--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp Fri Dec 12 10:19:39 2008 -0800
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp Fri Dec 12 15:37:46 2008 -0800
@@ -2954,7 +2954,7 @@
// The object has been either evacuated or is dead. Fill it with a
// dummy object.
MemRegion mr((HeapWord*)obj, obj->size());
- SharedHeap::fill_region_with_object(mr);
+ CollectedHeap::fill_with_object(mr);
_cm->clearRangeBothMaps(mr);
}
}
@@ -3225,7 +3225,7 @@
// Otherwise, try to claim it.
block = r->par_allocate(free_words);
} while (block == NULL);
- SharedHeap::fill_region_with_object(MemRegion(block, free_words));
+ fill_with_object(block, free_words);
}
#define use_local_bitmaps 1
@@ -3619,9 +3619,8 @@
guarantee(alloc_buffer(purpose)->contains(obj + word_sz - 1),
"should contain whole object");
alloc_buffer(purpose)->undo_allocation(obj, word_sz);
- }
- else {
- SharedHeap::fill_region_with_object(MemRegion(obj, word_sz));
+ } else {
+ CollectedHeap::fill_with_object(obj, word_sz);
add_to_undo_waste(word_sz);
}
}
--- a/hotspot/src/share/vm/gc_implementation/g1/heapRegionSeq.cpp Fri Dec 12 10:19:39 2008 -0800
+++ b/hotspot/src/share/vm/gc_implementation/g1/heapRegionSeq.cpp Fri Dec 12 15:37:46 2008 -0800
@@ -102,7 +102,7 @@
HeapWord* tmp = hr->allocate(sz);
assert(tmp != NULL, "Humongous allocation failure");
MemRegion mr = MemRegion(tmp, sz);
- SharedHeap::fill_region_with_object(mr);
+ CollectedHeap::fill_with_object(mr);
hr->declare_filled_region_to_BOT(mr);
if (i == first) {
first_hr->set_startsHumongous();
--- a/hotspot/src/share/vm/gc_implementation/parNew/parGCAllocBuffer.cpp Fri Dec 12 10:19:39 2008 -0800
+++ b/hotspot/src/share/vm/gc_implementation/parNew/parGCAllocBuffer.cpp Fri Dec 12 15:37:46 2008 -0800
@@ -51,14 +51,14 @@
if (_retained) {
// If the buffer had been retained shorten the previous filler object.
assert(_retained_filler.end() <= _top, "INVARIANT");
- SharedHeap::fill_region_with_object(_retained_filler);
+ CollectedHeap::fill_with_object(_retained_filler);
// Wasted space book-keeping, otherwise (normally) done in invalidate()
_wasted += _retained_filler.word_size();
_retained = false;
}
assert(!end_of_gc || !_retained, "At this point, end_of_gc ==> !_retained.");
if (_top < _hard_end) {
- SharedHeap::fill_region_with_object(MemRegion(_top, _hard_end));
+ CollectedHeap::fill_with_object(_top, _hard_end);
if (!retain) {
invalidate();
} else {
@@ -155,7 +155,7 @@
// modifying the _next_threshold state in the BOT.
void ParGCAllocBufferWithBOT::fill_region_with_block(MemRegion mr,
bool contig) {
- SharedHeap::fill_region_with_object(mr);
+ CollectedHeap::fill_with_object(mr);
if (contig) {
_bt.alloc_block(mr.start(), mr.end());
} else {
@@ -171,7 +171,7 @@
"or else _true_end should be equal to _hard_end");
assert(_retained, "or else _true_end should be equal to _hard_end");
assert(_retained_filler.end() <= _top, "INVARIANT");
- SharedHeap::fill_region_with_object(_retained_filler);
+ CollectedHeap::fill_with_object(_retained_filler);
if (_top < _hard_end) {
fill_region_with_block(MemRegion(_top, _hard_end), true);
}
@@ -316,11 +316,9 @@
while (_top <= chunk_boundary) {
assert(pointer_delta(_hard_end, chunk_boundary) >= AlignmentReserve,
"Consequence of last card handling above.");
- MemRegion chunk_portion(chunk_boundary, _hard_end);
- _bt.BlockOffsetArray::alloc_block(chunk_portion.start(),
- chunk_portion.end());
- SharedHeap::fill_region_with_object(chunk_portion);
- _hard_end = chunk_portion.start();
+ _bt.BlockOffsetArray::alloc_block(chunk_boundary, _hard_end);
+ CollectedHeap::fill_with_object(chunk_boundary, _hard_end);
+ _hard_end = chunk_boundary;
chunk_boundary -= ChunkSizeInWords;
}
_end = _hard_end - AlignmentReserve;
--- a/hotspot/src/share/vm/gc_implementation/parNew/parNewGeneration.cpp Fri Dec 12 10:19:39 2008 -0800
+++ b/hotspot/src/share/vm/gc_implementation/parNew/parNewGeneration.cpp Fri Dec 12 15:37:46 2008 -0800
@@ -201,7 +201,7 @@
"Should contain whole object.");
to_space_alloc_buffer()->undo_allocation(obj, word_sz);
} else {
- SharedHeap::fill_region_with_object(MemRegion(obj, word_sz));
+ CollectedHeap::fill_with_object(obj, word_sz);
}
}
--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/psMarkSweep.cpp Fri Dec 12 10:19:39 2008 -0800
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/psMarkSweep.cpp Fri Dec 12 15:37:46 2008 -0800
@@ -389,7 +389,7 @@
// full GC.
const size_t alignment = old_gen->virtual_space()->alignment();
const size_t eden_used = eden_space->used_in_bytes();
- const size_t promoted = (size_t)(size_policy->avg_promoted()->padded_average());
+ const size_t promoted = (size_t)size_policy->avg_promoted()->padded_average();
const size_t absorb_size = align_size_up(eden_used + promoted, alignment);
const size_t eden_capacity = eden_space->capacity_in_bytes();
@@ -416,16 +416,14 @@
// Fill the unused part of the old gen.
MutableSpace* const old_space = old_gen->object_space();
- MemRegion old_gen_unused(old_space->top(), old_space->end());
+ HeapWord* const unused_start = old_space->top();
+ size_t const unused_words = pointer_delta(old_space->end(), unused_start);
- // If the unused part of the old gen cannot be filled, skip
- // absorbing eden.
- if (old_gen_unused.word_size() < SharedHeap::min_fill_size()) {
- return false;
- }
-
- if (!old_gen_unused.is_empty()) {
- SharedHeap::fill_region_with_object(old_gen_unused);
+ if (unused_words > 0) {
+ if (unused_words < CollectedHeap::min_fill_size()) {
+ return false; // If the old gen cannot be filled, must give up.
+ }
+ CollectedHeap::fill_with_objects(unused_start, unused_words);
}
// Take the live data from eden and set both top and end in the old gen to
@@ -441,9 +439,8 @@
// Update the object start array for the filler object and the data from eden.
ObjectStartArray* const start_array = old_gen->start_array();
- HeapWord* const start = old_gen_unused.start();
- for (HeapWord* addr = start; addr < new_top; addr += oop(addr)->size()) {
- start_array->allocate_block(addr);
+ for (HeapWord* p = unused_start; p < new_top; p += oop(p)->size()) {
+ start_array->allocate_block(p);
}
// Could update the promoted average here, but it is not typically updated at
--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/psMarkSweepDecorator.cpp Fri Dec 12 10:19:39 2008 -0800
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/psMarkSweepDecorator.cpp Fri Dec 12 15:37:46 2008 -0800
@@ -275,22 +275,9 @@
HeapWord* q, size_t deadlength) {
if (allowed_deadspace_words >= deadlength) {
allowed_deadspace_words -= deadlength;
- oop(q)->set_mark(markOopDesc::prototype()->set_marked());
- const size_t aligned_min_int_array_size =
- align_object_size(typeArrayOopDesc::header_size(T_INT));
- if (deadlength >= aligned_min_int_array_size) {
- oop(q)->set_klass(Universe::intArrayKlassObj());
- assert(((deadlength - aligned_min_int_array_size) * (HeapWordSize/sizeof(jint))) < (size_t)max_jint,
- "deadspace too big for Arrayoop");
- typeArrayOop(q)->set_length((int)((deadlength - aligned_min_int_array_size)
- * (HeapWordSize/sizeof(jint))));
- } else {
- assert((int) deadlength == instanceOopDesc::header_size(),
- "size for smallest fake dead object doesn't match");
- oop(q)->set_klass(SystemDictionary::object_klass());
- }
- assert((int) deadlength == oop(q)->size(),
- "make sure size for fake dead object match");
+ CollectedHeap::fill_with_object(q, deadlength);
+ oop(q)->set_mark(oop(q)->mark()->set_marked());
+ assert((int) deadlength == oop(q)->size(), "bad filler object size");
// Recall that we required "q == compaction_top".
return true;
} else {
--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/psParallelCompact.cpp Fri Dec 12 10:19:39 2008 -0800
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/psParallelCompact.cpp Fri Dec 12 15:37:46 2008 -0800
@@ -88,6 +88,72 @@
GrowableArray<size_t> * PSParallelCompact::_last_gc_live_oops_size = NULL;
#endif
+void SplitInfo::record(size_t src_region_idx, size_t partial_obj_size,
+ HeapWord* destination)
+{
+ assert(src_region_idx != 0, "invalid src_region_idx");
+ assert(partial_obj_size != 0, "invalid partial_obj_size argument");
+ assert(destination != NULL, "invalid destination argument");
+
+ _src_region_idx = src_region_idx;
+ _partial_obj_size = partial_obj_size;
+ _destination = destination;
+
+ // These fields may not be updated below, so make sure they're clear.
+ assert(_dest_region_addr == NULL, "should have been cleared");
+ assert(_first_src_addr == NULL, "should have been cleared");
+
+ // Determine the number of destination regions for the partial object.
+ HeapWord* const last_word = destination + partial_obj_size - 1;
+ const ParallelCompactData& sd = PSParallelCompact::summary_data();
+ HeapWord* const beg_region_addr = sd.region_align_down(destination);
+ HeapWord* const end_region_addr = sd.region_align_down(last_word);
+
+ if (beg_region_addr == end_region_addr) {
+ // One destination region.
+ _destination_count = 1;
+ if (end_region_addr == destination) {
+ // The destination falls on a region boundary, thus the first word of the
+ // partial object will be the first word copied to the destination region.
+ _dest_region_addr = end_region_addr;
+ _first_src_addr = sd.region_to_addr(src_region_idx);
+ }
+ } else {
+ // Two destination regions. When copied, the partial object will cross a
+ // destination region boundary, so a word somewhere within the partial
+ // object will be the first word copied to the second destination region.
+ _destination_count = 2;
+ _dest_region_addr = end_region_addr;
+ const size_t ofs = pointer_delta(end_region_addr, destination);
+ assert(ofs < _partial_obj_size, "sanity");
+ _first_src_addr = sd.region_to_addr(src_region_idx) + ofs;
+ }
+}
+
+void SplitInfo::clear()
+{
+ _src_region_idx = 0;
+ _partial_obj_size = 0;
+ _destination = NULL;
+ _destination_count = 0;
+ _dest_region_addr = NULL;
+ _first_src_addr = NULL;
+ assert(!is_valid(), "sanity");
+}
+
+#ifdef ASSERT
+void SplitInfo::verify_clear()
+{
+ assert(_src_region_idx == 0, "not clear");
+ assert(_partial_obj_size == 0, "not clear");
+ assert(_destination == NULL, "not clear");
+ assert(_destination_count == 0, "not clear");
+ assert(_dest_region_addr == NULL, "not clear");
+ assert(_first_src_addr == NULL, "not clear");
+}
+#endif // #ifdef ASSERT
+
+
#ifndef PRODUCT
const char* PSParallelCompact::space_names[] = {
"perm", "old ", "eden", "from", "to "
@@ -416,21 +482,134 @@
}
}
-bool ParallelCompactData::summarize(HeapWord* target_beg, HeapWord* target_end,
- HeapWord* source_beg, HeapWord* source_end,
- HeapWord** target_next,
- HeapWord** source_next) {
- // This is too strict.
