--- a/hotspot/src/share/vm/gc_implementation/g1/heapRegionSeq.cpp Wed Jun 08 21:48:38 2011 -0400
+++ b/hotspot/src/share/vm/gc_implementation/g1/heapRegionSeq.cpp Fri Jun 10 13:16:40 2011 -0400
@@ -23,259 +23,182 @@
*/
#include "precompiled.hpp"
+#include "gc_implementation/g1/heapRegion.hpp"
+#include "gc_implementation/g1/heapRegionSeq.inline.hpp"
+#include "gc_implementation/g1/heapRegionSets.hpp"
#include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
-#include "gc_implementation/g1/heapRegionSeq.hpp"
#include "memory/allocation.hpp"
-// Local to this file.
-
-static int orderRegions(HeapRegion** hr1p, HeapRegion** hr2p) {
- if ((*hr1p)->end() <= (*hr2p)->bottom()) return -1;
- else if ((*hr2p)->end() <= (*hr1p)->bottom()) return 1;
- else if (*hr1p == *hr2p) return 0;
- else {
- assert(false, "We should never compare distinct overlapping regions.");
- }
- return 0;
-}
-
-HeapRegionSeq::HeapRegionSeq(const size_t max_size) :
- _alloc_search_start(0),
- // The line below is the worst bit of C++ hackery I've ever written
- // (Detlefs, 11/23). You should think of it as equivalent to
- // "_regions(100, true)": initialize the growable array and inform it
- // that it should allocate its elem array(s) on the C heap.
- //
- // The first argument, however, is actually a comma expression
- // (set_allocation_type(this, C_HEAP), 100). The purpose of the
- // set_allocation_type() call is to replace the default allocation
- // type for embedded objects STACK_OR_EMBEDDED with C_HEAP. It will
- // allow to pass the assert in GenericGrowableArray() which checks
- // that a growable array object must be on C heap if elements are.
- //
- // Note: containing object is allocated on C heap since it is CHeapObj.
- //
- _regions((ResourceObj::set_allocation_type((address)&_regions,
- ResourceObj::C_HEAP),
- (int)max_size),
- true),
- _next_rr_candidate(0),
- _seq_bottom(NULL)
-{}
-
-// Private methods.
+// Private
-void HeapRegionSeq::print_empty_runs() {
- int empty_run = 0;
- int n_empty = 0;
- int empty_run_start;
- for (int i = 0; i < _regions.length(); i++) {
- HeapRegion* r = _regions.at(i);
- if (r->continuesHumongous()) continue;
- if (r->is_empty()) {
- assert(!r->isHumongous(), "H regions should not be empty.");
- if (empty_run == 0) empty_run_start = i;
- empty_run++;
- n_empty++;
- } else {
- if (empty_run > 0) {
- gclog_or_tty->print(" %d:%d", empty_run_start, empty_run);
- empty_run = 0;
- }
- }
- }
- if (empty_run > 0) {
- gclog_or_tty->print(" %d:%d", empty_run_start, empty_run);
- }
- gclog_or_tty->print_cr(" [tot = %d]", n_empty);
-}
-
-int HeapRegionSeq::find(HeapRegion* hr) {
- // FIXME: optimized for adjacent regions of fixed size.
- int ind = hr->hrs_index();
- if (ind != -1) {
- assert(_regions.at(ind) == hr, "Mismatch");
- }
- return ind;
-}
-
-
-// Public methods.
