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7143490: G1: Remove HeapRegion::_top_at_conc_mark_count

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Removed the HeapRegion::_top_at_conc_mark_count field. It is no longer needed as a result of the changes for 6888336 and 7127706. Refactored the closures that finalize and verify the liveness counting data so that common functionality was placed into a base class.

Reviewed-by: brutisso, tonyp
This commit is contained in:
John Cuthbertson 2012-04-25 10:23:12 -07:00
parent f5558edf7b
commit 377a04fe57
6 changed files with 64 additions and 192 deletions
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207
hotspot/src/share/vm/gc_implementation/g1/concurrentMark.cpp
View File

@ -1183,35 +1183,31 @@ void ConcurrentMark::checkpointRootsFinal(bool clear_all_soft_refs) {
g1p->record_concurrent_mark_remark_end();
}
// Used to calculate the # live objects per region
// for verification purposes
class CalcLiveObjectsClosure: public HeapRegionClosure {
CMBitMapRO* _bm;
// Base class of the closures that finalize and verify the
// liveness counting data.
class CMCountDataClosureBase: public HeapRegionClosure {
protected:
ConcurrentMark* _cm;
BitMap* _region_bm;
BitMap* _card_bm;
size_t _region_marked_bytes;
void set_card_bitmap_range(BitMap::idx_t start_idx, BitMap::idx_t last_idx) {
assert(start_idx <= last_idx, "sanity");
intptr_t _bottom_card_num;
void mark_card_num_range(intptr_t start_card_num, intptr_t last_card_num) {
assert(start_card_num <= last_card_num, "sanity");
BitMap::idx_t start_idx = start_card_num - _bottom_card_num;
BitMap::idx_t last_idx = last_card_num - _bottom_card_num;
for (BitMap::idx_t i = start_idx; i <= last_idx; i += 1) {
_card_bm->par_at_put(i, 1);
// Set the inclusive bit range [start_idx, last_idx].
// For small ranges (up to 8 cards) use a simple loop; otherwise
// use par_at_put_range.
if ((last_idx - start_idx) < 8) {
for (BitMap::idx_t i = start_idx; i <= last_idx; i += 1) {
_card_bm->par_set_bit(i);
}
} else {
assert(last_idx < _card_bm->size(), "sanity");
// Note BitMap::par_at_put_range() is exclusive.
_card_bm->par_at_put_range(start_idx, last_idx+1, true);
}
}
public:
CalcLiveObjectsClosure(CMBitMapRO *bm, ConcurrentMark *cm,
BitMap* region_bm, BitMap* card_bm) :
_bm(bm), _cm(cm), _region_bm(region_bm), _card_bm(card_bm),
_region_marked_bytes(0), _bottom_card_num(cm->heap_bottom_card_num()) { }
// It takes a region that's not empty (i.e., it has at least one
// live object in it and sets its corresponding bit on the region
// bitmap to 1. If the region is "starts humongous" it will also set
@ -1234,6 +1230,24 @@ public:
}
}
public:
CMCountDataClosureBase(ConcurrentMark *cm,
BitMap* region_bm, BitMap* card_bm):
_cm(cm), _region_bm(region_bm), _card_bm(card_bm) { }
};
// Closure that calculates the # live objects per region. Used
// for verification purposes during the cleanup pause.
class CalcLiveObjectsClosure: public CMCountDataClosureBase {
CMBitMapRO* _bm;
size_t _region_marked_bytes;
public:
CalcLiveObjectsClosure(CMBitMapRO *bm, ConcurrentMark *cm,
BitMap* region_bm, BitMap* card_bm) :
CMCountDataClosureBase(cm, region_bm, card_bm),
_bm(bm), _region_marked_bytes(0) { }
bool doHeapRegion(HeapRegion* hr) {
if (hr->continuesHumongous()) {
@ -1260,65 +1274,31 @@ public:
size_t marked_bytes = 0;
// Below, the term "card num" means the result of shifting an address
// by the card shift -- address 0 corresponds to card number 0. One
// must subtract the card num of the bottom of the heap to obtain a
// card table index.
// The first card num of the sequence of live cards currently being