- // assert(region_offset(source_beg) == 0, "not RegionSize aligned");
+// Find the point at which a space can be split and, if necessary, record the
+// split point.
+//
+// If the current src region (which overflowed the destination space) doesn't
+// have a partial object, the split point is at the beginning of the current src
+// region (an "easy" split, no extra bookkeeping required).
+//
+// If the current src region has a partial object, the split point is in the
+// region where that partial object starts (call it the split_region). If
+// split_region has a partial object, then the split point is just after that
+// partial object (a "hard" split where we have to record the split data and
+// zero the partial_obj_size field). With a "hard" split, we know that the
+// partial_obj ends within split_region because the partial object that caused
+// the overflow starts in split_region. If split_region doesn't have a partial
+// obj, then the split is at the beginning of split_region (another "easy"
+// split).
+HeapWord*
+ParallelCompactData::summarize_split_space(size_t src_region,
+ SplitInfo& split_info,
+ HeapWord* destination,
+ HeapWord* target_end,
+ HeapWord** target_next)
+{
+ assert(destination <= target_end, "sanity");
+ assert(destination + _region_data[src_region].data_size() > target_end,
+ "region should not fit into target space");
+
+ size_t split_region = src_region;
+ HeapWord* split_destination = destination;
+ size_t partial_obj_size = _region_data[src_region].partial_obj_size();
+
+ if (destination + partial_obj_size > target_end) {
+ // The split point is just after the partial object (if any) in the
+ // src_region that contains the start of the object that overflowed the
+ // destination space.
+ //
+ // Find the start of the "overflow" object and set split_region to the
+ // region containing it.
+ HeapWord* const overflow_obj = _region_data[src_region].partial_obj_addr();
+ split_region = addr_to_region_idx(overflow_obj);
+
+ // Clear the source_region field of all destination regions whose first word
+ // came from data after the split point (a non-null source_region field
+ // implies a region must be filled).
+ //
+ // An alternative to the simple loop below: clear during post_compact(),
+ // which uses memcpy instead of individual stores, and is easy to
+ // parallelize. (The downside is that it clears the entire RegionData
+ // object as opposed to just one field.)
+ //
+ // post_compact() would have to clear the summary data up to the highest
+ // address that was written during the summary phase, which would be
+ //
+ // max(top, max(new_top, clear_top))
+ //
+ // where clear_top is a new field in SpaceInfo. Would have to set clear_top
+ // to destination + partial_obj_size, where both have the values passed to
+ // this routine.
+ const RegionData* const sr = region(split_region);
+ const size_t beg_idx =
+ addr_to_region_idx(region_align_up(sr->destination() +
+ sr->partial_obj_size()));
+ const size_t end_idx =
+ addr_to_region_idx(region_align_up(destination + partial_obj_size));
+
+ if (TraceParallelOldGCSummaryPhase) {
+ gclog_or_tty->print_cr("split: clearing source_region field in ["
+ SIZE_FORMAT ", " SIZE_FORMAT ")",
+ beg_idx, end_idx);
+ }
+ for (size_t idx = beg_idx; idx < end_idx; ++idx) {
+ _region_data[idx].set_source_region(0);
+ }
+
+ // Set split_destination and partial_obj_size to reflect the split region.
+ split_destination = sr->destination();
+ partial_obj_size = sr->partial_obj_size();
+ }
+
+ // The split is recorded only if a partial object extends onto the region.
+ if (partial_obj_size != 0) {
+ _region_data[split_region].set_partial_obj_size(0);
+ split_info.record(split_region, partial_obj_size, split_destination);
+ }
+
+ // Setup the continuation addresses.
+ *target_next = split_destination + partial_obj_size;
+ HeapWord* const source_next = region_to_addr(split_region) + partial_obj_size;
if (TraceParallelOldGCSummaryPhase) {
- tty->print_cr("tb=" PTR_FORMAT " te=" PTR_FORMAT " "
- "sb=" PTR_FORMAT " se=" PTR_FORMAT " "
- "tn=" PTR_FORMAT " sn=" PTR_FORMAT,
- target_beg, target_end,
- source_beg, source_end,
- target_next != 0 ? *target_next : (HeapWord*) 0,
- source_next != 0 ? *source_next : (HeapWord*) 0);
+ const char * split_type = partial_obj_size == 0 ? "easy" : "hard";
+ gclog_or_tty->print_cr("%s split: src=" PTR_FORMAT " src_c=" SIZE_FORMAT
+ " pos=" SIZE_FORMAT,
+ split_type, source_next, split_region,
+ partial_obj_size);
+ gclog_or_tty->print_cr("%s split: dst=" PTR_FORMAT " dst_c=" SIZE_FORMAT
+ " tn=" PTR_FORMAT,
+ split_type, split_destination,
+ addr_to_region_idx(split_destination),
+ *target_next);
+
+ if (partial_obj_size != 0) {
+ HeapWord* const po_beg = split_info.destination();
+ HeapWord* const po_end = po_beg + split_info.partial_obj_size();
+ gclog_or_tty->print_cr("%s split: "
+ "po_beg=" PTR_FORMAT " " SIZE_FORMAT " "
+ "po_end=" PTR_FORMAT " " SIZE_FORMAT,
+ split_type,
+ po_beg, addr_to_region_idx(po_beg),
+ po_end, addr_to_region_idx(po_end));
+ }
+ }
+
+ return source_next;
+}
+
+bool ParallelCompactData::summarize(SplitInfo& split_info,
+ HeapWord* source_beg, HeapWord* source_end,
+ HeapWord** source_next,
+ HeapWord* target_beg, HeapWord* target_end,
+ HeapWord** target_next)
+{
+ if (TraceParallelOldGCSummaryPhase) {
+ HeapWord* const source_next_val = source_next == NULL ? NULL : *source_next;
+ tty->print_cr("sb=" PTR_FORMAT " se=" PTR_FORMAT " sn=" PTR_FORMAT
+ "tb=" PTR_FORMAT " te=" PTR_FORMAT " tn=" PTR_FORMAT,
+ source_beg, source_end, source_next_val,
+ target_beg, target_end, *target_next);
}
size_t cur_region = addr_to_region_idx(source_beg);
@@ -438,45 +617,53 @@
HeapWord *dest_addr = target_beg;
while (cur_region < end_region) {
+ // The destination must be set even if the region has no data.
+ _region_data[cur_region].set_destination(dest_addr);
+
size_t words = _region_data[cur_region].data_size();
-
-#if 1
- assert(pointer_delta(target_end, dest_addr) >= words,
- "source region does not fit into target region");
-#else
- // XXX - need some work on the corner cases here. If the region does not
- // fit, then must either make sure any partial_obj from the region fits, or
- // "undo" the initial part of the partial_obj that is in the previous
- // region.
- if (dest_addr + words >= target_end) {
- // Let the caller know where to continue.
- *target_next = dest_addr;
- *source_next = region_to_addr(cur_region);
- return false;
- }
-#endif // #if 1
-
- _region_data[cur_region].set_destination(dest_addr);
-
- // Set the destination_count for cur_region, and if necessary, update
- // source_region for a destination region. The source_region field is
- // updated if cur_region is the first (left-most) region to be copied to a
- // destination region.
- //
- // The destination_count calculation is a bit subtle. A region that has
- // data that compacts into itself does not count itself as a destination.
- // This maintains the invariant that a zero count means the region is
- // available and can be claimed and then filled.
if (words > 0) {
+ // If cur_region does not fit entirely into the target space, find a point
+ // at which the source space can be 'split' so that part is copied to the
+ // target space and the rest is copied elsewhere.
+ if (dest_addr + words > target_end) {
+ assert(source_next != NULL, "source_next is NULL when splitting");
+ *source_next = summarize_split_space(cur_region, split_info, dest_addr,
+ target_end, target_next);
+ return false;
+ }
+
+ // Compute the destination_count for cur_region, and if necessary, update
+ // source_region for a destination region. The source_region field is
+ // updated if cur_region is the first (left-most) region to be copied to a
+ // destination region.
+ //
+ // The destination_count calculation is a bit subtle. A region that has
+ // data that compacts into itself does not count itself as a destination.
+ // This maintains the invariant that a zero count means the region is
+ // available and can be claimed and then filled.
+ uint destination_count = 0;
+ if (split_info.is_split(cur_region)) {
+ // The current region has been split: the partial object will be copied
+ // to one destination space and the remaining data will be copied to
+ // another destination space. Adjust the initial destination_count and,
+ // if necessary, set the source_region field if the partial object will
+ // cross a destination region boundary.
+ destination_count = split_info.destination_count();
+ if (destination_count == 2) {
+ size_t dest_idx = addr_to_region_idx(split_info.dest_region_addr());
+ _region_data[dest_idx].set_source_region(cur_region);
+ }
+ }
+
HeapWord* const last_addr = dest_addr + words - 1;
const size_t dest_region_1 = addr_to_region_idx(dest_addr);
const size_t dest_region_2 = addr_to_region_idx(last_addr);
-#if 0
+
// Initially assume that the destination regions will be the same and
// adjust the value below if necessary. Under this assumption, if
// cur_region == dest_region_2, then cur_region will be compacted
// completely into itself.
- uint destination_count = cur_region == dest_region_2 ? 0 : 1;
+ destination_count += cur_region == dest_region_2 ? 0 : 1;
if (dest_region_1 != dest_region_2) {
// Destination regions differ; adjust destination_count.
destination_count += 1;
@@ -487,25 +674,6 @@
// region.
_region_data[dest_region_1].set_source_region(cur_region);
}
-#else
- // Initially assume that the destination regions will be different and
- // adjust the value below if necessary. Under this assumption, if
- // cur_region == dest_region2, then cur_region will be compacted partially
- // into dest_region_1 and partially into itself.
- uint destination_count = cur_region == dest_region_2 ? 1 : 2;
- if (dest_region_1 != dest_region_2) {
- // Data from cur_region will be copied to the start of dest_region_2.
- _region_data[dest_region_2].set_source_region(cur_region);
- } else {
- // Destination regions are the same; adjust destination_count.
- destination_count -= 1;
- if (region_offset(dest_addr) == 0) {
- // Data from cur_region will be copied to the start of the destination
- // region.
- _region_data[dest_region_1].set_source_region(cur_region);
- }
- }
-#endif // #if 0
_region_data[cur_region].set_destination_count(destination_count);
_region_data[cur_region].set_data_location(region_to_addr(cur_region));
@@ -749,6 +917,13 @@
const size_t end_region =
_summary_data.addr_to_region_idx(_summary_data.region_align_up(max_top));
_summary_data.clear_range(beg_region, end_region);
+
+ // Clear the data used to 'split' regions.
