mark_start_bytes - marked_bytes();
}
+ // Return the amount of bytes we'll reclaim if we collect this
+ // region. This includes not only the known garbage bytes in the
+ // region but also any unallocated space in it, i.e., [top, end),
+ // since it will also be reclaimed if we collect the region.
+ size_t reclaimable_bytes() {
+ size_t known_live_bytes = live_bytes();
+ assert(known_live_bytes <= capacity(), "sanity");
+ return capacity() - known_live_bytes;
+ }
+
// An upper bound on the number of live bytes in the region.
size_t max_live_bytes() { return used() - garbage_bytes(); }
@@ -648,10 +658,8 @@
init_top_at_mark_start();
}
- // <PREDICTION>
void calc_gc_efficiency(void);
double gc_efficiency() { return _gc_efficiency;}
- // </PREDICTION>
bool is_young() const { return _young_type != NotYoung; }
bool is_survivor() const { return _young_type == Survivor; }
--- a/hotspot/src/share/vm/gc_implementation/parNew/parNewGeneration.cpp Wed Feb 15 16:09:49 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/parNew/parNewGeneration.cpp Fri Feb 17 13:23:29 2012 +0100
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2012, 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
@@ -1042,7 +1042,11 @@
size_policy->avg_survived()->sample(from()->used());
}
- update_time_of_last_gc(os::javaTimeMillis());
+ // We need to use a monotonically non-deccreasing time in ms
+ // or we will see time-warp warnings and os::javaTimeMillis()
+ // does not guarantee monotonicity.
+ jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
+ update_time_of_last_gc(now);
SpecializationStats::print();
--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/parallelScavengeHeap.cpp Wed Feb 15 16:09:49 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/parallelScavengeHeap.cpp Fri Feb 17 13:23:29 2012 +0100
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2012, 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
@@ -418,25 +418,17 @@
gc_count = Universe::heap()->total_collections();
result = young_gen()->allocate(size);
-
- // (1) If the requested object is too large to easily fit in the
- // young_gen, or
- // (2) If GC is locked out via GCLocker, young gen is full and
- // the need for a GC already signalled to GCLocker (done
- // at a safepoint),
- // ... then, rather than force a safepoint and (a potentially futile)
- // collection (attempt) for each allocation, try allocation directly
- // in old_gen. For case (2) above, we may in the future allow
- // TLAB allocation directly in the old gen.
if (result != NULL) {
return result;
}
- if (size >= (young_gen()->eden_space()->capacity_in_words(Thread::current()) / 2)) {
- result = old_gen()->allocate(size);
- if (result != NULL) {
- return result;
- }
+
+ // If certain conditions hold, try allocating from the old gen.
+ result = mem_allocate_old_gen(size);
+ if (result != NULL) {
+ return result;
}
+
+ // Failed to allocate without a gc.
if (GC_locker::is_active_and_needs_gc()) {
// If this thread is not in a jni critical section, we stall
// the requestor until the critical section has cleared and
@@ -460,7 +452,6 @@
}
if (result == NULL) {
-
// Generate a VM operation
VM_ParallelGCFailedAllocation op(size, gc_count);
VMThread::execute(&op);
@@ -523,6 +514,42 @@
return result;
}
+// A "death march" is a series of ultra-slow allocations in which a full gc is
+// done before each allocation, and after the full gc the allocation still
+// cannot be satisfied from the young gen. This routine detects that condition;
+// it should be called after a full gc has been done and the allocation
+// attempted from the young gen. The parameter 'addr' should be the result of
+// that young gen allocation attempt.
+void
+ParallelScavengeHeap::death_march_check(HeapWord* const addr, size_t size) {
+ if (addr != NULL) {
+ _death_march_count = 0; // death march has ended
+ } else if (_death_march_count == 0) {
+ if (should_alloc_in_eden(size)) {
+ _death_march_count = 1; // death march has started
+ }
+ }
+}
+
+HeapWord* ParallelScavengeHeap::mem_allocate_old_gen(size_t size) {
+ if (!should_alloc_in_eden(size) || GC_locker::is_active_and_needs_gc()) {
+ // Size is too big for eden, or gc is locked out.
+ return old_gen()->allocate(size);
+ }
+
+ // If a "death march" is in progress, allocate from the old gen a limited
+ // number of times before doing a GC.