// constructed. -1 ==> no sequence.
intptr_t start_card_num = -1;
// The last card num of the sequence of live cards currently being
// constructed. -1 ==> no sequence.
intptr_t last_card_num = -1;
while (start < nextTop) {
oop obj = oop(start);
int obj_sz = obj->size();
// The card num of the start of the current object.
intptr_t obj_card_num =
intptr_t(uintptr_t(start) >> CardTableModRefBS::card_shift);
HeapWord* obj_last = start + obj_sz - 1;
intptr_t obj_last_card_num =
intptr_t(uintptr_t(obj_last) >> CardTableModRefBS::card_shift);
if (obj_card_num != last_card_num) {
if (start_card_num == -1) {
assert(last_card_num == -1, "Both or neither.");
start_card_num = obj_card_num;
} else {
assert(last_card_num != -1, "Both or neither.");
assert(obj_card_num >= last_card_num, "Inv");
if ((obj_card_num - last_card_num) > 1) {
// Mark the last run, and start a new one.
mark_card_num_range(start_card_num, last_card_num);
start_card_num = obj_card_num;
}
}
}
// In any case, we set the last card num.
last_card_num = obj_last_card_num;
BitMap::idx_t start_idx = _cm->card_bitmap_index_for(start);
BitMap::idx_t last_idx = _cm->card_bitmap_index_for(obj_last);
// Set the bits in the card BM for this object (inclusive).
set_card_bitmap_range(start_idx, last_idx);
// Add the size of this object to the number of marked bytes.
marked_bytes += (size_t)obj_sz * HeapWordSize;
// Find the next marked object after this one.
start = _bm->getNextMarkedWordAddress(start + 1, nextTop);
}
// Handle the last range, if any.
if (start_card_num != -1) {
mark_card_num_range(start_card_num, last_card_num);
start = _bm->getNextMarkedWordAddress(obj_last + 1, nextTop);
}
// Mark the allocated-since-marking portion...
HeapWord* top = hr->top();
if (nextTop < top) {
start_card_num = intptr_t(uintptr_t(nextTop) >> CardTableModRefBS::card_shift);
last_card_num = intptr_t(uintptr_t(top) >> CardTableModRefBS::card_shift);
BitMap::idx_t start_idx = _cm->card_bitmap_index_for(nextTop);
BitMap::idx_t last_idx = _cm->card_bitmap_index_for(top - 1);
mark_card_num_range(start_card_num, last_card_num);
set_card_bitmap_range(start_idx, last_idx);
// This definitely means the region has live objects.
set_bit_for_region(hr);
@ -1394,17 +1374,6 @@ public:
MutexLockerEx x((_verbose ? ParGCRareEvent_lock : NULL),
Mutex::_no_safepoint_check_flag);
// Verify that _top_at_conc_count == ntams
if (hr->top_at_conc_mark_count() != hr->next_top_at_mark_start()) {
if (_verbose) {
gclog_or_tty->print_cr("Region %u: top at conc count incorrect: "
"expected " PTR_FORMAT ", actual: " PTR_FORMAT,
hr->hrs_index(), hr->next_top_at_mark_start(),
hr->top_at_conc_mark_count());
}
failures += 1;
}
// Verify the marked bytes for this region.
size_t exp_marked_bytes = _calc_cl.region_marked_bytes();
size_t act_marked_bytes = hr->next_marked_bytes();
@ -1470,7 +1439,7 @@ public:
_failures += failures;
// We could stop iteration over the heap when we
// find the first voilating region by returning true.
// find the first violating region by returning true.
return false;
}
};
@ -1543,62 +1512,19 @@ public:
int failures() const { return _failures; }
};
// Final update of count data (during cleanup).
// Adds [top_at_count, NTAMS) to the marked bytes for each
// region. Sets the bits in the card bitmap corresponding
// to the interval [top_at_count, top], and sets the
// liveness bit for each region containing live data
// in the region bitmap.
class FinalCountDataUpdateClosure: public HeapRegionClosure {
ConcurrentMark* _cm;
BitMap* _region_bm;
BitMap* _card_bm;
void set_card_bitmap_range(BitMap::idx_t start_idx, BitMap::idx_t last_idx) {
assert(start_idx <= last_idx, "sanity");