+ SplitInfo& split_info = _space_info[id].split_info();
+ if (split_info.is_valid()) {
+ split_info.clear();
+ }
+ DEBUG_ONLY(split_info.verify_clear();)
}
void PSParallelCompact::pre_compact(PreGCValues* pre_gc_values)
@@ -807,10 +982,11 @@
{
TraceTime tm("post compact", print_phases(), true, gclog_or_tty);
- // Clear the marking bitmap and summary data and update top() in each space.
for (unsigned int id = perm_space_id; id < last_space_id; ++id) {
+ // Clear the marking bitmap, summary data and split info.
clear_data_covering_space(SpaceId(id));
- _space_info[id].space()->set_top(_space_info[id].new_top());
+ // Update top(). Must be done after clearing the bitmap and summary data.
+ _space_info[id].publish_new_top();
}
MutableSpace* const eden_space = _space_info[eden_space_id].space();
@@ -1151,6 +1327,13 @@
PSParallelCompact::compute_dense_prefix(const SpaceId id,
bool maximum_compaction)
{
+ if (ParallelOldGCSplitALot) {
+ if (_space_info[id].dense_prefix() != _space_info[id].space()->bottom()) {
+ // The value was chosen to provoke splitting a young gen space; use it.
+ return _space_info[id].dense_prefix();
+ }
+ }
+
const size_t region_size = ParallelCompactData::RegionSize;
const ParallelCompactData& sd = summary_data();
@@ -1239,14 +1422,169 @@
return sd.region_to_addr(best_cp);
}
+#ifndef PRODUCT
+void
+PSParallelCompact::fill_with_live_objects(SpaceId id, HeapWord* const start,
+ size_t words)
+{
+ if (TraceParallelOldGCSummaryPhase) {
+ tty->print_cr("fill_with_live_objects [" PTR_FORMAT " " PTR_FORMAT ") "
+ SIZE_FORMAT, start, start + words, words);
+ }
+
+ ObjectStartArray* const start_array = _space_info[id].start_array();
+ CollectedHeap::fill_with_objects(start, words);
+ for (HeapWord* p = start; p < start + words; p += oop(p)->size()) {
+ _mark_bitmap.mark_obj(p, words);
+ _summary_data.add_obj(p, words);
+ start_array->allocate_block(p);
+ }
+}
+
+void
+PSParallelCompact::summarize_new_objects(SpaceId id, HeapWord* start)
+{
+ ParallelCompactData& sd = summary_data();
+ MutableSpace* space = _space_info[id].space();
+
+ // Find the source and destination start addresses.
+ HeapWord* const src_addr = sd.region_align_down(start);
+ HeapWord* dst_addr;
+ if (src_addr < start) {
+ dst_addr = sd.addr_to_region_ptr(src_addr)->destination();
+ } else if (src_addr > space->bottom()) {
+ // The start (the original top() value) is aligned to a region boundary so
+ // the associated region does not have a destination. Compute the
+ // destination from the previous region.
+ RegionData* const cp = sd.addr_to_region_ptr(src_addr) - 1;
+ dst_addr = cp->destination() + cp->data_size();
+ } else {
+ // Filling the entire space.
+ dst_addr = space->bottom();
+ }
+ assert(dst_addr != NULL, "sanity");
+
+ // Update the summary data.
+ bool result = _summary_data.summarize(_space_info[id].split_info(),
+ src_addr, space->top(), NULL,
+ dst_addr, space->end(),
+ _space_info[id].new_top_addr());
+ assert(result, "should not fail: bad filler object size");
+}
+
+void
+PSParallelCompact::provoke_split(bool & max_compaction)
+{
+ const size_t region_size = ParallelCompactData::RegionSize;
+ ParallelCompactData& sd = summary_data();
+
+ MutableSpace* const eden_space = _space_info[eden_space_id].space();
+ MutableSpace* const from_space = _space_info[from_space_id].space();
+ const size_t eden_live = pointer_delta(eden_space->top(),
+ _space_info[eden_space_id].new_top());
+ const size_t from_live = pointer_delta(from_space->top(),
+ _space_info[from_space_id].new_top());
+
+ const size_t min_fill_size = CollectedHeap::min_fill_size();
+ const size_t eden_free = pointer_delta(eden_space->end(), eden_space->top());
+ const size_t eden_fillable = eden_free >= min_fill_size ? eden_free : 0;
+ const size_t from_free = pointer_delta(from_space->end(), from_space->top());
+ const size_t from_fillable = from_free >= min_fill_size ? from_free : 0;
+
+ // Choose the space to split; need at least 2 regions live (or fillable).
+ SpaceId id;
+ MutableSpace* space;
+ size_t live_words;
+ size_t fill_words;
+ if (eden_live + eden_fillable >= region_size * 2) {
+ id = eden_space_id;
+ space = eden_space;
+ live_words = eden_live;
+ fill_words = eden_fillable;
+ } else if (from_live + from_fillable >= region_size * 2) {
+ id = from_space_id;
+ space = from_space;
+ live_words = from_live;
+ fill_words = from_fillable;
+ } else {
+ return; // Give up.
+ }
+ assert(fill_words == 0 || fill_words >= min_fill_size, "sanity");
+
+ if (live_words < region_size * 2) {
+ // Fill from top() to end() w/live objects of mixed sizes.
+ HeapWord* const fill_start = space->top();
+ live_words += fill_words;
+
+ space->set_top(fill_start + fill_words);
+ if (ZapUnusedHeapArea) {
+ space->set_top_for_allocations();
+ }
+
+ HeapWord* cur_addr = fill_start;
+ while (fill_words > 0) {
+ const size_t r = (size_t)os::random() % (region_size / 2) + min_fill_size;
+ size_t cur_size = MIN2(align_object_size_(r), fill_words);
+ if (fill_words - cur_size < min_fill_size) {
+ cur_size = fill_words; // Avoid leaving a fragment too small to fill.
+ }
+
+ CollectedHeap::fill_with_object(cur_addr, cur_size);
+ mark_bitmap()->mark_obj(cur_addr, cur_size);
+ sd.add_obj(cur_addr, cur_size);
+
+ cur_addr += cur_size;
+ fill_words -= cur_size;
+ }
+
+ summarize_new_objects(id, fill_start);
+ }
+
+ max_compaction = false;
+
+ // Manipulate the old gen so that it has room for about half of the live data
+ // in the target young gen space (live_words / 2).
+ id = old_space_id;
+ space = _space_info[id].space();
+ const size_t free_at_end = space->free_in_words();
+ const size_t free_target = align_object_size(live_words / 2);
+ const size_t dead = pointer_delta(space->top(), _space_info[id].new_top());
+
+ if (free_at_end >= free_target + min_fill_size) {
+ // Fill space above top() and set the dense prefix so everything survives.
+ HeapWord* const fill_start = space->top();
+ const size_t fill_size = free_at_end - free_target;
+ space->set_top(space->top() + fill_size);
+ if (ZapUnusedHeapArea) {
+ space->set_top_for_allocations();
+ }
+ fill_with_live_objects(id, fill_start, fill_size);
+ summarize_new_objects(id, fill_start);
+ _space_info[id].set_dense_prefix(sd.region_align_down(space->top()));
+ } else if (dead + free_at_end > free_target) {
+ // Find a dense prefix that makes the right amount of space available.
+ HeapWord* cur = sd.region_align_down(space->top());
+ HeapWord* cur_destination = sd.addr_to_region_ptr(cur)->destination();
+ size_t dead_to_right = pointer_delta(space->end(), cur_destination);
+ while (dead_to_right < free_target) {
+ cur -= region_size;
+ cur_destination = sd.addr_to_region_ptr(cur)->destination();
+ dead_to_right = pointer_delta(space->end(), cur_destination);
+ }
+ _space_info[id].set_dense_prefix(cur);
+ }
+}
+#endif // #ifndef PRODUCT
+
void PSParallelCompact::summarize_spaces_quick()
{
for (unsigned int i = 0; i < last_space_id; ++i) {
const MutableSpace* space = _space_info[i].space();
- bool result = _summary_data.summarize(space->bottom(), space->end(),
- space->bottom(), space->top(),
- _space_info[i].new_top_addr());
- assert(result, "should never fail");
+ HeapWord** nta = _space_info[i].new_top_addr();
+ bool result = _summary_data.summarize(_space_info[i].split_info(),
+ space->bottom(), space->top(), NULL,
+ space->bottom(), space->end(), nta);
+ assert(result, "space must fit into itself");
_space_info[i].set_dense_prefix(space->bottom());
}
}
@@ -1308,8 +1646,7 @@
}
#endif // #ifdef _LP64
- MemRegion region(obj_beg, obj_len);
- SharedHeap::fill_region_with_object(region);
+ CollectedHeap::fill_with_object(obj_beg, obj_len);
_mark_bitmap.mark_obj(obj_beg, obj_len);
_summary_data.add_obj(obj_beg, obj_len);
assert(start_array(id) != NULL, "sanity");
@@ -1318,11 +1655,23 @@
}
void
+PSParallelCompact::clear_source_region(HeapWord* beg_addr, HeapWord* end_addr)
+{
+ RegionData* const beg_ptr = _summary_data.addr_to_region_ptr(beg_addr);
+ HeapWord* const end_aligned_up = _summary_data.region_align_up(end_addr);
+ RegionData* const end_ptr = _summary_data.addr_to_region_ptr(end_aligned_up);
+ for (RegionData* cur = beg_ptr; cur < end_ptr; ++cur) {
+ cur->set_source_region(0);
+ }
+}
+
+void
PSParallelCompact::summarize_space(SpaceId id, bool maximum_compaction)
{
assert(id < last_space_id, "id out of range");
- assert(_space_info[id].dense_prefix() == _space_info[id].space()->bottom(),
- "should have been set in summarize_spaces_quick()");
+ assert(_space_info[id].dense_prefix() == _space_info[id].space()->bottom() ||
+ ParallelOldGCSplitALot && id == old_space_id,
+ "should have been reset in summarize_spaces_quick()");
const MutableSpace* space = _space_info[id].space();
if (_space_info[id].new_top() != space->bottom()) {
@@ -1338,20 +1687,24 @@
}
#endif // #ifndef PRODUCT
- // If dead space crosses the dense prefix boundary, it is (at least
- // partially) filled with a dummy object, marked live and added to the
- // summary data. This simplifies the copy/update phase and must be done
- // before the final locations of objects are determined, to prevent leaving
- // a fragment of dead space that is too small to fill with an object.
+ // Recompute the summary data, taking into account the dense prefix. If
+ // every last byte will be reclaimed, then the existing summary data which
+ // compacts everything can be left in place.
if (!maximum_compaction && dense_prefix_end != space->bottom()) {
+ // If dead space crosses the dense prefix boundary, it is (at least
+ // partially) filled with a dummy object, marked live and added to the
+ // summary data. This simplifies the copy/update phase and must be done
+ // before the final locations of objects are determined, to prevent
+ // leaving a fragment of dead space that is too small to fill.
fill_dense_prefix_end(id);
+
+ // Compute the destination of each Region, and thus each object.
+ _summary_data.summarize_dense_prefix(space->bottom(), dense_prefix_end);
+ _summary_data.summarize(_space_info[id].split_info(),
+ dense_prefix_end, space->top(), NULL,
+ dense_prefix_end, space->end(),
+ _space_info[id].new_top_addr());
}
-
- // Compute the destination of each Region, and thus each object.
