src/share/vm/gc_implementation/g1/heapRegionSeq.cpp
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rev 4204 : 7163191: G1: introduce a "heap spanning table" abstraction
Summary: Add a heap spanning table and employ it for the heap region sequence table.
Reviewed-by:
rev 4205 : imported patch bengt-and-thomas-comments
*** 69,153 ****
}
}
// Public
! void HeapRegionSeq::initialize(HeapWord* bottom, HeapWord* end,
! uint max_length) {
! assert((uintptr_t) bottom % HeapRegion::GrainBytes == 0,
! "bottom should be heap region aligned");
! assert((uintptr_t) end % HeapRegion::GrainBytes == 0,
! "end should be heap region aligned");
!
! _length = 0;
! _heap_bottom = bottom;
! _heap_end = end;
! _region_shift = HeapRegion::LogOfHRGrainBytes;
! _next_search_index = 0;
! _allocated_length = 0;
! _max_length = max_length;
!
! _regions = NEW_C_HEAP_ARRAY(HeapRegion*, max_length, mtGC);
! memset(_regions, 0, (size_t) max_length * sizeof(HeapRegion*));
! _regions_biased = _regions - ((uintx) bottom >> _region_shift);
!
! assert(&_regions[0] == &_regions_biased[addr_to_index_biased(bottom)],
! "bottom should be included in the region with index 0");
! }
!
! MemRegion HeapRegionSeq::expand_by(HeapWord* old_end,
! HeapWord* new_end,
! FreeRegionList* list) {
! assert(old_end < new_end, "don't call it otherwise");
G1CollectedHeap* g1h = G1CollectedHeap::heap();
! HeapWord* next_bottom = old_end;
! assert(_heap_bottom <= next_bottom, "invariant");
! while (next_bottom < new_end) {
! assert(next_bottom < _heap_end, "invariant");
uint index = length();
- assert(index < _max_length, "otherwise we cannot expand further");
if (index == 0) {
! // We have not allocated any regions so far
! assert(next_bottom == _heap_bottom, "invariant");
} else {
! // next_bottom should match the end of the last/previous region
! assert(next_bottom == at(index - 1)->end(), "invariant");
}
! if (index == _allocated_length) {
! // We have to allocate a new HeapRegion.
! HeapRegion* new_hr = g1h->new_heap_region(index, next_bottom);
! if (new_hr == NULL) {
! // allocation failed, we bail out and return what we have done so far
! return MemRegion(old_end, next_bottom);
! }
! assert(_regions[index] == NULL, "invariant");
! _regions[index] = new_hr;
! increment_length(&_allocated_length);
! }
! // Have to increment the length first, otherwise we will get an
! // assert failure at(index) below.
! increment_length(&_length);
! HeapRegion* hr = at(index);
list->add_as_tail(hr);
! next_bottom = hr->end();
}
! assert(next_bottom == new_end, "post-condition");
! return MemRegion(old_end, next_bottom);
}
uint HeapRegionSeq::free_suffix() {
uint res = 0;
uint index = length();
while (index > 0) {
index -= 1;
! if (!at(index)->is_empty()) {
! break;
! }
res += 1;
}
return res;
}
--- 69,133 ----
}
}
// Public
! MemRegion HeapRegionSeq::expand_to(HeapWord* new_end, FreeRegionList* list) {
! assert(_heap_end < new_end && new_end <= _max_heap_end,
! err_msg("new_end: "PTR_FORMAT" heap end: "PTR_FORMAT" "
! "max heap end: "PTR_FORMAT, new_end, _heap_end, _max_heap_end));
G1CollectedHeap* g1h = G1CollectedHeap::heap();
! uint new_length = length_for(new_end);
uint index = length();
+ HeapWord* next_hr_bottom = _heap_end;
+ while (index < new_length) {
+ assert(length_for(next_hr_bottom) == index,
+ err_msg("invariant, length_for: "PTR_FORMAT" %u index: %u",
+ next_hr_bottom, length_for(next_hr_bottom), index));
if (index == 0) {
! // We have not allocated any regions so far.
! assert(next_hr_bottom == _heap_bottom, "invariant");
} else {
! // The previous region should exist.