+ if (_death_march_count > 0) {
+ if (_death_march_count < 64) {
+ ++_death_march_count;
+ return old_gen()->allocate(size);
+ } else {
+ _death_march_count = 0;
+ }
+ }
+ return NULL;
+}
+
// Failed allocation policy. Must be called from the VM thread, and
// only at a safepoint! Note that this method has policy for allocation
// flow, and NOT collection policy. So we do not check for gc collection
@@ -535,27 +562,22 @@
assert(!Universe::heap()->is_gc_active(), "not reentrant");
assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
- size_t mark_sweep_invocation_count = total_invocations();
-
- // We assume (and assert!) that an allocation at this point will fail
- // unless we collect.
+ // We assume that allocation in eden will fail unless we collect.
// First level allocation failure, scavenge and allocate in young gen.
GCCauseSetter gccs(this, GCCause::_allocation_failure);
- PSScavenge::invoke();
+ const bool invoked_full_gc = PSScavenge::invoke();
HeapWord* result = young_gen()->allocate(size);
// Second level allocation failure.
// Mark sweep and allocate in young generation.
- if (result == NULL) {
- // There is some chance the scavenge method decided to invoke mark_sweep.
- // Don't mark sweep twice if so.
- if (mark_sweep_invocation_count == total_invocations()) {
- invoke_full_gc(false);
- result = young_gen()->allocate(size);
- }
+ if (result == NULL && !invoked_full_gc) {
+ invoke_full_gc(false);
+ result = young_gen()->allocate(size);
}
+ death_march_check(result, size);
+
// Third level allocation failure.
// After mark sweep and young generation allocation failure,
// allocate in old generation.
--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/parallelScavengeHeap.hpp Wed Feb 15 16:09:49 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/parallelScavengeHeap.hpp Fri Feb 17 13:23:29 2012 +0100
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2012, 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
@@ -64,6 +64,7 @@
// Collection of generations that are adjacent in the
// space reserved for the heap.
AdjoiningGenerations* _gens;
+ unsigned int _death_march_count;
static GCTaskManager* _gc_task_manager; // The task manager.
@@ -71,8 +72,13 @@
static inline size_t total_invocations();
HeapWord* allocate_new_tlab(size_t size);
+ inline bool should_alloc_in_eden(size_t size) const;
+ inline void death_march_check(HeapWord* const result, size_t size);
+ HeapWord* mem_allocate_old_gen(size_t size);
+
public:
ParallelScavengeHeap() : CollectedHeap() {
+ _death_march_count = 0;
set_alignment(_perm_gen_alignment, intra_heap_alignment());
set_alignment(_young_gen_alignment, intra_heap_alignment());
set_alignment(_old_gen_alignment, intra_heap_alignment());
--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/parallelScavengeHeap.inline.hpp Wed Feb 15 16:09:49 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/parallelScavengeHeap.inline.hpp Fri Feb 17 13:23:29 2012 +0100
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2006, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2006, 2012, 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
@@ -36,6 +36,12 @@
PSMarkSweep::total_invocations();
}
+inline bool ParallelScavengeHeap::should_alloc_in_eden(const size_t size) const
+{
+ const size_t eden_size = young_gen()->eden_space()->capacity_in_words();
+ return size < eden_size / 2;
+}
+
inline void ParallelScavengeHeap::invoke_scavenge()
{
PSScavenge::invoke();
--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/psMarkSweep.cpp Wed Feb 15 16:09:49 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/psMarkSweep.cpp Fri Feb 17 13:23:29 2012 +0100
@@ -100,12 +100,12 @@
// This method contains no policy. You should probably
// be calling invoke() instead.
-void PSMarkSweep::invoke_no_policy(bool clear_all_softrefs) {
+bool PSMarkSweep::invoke_no_policy(bool clear_all_softrefs) {
assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
assert(ref_processor() != NULL, "Sanity");
if (GC_locker::check_active_before_gc()) {
- return;
+ return false;
}
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
@@ -382,6 +382,8 @@
#ifdef TRACESPINNING
ParallelTaskTerminator::print_termination_counts();
#endif
+
+ return true;
}
bool PSMarkSweep::absorb_live_data_from_eden(PSAdaptiveSizePolicy* size_policy,
--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/psMarkSweep.hpp Wed Feb 15 16:09:49 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/psMarkSweep.hpp Fri Feb 17 13:23:29 2012 +0100
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2012, 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
@@ -78,7 +78,7 @@
public:
static void invoke(bool clear_all_softrefs);
- static void invoke_no_policy(bool clear_all_softrefs);
+ static bool invoke_no_policy(bool clear_all_softrefs);
static void initialize();
--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/psParallelCompact.cpp Wed Feb 15 16:09:49 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/psParallelCompact.cpp Fri Feb 17 13:23:29 2012 +0100
@@ -1993,12 +1993,12 @@
// This method contains no policy. You should probably
// be calling invoke() instead.