- _summary_data.summarize_dense_prefix(space->bottom(), dense_prefix_end);
- _summary_data.summarize(dense_prefix_end, space->end(),
- dense_prefix_end, space->top(),
- _space_info[id].new_top_addr());
}
if (TraceParallelOldGCSummaryPhase) {
@@ -1371,6 +1724,30 @@
}
}
+#ifndef PRODUCT
+void PSParallelCompact::summary_phase_msg(SpaceId dst_space_id,
+ HeapWord* dst_beg, HeapWord* dst_end,
+ SpaceId src_space_id,
+ HeapWord* src_beg, HeapWord* src_end)
+{
+ if (TraceParallelOldGCSummaryPhase) {
+ tty->print_cr("summarizing %d [%s] into %d [%s]: "
+ "src=" PTR_FORMAT "-" PTR_FORMAT " "
+ SIZE_FORMAT "-" SIZE_FORMAT " "
+ "dst=" PTR_FORMAT "-" PTR_FORMAT " "
+ SIZE_FORMAT "-" SIZE_FORMAT,
+ src_space_id, space_names[src_space_id],
+ dst_space_id, space_names[dst_space_id],
+ src_beg, src_end,
+ _summary_data.addr_to_region_idx(src_beg),
+ _summary_data.addr_to_region_idx(src_end),
+ dst_beg, dst_end,
+ _summary_data.addr_to_region_idx(dst_beg),
+ _summary_data.addr_to_region_idx(dst_end));
+ }
+}
+#endif // #ifndef PRODUCT
+
void PSParallelCompact::summary_phase(ParCompactionManager* cm,
bool maximum_compaction)
{
@@ -1403,57 +1780,98 @@
// The amount of live data that will end up in old space (assuming it fits).
size_t old_space_total_live = 0;
- unsigned int id;
- for (id = old_space_id; id < last_space_id; ++id) {
+ assert(perm_space_id < old_space_id, "should not count perm data here");
+ for (unsigned int id = old_space_id; id < last_space_id; ++id) {
old_space_total_live += pointer_delta(_space_info[id].new_top(),
_space_info[id].space()->bottom());
}
- const MutableSpace* old_space = _space_info[old_space_id].space();
- if (old_space_total_live > old_space->capacity_in_words()) {
+ MutableSpace* const old_space = _space_info[old_space_id].space();
+ const size_t old_capacity = old_space->capacity_in_words();
+ if (old_space_total_live > old_capacity) {
// XXX - should also try to expand
maximum_compaction = true;
- } else if (!UseParallelOldGCDensePrefix) {
- maximum_compaction = true;
}
+#ifndef PRODUCT
+ if (ParallelOldGCSplitALot && old_space_total_live < old_capacity) {
+ if (total_invocations() % ParallelOldGCSplitInterval == 0) {
+ provoke_split(maximum_compaction);
+ }
+ }
+#endif // #ifndef PRODUCT
// Permanent and Old generations.
summarize_space(perm_space_id, maximum_compaction);
summarize_space(old_space_id, maximum_compaction);
- // Summarize the remaining spaces (those in the young gen) into old space. If
- // the live data from a space doesn't fit, the existing summarization is left
- // intact, so the data is compacted down within the space itself.
- HeapWord** new_top_addr = _space_info[old_space_id].new_top_addr();
- HeapWord* const target_space_end = old_space->end();
- for (id = eden_space_id; id < last_space_id; ++id) {
+ // Summarize the remaining spaces in the young gen. The initial target space
+ // is the old gen. If a space does not fit entirely into the target, then the
+ // remainder is compacted into the space itself and that space becomes the new
+ // target.
+ SpaceId dst_space_id = old_space_id;
+ HeapWord* dst_space_end = old_space->end();
+ HeapWord** new_top_addr = _space_info[dst_space_id].new_top_addr();
+ for (unsigned int id = eden_space_id; id < last_space_id; ++id) {
const MutableSpace* space = _space_info[id].space();
const size_t live = pointer_delta(_space_info[id].new_top(),
space->bottom());
- const size_t available = pointer_delta(target_space_end, *new_top_addr);
+ const size_t available = pointer_delta(dst_space_end, *new_top_addr);
+
+ NOT_PRODUCT(summary_phase_msg(dst_space_id, *new_top_addr, dst_space_end,
+ SpaceId(id), space->bottom(), space->top());)
if (live > 0 && live <= available) {
// All the live data will fit.
- if (TraceParallelOldGCSummaryPhase) {
- tty->print_cr("summarizing %d into old_space @ " PTR_FORMAT,
- id, *new_top_addr);
- }
- _summary_data.summarize(*new_top_addr, target_space_end,
- space->bottom(), space->top(),
- new_top_addr);
-
+ bool done = _summary_data.summarize(_space_info[id].split_info(),
+ space->bottom(), space->top(),
+ NULL,
+ *new_top_addr, dst_space_end,
+ new_top_addr);
+ assert(done, "space must fit into old gen");
+
+ // XXX - this is necessary because decrement_destination_counts() tests
+ // source_region() to determine if a region will be filled. Probably
+ // better to pass src_space->new_top() into decrement_destination_counts
+ // and test that instead.
+ //
// Clear the source_region field for each region in the space.
- HeapWord* const new_top = _space_info[id].new_top();
- HeapWord* const clear_end = _summary_data.region_align_up(new_top);
- RegionData* beg_region =
- _summary_data.addr_to_region_ptr(space->bottom());
- RegionData* end_region = _summary_data.addr_to_region_ptr(clear_end);
- while (beg_region < end_region) {
- beg_region->set_source_region(0);
- ++beg_region;
- }
+ clear_source_region(space->bottom(), _space_info[id].new_top());
// Reset the new_top value for the space.
_space_info[id].set_new_top(space->bottom());
+ } else if (live > 0) {
+ // Attempt to fit part of the source space into the target space.
+ HeapWord* next_src_addr = NULL;
+ bool done = _summary_data.summarize(_space_info[id].split_info(),
+ space->bottom(), space->top(),
+ &next_src_addr,
+ *new_top_addr, dst_space_end,
+ new_top_addr);
+ assert(!done, "space should not fit into old gen");
+ assert(next_src_addr != NULL, "sanity");
+
+ // The source space becomes the new target, so the remainder is compacted
+ // within the space itself.
+ dst_space_id = SpaceId(id);
+ dst_space_end = space->end();
+ new_top_addr = _space_info[id].new_top_addr();
+ HeapWord* const clear_end = _space_info[id].new_top();
+ NOT_PRODUCT(summary_phase_msg(dst_space_id,
+ space->bottom(), dst_space_end,
+ SpaceId(id), next_src_addr, space->top());)
+ done = _summary_data.summarize(_space_info[id].split_info(),
+ next_src_addr, space->top(),
+ NULL,
+ space->bottom(), dst_space_end,
+ new_top_addr);
+ assert(done, "space must fit when compacted into itself");
+ assert(*new_top_addr <= space->top(), "usage should not grow");
+
+ // XXX - this should go away. See comments above.
+ //
+ // Clear the source_region field in regions at the end of the space that
+ // will not be filled.
+ HeapWord* const clear_beg = _summary_data.region_align_up(*new_top_addr);
+ clear_source_region(clear_beg, clear_end);
}
}
@@ -1807,9 +2225,14 @@
// Fill the unused part of the old gen.
MutableSpace* const old_space = old_gen->object_space();
- MemRegion old_gen_unused(old_space->top(), old_space->end());
- if (!old_gen_unused.is_empty()) {
- SharedHeap::fill_region_with_object(old_gen_unused);
+ HeapWord* const unused_start = old_space->top();
+ size_t const unused_words = pointer_delta(old_space->end(), unused_start);
+
+ if (unused_words > 0) {
+ if (unused_words < CollectedHeap::min_fill_size()) {
+ return false; // If the old gen cannot be filled, must give up.
+ }
+ CollectedHeap::fill_with_objects(unused_start, unused_words);
}
// Take the live data from eden and set both top and end in the old gen to
@@ -1825,9 +2248,8 @@
// Update the object start array for the filler object and the data from eden.
ObjectStartArray* const start_array = old_gen->start_array();
- HeapWord* const start = old_gen_unused.start();
- for (HeapWord* addr = start; addr < new_top; addr += oop(addr)->size()) {
- start_array->allocate_block(addr);
+ for (HeapWord* p = unused_start; p < new_top; p += oop(p)->size()) {
+ start_array->allocate_block(p);
}
// Could update the promoted average here, but it is not typically updated at
@@ -2048,14 +2470,13 @@
// regions in the dense prefix. Assume that 1 gc thread
// will work on opening the gaps and the remaining gc threads
// will work on the dense prefix.
- SpaceId space_id = old_space_id;
- while (space_id != last_space_id) {
+ unsigned int space_id;
+ for (space_id = old_space_id; space_id < last_space_id; ++ space_id) {
HeapWord* const dense_prefix_end = _space_info[space_id].dense_prefix();
const MutableSpace* const space = _space_info[space_id].space();
if (dense_prefix_end == space->bottom()) {
// There is no dense prefix for this space.
- space_id = next_compaction_space_id(space_id);
continue;
}
@@ -2105,23 +2526,20 @@
// region_index_end is not processed
size_t region_index_end = MIN2(region_index_start + regions_per_thread,
region_index_end_dense_prefix);
- q->enqueue(new UpdateDensePrefixTask(
- space_id,
- region_index_start,
- region_index_end));
+ q->enqueue(new UpdateDensePrefixTask(SpaceId(space_id),
+ region_index_start,
+ region_index_end));
region_index_start = region_index_end;
}
}
// This gets any part of the dense prefix that did not
// fit evenly.
if (region_index_start < region_index_end_dense_prefix) {
- q->enqueue(new UpdateDensePrefixTask(
- space_id,
- region_index_start,
- region_index_end_dense_prefix));
+ q->enqueue(new UpdateDensePrefixTask(SpaceId(space_id),
+ region_index_start,
+ region_index_end_dense_prefix));
}
- space_id = next_compaction_space_id(space_id);
- } // End tasks for dense prefix
+ }
}
void PSParallelCompact::enqueue_region_stealing_tasks(
@@ -2567,16 +2985,24 @@
return m->bit_to_addr(cur_beg);
}
-HeapWord*
-PSParallelCompact::first_src_addr(HeapWord* const dest_addr,
- size_t src_region_idx)
+HeapWord* PSParallelCompact::first_src_addr(HeapWord* const dest_addr,
+ SpaceId src_space_id,
+ size_t src_region_idx)
{
+ assert(summary_data().is_region_aligned(dest_addr), "not aligned");
+
+ const SplitInfo& split_info = _space_info[src_space_id].split_info();
+ if (split_info.dest_region_addr() == dest_addr) {
+ // The partial object ending at the split point contains the first word to
+ // be copied to dest_addr.
+ return split_info.first_src_addr();
+ }
+
+ const ParallelCompactData& sd = summary_data();
ParMarkBitMap* const bitmap = mark_bitmap();
- const ParallelCompactData& sd = summary_data();
const size_t RegionSize = ParallelCompactData::RegionSize;
assert(sd.is_region_aligned(dest_addr), "not aligned");
-
const RegionData* const src_region_ptr = sd.region(src_region_idx);
const size_t partial_obj_size = src_region_ptr->partial_obj_size();
HeapWord* const src_region_destination = src_region_ptr->destination();
@@ -2737,7 +3163,7 @@
HeapWord* src_space_top = _space_info[src_space_id].space()->top();
MoveAndUpdateClosure closure(bitmap, cm, start_array, dest_addr, words);
- closure.set_source(first_src_addr(dest_addr, src_region_idx));
+ closure.set_source(first_src_addr(dest_addr, src_space_id, src_region_idx));
// Adjust src_region_idx to prepare for decrementing destination counts (the
// destination count is not decremented when a region is copied to itself).