! assert(_regions[index - 1] != NULL, "invariant");
! // next_hr_bottom should match the end of the previous region.
! assert(next_hr_bottom == _regions[index - 1]->end(), "invariant");
}
! HeapRegion* hr;
! if (index < _length_high_watermark) {
! // This region should have been previously allocated.
! assert(_regions[index] != NULL, err_msg("invariant, index: %u", index));
!
! hr = _regions[index];
! } else {
! // We have to allocate a new region.
! assert(_regions[index] == NULL, err_msg("invariant, index: %u", index));
!
! hr = g1h->new_heap_region(index, next_hr_bottom);
! // If allocation fails, bail out and return what we have done so far.
! if (hr == NULL) break;
! _regions[index] = hr;
! }
list->add_as_tail(hr);
! index += 1;
! next_hr_bottom = hr->end();
}
!
! HeapWord* prev_heap_end = update_heap_end(next_hr_bottom);
! return MemRegion(prev_heap_end, next_hr_bottom);
}
uint HeapRegionSeq::free_suffix() {
uint res = 0;
uint index = length();
while (index > 0) {
index -= 1;
! if (!at(index)->is_empty()) break;
res += 1;
}
return res;
}
*** 199,275 ****
return;
}
}
}
! MemRegion HeapRegionSeq::shrink_by(size_t shrink_bytes,
uint* num_regions_deleted) {
// Reset this in case it's currently pointing into the regions that
// we just removed.
_next_search_index = 0;
! assert(shrink_bytes % os::vm_page_size() == 0, "unaligned");
! assert(shrink_bytes % HeapRegion::GrainBytes == 0, "unaligned");
! assert(length() > 0, "the region sequence should not be empty");
! assert(length() <= _allocated_length, "invariant");
! assert(_allocated_length > 0, "we should have at least one region committed");
!
! // around the loop, i will be the next region to be removed
! uint i = length() - 1;
! assert(i > 0, "we should never remove all regions");
! // [last_start, end) is the MemRegion that covers the regions we will remove.
! HeapWord* end = at(i)->end();
! HeapWord* last_start = end;
! *num_regions_deleted = 0;
! while (shrink_bytes > 0) {
! HeapRegion* cur = at(i);
// We should leave the humongous regions where they are.
! if (cur->isHumongous()) break;
// We should stop shrinking if we come across a non-empty region.
! if (!cur->is_empty()) break;
! i -= 1;
! *num_regions_deleted += 1;
! shrink_bytes -= cur->capacity();
! last_start = cur->bottom();
! decrement_length(&_length);
! // We will reclaim the HeapRegion. _allocated_length should be
! // covering this index. So, even though we removed the region from
! // the active set by decreasing _length, we still have it
! // available in the future if we need to re-use it.
! assert(i > 0, "we should never remove all regions");
! assert(length() > 0, "we should never remove all regions");
}
! return MemRegion(last_start, end);
}
#ifndef PRODUCT
void HeapRegionSeq::verify_optional() {
! guarantee(_length <= _allocated_length,
! err_msg("invariant: _length: %u _allocated_length: %u",
! _length, _allocated_length));
! guarantee(_allocated_length <= _max_length,
! err_msg("invariant: _allocated_length: %u _max_length: %u",
! _allocated_length, _max_length));
guarantee(_next_search_index <= _length,
err_msg("invariant: _next_search_index: %u _length: %u",
_next_search_index, _length));
HeapWord* prev_end = _heap_bottom;
! for (uint i = 0; i < _allocated_length; i += 1) {
HeapRegion* hr = _regions[i];
guarantee(hr != NULL, err_msg("invariant: i: %u", i));
guarantee(hr->bottom() == prev_end,
err_msg("invariant i: %u "HR_FORMAT" prev_end: "PTR_FORMAT,
i, HR_FORMAT_PARAMS(hr), prev_end));
guarantee(hr->hrs_index() == i,
err_msg("invariant: i: %u hrs_index(): %u", i, hr->hrs_index()));
if (i < _length) {
// Asserts will fire if i is >= _length
HeapWord* addr = hr->bottom();
! guarantee(addr_to_region(addr) == hr, "sanity");
! guarantee(addr_to_region_unsafe(addr) == hr, "sanity");
} else {
guarantee(hr->is_empty(), "sanity");
guarantee(!hr->isHumongous(), "sanity");
// using assert instead of guarantee here since containing_set()
// is only available in non-product builds.