-void PSParallelCompact::invoke_no_policy(bool maximum_heap_compaction) {
+bool PSParallelCompact::invoke_no_policy(bool maximum_heap_compaction) {
assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
assert(ref_processor() != NULL, "Sanity");
if (GC_locker::check_active_before_gc()) {
- return;
+ return false;
}
TimeStamp marking_start;
@@ -2248,6 +2248,8 @@
#ifdef TRACESPINNING
ParallelTaskTerminator::print_termination_counts();
#endif
+
+ return true;
}
bool PSParallelCompact::absorb_live_data_from_eden(PSAdaptiveSizePolicy* size_policy,
--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/psParallelCompact.hpp Wed Feb 15 16:09:49 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/psParallelCompact.hpp Fri Feb 17 13:23:29 2012 +0100
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2005, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2012, 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
@@ -1057,7 +1057,7 @@
}
static void invoke(bool maximum_heap_compaction);
- static void invoke_no_policy(bool maximum_heap_compaction);
+ static bool invoke_no_policy(bool maximum_heap_compaction);
static void post_initialize();
// Perform initialization for PSParallelCompact that requires
--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.cpp Wed Feb 15 16:09:49 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.cpp Fri Feb 17 13:23:29 2012 +0100
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2002, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2002, 2012, 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
@@ -247,167 +247,6 @@
}
}
-//
-// This method is pretty bulky. It would be nice to split it up
-// into smaller submethods, but we need to be careful not to hurt
-// performance.
-//
-
-oop PSPromotionManager::copy_to_survivor_space(oop o) {
- assert(PSScavenge::should_scavenge(&o), "Sanity");
-
- oop new_obj = NULL;
-
- // NOTE! We must be very careful with any methods that access the mark
- // in o. There may be multiple threads racing on it, and it may be forwarded
- // at any time. Do not use oop methods for accessing the mark!
- markOop test_mark = o->mark();
-
- // The same test as "o->is_forwarded()"
- if (!test_mark->is_marked()) {
- bool new_obj_is_tenured = false;
- size_t new_obj_size = o->size();
-
- // Find the objects age, MT safe.
- int age = (test_mark->has_displaced_mark_helper() /* o->has_displaced_mark() */) ?
- test_mark->displaced_mark_helper()->age() : test_mark->age();
-
- // Try allocating obj in to-space (unless too old)
- if (age < PSScavenge::tenuring_threshold()) {
- new_obj = (oop) _young_lab.allocate(new_obj_size);
- if (new_obj == NULL && !_young_gen_is_full) {
- // Do we allocate directly, or flush and refill?
- if (new_obj_size > (YoungPLABSize / 2)) {
- // Allocate this object directly
- new_obj = (oop)young_space()->cas_allocate(new_obj_size);
- } else {
- // Flush and fill
- _young_lab.flush();
-
- HeapWord* lab_base = young_space()->cas_allocate(YoungPLABSize);
- if (lab_base != NULL) {
- _young_lab.initialize(MemRegion(lab_base, YoungPLABSize));
- // Try the young lab allocation again.
- new_obj = (oop) _young_lab.allocate(new_obj_size);
- } else {
- _young_gen_is_full = true;
- }
- }
- }
- }
-
- // Otherwise try allocating obj tenured
- if (new_obj == NULL) {
-#ifndef PRODUCT
- if (Universe::heap()->promotion_should_fail()) {
- return oop_promotion_failed(o, test_mark);
- }
-#endif // #ifndef PRODUCT
-
- new_obj = (oop) _old_lab.allocate(new_obj_size);
- new_obj_is_tenured = true;
-
- if (new_obj == NULL) {
- if (!_old_gen_is_full) {
- // Do we allocate directly, or flush and refill?