+size_t HeapRegionSeq::find_contiguous_from(size_t from, size_t num) {
+ size_t len = length();
+ assert(num > 1, "use this only for sequences of length 2 or greater");
+ assert(from <= len,
+ err_msg("from: "SIZE_FORMAT" should be valid and <= than "SIZE_FORMAT,
+ from, len));
-void HeapRegionSeq::insert(HeapRegion* hr) {
- assert(!_regions.is_full(), "Too many elements in HeapRegionSeq");
- if (_regions.length() == 0
- || _regions.top()->end() <= hr->bottom()) {
- hr->set_hrs_index(_regions.length());
- _regions.append(hr);
- } else {
- _regions.append(hr);
- _regions.sort(orderRegions);
- for (int i = 0; i < _regions.length(); i++) {
- _regions.at(i)->set_hrs_index(i);
- }
- }
- char* bot = (char*)_regions.at(0)->bottom();
- if (_seq_bottom == NULL || bot < _seq_bottom) _seq_bottom = bot;
-}
-
-size_t HeapRegionSeq::length() {
- return _regions.length();
-}
-
-size_t HeapRegionSeq::free_suffix() {
- size_t res = 0;
- int first = _regions.length() - 1;
- int cur = first;
- while (cur >= 0 &&
- (_regions.at(cur)->is_empty()
- && (first == cur
- || (_regions.at(cur+1)->bottom() ==
- _regions.at(cur)->end())))) {
- res++;
- cur--;
- }
- return res;
-}
-
-int HeapRegionSeq::find_contiguous_from(int from, size_t num) {
- assert(num > 1, "pre-condition");
- assert(0 <= from && from <= _regions.length(),
- err_msg("from: %d should be valid and <= than %d",
- from, _regions.length()));
-
- int curr = from;
- int first = -1;
+ size_t curr = from;
+ size_t first = G1_NULL_HRS_INDEX;
size_t num_so_far = 0;
- while (curr < _regions.length() && num_so_far < num) {
- HeapRegion* curr_hr = _regions.at(curr);
- if (curr_hr->is_empty()) {
- if (first == -1) {
+ while (curr < len && num_so_far < num) {
+ if (at(curr)->is_empty()) {
+ if (first == G1_NULL_HRS_INDEX) {
first = curr;
num_so_far = 1;
} else {
num_so_far += 1;
}
} else {
- first = -1;
+ first = G1_NULL_HRS_INDEX;
num_so_far = 0;
}
curr += 1;
}
-
assert(num_so_far <= num, "post-condition");
if (num_so_far == num) {
// we found enough space for the humongous object
- assert(from <= first && first < _regions.length(), "post-condition");
- assert(first < curr && (curr - first) == (int) num, "post-condition");
- for (int i = first; i < first + (int) num; ++i) {
- assert(_regions.at(i)->is_empty(), "post-condition");
+ assert(from <= first && first < len, "post-condition");
+ assert(first < curr && (curr - first) == num, "post-condition");
+ for (size_t i = first; i < first + num; ++i) {
+ assert(at(i)->is_empty(), "post-condition");
}
return first;
} else {
// we failed to find enough space for the humongous object
- return -1;
+ return G1_NULL_HRS_INDEX;
}
}
-int HeapRegionSeq::find_contiguous(size_t num) {
- assert(num > 1, "otherwise we should not be calling this");
- assert(0 <= _alloc_search_start && _alloc_search_start <= _regions.length(),
- err_msg("_alloc_search_start: %d should be valid and <= than %d",
- _alloc_search_start, _regions.length()));
+// Public
+
+void HeapRegionSeq::initialize(HeapWord* bottom, HeapWord* end,
+ size_t max_length) {
+ assert((size_t) bottom % HeapRegion::GrainBytes == 0,
+ "bottom should be heap region aligned");
+ assert((size_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);
+ memset(_regions, 0, max_length * sizeof(HeapRegion*));
+ _regions_biased = _regions - ((size_t) 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");
+ size_t index = length();
- int start = _alloc_search_start;
- int res = find_contiguous_from(start, num);
- if (res == -1 && start != 0) {
- // Try starting from the beginning. If _alloc_search_start was 0,
- // no point in doing this again.
