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8038423: G1: Decommit memory within heap

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Allow G1 to decommit memory of arbitrary regions within the heap and their associated auxiliary data structures card table, BOT, hot card cache, and mark bitmaps.

Reviewed-by: mgerdin, brutisso, jwilhelm
This commit is contained in:
Thomas Schatzl 2014-08-19 14:09:10 +02:00
parent 2617d54723
commit 100e51a339
32 changed files with 1322 additions and 579 deletions
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17
hotspot/src/share/vm/memory/cardTableModRefBS.hpp
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@ -96,12 +96,12 @@ class CardTableModRefBS: public ModRefBarrierSet {
// The declaration order of these const fields is important; see the
// constructor before changing.
const MemRegion _whole_heap; // the region covered by the card table
const size_t _guard_index; // index of very last element in the card
size_t _guard_index; // index of very last element in the card
// table; it is set to a guard value
// (last_card) and should never be modified
const size_t _last_valid_index; // index of the last valid element
size_t _last_valid_index; // index of the last valid element
const size_t _page_size; // page size used when mapping _byte_map
const size_t _byte_map_size; // in bytes
size_t _byte_map_size; // in bytes
jbyte* _byte_map; // the card marking array
int _cur_covered_regions;
@ -123,7 +123,12 @@ class CardTableModRefBS: public ModRefBarrierSet {
protected:
// Initialization utilities; covered_words is the size of the covered region
// in, um, words.
inline size_t cards_required(size_t covered_words);
inline size_t cards_required(size_t covered_words) {
// Add one for a guard card, used to detect errors.
const size_t words = align_size_up(covered_words, card_size_in_words);
return words / card_size_in_words + 1;
}
inline size_t compute_byte_map_size();
// Finds and return the index of the region, if any, to which the given
@ -137,7 +142,7 @@ class CardTableModRefBS: public ModRefBarrierSet {
int find_covering_region_containing(HeapWord* addr);
// Resize one of the regions covered by the remembered set.
void resize_covered_region(MemRegion new_region);
virtual void resize_covered_region(MemRegion new_region);
// Returns the leftmost end of a committed region corresponding to a
// covered region before covered region "ind", or else "NULL" if "ind" is
@ -282,6 +287,8 @@ public:
CardTableModRefBS(MemRegion whole_heap, int max_covered_regions);
~CardTableModRefBS();
virtual void initialize();
// *** Barrier set functions.
bool has_write_ref_pre_barrier() { return false; }