// Set the inclusive bit range [start_idx, last_idx].
// For small ranges (up to 8 cards) use a simple loop; otherwise
// use par_at_put_range.
if ((last_idx - start_idx) <= 8) {
for (BitMap::idx_t i = start_idx; i <= last_idx; i += 1) {
_card_bm->par_set_bit(i);
}
} else {
assert(last_idx < _card_bm->size(), "sanity");
// Note BitMap::par_at_put_range() is exclusive.
_card_bm->par_at_put_range(start_idx, last_idx+1, true);
}
}
// It takes a region that's not empty (i.e., it has at least one
// live object in it and sets its corresponding bit on the region
// bitmap to 1. If the region is "starts humongous" it will also set
// to 1 the bits on the region bitmap that correspond to its
// associated "continues humongous" regions.
void set_bit_for_region(HeapRegion* hr) {
assert(!hr->continuesHumongous(), "should have filtered those out");
BitMap::idx_t index = (BitMap::idx_t) hr->hrs_index();
if (!hr->startsHumongous()) {
// Normal (non-humongous) case: just set the bit.
_region_bm->par_set_bit(index);
} else {
// Starts humongous case: calculate how many regions are part of
// this humongous region and then set the bit range.
G1CollectedHeap* g1h = G1CollectedHeap::heap();
HeapRegion *last_hr = g1h->heap_region_containing_raw(hr->end() - 1);
BitMap::idx_t end_index = (BitMap::idx_t) last_hr->hrs_index() + 1;
_region_bm->par_at_put_range(index, end_index, true);
}
}
// Closure that finalizes the liveness counting data.
// Used during the cleanup pause.
// Sets the bits corresponding to the interval [NTAMS, top]
// (which contains the implicitly live objects) in the
// card liveness bitmap. Also sets the bit for each region,
// containing live data, in the region liveness bitmap.
class FinalCountDataUpdateClosure: public CMCountDataClosureBase {
public:
FinalCountDataUpdateClosure(ConcurrentMark* cm,
BitMap* region_bm,
BitMap* card_bm) :
_cm(cm), _region_bm(region_bm), _card_bm(card_bm) { }
CMCountDataClosureBase(cm, region_bm, card_bm) { }
bool doHeapRegion(HeapRegion* hr) {
@ -1613,26 +1539,10 @@ class FinalCountDataUpdateClosure: public HeapRegionClosure {
return false;
}
HeapWord* start = hr->top_at_conc_mark_count();
HeapWord* ntams = hr->next_top_at_mark_start();
HeapWord* top = hr->top();
assert(hr->bottom() <= start && start <= hr->end() &&
hr->bottom() <= ntams && ntams <= hr->end(), "Preconditions.");
if (start < ntams) {
// Region was changed between remark and cleanup pauses
// We need to add (ntams - start) to the marked bytes
// for this region, and set bits for the range
// [ card_idx(start), card_idx(ntams) ) in the card bitmap.
size_t live_bytes = (ntams - start) * HeapWordSize;
hr->add_to_marked_bytes(live_bytes);
// Record the new top at conc count
hr->set_top_at_conc_mark_count(ntams);
// The setting of the bits in the card bitmap takes place below
}
assert(hr->bottom() <= ntams && ntams <= hr->end(), "Preconditions.");
// Mark the allocated-since-marking portion...
if (ntams < top) {
@ -1640,8 +1550,8 @@ class FinalCountDataUpdateClosure: public HeapRegionClosure {
set_bit_for_region(hr);
}
// Now set the bits for [start, top]
BitMap::idx_t start_idx = _cm->card_bitmap_index_for(start);
// Now set the bits for [ntams, top]
BitMap::idx_t start_idx = _cm->card_bitmap_index_for(ntams);
BitMap::idx_t last_idx = _cm->card_bitmap_index_for(top);
set_card_bitmap_range(start_idx, last_idx);
@ -3072,9 +2982,6 @@ class AggregateCountDataHRClosure: public HeapRegionClosure {
// Update the marked bytes for this region.
hr->add_to_marked_bytes(marked_bytes);
// Now set the top at count to NTAMS.
hr->set_top_at_conc_mark_count(limit);
// Next heap region
return false;
}