- res = find_contiguous_from(0, num);
+ 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();
}
- if (res != -1) {
- assert(0 <= res && res < _regions.length(),
- err_msg("res: %d should be valid", res));
- _alloc_search_start = res + (int) num;
- assert(0 < _alloc_search_start && _alloc_search_start <= _regions.length(),
- err_msg("_alloc_search_start: %d should be valid",
- _alloc_search_start));
+ assert(next_bottom == new_end, "post-condition");
+ return MemRegion(old_end, next_bottom);
+}
+
+size_t HeapRegionSeq::free_suffix() {
+ size_t res = 0;
+ size_t index = length();
+ while (index > 0) {
+ index -= 1;
+ if (!at(index)->is_empty()) {
+ break;
+ }
+ res += 1;
}
return res;
}
-void HeapRegionSeq::iterate(HeapRegionClosure* blk) {
- iterate_from((HeapRegion*)NULL, blk);
+size_t HeapRegionSeq::find_contiguous(size_t num) {
+ assert(num > 1, "use this only for sequences of length 2 or greater");
+ assert(_next_search_index <= length(),
+ err_msg("_next_search_indeex: "SIZE_FORMAT" "
+ "should be valid and <= than "SIZE_FORMAT,
+ _next_search_index, length()));
+
+ size_t start = _next_search_index;
+ size_t res = find_contiguous_from(start, num);
+ if (res == G1_NULL_HRS_INDEX && start > 0) {
+ // Try starting from the beginning. If _next_search_index was 0,
+ // no point in doing this again.
+ res = find_contiguous_from(0, num);
+ }
+ if (res != G1_NULL_HRS_INDEX) {
+ assert(res < length(),
+ err_msg("res: "SIZE_FORMAT" should be valid", res));
+ _next_search_index = res + num;
+ assert(_next_search_index <= length(),
+ err_msg("_next_search_indeex: "SIZE_FORMAT" "
+ "should be valid and <= than "SIZE_FORMAT,
+ _next_search_index, length()));
+ }
+ return res;
}
-// The first argument r is the heap region at which iteration begins.
-// This operation runs fastest when r is NULL, or the heap region for
-// which a HeapRegionClosure most recently returned true, or the
-// heap region immediately to its right in the sequence. In all
-// other cases a linear search is required to find the index of r.
-
-void HeapRegionSeq::iterate_from(HeapRegion* r, HeapRegionClosure* blk) {
-
- // :::: FIXME ::::
- // Static cache value is bad, especially when we start doing parallel
- // remembered set update. For now just don't cache anything (the
- // code in the def'd out blocks).
+void HeapRegionSeq::iterate(HeapRegionClosure* blk) const {
+ iterate_from((HeapRegion*) NULL, blk);
+}
-#if 0
- static int cached_j = 0;
-#endif
- int len = _regions.length();
- int j = 0;
- // Find the index of r.
- if (r != NULL) {
-#if 0
- assert(cached_j >= 0, "Invariant.");
- if ((cached_j < len) && (r == _regions.at(cached_j))) {
- j = cached_j;
- } else if ((cached_j + 1 < len) && (r == _regions.at(cached_j + 1))) {
- j = cached_j + 1;
- } else {
- j = find(r);
-#endif
- if (j < 0) {
- j = 0;
- }
-#if 0
- }
-#endif
+void HeapRegionSeq::iterate_from(HeapRegion* hr, HeapRegionClosure* blk) const {
+ size_t hr_index = 0;
+ if (hr != NULL) {
+ hr_index = (size_t) hr->hrs_index();
}
- int i;
- for (i = j; i < len; i += 1) {
- int res = blk->doHeapRegion(_regions.at(i));
+
+ size_t len = length();
+ for (size_t i = hr_index; i < len; i += 1) {
+ bool res = blk->doHeapRegion(at(i));
if (res) {
-#if 0
- cached_j = i;
-#endif
blk->incomplete();
return;
}
}
- for (i = 0; i < j; i += 1) {
- int res = blk->doHeapRegion(_regions.at(i));
+ for (size_t i = 0; i < hr_index; i += 1) {
+ bool res = blk->doHeapRegion(at(i));
if (res) {
-#if 0
- cached_j = i;
-#endif
- blk->incomplete();
- return;
- }
- }
-}
-
-void HeapRegionSeq::iterate_from(int idx, HeapRegionClosure* blk) {
- int len = _regions.length();
- int i;
- for (i = idx; i < len; i++) {
- if (blk->doHeapRegion(_regions.at(i))) {
- blk->incomplete();
- return;
- }
- }
- for (i = 0; i < idx; i++) {
- if (blk->doHeapRegion(_regions.at(i))) {
blk->incomplete();
return;
}
@@ -283,54 +206,92 @@
}
MemRegion HeapRegionSeq::shrink_by(size_t shrink_bytes,
- size_t& num_regions_deleted) {
+ size_t* num_regions_deleted) {
// Reset this in case it's currently pointing into the regions that
// we just removed.