@@ -3008,34 +3434,3 @@
summary_data().calc_new_pointer(Universe::intArrayKlassObj());
}
-// The initial implementation of this method created a field
-// _next_compaction_space_id in SpaceInfo and initialized
-// that field in SpaceInfo::initialize_space_info(). That
-// required that _next_compaction_space_id be declared a
-// SpaceId in SpaceInfo and that would have required that
-// either SpaceId be declared in a separate class or that
-// it be declared in SpaceInfo. It didn't seem consistent
-// to declare it in SpaceInfo (didn't really fit logically).
-// Alternatively, defining a separate class to define SpaceId
-// seem excessive. This implementation is simple and localizes
-// the knowledge.
-
-PSParallelCompact::SpaceId
-PSParallelCompact::next_compaction_space_id(SpaceId id) {
- assert(id < last_space_id, "id out of range");
- switch (id) {
- case perm_space_id :
- return last_space_id;
- case old_space_id :
- return eden_space_id;
- case eden_space_id :
- return from_space_id;
- case from_space_id :
- return to_space_id;
- case to_space_id :
- return last_space_id;
- default:
- assert(false, "Bad space id");
- return last_space_id;
- }
-}
--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/psParallelCompact.hpp Fri Dec 12 10:19:39 2008 -0800
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/psParallelCompact.hpp Fri Dec 12 15:37:46 2008 -0800
@@ -36,6 +36,123 @@
class MoveAndUpdateClosure;
class RefProcTaskExecutor;
+// The SplitInfo class holds the information needed to 'split' a source region
+// so that the live data can be copied to two destination *spaces*. Normally,
+// all the live data in a region is copied to a single destination space (e.g.,
+// everything live in a region in eden is copied entirely into the old gen).
+// However, when the heap is nearly full, all the live data in eden may not fit
+// into the old gen. Copying only some of the regions from eden to old gen
+// requires finding a region that does not contain a partial object (i.e., no
+// live object crosses the region boundary) somewhere near the last object that
+// does fit into the old gen. Since it's not always possible to find such a
+// region, splitting is necessary for predictable behavior.
+//
+// A region is always split at the end of the partial object. This avoids
+// additional tests when calculating the new location of a pointer, which is a
+// very hot code path. The partial object and everything to its left will be
+// copied to another space (call it dest_space_1). The live data to the right
+// of the partial object will be copied either within the space itself, or to a
+// different destination space (distinct from dest_space_1).
+//
+// Split points are identified during the summary phase, when region
+// destinations are computed: data about the split, including the
+// partial_object_size, is recorded in a SplitInfo record and the
+// partial_object_size field in the summary data is set to zero. The zeroing is
+// possible (and necessary) since the partial object will move to a different
+// destination space than anything to its right, thus the partial object should
+// not affect the locations of any objects to its right.
+//
+// The recorded data is used during the compaction phase, but only rarely: when
+// the partial object on the split region will be copied across a destination
+// region boundary. This test is made once each time a region is filled, and is
+// a simple address comparison, so the overhead is negligible (see
+// PSParallelCompact::first_src_addr()).
+//
+// Notes:
+//
+// Only regions with partial objects are split; a region without a partial
+// object does not need any extra bookkeeping.
+//
+// At most one region is split per space, so the amount of data required is
+// constant.
+//
+// A region is split only when the destination space would overflow. Once that
+// happens, the destination space is abandoned and no other data (even from
+// other source spaces) is targeted to that destination space. Abandoning the
+// destination space may leave a somewhat large unused area at the end, if a
+// large object caused the overflow.
+//
+// Future work:
+//
+// More bookkeeping would be required to continue to use the destination space.
+// The most general solution would allow data from regions in two different
+// source spaces to be "joined" in a single destination region. At the very
+// least, additional code would be required in next_src_region() to detect the
+// join and skip to an out-of-order source region. If the join region was also
+// the last destination region to which a split region was copied (the most
+// likely case), then additional work would be needed to get fill_region() to
+// stop iteration and switch to a new source region at the right point. Basic
+// idea would be to use a fake value for the top of the source space. It is
+// doable, if a bit tricky.
+//
+// A simpler (but less general) solution would fill the remainder of the
+// destination region with a dummy object and continue filling the next
+// destination region.
+
+class SplitInfo
+{
+public:
+ // Return true if this split info is valid (i.e., if a split has been
+ // recorded). The very first region cannot have a partial object and thus is
+ // never split, so 0 is the 'invalid' value.
+ bool is_valid() const { return _src_region_idx > 0; }
+
+ // Return true if this split holds data for the specified source region.
+ inline bool is_split(size_t source_region) const;
+
+ // The index of the split region, the size of the partial object on that
+ // region and the destination of the partial object.
+ size_t src_region_idx() const { return _src_region_idx; }
+ size_t partial_obj_size() const { return _partial_obj_size; }
+ HeapWord* destination() const { return _destination; }
+
+ // The destination count of the partial object referenced by this split
+ // (either 1 or 2). This must be added to the destination count of the
+ // remainder of the source region.
+ unsigned int destination_count() const { return _destination_count; }
+
+ // If a word within the partial object will be written to the first word of a
+ // destination region, this is the address of the destination region;
+ // otherwise this is NULL.
+ HeapWord* dest_region_addr() const { return _dest_region_addr; }
+
+ // If a word within the partial object will be written to the first word of a
+ // destination region, this is the address of that word within the partial
+ // object; otherwise this is NULL.
+ HeapWord* first_src_addr() const { return _first_src_addr; }
+
+ // Record the data necessary to split the region src_region_idx.
+ void record(size_t src_region_idx, size_t partial_obj_size,
+ HeapWord* destination);
+
+ void clear();
+
+ DEBUG_ONLY(void verify_clear();)
+
+private:
+ size_t _src_region_idx;
+ size_t _partial_obj_size;
+ HeapWord* _destination;
+ unsigned int _destination_count;
+ HeapWord* _dest_region_addr;
+ HeapWord* _first_src_addr;
+};
+
+inline bool SplitInfo::is_split(size_t region_idx) const
+{
+ return _src_region_idx == region_idx && is_valid();
+}
+
class SpaceInfo
{
public:
@@ -58,18 +175,23 @@
// is no start array.
ObjectStartArray* start_array() const { return _start_array; }
+ SplitInfo& split_info() { return _split_info; }
+
void set_space(MutableSpace* s) { _space = s; }
void set_new_top(HeapWord* addr) { _new_top = addr; }
void set_min_dense_prefix(HeapWord* addr) { _min_dense_prefix = addr; }
void set_dense_prefix(HeapWord* addr) { _dense_prefix = addr; }
void set_start_array(ObjectStartArray* s) { _start_array = s; }
+ void publish_new_top() const { _space->set_top(_new_top); }
+
private:
MutableSpace* _space;
HeapWord* _new_top;
HeapWord* _min_dense_prefix;
HeapWord* _dense_prefix;
ObjectStartArray* _start_array;
+ SplitInfo _split_info;
};
class ParallelCompactData
@@ -230,9 +352,14 @@
// must be region-aligned; end need not be.
void summarize_dense_prefix(HeapWord* beg, HeapWord* end);
- bool summarize(HeapWord* target_beg, HeapWord* target_end,
+ HeapWord* summarize_split_space(size_t src_region, SplitInfo& split_info,
+ HeapWord* destination, HeapWord* target_end,
+ HeapWord** target_next);
+ bool summarize(SplitInfo& split_info,
HeapWord* source_beg, HeapWord* source_end,
- HeapWord** target_next, HeapWord** source_next = 0);
+ HeapWord** source_next,
+ HeapWord* target_beg, HeapWord* target_end,
+ HeapWord** target_next);
void clear();
void clear_range(size_t beg_region, size_t end_region);
@@ -838,13 +965,27 @@
// non-empty.
static void fill_dense_prefix_end(SpaceId id);
+ // Clear the summary data source_region field for the specified addresses.
+ static void clear_source_region(HeapWord* beg_addr, HeapWord* end_addr);
+
+#ifndef PRODUCT
+ // Routines to provoke splitting a young gen space (ParallelOldGCSplitALot).
+
+ // Fill the region [start, start + words) with live object(s). Only usable
+ // for the old and permanent generations.
+ static void fill_with_live_objects(SpaceId id, HeapWord* const start,
+ size_t words);
+ // Include the new objects in the summary data.
+ static void summarize_new_objects(SpaceId id, HeapWord* start);
+
+ // Add live objects and/or choose the dense prefix to provoke splitting.
+ static void provoke_split(bool & maximum_compaction);
+#endif
+
static void summarize_spaces_quick();
static void summarize_space(SpaceId id, bool maximum_compaction);
static void summary_phase(ParCompactionManager* cm, bool maximum_compaction);
- // The space that is compacted after space_id.
- static SpaceId next_compaction_space_id(SpaceId space_id);
-
// Adjust addresses in roots. Does not adjust addresses in heap.
static void adjust_roots();
@@ -999,6 +1140,7 @@
// Return the address of the word to be copied to dest_addr, which must be
// aligned to a region boundary.
static HeapWord* first_src_addr(HeapWord* const dest_addr,
+ SpaceId src_space_id,
size_t src_region_idx);
// Determine the next source region, set closure.source() to the start of the
@@ -1081,6 +1223,10 @@
const SpaceId id,
const bool maximum_compaction,
HeapWord* const addr);
+ static void summary_phase_msg(SpaceId dst_space_id,
+ HeapWord* dst_beg, HeapWord* dst_end,
+ SpaceId src_space_id,
+ HeapWord* src_beg, HeapWord* src_end);
#endif // #ifndef PRODUCT
#ifdef ASSERT
@@ -1324,31 +1470,28 @@
oop(addr)->update_contents(compaction_manager());
}
-class FillClosure: public ParMarkBitMapClosure {
- public:
+class FillClosure: public ParMarkBitMapClosure
+{
+public:
FillClosure(ParCompactionManager* cm, PSParallelCompact::SpaceId space_id) :
ParMarkBitMapClosure(PSParallelCompact::mark_bitmap(), cm),
- _space_id(space_id),
- _start_array(PSParallelCompact::start_array(space_id)) {
- assert(_space_id == PSParallelCompact::perm_space_id ||
- _space_id == PSParallelCompact::old_space_id,
+ _start_array(PSParallelCompact::start_array(space_id))
+ {
+ assert(space_id == PSParallelCompact::perm_space_id ||
+ space_id == PSParallelCompact::old_space_id,
"cannot use FillClosure in the young gen");
- assert(bitmap() != NULL, "need a bitmap");
- assert(_start_array != NULL, "need a start array");
- }
-
- void fill_region(HeapWord* addr, size_t size) {
- MemRegion region(addr, size);
- SharedHeap::fill_region_with_object(region);
- _start_array->allocate_block(addr);
}
virtual IterationStatus do_addr(HeapWord* addr, size_t size) {
- fill_region(addr, size);
+ CollectedHeap::fill_with_objects(addr, size);
+ HeapWord* const end = addr + size;
+ do {
+ _start_array->allocate_block(addr);
+ addr += oop(addr)->size();
+ } while (addr < end);
return ParMarkBitMap::incomplete;
}
private:
- const PSParallelCompact::SpaceId _space_id;
- ObjectStartArray* const _start_array;
+ ObjectStartArray* const _start_array;
};
--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.cpp Fri Dec 12 10:19:39 2008 -0800
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.cpp Fri Dec 12 15:37:46 2008 -0800
@@ -499,26 +499,15 @@
// We lost, someone else "owns" this object
guarantee(o->is_forwarded(), "Object must be forwarded if the cas failed.");
- // Unallocate the space used. NOTE! We may have directly allocated
- // the object. If so, we cannot deallocate it, so we have to test!
