CardGeneration::CardGeneration(ReservedSpace rs,
size_t initial_byte_size,
CardTableRS* remset) :
Generation(rs, initial_byte_size), _rs(remset),
_shrink_factor(0), _min_heap_delta_bytes(), _capacity_at_prologue(),
_used_at_prologue()
{
HeapWord* start = (HeapWord*)rs.base();
size_t reserved_byte_size = rs.size();
assert((uintptr_t(start) & 3) == 0, "bad alignment");
assert((reserved_byte_size & 3) == 0, "bad alignment");
MemRegion reserved_mr(start, heap_word_size(reserved_byte_size));
_bts = new BlockOffsetSharedArray(reserved_mr,
heap_word_size(initial_byte_size));
MemRegion committed_mr(start, heap_word_size(initial_byte_size));
_rs->resize_covered_region(committed_mr);
if (_bts == NULL) {
vm_exit_during_initialization("Could not allocate a BlockOffsetArray");
}
// Verify that the start and end of this generation is the start of a card.
// If this wasn't true, a single card could span more than on generation,
// which would cause problems when we commit/uncommit memory, and when we
// clear and dirty cards.
guarantee(_rs->is_aligned(reserved_mr.start()), "generation must be card aligned");
if (reserved_mr.end() != GenCollectedHeap::heap()->reserved_region().end()) {
// Don't check at the very end of the heap as we'll assert that we're probing off
// the end if we try.
guarantee(_rs->is_aligned(reserved_mr.end()), "generation must be card aligned");
}
_min_heap_delta_bytes = MinHeapDeltaBytes;
_capacity_at_prologue = initial_byte_size;
_used_at_prologue = 0;
}
CardGeneration::CardGeneration(ReservedSpace rs, size_t initial_byte_size,
int level,
GenRemSet* remset) :
Generation(rs, initial_byte_size, level), _rs(remset)
{
HeapWord* start = (HeapWord*)rs.base();
size_t reserved_byte_size = rs.size();
assert((uintptr_t(start) & 3) == 0, "bad alignment");
assert((reserved_byte_size & 3) == 0, "bad alignment");
MemRegion reserved_mr(start, heap_word_size(reserved_byte_size));
_bts = new BlockOffsetSharedArray(reserved_mr,
heap_word_size(initial_byte_size));
MemRegion committed_mr(start, heap_word_size(initial_byte_size));
_rs->resize_covered_region(committed_mr);
if (_bts == NULL)
vm_exit_during_initialization("Could not allocate a BlockOffsetArray");
// Verify that the start and end of this generation is the start of a card.
// If this wasn't true, a single card could span more than on generation,
// which would cause problems when we commit/uncommit memory, and when we
// clear and dirty cards.
guarantee(_rs->is_aligned(reserved_mr.start()), "generation must be card aligned");
if (reserved_mr.end() != Universe::heap()->reserved_region().end()) {
// Don't check at the very end of the heap as we'll assert that we're probing off
// the end if we try.
guarantee(_rs->is_aligned(reserved_mr.end()), "generation must be card aligned");
}
}
bool CardGeneration::grow_by(size_t bytes) {
assert_correct_size_change_locking();
bool result = _virtual_space.expand_by(bytes);
if (result) {
size_t new_word_size =
heap_word_size(_virtual_space.committed_size());
MemRegion mr(space()->bottom(), new_word_size);
// Expand card table
GenCollectedHeap::heap()->barrier_set()->resize_covered_region(mr);
// Expand shared block offset array
_bts->resize(new_word_size);
// Fix for bug #4668531
if (ZapUnusedHeapArea) {
MemRegion mangle_region(space()->end(),
(HeapWord*)_virtual_space.high());
SpaceMangler::mangle_region(mangle_region);
}
// Expand space -- also expands space's BOT
// (which uses (part of) shared array above)
space()->set_end((HeapWord*)_virtual_space.high());
// update the space and generation capacity counters
update_counters();
size_t new_mem_size = _virtual_space.committed_size();
size_t old_mem_size = new_mem_size - bytes;
log_trace(gc, heap)("Expanding %s from " SIZE_FORMAT "K by " SIZE_FORMAT "K to " SIZE_FORMAT "K",