- _alloc_search_start = 0;
+ _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");
- if (_regions.length() == 0) {
- num_regions_deleted = 0;
- return MemRegion();
- }
- int j = _regions.length() - 1;
- HeapWord* end = _regions.at(j)->end();
+ // around the loop, i will be the next region to be removed
+ size_t 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;
- while (j >= 0 && shrink_bytes > 0) {
- HeapRegion* cur = _regions.at(j);
- // We have to leave humongous regions where they are,
- // and work around them.
- if (cur->isHumongous()) {
- return MemRegion(last_start, end);
- }
- assert(cur == _regions.top(), "Should be top");
+ *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();
- num_regions_deleted++;
- _regions.pop();
last_start = cur->bottom();
- // We need to delete these somehow, but can't currently do so here: if
- // we do, the ZF thread may still access the deleted region. We'll
- // leave this here as a reminder that we have to do something about
- // this.
- // delete cur;
- j--;
+ 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);
}
-class PrintHeapRegionClosure : public HeapRegionClosure {
-public:
- bool doHeapRegion(HeapRegion* r) {
- gclog_or_tty->print(PTR_FORMAT ":", r);
- r->print();
- return false;
+#ifndef PRODUCT
+void HeapRegionSeq::verify_optional() {
+ guarantee(_length <= _allocated_length,
+ err_msg("invariant: _length: "SIZE_FORMAT" "
+ "_allocated_length: "SIZE_FORMAT,
+ _length, _allocated_length));
+ guarantee(_allocated_length <= _max_length,
+ err_msg("invariant: _allocated_length: "SIZE_FORMAT" "
+ "_max_length: "SIZE_FORMAT,
+ _allocated_length, _max_length));
+ guarantee(_next_search_index <= _length,
+ err_msg("invariant: _next_search_index: "SIZE_FORMAT" "
+ "_length: "SIZE_FORMAT,
+ _next_search_index, _length));
+
+ HeapWord* prev_end = _heap_bottom;
+ for (size_t i = 0; i < _allocated_length; i += 1) {
+ HeapRegion* hr = _regions[i];
+ guarantee(hr != NULL, err_msg("invariant: i: "SIZE_FORMAT, i));
+ guarantee(hr->bottom() == prev_end,
+ err_msg("invariant i: "SIZE_FORMAT" "HR_FORMAT" "
+ "prev_end: "PTR_FORMAT,
+ i, HR_FORMAT_PARAMS(hr), prev_end));
+ guarantee(hr->hrs_index() == i,
+ err_msg("invariant: i: "SIZE_FORMAT" hrs_index(): "SIZE_FORMAT,
+ 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.
+ assert(hr->containing_set() == NULL, "sanity");
+ }
+ if (hr->startsHumongous()) {
+ prev_end = hr->orig_end();
+ } else {
+ prev_end = hr->end();
+ }
}
-};
-
-void HeapRegionSeq::print() {
- PrintHeapRegionClosure cl;
- iterate(&cl);
+ for (size_t i = _allocated_length; i < _max_length; i += 1) {
+ guarantee(_regions[i] == NULL, err_msg("invariant i: "SIZE_FORMAT, i));
+ }
}
+#endif // PRODUCT