+ // 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(new_obj)) {
- // The promotion lab failed to unallocate the object.
- // We need to overwrite the object with a filler that
- // contains no interior pointers.
- MemRegion mr((HeapWord*)new_obj, new_obj_size);
- // Clean this up and move to oopFactory (see bug 4718422)
- SharedHeap::fill_region_with_object(mr);
+ CollectedHeap::fill_with_object((HeapWord*) new_obj, new_obj_size);
}
- } else {
- if (!_young_lab.unallocate_object(new_obj)) {
- // The promotion lab failed to unallocate the object.
- // We need to overwrite the object with a filler that
- // contains no interior pointers.
- MemRegion mr((HeapWord*)new_obj, new_obj_size);
- // Clean this up and move to oopFactory (see bug 4718422)
- SharedHeap::fill_region_with_object(mr);
- }
+ } else if (!_young_lab.unallocate_object(new_obj)) {
+ CollectedHeap::fill_with_object((HeapWord*) new_obj, new_obj_size);
}
// don't update this before the unallocation!
--- a/hotspot/src/share/vm/gc_implementation/shared/mutableNUMASpace.cpp Fri Dec 12 10:19:39 2008 -0800
+++ b/hotspot/src/share/vm/gc_implementation/shared/mutableNUMASpace.cpp Fri Dec 12 15:37:46 2008 -0800
@@ -76,8 +76,8 @@
MutableSpace *s = ls->space();
if (s->top() < top()) { // For all spaces preceeding the one containing top()
if (s->free_in_words() > 0) {
- SharedHeap::fill_region_with_object(MemRegion(s->top(), s->end()));
size_t area_touched_words = pointer_delta(s->end(), s->top());
+ CollectedHeap::fill_with_object(s->top(), area_touched_words);
#ifndef ASSERT
if (!ZapUnusedHeapArea) {
area_touched_words = MIN2((size_t)align_object_size(typeArrayOopDesc::header_size(T_INT)),
@@ -686,11 +686,11 @@
// a minimal object; assuming that's not the last chunk in which case we don't care.
if (i < lgrp_spaces()->length() - 1) {
size_t remainder = pointer_delta(s->end(), value);
- const size_t minimal_object_size = oopDesc::header_size();
- if (remainder < minimal_object_size && remainder > 0) {
- // Add a filler object of a minimal size, it will cross the chunk boundary.
- SharedHeap::fill_region_with_object(MemRegion(value, minimal_object_size));
- value += minimal_object_size;
+ const size_t min_fill_size = CollectedHeap::min_fill_size();
+ if (remainder < min_fill_size && remainder > 0) {
+ // Add a minimum size filler object; it will cross the chunk boundary.
+ CollectedHeap::fill_with_object(value, min_fill_size);
+ value += min_fill_size;
assert(!s->contains(value), "Should be in the next chunk");
// Restart the loop from the same chunk, since the value has moved
// to the next one.
--- a/hotspot/src/share/vm/gc_interface/collectedHeap.cpp Fri Dec 12 10:19:39 2008 -0800
+++ b/hotspot/src/share/vm/gc_interface/collectedHeap.cpp Fri Dec 12 15:37:46 2008 -0800
@@ -30,12 +30,21 @@
int CollectedHeap::_fire_out_of_memory_count = 0;
#endif
+size_t CollectedHeap::_filler_array_max_size = 0;
+
// Memory state functions.
-CollectedHeap::CollectedHeap() :
- _reserved(), _barrier_set(NULL), _is_gc_active(false),
- _total_collections(0), _total_full_collections(0),
- _gc_cause(GCCause::_no_gc), _gc_lastcause(GCCause::_no_gc) {
+CollectedHeap::CollectedHeap()
+{
+ const size_t max_len = size_t(arrayOopDesc::max_array_length(T_INT));
+ const size_t elements_per_word = HeapWordSize / sizeof(jint);
+ _filler_array_max_size = align_object_size(filler_array_hdr_size() +
+ max_len * elements_per_word);
+
+ _barrier_set = NULL;
+ _is_gc_active = false;
+ _total_collections = _total_full_collections = 0;
+ _gc_cause = _gc_lastcause = GCCause::_no_gc;
NOT_PRODUCT(_promotion_failure_alot_count = 0;)
NOT_PRODUCT(_promotion_failure_alot_gc_number = 0;)
@@ -128,6 +137,95 @@
return obj;
}
+size_t CollectedHeap::filler_array_hdr_size() {
+ return size_t(arrayOopDesc::header_size(T_INT));
+}
+
+size_t CollectedHeap::filler_array_min_size() {
+ return align_object_size(filler_array_hdr_size());
+}
+
+size_t CollectedHeap::filler_array_max_size() {
+ return _filler_array_max_size;
+}
+
+#ifdef ASSERT
+void CollectedHeap::fill_args_check(HeapWord* start, size_t words)
+{
+ assert(words >= min_fill_size(), "too small to fill");
+ assert(words % MinObjAlignment == 0, "unaligned size");
+ assert(Universe::heap()->is_in_reserved(start), "not in heap");
+ assert(Universe::heap()->is_in_reserved(start + words - 1), "not in heap");
+}
+
+void CollectedHeap::zap_filler_array(HeapWord* start, size_t words)
+{
+ if (ZapFillerObjects) {
+ Copy::fill_to_words(start + filler_array_hdr_size(),
+ words - filler_array_hdr_size(), 0XDEAFBABE);
+ }
+}
+#endif // ASSERT
+
+void
+CollectedHeap::fill_with_array(HeapWord* start, size_t words)
+{
+ assert(words >= filler_array_min_size(), "too small for an array");
+ assert(words <= filler_array_max_size(), "too big for a single object");
+
+ const size_t payload_size = words - filler_array_hdr_size();
+ const size_t len = payload_size * HeapWordSize / sizeof(jint);
+
+ // Set the length first for concurrent GC.
+ ((arrayOop)start)->set_length((int)len);
+ post_allocation_setup_common(Universe::fillerArrayKlassObj(), start,
+ words);
+ DEBUG_ONLY(zap_filler_array(start, words);)
+}
+
+void
+CollectedHeap::fill_with_object_impl(HeapWord* start, size_t words)
+{
+ assert(words <= filler_array_max_size(), "too big for a single object");
+
+ if (words >= filler_array_min_size()) {
+ fill_with_array(start, words);
+ } else if (words > 0) {
+ assert(words == min_fill_size(), "unaligned size");
+ post_allocation_setup_common(SystemDictionary::object_klass(), start,
+ words);
+ }
+}
+
+void CollectedHeap::fill_with_object(HeapWord* start, size_t words)
+{
+ DEBUG_ONLY(fill_args_check(start, words);)
+ HandleMark hm; // Free handles before leaving.
+ fill_with_object_impl(start, words);
+}
+
+void CollectedHeap::fill_with_objects(HeapWord* start, size_t words)
+{
+ DEBUG_ONLY(fill_args_check(start, words);)
+ HandleMark hm; // Free handles before leaving.
+
+#ifdef LP64
+ // A single array can fill ~8G, so multiple objects are needed only in 64-bit.
+ // First fill with arrays, ensuring that any remaining space is big enough to
+ // fill. The remainder is filled with a single object.
+ const size_t min = min_fill_size();
+ const size_t max = filler_array_max_size();
+ while (words > max) {
+ const size_t cur = words - max >= min ? max : max - min;
+ fill_with_array(start, cur);
+ start += cur;
+ words -= cur;
+ }
+#endif
+
+ fill_with_object_impl(start, words);
+}
+
oop CollectedHeap::new_store_barrier(oop new_obj) {
// %%% This needs refactoring. (It was imported from the server compiler.)
guarantee(can_elide_tlab_store_barriers(), "store barrier elision not supported");
--- a/hotspot/src/share/vm/gc_interface/collectedHeap.hpp Fri Dec 12 10:19:39 2008 -0800
+++ b/hotspot/src/share/vm/gc_interface/collectedHeap.hpp Fri Dec 12 15:37:46 2008 -0800
@@ -47,6 +47,9 @@
static int _fire_out_of_memory_count;
#endif
+ // Used for filler objects (static, but initialized in ctor).
+ static size_t _filler_array_max_size;
+
protected:
MemRegion _reserved;
BarrierSet* _barrier_set;
@@ -119,6 +122,21 @@
// Clears an allocated object.
inline static void init_obj(HeapWord* obj, size_t size);
+ // Filler object utilities.
+ static inline size_t filler_array_hdr_size();
+ static inline size_t filler_array_min_size();
+ static inline size_t filler_array_max_size();
+
+ DEBUG_ONLY(static void fill_args_check(HeapWord* start, size_t words);)
+ DEBUG_ONLY(static void zap_filler_array(HeapWord* start, size_t words);)
+
+ // Fill with a single array; caller must ensure filler_array_min_size() <=
+ // words <= filler_array_max_size().
+ static inline void fill_with_array(HeapWord* start, size_t words);
+
+ // Fill with a single object (either an int array or a java.lang.Object).
+ static inline void fill_with_object_impl(HeapWord* start, size_t words);
+
// Verification functions
virtual void check_for_bad_heap_word_value(HeapWord* addr, size_t size)
PRODUCT_RETURN;
@@ -294,6 +312,27 @@
// The boundary between a "large" and "small" array of primitives, in words.
virtual size_t large_typearray_limit() = 0;
+ // Utilities for turning raw memory into filler objects.
+ //
+ // min_fill_size() is the smallest region that can be filled.
+ // fill_with_objects() can fill arbitrary-sized regions of the heap using
+ // multiple objects. fill_with_object() is for regions known to be smaller
+ // than the largest array of integers; it uses a single object to fill the
+ // region and has slightly less overhead.
+ static size_t min_fill_size() {
+ return size_t(align_object_size(oopDesc::header_size()));
+ }
+
+ static void fill_with_objects(HeapWord* start, size_t words);
+
+ static void fill_with_object(HeapWord* start, size_t words);
+ static void fill_with_object(MemRegion region) {
+ fill_with_object(region.start(), region.word_size());
+ }
+ static void fill_with_object(HeapWord* start, HeapWord* end) {
+ fill_with_object(start, pointer_delta(end, start));
+ }
+
// Some heaps may offer a contiguous region for shared non-blocking
// allocation, via inlined code (by exporting the address of the top and
// end fields defining the extent of the contiguous allocation region.)