- if (new_obj_size > (OldPLABSize / 2)) {
- // Allocate this object directly
- new_obj = (oop)old_gen()->cas_allocate(new_obj_size);
- } else {
- // Flush and fill
- _old_lab.flush();
-
- HeapWord* lab_base = old_gen()->cas_allocate(OldPLABSize);
- if(lab_base != NULL) {
- _old_lab.initialize(MemRegion(lab_base, OldPLABSize));
- // Try the old lab allocation again.
- new_obj = (oop) _old_lab.allocate(new_obj_size);
- }
- }
- }
-
- // This is the promotion failed test, and code handling.
- // The code belongs here for two reasons. It is slightly
- // different thatn the code below, and cannot share the
- // CAS testing code. Keeping the code here also minimizes
- // the impact on the common case fast path code.
-
- if (new_obj == NULL) {
- _old_gen_is_full = true;
- return oop_promotion_failed(o, test_mark);
- }
- }
- }
-
- assert(new_obj != NULL, "allocation should have succeeded");
-
- // Copy obj
- Copy::aligned_disjoint_words((HeapWord*)o, (HeapWord*)new_obj, new_obj_size);
-
- // Now we have to CAS in the header.
- if (o->cas_forward_to(new_obj, test_mark)) {
- // We won any races, we "own" this object.
- assert(new_obj == o->forwardee(), "Sanity");
-
- // Increment age if obj still in new generation. Now that
- // we're dealing with a markOop that cannot change, it is
- // okay to use the non mt safe oop methods.
- if (!new_obj_is_tenured) {
- new_obj->incr_age();
- assert(young_space()->contains(new_obj), "Attempt to push non-promoted obj");
- }
-
- // Do the size comparison first with new_obj_size, which we
- // already have. Hopefully, only a few objects are larger than
- // _min_array_size_for_chunking, and most of them will be arrays.
- // So, the is->objArray() test would be very infrequent.
- if (new_obj_size > _min_array_size_for_chunking &&
- new_obj->is_objArray() &&
- PSChunkLargeArrays) {
- // we'll chunk it
- oop* const masked_o = mask_chunked_array_oop(o);
- push_depth(masked_o);
- TASKQUEUE_STATS_ONLY(++_arrays_chunked; ++_masked_pushes);
- } else {
- // we'll just push its contents
- new_obj->push_contents(this);
- }
- } else {
- // We lost, someone else "owns" this object
- guarantee(o->is_forwarded(), "Object must be forwarded if the cas failed.");
-
- // Try to deallocate the space. If it was directly allocated we cannot
- // deallocate it, so we have to test. If the deallocation fails,
- // overwrite with a filler object.
- if (new_obj_is_tenured) {
- if (!_old_lab.unallocate_object((HeapWord*) new_obj, new_obj_size)) {
- CollectedHeap::fill_with_object((HeapWord*) new_obj, new_obj_size);
- }
- } else if (!_young_lab.unallocate_object((HeapWord*) new_obj, new_obj_size)) {
- CollectedHeap::fill_with_object((HeapWord*) new_obj, new_obj_size);
- }
-
- // don't update this before the unallocation!
- new_obj = o->forwardee();
- }
- } else {
- assert(o->is_forwarded(), "Sanity");
- new_obj = o->forwardee();
- }
-
-#ifdef DEBUG
- // This code must come after the CAS test, or it will print incorrect
- // information.
- if (TraceScavenge) {
- gclog_or_tty->print_cr("{%s %s " PTR_FORMAT " -> " PTR_FORMAT " (" SIZE_FORMAT ")}",
- PSScavenge::should_scavenge(&new_obj) ? "copying" : "tenuring",
- new_obj->blueprint()->internal_name(), o, new_obj, new_obj->size());
- }
-#endif
-
- return new_obj;
-}
-
template <class T> void PSPromotionManager::process_array_chunk_work(
oop obj,
int start, int end) {
--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.hpp Wed Feb 15 16:09:49 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.hpp Fri Feb 17 13:23:29 2012 +0100
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2002, 2012, 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
@@ -171,7 +171,7 @@
void set_old_gen_is_full(bool state) { _old_gen_is_full = state; }
// Promotion methods
- oop copy_to_survivor_space(oop o);
+ template<bool promote_immediately> oop copy_to_survivor_space(oop o);
oop oop_promotion_failed(oop obj, markOop obj_mark);
void reset();
--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.inline.hpp Wed Feb 15 16:09:49 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.inline.hpp Fri Feb 17 13:23:29 2012 +0100
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2002, 2012, 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
@@ -61,6 +61,170 @@
claim_or_forward_internal_depth(p);
}
+//
+// This method is pretty bulky. It would be nice to split it up
+// into smaller submethods, but we need to be careful not to hurt
+// performance.
