942
943 #ifndef PRODUCT
944 void ParallelScavengeHeap::record_gen_tops_before_GC() {
945 if (ZapUnusedHeapArea) {
946 young_gen()->record_spaces_top();
947 old_gen()->record_spaces_top();
948 perm_gen()->record_spaces_top();
949 }
950 }
951
952 void ParallelScavengeHeap::gen_mangle_unused_area() {
953 if (ZapUnusedHeapArea) {
954 young_gen()->eden_space()->mangle_unused_area();
955 young_gen()->to_space()->mangle_unused_area();
956 young_gen()->from_space()->mangle_unused_area();
957 old_gen()->object_space()->mangle_unused_area();
958 perm_gen()->object_space()->mangle_unused_area();
959 }
960 }
961 #endif
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942
943 #ifndef PRODUCT
944 void ParallelScavengeHeap::record_gen_tops_before_GC() {
945 if (ZapUnusedHeapArea) {
946 young_gen()->record_spaces_top();
947 old_gen()->record_spaces_top();
948 perm_gen()->record_spaces_top();
949 }
950 }
951
952 void ParallelScavengeHeap::gen_mangle_unused_area() {
953 if (ZapUnusedHeapArea) {
954 young_gen()->eden_space()->mangle_unused_area();
955 young_gen()->to_space()->mangle_unused_area();
956 young_gen()->from_space()->mangle_unused_area();
957 old_gen()->object_space()->mangle_unused_area();
958 perm_gen()->object_space()->mangle_unused_area();
959 }
960 }
961 #endif
962
963 bool ParallelScavengeHeap::try_to_shrink_by_free_ratio(bool isFullGC) {
964 if (MaxHeapFreeRatio >= 100) {
965 // nothing to do in this case
966 return false;
967 }
968
969 size_t capacity = old_gen()->capacity_in_bytes() + young_gen()->capacity_in_bytes();
970 size_t used = old_gen()->used_in_bytes() + young_gen()->used_in_bytes();
971 size_t init_size = old_gen()->init_gen_size() + young_gen()->init_gen_size();
972 const double maximum_free_percentage = MaxHeapFreeRatio / 100.0;
973 const double minimum_used_percentage = 1.0 - maximum_free_percentage;
974 const double max_tmp = used / minimum_used_percentage;
975 size_t maximum_desired_capacity = (size_t)MIN2(max_tmp, double(max_uintx));
976 maximum_desired_capacity = MAX2(maximum_desired_capacity, init_size);
977
978 if (PrintGC && Verbose) {
979 const double free_ratio = 1.0 - (double) used / capacity;
980 gclog_or_tty->print("Shrink by free ratio: ");
981 gclog_or_tty->print("capacity : " SIZE_FORMAT ", ", capacity);
982 gclog_or_tty->print("used : " SIZE_FORMAT ", ", used);
983 gclog_or_tty->print_cr("free ratio : %f.2", free_ratio);
984 }
985
986 size_t free_bytes = capacity - used;
987 if (capacity > maximum_desired_capacity && free_bytes > 0) {
988 size_t young_gen_free_bytes = young_gen()->capacity_in_bytes() - young_gen()->used_in_bytes();
989 size_t old_gen_free_bytes = old_gen()->capacity_in_bytes() - old_gen()->used_in_bytes();
990 size_t shrink_bytes = capacity - maximum_desired_capacity;
991 if (isFullGC) {
992 size_t old_gen_shrink_bytes =
993 (size_t) (shrink_bytes * ((double) old_gen_free_bytes / free_bytes));
994 old_gen()->try_to_shrink_by(old_gen_shrink_bytes);
995 }
996 size_t young_gen_shrink_bytes =
997 (size_t) (shrink_bytes * ((double) young_gen_free_bytes / free_bytes));
998 young_gen()->try_to_shrink_by(young_gen_shrink_bytes);
999 return true;
1000 }
1001 return false;
1002 }
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