--- a/hotspot/src/share/vm/gc_interface/collectedHeap.inline.hpp Fri Dec 12 10:19:39 2008 -0800
+++ b/hotspot/src/share/vm/gc_interface/collectedHeap.inline.hpp Fri Dec 12 15:37:46 2008 -0800
@@ -34,7 +34,6 @@
void CollectedHeap::post_allocation_setup_no_klass_install(KlassHandle klass,
HeapWord* objPtr,
size_t size) {
-
oop obj = (oop)objPtr;
assert(obj != NULL, "NULL object pointer");
@@ -44,9 +43,6 @@
// May be bootstrapping
obj->set_mark(markOopDesc::prototype());
}
-
- // support low memory notifications (no-op if not enabled)
- LowMemoryDetector::detect_low_memory_for_collected_pools();
}
void CollectedHeap::post_allocation_install_obj_klass(KlassHandle klass,
@@ -65,6 +61,9 @@
// Support for jvmti and dtrace
inline void post_allocation_notify(KlassHandle klass, oop obj) {
+ // support low memory notifications (no-op if not enabled)
+ LowMemoryDetector::detect_low_memory_for_collected_pools();
+
// support for JVMTI VMObjectAlloc event (no-op if not enabled)
JvmtiExport::vm_object_alloc_event_collector(obj);
--- a/hotspot/src/share/vm/includeDB_gc Fri Dec 12 10:19:39 2008 -0800
+++ b/hotspot/src/share/vm/includeDB_gc Fri Dec 12 15:37:46 2008 -0800
@@ -28,21 +28,22 @@
collectedHeap.cpp collectedHeap.inline.hpp
collectedHeap.cpp init.hpp
collectedHeap.cpp oop.inline.hpp
+collectedHeap.cpp systemDictionary.hpp
collectedHeap.cpp thread_<os_family>.inline.hpp
collectedHeap.hpp allocation.hpp
collectedHeap.hpp barrierSet.hpp
collectedHeap.hpp gcCause.hpp
collectedHeap.hpp handles.hpp
-collectedHeap.hpp perfData.hpp
+collectedHeap.hpp perfData.hpp
collectedHeap.hpp safepoint.hpp
collectedHeap.inline.hpp arrayOop.hpp
collectedHeap.inline.hpp collectedHeap.hpp
collectedHeap.inline.hpp copy.hpp
collectedHeap.inline.hpp jvmtiExport.hpp
-collectedHeap.inline.hpp lowMemoryDetector.hpp
-collectedHeap.inline.hpp sharedRuntime.hpp
+collectedHeap.inline.hpp lowMemoryDetector.hpp
+collectedHeap.inline.hpp sharedRuntime.hpp
collectedHeap.inline.hpp thread.hpp
collectedHeap.inline.hpp threadLocalAllocBuffer.inline.hpp
collectedHeap.inline.hpp universe.hpp
--- a/hotspot/src/share/vm/memory/permGen.cpp Fri Dec 12 10:19:39 2008 -0800
+++ b/hotspot/src/share/vm/memory/permGen.cpp Fri Dec 12 15:37:46 2008 -0800
@@ -26,20 +26,24 @@
#include "incls/_permGen.cpp.incl"
HeapWord* PermGen::mem_allocate_in_gen(size_t size, Generation* gen) {
- MutexLocker ml(Heap_lock);
GCCause::Cause next_cause = GCCause::_permanent_generation_full;
GCCause::Cause prev_cause = GCCause::_no_gc;
+ unsigned int gc_count_before, full_gc_count_before;
+ HeapWord* obj;
for (;;) {
- HeapWord* obj = gen->allocate(size, false);
- if (obj != NULL) {
- return obj;
- }
- if (gen->capacity() < _capacity_expansion_limit ||
- prev_cause != GCCause::_no_gc) {
- obj = gen->expand_and_allocate(size, false);
- }
- if (obj == NULL && prev_cause != GCCause::_last_ditch_collection) {
+ {
+ MutexLocker ml(Heap_lock);
+ if ((obj = gen->allocate(size, false)) != NULL) {
+ return obj;
+ }
+ if (gen->capacity() < _capacity_expansion_limit ||
+ prev_cause != GCCause::_no_gc) {
+ obj = gen->expand_and_allocate(size, false);
+ }
+ if (obj != NULL || prev_cause == GCCause::_last_ditch_collection) {
+ return obj;
+ }
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
@@ -61,31 +65,27 @@
return NULL;
}
}
+ // 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();
+ }
- // Read the GC count while holding the Heap_lock
- unsigned int gc_count_before = SharedHeap::heap()->total_collections();
- unsigned int full_gc_count_before = SharedHeap::heap()->total_full_collections();
- {
- MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back
- VM_GenCollectForPermanentAllocation op(size, gc_count_before, full_gc_count_before,
- next_cause);
- VMThread::execute(&op);
- if (!op.prologue_succeeded() || op.gc_locked()) {
- assert(op.result() == NULL, "must be NULL if gc_locked() is true");
- continue; // retry and/or stall as necessary
- }
- obj = op.result();
- assert(obj == NULL || SharedHeap::heap()->is_in_reserved(obj),
- "result not in heap");
- if (obj != NULL) {
- return obj;
- }
- }
- prev_cause = next_cause;
- next_cause = GCCause::_last_ditch_collection;
- } else {
+ // Give up heap lock above, VMThread::execute below gets it back
+ VM_GenCollectForPermanentAllocation op(size, gc_count_before, full_gc_count_before,
+ next_cause);
+ VMThread::execute(&op);
+ if (!op.prologue_succeeded() || op.gc_locked()) {
+ assert(op.result() == NULL, "must be NULL if gc_locked() is true");
+ continue; // retry and/or stall as necessary
+ }
+ obj = op.result();
+ assert(obj == NULL || SharedHeap::heap()->is_in_reserved(obj),
+ "result not in heap");
+ if (obj != NULL) {
return obj;
}
+ prev_cause = next_cause;
+ next_cause = GCCause::_last_ditch_collection;
}
}
--- a/hotspot/src/share/vm/memory/sharedHeap.cpp Fri Dec 12 10:19:39 2008 -0800
+++ b/hotspot/src/share/vm/memory/sharedHeap.cpp Fri Dec 12 15:37:46 2008 -0800
@@ -248,46 +248,6 @@
perm_gen()->ref_processor_init();
}
-void SharedHeap::fill_region_with_object(MemRegion mr) {
- // Disable the posting of JVMTI VMObjectAlloc events as we
- // don't want the filling of tlabs with filler arrays to be
- // reported to the profiler.
- NoJvmtiVMObjectAllocMark njm;
-
- // Disable low memory detector because there is no real allocation.
- LowMemoryDetectorDisabler lmd_dis;
-
- // It turns out that post_allocation_setup_array takes a handle, so the
- // call below contains an implicit conversion. Best to free that handle
- // as soon as possible.
- HandleMark hm;
-
- size_t word_size = mr.word_size();
- size_t aligned_array_header_size =
- align_object_size(typeArrayOopDesc::header_size(T_INT));
-
- if (word_size >= aligned_array_header_size) {
- const size_t array_length =
- pointer_delta(mr.end(), mr.start()) -
- typeArrayOopDesc::header_size(T_INT);
- const size_t array_length_words =
- array_length * (HeapWordSize/sizeof(jint));
- post_allocation_setup_array(Universe::intArrayKlassObj(),
- mr.start(),
- mr.word_size(),
- (int)array_length_words);
-#ifdef ASSERT
- HeapWord* elt_words = (mr.start() + typeArrayOopDesc::header_size(T_INT));
- Copy::fill_to_words(elt_words, array_length, 0xDEAFBABE);
-#endif
- } else {
- assert(word_size == (size_t)oopDesc::header_size(), "Unaligned?");
- post_allocation_setup_obj(SystemDictionary::object_klass(),
- mr.start(),
- mr.word_size());
- }
-}
-
// Some utilities.
void SharedHeap::print_size_transition(outputStream* out,
size_t bytes_before,
--- a/hotspot/src/share/vm/memory/sharedHeap.hpp Fri Dec 12 10:19:39 2008 -0800
+++ b/hotspot/src/share/vm/memory/sharedHeap.hpp Fri Dec 12 15:37:46 2008 -0800
@@ -108,14 +108,6 @@
void set_perm(PermGen* perm_gen) { _perm_gen = perm_gen; }
- // A helper function that fills a region of the heap with
- // with a single object.
- static void fill_region_with_object(MemRegion mr);
-
- // Minimum garbage fill object size
- static size_t min_fill_size() { return (size_t)align_object_size(oopDesc::header_size()); }
- static size_t min_fill_size_in_bytes() { return min_fill_size() * HeapWordSize; }
-
// This function returns the "GenRemSet" object that allows us to scan
// generations; at least the perm gen, possibly more in a fully
// generational heap.
--- a/hotspot/src/share/vm/memory/space.cpp Fri Dec 12 10:19:39 2008 -0800
+++ b/hotspot/src/share/vm/memory/space.cpp Fri Dec 12 15:37:46 2008 -0800
@@ -409,19 +409,9 @@
HeapWord* q, size_t deadlength) {
if (allowed_deadspace_words >= deadlength) {
allowed_deadspace_words -= deadlength;
- oop(q)->set_mark(markOopDesc::prototype()->set_marked());
- const size_t min_int_array_size = typeArrayOopDesc::header_size(T_INT);
- if (deadlength >= min_int_array_size) {
- oop(q)->set_klass(Universe::intArrayKlassObj());
- typeArrayOop(q)->set_length((int)((deadlength - min_int_array_size)
- * (HeapWordSize/sizeof(jint))));
- } else {
- assert((int) deadlength == instanceOopDesc::header_size(),
- "size for smallest fake dead object doesn't match");
- oop(q)->set_klass(SystemDictionary::object_klass());
- }
- assert((int) deadlength == oop(q)->size(),
- "make sure size for fake dead object match");
+ CollectedHeap::fill_with_object(q, deadlength);
+ oop(q)->set_mark(oop(q)->mark()->set_marked());
+ assert((int) deadlength == oop(q)->size(), "bad filler object size");
// Recall that we required "q == compaction_top".