+//
+template<bool promote_immediately>
+oop PSPromotionManager::copy_to_survivor_space(oop o) {
+ assert(PSScavenge::should_scavenge(&o), "Sanity");
+
+ oop new_obj = NULL;
+
+ // NOTE! We must be very careful with any methods that access the mark
+ // in o. There may be multiple threads racing on it, and it may be forwarded
+ // at any time. Do not use oop methods for accessing the mark!
+ markOop test_mark = o->mark();
+
+ // The same test as "o->is_forwarded()"
+ if (!test_mark->is_marked()) {
+ bool new_obj_is_tenured = false;
+ size_t new_obj_size = o->size();
+
+ if (!promote_immediately) {
+ // Find the objects age, MT safe.
+ int age = (test_mark->has_displaced_mark_helper() /* o->has_displaced_mark() */) ?
+ test_mark->displaced_mark_helper()->age() : test_mark->age();
+
+ // Try allocating obj in to-space (unless too old)
+ if (age < PSScavenge::tenuring_threshold()) {
+ new_obj = (oop) _young_lab.allocate(new_obj_size);
+ if (new_obj == NULL && !_young_gen_is_full) {
+ // Do we allocate directly, or flush and refill?
+ if (new_obj_size > (YoungPLABSize / 2)) {
+ // Allocate this object directly
+ new_obj = (oop)young_space()->cas_allocate(new_obj_size);
+ } else {
+ // Flush and fill
+ _young_lab.flush();
+
+ HeapWord* lab_base = young_space()->cas_allocate(YoungPLABSize);
+ if (lab_base != NULL) {
+ _young_lab.initialize(MemRegion(lab_base, YoungPLABSize));
+ // Try the young lab allocation again.
+ new_obj = (oop) _young_lab.allocate(new_obj_size);
+ } else {
+ _young_gen_is_full = true;
+ }
+ }
+ }
+ }
+ }
+
+ // Otherwise try allocating obj tenured
+ if (new_obj == NULL) {
+#ifndef PRODUCT
+ if (Universe::heap()->promotion_should_fail()) {
+ return oop_promotion_failed(o, test_mark);
+ }
+#endif // #ifndef PRODUCT
+
+ new_obj = (oop) _old_lab.allocate(new_obj_size);
+ new_obj_is_tenured = true;
+
+ if (new_obj == NULL) {
+ if (!_old_gen_is_full) {
+ // Do we allocate directly, or flush and refill?
+ if (new_obj_size > (OldPLABSize / 2)) {
+ // Allocate this object directly
+ new_obj = (oop)old_gen()->cas_allocate(new_obj_size);
+ } else {
+ // Flush and fill
+ _old_lab.flush();
+
+ HeapWord* lab_base = old_gen()->cas_allocate(OldPLABSize);
+ if(lab_base != NULL) {
+ _old_lab.initialize(MemRegion(lab_base, OldPLABSize));
+ // Try the old lab allocation again.
+ new_obj = (oop) _old_lab.allocate(new_obj_size);
+ }
+ }
+ }
+
+ // This is the promotion failed test, and code handling.
+ // The code belongs here for two reasons. It is slightly
+ // different thatn the code below, and cannot share the
+ // CAS testing code. Keeping the code here also minimizes
+ // the impact on the common case fast path code.
+
+ if (new_obj == NULL) {
+ _old_gen_is_full = true;
+ return oop_promotion_failed(o, test_mark);
+ }
+ }
+ }
+
+ assert(new_obj != NULL, "allocation should have succeeded");
+
+ // Copy obj
+ Copy::aligned_disjoint_words((HeapWord*)o, (HeapWord*)new_obj, new_obj_size);
+
+ // Now we have to CAS in the header.
+ if (o->cas_forward_to(new_obj, test_mark)) {
+ // We won any races, we "own" this object.
+ assert(new_obj == o->forwardee(), "Sanity");
+
+ // Increment age if obj still in new generation. Now that
+ // we're dealing with a markOop that cannot change, it is
+ // okay to use the non mt safe oop methods.