11
hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp
View File

@ -368,16 +368,11 @@ void YoungList::print() {
if (curr == NULL)
gclog_or_tty->print_cr(" empty");
while (curr != NULL) {
gclog_or_tty->print_cr(" [%08x-%08x], t: %08x, P: %08x, N: %08x, C: %08x, "
"age: %4d, y: %d, surv: %d",
curr->bottom(), curr->end(),
curr->top(),
gclog_or_tty->print_cr(" "HR_FORMAT", P: "PTR_FORMAT "N: "PTR_FORMAT", age: %4d",
HR_FORMAT_PARAMS(curr),
curr->prev_top_at_mark_start(),
curr->next_top_at_mark_start(),
curr->top_at_conc_mark_count(),
curr->age_in_surv_rate_group_cond(),
curr->is_young(),
curr->is_survivor());
curr->age_in_surv_rate_group_cond());
curr = curr->get_next_young_region();
}
}

14
hotspot/src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp
View File

@ -2459,16 +2459,10 @@ void G1CollectorPolicy::print_collection_set(HeapRegion* list_head, outputStream
while (csr != NULL) {
HeapRegion* next = csr->next_in_collection_set();
assert(csr->in_collection_set(), "bad CS");
st->print_cr(" [%08x-%08x], t: %08x, P: %08x, N: %08x, C: %08x, "
"age: %4d, y: %d, surv: %d",
csr->bottom(), csr->end(),
csr->top(),
csr->prev_top_at_mark_start(),
csr->next_top_at_mark_start(),
csr->top_at_conc_mark_count(),
csr->age_in_surv_rate_group_cond(),
csr->is_young(),
csr->is_survivor());
st->print_cr(" "HR_FORMAT", P: "PTR_FORMAT "N: "PTR_FORMAT", age: %4d",
HR_FORMAT_PARAMS(csr),
csr->prev_top_at_mark_start(), csr->next_top_at_mark_start(),
csr->age_in_surv_rate_group_cond());
csr = next;
}
}

5
hotspot/src/share/vm/gc_implementation/g1/heapRegion.cpp
View File

@ -510,9 +510,6 @@ HeapRegion::HeapRegion(uint hrs_index,
_rem_set = new HeapRegionRemSet(sharedOffsetArray, this);
assert(HeapRegionRemSet::num_par_rem_sets() > 0, "Invariant.");
// In case the region is allocated during a pause, note the top.
// We haven't done any counting on a brand new region.
_top_at_conc_mark_count = bottom();
}
class NextCompactionHeapRegionClosure: public HeapRegionClosure {
@ -585,14 +582,12 @@ void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark,
// we find to be self-forwarded on the next bitmap. So all
// objects need to be below NTAMS.
_next_top_at_mark_start = top();
set_top_at_conc_mark_count(bottom());
_next_marked_bytes = 0;
} else if (during_conc_mark) {
// During concurrent mark, all objects in the CSet (including
// the ones we find to be self-forwarded) are implicitly live.
// So all objects need to be above NTAMS.
_next_top_at_mark_start = bottom();
set_top_at_conc_mark_count(bottom());
_next_marked_bytes = 0;
}
}

18
hotspot/src/share/vm/gc_implementation/g1/heapRegion.hpp
View File

@ -306,9 +306,6 @@ class HeapRegion: public G1OffsetTableContigSpace {
// If a collection pause is in progress, this is the top at the start
// of that pause.
// We've counted the marked bytes of objects below here.
HeapWord* _top_at_conc_mark_count;
void init_top_at_mark_start() {
assert(_prev_marked_bytes == 0 &&
_next_marked_bytes == 0,
@ -316,7 +313,6 @@ class HeapRegion: public G1OffsetTableContigSpace {
HeapWord* bot = bottom();
_prev_top_at_mark_start = bot;
_next_top_at_mark_start = bot;
_top_at_conc_mark_count = bot;
}
void set_young_type(YoungType new_type) {
@ -625,19 +621,6 @@ class HeapRegion: public G1OffsetTableContigSpace {
// last mark phase ended.
bool is_marked() { return _prev_top_at_mark_start != bottom(); }
void init_top_at_conc_mark_count() {
_top_at_conc_mark_count = bottom();
}
void set_top_at_conc_mark_count(HeapWord *cur) {
assert(bottom() <= cur && cur <= end(), "Sanity.");
_top_at_conc_mark_count = cur;
}
HeapWord* top_at_conc_mark_count() {
return _top_at_conc_mark_count;
}
void reset_during_compaction() {
guarantee( isHumongous() && startsHumongous(),
"should only be called for humongous regions");
@ -733,7 +716,6 @@ class HeapRegion: public G1OffsetTableContigSpace {
_evacuation_failed = b;
if (b) {
init_top_at_conc_mark_count();
_next_marked_bytes = 0;
}
}

1
hotspot/src/share/vm/gc_implementation/g1/heapRegion.inline.hpp
View File

@ -56,7 +56,6 @@ G1OffsetTableContigSpace::block_start_const(const void* p) const {
}
inline void HeapRegion::note_start_of_marking() {
init_top_at_conc_mark_count();
_next_marked_bytes = 0;
_next_top_at_mark_start = top();
}