return true;
} else {
--- a/hotspot/src/share/vm/memory/tenuredGeneration.cpp Fri Dec 12 10:19:39 2008 -0800
+++ b/hotspot/src/share/vm/memory/tenuredGeneration.cpp Fri Dec 12 15:37:46 2008 -0800
@@ -387,7 +387,7 @@
"should contain whole object");
buf->undo_allocation(obj, word_sz);
} else {
- SharedHeap::fill_region_with_object(MemRegion(obj, word_sz));
+ CollectedHeap::fill_with_object(obj, word_sz);
}
}
--- a/hotspot/src/share/vm/memory/threadLocalAllocBuffer.cpp Fri Dec 12 10:19:39 2008 -0800
+++ b/hotspot/src/share/vm/memory/threadLocalAllocBuffer.cpp Fri Dec 12 15:37:46 2008 -0800
@@ -100,8 +100,7 @@
void ThreadLocalAllocBuffer::make_parsable(bool retire) {
if (end() != NULL) {
invariants();
- MemRegion mr(top(), hard_end());
- SharedHeap::fill_region_with_object(mr);
+ CollectedHeap::fill_with_object(top(), hard_end());
if (retire || ZeroTLAB) { // "Reset" the TLAB
set_start(NULL);
--- a/hotspot/src/share/vm/memory/universe.cpp Fri Dec 12 10:19:39 2008 -0800
+++ b/hotspot/src/share/vm/memory/universe.cpp Fri Dec 12 15:37:46 2008 -0800
@@ -49,16 +49,17 @@
klassOop Universe::_constantPoolCacheKlassObj = NULL;
klassOop Universe::_compiledICHolderKlassObj = NULL;
klassOop Universe::_systemObjArrayKlassObj = NULL;
-oop Universe::_int_mirror = NULL;
-oop Universe::_float_mirror = NULL;
-oop Universe::_double_mirror = NULL;
-oop Universe::_byte_mirror = NULL;
-oop Universe::_bool_mirror = NULL;
-oop Universe::_char_mirror = NULL;
-oop Universe::_long_mirror = NULL;
-oop Universe::_short_mirror = NULL;
-oop Universe::_void_mirror = NULL;
-oop Universe::_mirrors[T_VOID+1] = { NULL /*, NULL...*/ };
+klassOop Universe::_fillerArrayKlassObj = NULL;
+oop Universe::_int_mirror = NULL;
+oop Universe::_float_mirror = NULL;
+oop Universe::_double_mirror = NULL;
+oop Universe::_byte_mirror = NULL;
+oop Universe::_bool_mirror = NULL;
+oop Universe::_char_mirror = NULL;
+oop Universe::_long_mirror = NULL;
+oop Universe::_short_mirror = NULL;
+oop Universe::_void_mirror = NULL;
+oop Universe::_mirrors[T_VOID+1] = { NULL /*, NULL...*/ };
oop Universe::_main_thread_group = NULL;
oop Universe::_system_thread_group = NULL;
typeArrayOop Universe::_the_empty_byte_array = NULL;
@@ -126,6 +127,7 @@
f(instanceKlassKlassObj());
f(constantPoolKlassObj());
f(systemObjArrayKlassObj());
+ f(fillerArrayKlassObj());
}
void Universe::oops_do(OopClosure* f, bool do_all) {
@@ -180,6 +182,7 @@
f->do_oop((oop*)&_constantPoolCacheKlassObj);
f->do_oop((oop*)&_compiledICHolderKlassObj);
f->do_oop((oop*)&_systemObjArrayKlassObj);
+ f->do_oop((oop*)&_fillerArrayKlassObj);
f->do_oop((oop*)&_the_empty_byte_array);
f->do_oop((oop*)&_the_empty_short_array);
f->do_oop((oop*)&_the_empty_int_array);
@@ -257,16 +260,17 @@
_typeArrayKlassObjs[T_INT] = _intArrayKlassObj;
_typeArrayKlassObjs[T_LONG] = _longArrayKlassObj;
- _methodKlassObj = methodKlass::create_klass(CHECK);
- _constMethodKlassObj = constMethodKlass::create_klass(CHECK);
- _methodDataKlassObj = methodDataKlass::create_klass(CHECK);
+ _methodKlassObj = methodKlass::create_klass(CHECK);
+ _constMethodKlassObj = constMethodKlass::create_klass(CHECK);
+ _methodDataKlassObj = methodDataKlass::create_klass(CHECK);
_constantPoolKlassObj = constantPoolKlass::create_klass(CHECK);
_constantPoolCacheKlassObj = constantPoolCacheKlass::create_klass(CHECK);
_compiledICHolderKlassObj = compiledICHolderKlass::create_klass(CHECK);
_systemObjArrayKlassObj = objArrayKlassKlass::cast(objArrayKlassKlassObj())->allocate_system_objArray_klass(CHECK);
+ _fillerArrayKlassObj = typeArrayKlass::create_klass(T_INT, sizeof(jint), "<filler>", CHECK);
- _the_empty_byte_array = oopFactory::new_permanent_byteArray(0, CHECK);
+ _the_empty_byte_array = oopFactory::new_permanent_byteArray(0, CHECK);
_the_empty_short_array = oopFactory::new_permanent_shortArray(0, CHECK);
_the_empty_int_array = oopFactory::new_permanent_intArray(0, CHECK);
_the_empty_system_obj_array = oopFactory::new_system_objArray(0, CHECK);
@@ -274,7 +278,6 @@
_the_array_interfaces_array = oopFactory::new_system_objArray(2, CHECK);
_vm_exception = oopFactory::new_symbol("vm exception holder", CHECK);
} else {
-
FileMapInfo *mapinfo = FileMapInfo::current_info();
char* buffer = mapinfo->region_base(CompactingPermGenGen::md);
void** vtbl_list = (void**)buffer;
--- a/hotspot/src/share/vm/memory/universe.hpp Fri Dec 12 10:19:39 2008 -0800
+++ b/hotspot/src/share/vm/memory/universe.hpp Fri Dec 12 15:37:46 2008 -0800
@@ -92,6 +92,7 @@
class Universe: AllStatic {
+ // Ugh. Universe is much too friendly.
friend class MarkSweep;
friend class oopDesc;
friend class ClassLoader;
@@ -132,6 +133,7 @@
static klassOop _constantPoolCacheKlassObj;
static klassOop _compiledICHolderKlassObj;
static klassOop _systemObjArrayKlassObj;
+ static klassOop _fillerArrayKlassObj;
// Known objects in the VM
@@ -264,6 +266,7 @@
static klassOop constantPoolCacheKlassObj() { return _constantPoolCacheKlassObj; }
static klassOop compiledICHolderKlassObj() { return _compiledICHolderKlassObj; }
static klassOop systemObjArrayKlassObj() { return _systemObjArrayKlassObj; }
+ static klassOop fillerArrayKlassObj() { return _fillerArrayKlassObj; }
// Known objects in tbe VM
static oop int_mirror() { return check_mirror(_int_mirror);
--- a/hotspot/src/share/vm/oops/arrayOop.hpp Fri Dec 12 10:19:39 2008 -0800
+++ b/hotspot/src/share/vm/oops/arrayOop.hpp Fri Dec 12 15:37:46 2008 -0800
@@ -96,19 +96,20 @@
: typesize_in_bytes/HeapWordSize);
}
- // This method returns the maximum length that can passed into
- // typeArrayOop::object_size(scale, length, header_size) without causing an
- // overflow. We substract an extra 2*wordSize to guard against double word
- // alignments. It gets the scale from the type2aelembytes array.
+ // Return the maximum length of an array of BasicType. The length can passed
+ // to typeArrayOop::object_size(scale, length, header_size) without causing an
+ // overflow.
static int32_t max_array_length(BasicType type) {
assert(type >= 0 && type < T_CONFLICT, "wrong type");
assert(type2aelembytes(type) != 0, "wrong type");
- // We use max_jint, since object_size is internally represented by an 'int'
- // This gives us an upper bound of max_jint words for the size of the oop.
- int32_t max_words = (max_jint - header_size(type) - 2);
- int elembytes = type2aelembytes(type);
- jlong len = ((jlong)max_words * HeapWordSize) / elembytes;
- return (len > max_jint) ? max_jint : (int32_t)len;
+ const int bytes_per_element = type2aelembytes(type);
+ if (bytes_per_element < HeapWordSize) {
+ return max_jint;
+ }
+
+ const int32_t max_words = align_size_down(max_jint, MinObjAlignment);
+ const int32_t max_element_words = max_words - header_size(type);
+ const int32_t words_per_element = bytes_per_element >> LogHeapWordSize;
+ return max_element_words / words_per_element;
}
-
};
--- a/hotspot/src/share/vm/oops/typeArrayKlass.cpp Fri Dec 12 10:19:39 2008 -0800
+++ b/hotspot/src/share/vm/oops/typeArrayKlass.cpp Fri Dec 12 15:37:46 2008 -0800
@@ -36,13 +36,14 @@
return element_type() == tak->element_type();
}
-klassOop typeArrayKlass::create_klass(BasicType type, int scale, TRAPS) {
+klassOop typeArrayKlass::create_klass(BasicType type, int scale,
+ const char* name_str, TRAPS) {
typeArrayKlass o;
symbolHandle sym(symbolOop(NULL));
// bootstrapping: don't create sym if symbolKlass not created yet
- if (Universe::symbolKlassObj() != NULL) {
- sym = oopFactory::new_symbol_handle(external_name(type), CHECK_NULL);
+ if (Universe::symbolKlassObj() != NULL && name_str != NULL) {
+ sym = oopFactory::new_symbol_handle(name_str, CHECK_NULL);
}
KlassHandle klassklass (THREAD, Universe::typeArrayKlassKlassObj());
--- a/hotspot/src/share/vm/oops/typeArrayKlass.hpp Fri Dec 12 10:19:39 2008 -0800
+++ b/hotspot/src/share/vm/oops/typeArrayKlass.hpp Fri Dec 12 15:37:46 2008 -0800
@@ -39,7 +39,11 @@
// klass allocation
DEFINE_ALLOCATE_PERMANENT(typeArrayKlass);
- static klassOop create_klass(BasicType type, int scale, TRAPS);
+ static klassOop create_klass(BasicType type, int scale, const char* name_str,
+ TRAPS);
+ static inline klassOop create_klass(BasicType type, int scale, TRAPS) {
+ return create_klass(type, scale, external_name(type), CHECK_NULL);
+ }
int oop_size(oop obj) const;
int klass_oop_size() const { return object_size(); }
--- a/hotspot/src/share/vm/runtime/arguments.cpp Fri Dec 12 10:19:39 2008 -0800
+++ b/hotspot/src/share/vm/runtime/arguments.cpp Fri Dec 12 15:37:46 2008 -0800
@@ -1517,6 +1517,16 @@
MarkSweepAlwaysCompactCount = 1; // Move objects every gc.
}
+ if (UseParallelOldGC && ParallelOldGCSplitALot) {
+ // Settings to encourage splitting.
+ if (!FLAG_IS_CMDLINE(NewRatio)) {
+ FLAG_SET_CMDLINE(intx, NewRatio, 2);
+ }
+ if (!FLAG_IS_CMDLINE(ScavengeBeforeFullGC)) {
+ FLAG_SET_CMDLINE(bool, ScavengeBeforeFullGC, false);
+ }
+ }
+
status = status && verify_percentage(GCHeapFreeLimit, "GCHeapFreeLimit");
status = status && verify_percentage(GCTimeLimit, "GCTimeLimit");
if (GCTimeLimit == 100) {
--- a/hotspot/src/share/vm/runtime/globals.hpp Fri Dec 12 10:19:39 2008 -0800
+++ b/hotspot/src/share/vm/runtime/globals.hpp Fri Dec 12 15:37:46 2008 -0800
@@ -625,6 +625,9 @@
develop(bool, CheckZapUnusedHeapArea, false, \
"Check zapping of unused heap space") \
\
+ develop(bool, ZapFillerObjects, trueInDebug, \
+ "Zap filler objects with 0xDEAFBABE") \
+ \
develop(bool, PrintVMMessages, true, \
"Print vm messages on console") \
\
@@ -1200,11 +1203,12 @@
product(uintx, ParallelCMSThreads, 0, \
"Max number of threads CMS will use for concurrent work") \
\
- develop(bool, ParallelOldMTUnsafeMarkBitMap, false, \
- "Use the Parallel Old MT unsafe in marking the bitmap") \
- \
- develop(bool, ParallelOldMTUnsafeUpdateLiveData, false, \
- "Use the Parallel Old MT unsafe in update of live size") \
+ develop(bool, ParallelOldGCSplitALot, false, \
+ "Provoke splitting (copying data from a young gen space to" \
+ "multiple destination spaces)") \
+ \
+ develop(uintx, ParallelOldGCSplitInterval, 3, \
+ "How often to provoke splitting a young gen space") \
\
develop(bool, TraceRegionTasksQueuing, false, \
"Trace the queuing of the region tasks") \