+ if (!new_obj_is_tenured) {
+ new_obj->incr_age();
+ assert(young_space()->contains(new_obj), "Attempt to push non-promoted obj");
+ }
+
+ // Do the size comparison first with new_obj_size, which we
+ // already have. Hopefully, only a few objects are larger than
+ // _min_array_size_for_chunking, and most of them will be arrays.
+ // So, the is->objArray() test would be very infrequent.
+ if (new_obj_size > _min_array_size_for_chunking &&
+ new_obj->is_objArray() &&
+ PSChunkLargeArrays) {
+ // we'll chunk it
+ oop* const masked_o = mask_chunked_array_oop(o);
+ push_depth(masked_o);
+ TASKQUEUE_STATS_ONLY(++_arrays_chunked; ++_masked_pushes);
+ } else {
+ // we'll just push its contents
+ new_obj->push_contents(this);
+ }
+ } else {
+ // We lost, someone else "owns" this object
+ guarantee(o->is_forwarded(), "Object must be forwarded if the cas failed.");
+
+ // Try to deallocate the space. If it was directly allocated we cannot
+ // deallocate it, so we have to test. If the deallocation fails,
+ // overwrite with a filler object.
+ if (new_obj_is_tenured) {
+ if (!_old_lab.unallocate_object((HeapWord*) new_obj, new_obj_size)) {
+ CollectedHeap::fill_with_object((HeapWord*) new_obj, new_obj_size);
+ }
+ } else if (!_young_lab.unallocate_object((HeapWord*) new_obj, new_obj_size)) {
+ CollectedHeap::fill_with_object((HeapWord*) new_obj, new_obj_size);
+ }
+
+ // don't update this before the unallocation!
+ new_obj = o->forwardee();
+ }
+ } else {
+ assert(o->is_forwarded(), "Sanity");
+ new_obj = o->forwardee();
+ }
+
+#ifdef DEBUG
+ // This code must come after the CAS test, or it will print incorrect
+ // information.
+ if (TraceScavenge) {
+ gclog_or_tty->print_cr("{%s %s " PTR_FORMAT " -> " PTR_FORMAT " (" SIZE_FORMAT ")}",
+ PSScavenge::should_scavenge(&new_obj) ? "copying" : "tenuring",
+ new_obj->blueprint()->internal_name(), o, new_obj, new_obj->size());
+ }
+#endif
+
+ return new_obj;
+}
+
+
inline void PSPromotionManager::process_popped_location_depth(StarTask p) {
if (is_oop_masked(p)) {
assert(PSChunkLargeArrays, "invariant");
@@ -69,9 +233,9 @@
} else {
if (p.is_narrow()) {
assert(UseCompressedOops, "Error");
- PSScavenge::copy_and_push_safe_barrier(this, (narrowOop*)p);
+ PSScavenge::copy_and_push_safe_barrier<narrowOop, /*promote_immediately=*/false>(this, p);
} else {
- PSScavenge::copy_and_push_safe_barrier(this, (oop*)p);
+ PSScavenge::copy_and_push_safe_barrier<oop, /*promote_immediately=*/false>(this, p);
}
}
}
--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/psScavenge.cpp Wed Feb 15 16:09:49 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/psScavenge.cpp Fri Feb 17 13:23:29 2012 +0100
@@ -24,6 +24,7 @@
#include "precompiled.hpp"
#include "classfile/symbolTable.hpp"
+#include "code/codeCache.hpp"
#include "gc_implementation/parallelScavenge/cardTableExtension.hpp"
#include "gc_implementation/parallelScavenge/gcTaskManager.hpp"
#include "gc_implementation/parallelScavenge/generationSizer.hpp"
@@ -100,7 +101,7 @@
// Weak refs may be visited more than once.
if (PSScavenge::should_scavenge(p, _to_space)) {
- PSScavenge::copy_and_push_safe_barrier(_promotion_manager, p);
+ PSScavenge::copy_and_push_safe_barrier<T, /*promote_immediately=*/false>(_promotion_manager, p);
}
}
virtual void do_oop(oop* p) { PSKeepAliveClosure::do_oop_work(p); }
@@ -214,36 +215,41 @@
//
// Note that this method should only be called from the vm_thread while
// at a safepoint!