--- 179,250 ----
return;
}
}
}
! MemRegion HeapRegionSeq::shrink_to(HeapWord* new_end,
uint* num_regions_deleted) {
+ assert(_heap_bottom < new_end && new_end <= _heap_end,
+ err_msg("new_end: "PTR_FORMAT" heap bottom: "PTR_FORMAT" "
+ "heap end: "PTR_FORMAT, new_end, _heap_bottom, _heap_end));
+
// Reset this in case it's currently pointing into the regions that
// we just removed.
_next_search_index = 0;
! uint new_length = length_for(new_end);
! uint index = length();
! HeapWord* last_hr_bottom = _heap_end;
! while (index > new_length) {
! assert(length_for(last_hr_bottom) == index,
! err_msg("invariant, length_for: "PTR_FORMAT" %u index: %u",
! last_hr_bottom, length_for(last_hr_bottom), index));
!
! HeapRegion* hr = at(index - 1);
// We should leave the humongous regions where they are.
! if (hr->isHumongous()) break;
// We should stop shrinking if we come across a non-empty region.
! if (!hr->is_empty()) break;
!
! index -= 1;
! last_hr_bottom = hr->bottom();
! }
!
! *num_regions_deleted = length() - index;
! if (new_end == _heap_end) {
! assert(*num_regions_deleted == 0, "invariant");
! } else {
! assert(*num_regions_deleted > 0, "invariant");
}
!
! HeapWord* prev_heap_end = update_heap_end(last_hr_bottom);
! return MemRegion(last_hr_bottom, prev_heap_end);
}
#ifndef PRODUCT
void HeapRegionSeq::verify_optional() {
! G1HeapSpanningTable<HeapRegion*>::verify_optional();
!
guarantee(_next_search_index <= _length,
err_msg("invariant: _next_search_index: %u _length: %u",
_next_search_index, _length));
HeapWord* prev_end = _heap_bottom;
! for (uint i = 0; i < _length_high_watermark; i += 1) {
HeapRegion* hr = _regions[i];
guarantee(hr != NULL, err_msg("invariant: i: %u", i));
guarantee(hr->bottom() == prev_end,
err_msg("invariant i: %u "HR_FORMAT" prev_end: "PTR_FORMAT,
i, HR_FORMAT_PARAMS(hr), prev_end));
guarantee(hr->hrs_index() == i,
err_msg("invariant: i: %u hrs_index(): %u", i, hr->hrs_index()));
if (i < _length) {
// Asserts will fire if i is >= _length
HeapWord* addr = hr->bottom();
! guarantee(at(addr) == hr, "sanity");
! guarantee(at_unsafe(addr) == hr, "sanity");
} else {
guarantee(hr->is_empty(), "sanity");
guarantee(!hr->isHumongous(), "sanity");
// using assert instead of guarantee here since containing_set()
// is only available in non-product builds.
*** 279,288 ****
prev_end = hr->orig_end();
} else {
prev_end = hr->end();
}
}
! for (uint i = _allocated_length; i < _max_length; i += 1) {
guarantee(_regions[i] == NULL, err_msg("invariant i: %u", i));
}
}
#endif // PRODUCT
--- 254,270 ----
prev_end = hr->orig_end();
} else {
prev_end = hr->end();
}
}
! for (uint i = _length_high_watermark; i < _max_length; i += 1) {
guarantee(_regions[i] == NULL, err_msg("invariant i: %u", i));
}
}
#endif // PRODUCT
+
+ void HeapRegionSeq::initialize(HeapWord* bottom, HeapWord* max_end) {
+ initialize_base(bottom, max_end, HeapRegion::LogOfHRGrainBytes);
+ _next_search_index = 0;
+ _regions = create_new_array();
+ _regions_biased = get_biased_array(_regions);
+ }