-void PSScavenge::invoke() {
+bool PSScavenge::invoke() {
assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
assert(!Universe::heap()->is_gc_active(), "not reentrant");
- ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
+ ParallelScavengeHeap* const heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
PSAdaptiveSizePolicy* policy = heap->size_policy();
IsGCActiveMark mark;
- bool scavenge_was_done = PSScavenge::invoke_no_policy();
+ const bool scavenge_done = PSScavenge::invoke_no_policy();
+ const bool need_full_gc = !scavenge_done ||
+ policy->should_full_GC(heap->old_gen()->free_in_bytes());
+ bool full_gc_done = false;
- PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters();
- if (UsePerfData)
- counters->update_full_follows_scavenge(0);
- if (!scavenge_was_done ||
- policy->should_full_GC(heap->old_gen()->free_in_bytes())) {
- if (UsePerfData)
- counters->update_full_follows_scavenge(full_follows_scavenge);
+ if (UsePerfData) {
+ PSGCAdaptivePolicyCounters* const counters = heap->gc_policy_counters();
+ const int ffs_val = need_full_gc ? full_follows_scavenge : not_skipped;
+ counters->update_full_follows_scavenge(ffs_val);
+ }
+
+ if (need_full_gc) {
GCCauseSetter gccs(heap, GCCause::_adaptive_size_policy);
CollectorPolicy* cp = heap->collector_policy();
const bool clear_all_softrefs = cp->should_clear_all_soft_refs();
if (UseParallelOldGC) {
- PSParallelCompact::invoke_no_policy(clear_all_softrefs);
+ full_gc_done = PSParallelCompact::invoke_no_policy(clear_all_softrefs);
} else {
- PSMarkSweep::invoke_no_policy(clear_all_softrefs);
+ full_gc_done = PSMarkSweep::invoke_no_policy(clear_all_softrefs);
}
}
+
+ return full_gc_done;
}
// This method contains no policy. You should probably
@@ -602,6 +608,8 @@
NOT_PRODUCT(reference_processor()->verify_no_references_recorded());
+ CodeCache::prune_scavenge_root_nmethods();
+
// Re-verify object start arrays
if (VerifyObjectStartArray &&
VerifyAfterGC) {
--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/psScavenge.hpp Wed Feb 15 16:09:49 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/psScavenge.hpp Fri Feb 17 13:23:29 2012 +0100
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2002, 2012, 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
@@ -117,10 +117,9 @@
// Called by parallelScavengeHeap to init the tenuring threshold
static void initialize();
- // Scavenge entry point
- static void invoke();
- // Return true is a collection was done. Return
- // false if the collection was skipped.
+ // Scavenge entry point. This may invoke a full gc; return true if so.
+ static bool invoke();
+ // Return true if a collection was done; false otherwise.
static bool invoke_no_policy();
// If an attempt to promote fails, this method is invoked
@@ -135,7 +134,8 @@
template <class T> static inline bool should_scavenge(T* p, MutableSpace* to_space);
template <class T> static inline bool should_scavenge(T* p, bool check_to_space);
- template <class T> inline static void copy_and_push_safe_barrier(PSPromotionManager* pm, T* p);
+ template <class T, bool promote_immediately>
+ inline static void copy_and_push_safe_barrier(PSPromotionManager* pm, T* p);
// Is an object in the young generation
// This assumes that the HeapWord argument is in the heap,
--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/psScavenge.inline.hpp Wed Feb 15 16:09:49 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/psScavenge.inline.hpp Fri Feb 17 13:23:29 2012 +0100
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2002, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2002, 2012, 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
@@ -28,6 +28,7 @@
#include "gc_implementation/parallelScavenge/cardTableExtension.hpp"
#include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"
#include "gc_implementation/parallelScavenge/psPromotionManager.hpp"
+#include "gc_implementation/parallelScavenge/psPromotionManager.inline.hpp"
#include "gc_implementation/parallelScavenge/psScavenge.hpp"
inline void PSScavenge::save_to_space_top_before_gc() {
@@ -65,7 +66,7 @@
// Attempt to "claim" oop at p via CAS, push the new obj if successful
// This version tests the oop* to make sure it is within the heap before
// attempting marking.
-template <class T>
+template <class T, bool promote_immediately>
inline void PSScavenge::copy_and_push_safe_barrier(PSPromotionManager* pm,
T* p) {
assert(should_scavenge(p, true), "revisiting object?");
@@ -73,7 +74,7 @@
oop o = oopDesc::load_decode_heap_oop_not_null(p);
oop new_obj = o->is_forwarded()
? o->forwardee()
- : pm->copy_to_survivor_space(o);
+ : pm->copy_to_survivor_space<promote_immediately>(o);
oopDesc::encode_store_heap_oop_not_null(p, new_obj);
// We cannot mark without test, as some code passes us pointers
@@ -86,7 +87,8 @@
}
}
-class PSScavengeRootsClosure: public OopClosure {
+template<bool promote_immediately>
+class PSRootsClosure: public OopClosure {
private:
PSPromotionManager* _promotion_manager;
@@ -94,13 +96,16 @@
template <class T> void do_oop_work(T *p) {
if (PSScavenge::should_scavenge(p)) {
// We never card mark roots, maybe call a func without test?
- PSScavenge::copy_and_push_safe_barrier(_promotion_manager, p);
+ PSScavenge::copy_and_push_safe_barrier<T, promote_immediately>(_promotion_manager, p);
}
}
public:
- PSScavengeRootsClosure(PSPromotionManager* pm) : _promotion_manager(pm) { }
- void do_oop(oop* p) { PSScavengeRootsClosure::do_oop_work(p); }
- void do_oop(narrowOop* p) { PSScavengeRootsClosure::do_oop_work(p); }
+ PSRootsClosure(PSPromotionManager* pm) : _promotion_manager(pm) { }
+ void do_oop(oop* p) { PSRootsClosure::do_oop_work(p); }
+ void do_oop(narrowOop* p) { PSRootsClosure::do_oop_work(p); }
};
+typedef PSRootsClosure</*promote_immediately=*/false> PSScavengeRootsClosure;
+typedef PSRootsClosure</*promote_immediately=*/true> PSPromoteRootsClosure;
+
#endif // SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSSCAVENGE_INLINE_HPP
--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/psTasks.cpp Wed Feb 15 16:09:49 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/psTasks.cpp Fri Feb 17 13:23:29 2012 +0100
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2002, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2002, 2012, 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
@@ -51,6 +51,7 @@
PSPromotionManager* pm = PSPromotionManager::gc_thread_promotion_manager(which);
PSScavengeRootsClosure roots_closure(pm);
+ PSPromoteRootsClosure roots_to_old_closure(pm);
switch (_root_type) {
case universe:
@@ -91,7 +92,7 @@
case code_cache:
{
- CodeBlobToOopClosure each_scavengable_code_blob(&roots_closure, /*do_marking=*/ true);
+ CodeBlobToOopClosure each_scavengable_code_blob(&roots_to_old_closure, /*do_marking=*/ true);
CodeCache::scavenge_root_nmethods_do(&each_scavengable_code_blob);
}
break;
--- a/hotspot/src/share/vm/memory/defNewGeneration.cpp Wed Feb 15 16:09:49 2012 -0500
+++ b/hotspot/src/share/vm/memory/defNewGeneration.cpp Fri Feb 17 13:23:29 2012 +0100
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2012, 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
@@ -655,7 +655,12 @@
from()->set_concurrent_iteration_safe_limit(from()->top());
to()->set_concurrent_iteration_safe_limit(to()->top());
SpecializationStats::print();
- update_time_of_last_gc(os::javaTimeMillis());
+
+ // We need to use a monotonically non-deccreasing time in ms
+ // or we will see time-warp warnings and os::javaTimeMillis()
+ // does not guarantee monotonicity.
+ jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
+ update_time_of_last_gc(now);
}
class RemoveForwardPointerClosure: public ObjectClosure {
--- a/hotspot/src/share/vm/memory/genMarkSweep.cpp Wed Feb 15 16:09:49 2012 -0500
+++ b/hotspot/src/share/vm/memory/genMarkSweep.cpp Fri Feb 17 13:23:29 2012 +0100
@@ -176,7 +176,11 @@
// Update time of last gc for all generations we collected
// (which curently is all the generations in the heap).
- gch->update_time_of_last_gc(os::javaTimeMillis());
+ // We need to use a monotonically non-deccreasing time in ms
+ // or we will see time-warp warnings and os::javaTimeMillis()
+ // does not guarantee monotonicity.
+ jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
+ gch->update_time_of_last_gc(now);
}
void GenMarkSweep::allocate_stacks() {