name(), old_mem_size/K, bytes/K, new_mem_size/K);
}
return result;
}
/**
* 当前是否需要尝试在旧生代分配内存
* 1).待分配的内存大小 > 年青代容量
* 2).当前内存堆需要一次GC
* 3).内存堆的增量式GC刚刚失败
*/
bool GenCollectorPolicy::should_try_older_generation_allocation(
size_t word_size) const {
GenCollectedHeap* gch = GenCollectedHeap::heap();
size_t gen0_capacity = gch->get_gen(0)->capacity_before_gc();
return (word_size > heap_word_size(gen0_capacity))
|| GC_locker::is_active_and_needs_gc() || gch->incremental_collection_failed();
}
bool OneContigSpaceCardGeneration::grow_by(size_t bytes) {
assert_locked_or_safepoint(ExpandHeap_lock);
bool result = _virtual_space.expand_by(bytes);
if (result) {
size_t new_word_size =
heap_word_size(_virtual_space.committed_size());
MemRegion mr(_the_space->bottom(), new_word_size);
// Expand card table
Universe::heap()->barrier_set()->resize_covered_region(mr);
// Expand shared block offset array
_bts->resize(new_word_size);
// Fix for bug #4668531
if (ZapUnusedHeapArea) {
MemRegion mangle_region(_the_space->end(),
(HeapWord*)_virtual_space.high());
SpaceMangler::mangle_region(mangle_region);
}
// Expand space -- also expands space's BOT
// (which uses (part of) shared array above)
_the_space->set_end((HeapWord*)_virtual_space.high());
// update the space and generation capacity counters
update_counters();
if (Verbose && PrintGC) {
size_t new_mem_size = _virtual_space.committed_size();
size_t old_mem_size = new_mem_size - bytes;
gclog_or_tty->print_cr("Expanding %s from " SIZE_FORMAT "K by "
SIZE_FORMAT "K to " SIZE_FORMAT "K",
name(), old_mem_size/K, bytes/K, new_mem_size/K);
}
}
return result;
}
// NOTE! We need to be careful about resizing. During a GC, multiple
// allocators may be active during heap expansion. If we allow the
// heap resizing to become visible before we have correctly resized
// all heap related data structures, we may cause program failures.
void PSOldGen::post_resize() {
// First construct a memregion representing the new size
MemRegion new_memregion((HeapWord*)_virtual_space.low(), (HeapWord*)_virtual_space.high());
size_t new_word_size = new_memregion.word_size();
// Block offset table resize FIX ME!!!!!
// _bts->resize(new_word_size);
Universe::heap()->barrier_set()->resize_covered_region(new_memregion);
// Did we expand?
if (object_space()->end() < (HeapWord*) _virtual_space.high()) {
// We need to mangle the newly expanded area. The memregion spans
// end -> new_end, we assume that top -> end is already mangled.
// This cannot be safely tested for, as allocation may be taking
// place.
MemRegion mangle_region(object_space()->end(),(HeapWord*) _virtual_space.high());
object_space()->mangle_region(mangle_region);
}
// ALWAYS do this last!!
object_space()->set_end((HeapWord*) _virtual_space.high());
assert(new_word_size == heap_word_size(object_space()->capacity_in_bytes()), "Sanity");
}
CompactingPermGenGen::CompactingPermGenGen(ReservedSpace rs,
ReservedSpace shared_rs,
size_t initial_byte_size,
int level, GenRemSet* remset,
ContiguousSpace* space,
PermanentGenerationSpec* spec_) :
OneContigSpaceCardGeneration(rs, initial_byte_size, MinPermHeapExpansion,
level, remset, space) {
set_spec(spec_);
if (!UseSharedSpaces && !DumpSharedSpaces) {
spec()->disable_sharing();
}
// Break virtual space into address ranges for all spaces.
if (spec()->enable_shared_spaces()) {
shared_end = (HeapWord*)(shared_rs.base() + shared_rs.size());
misccode_end = shared_end;
misccode_bottom = misccode_end - heap_word_size(spec()->misc_code_size());
miscdata_end = misccode_bottom;
miscdata_bottom = miscdata_end - heap_word_size(spec()->misc_data_size());
readwrite_end = miscdata_bottom;
readwrite_bottom =
readwrite_end - heap_word_size(spec()->read_write_size());
readonly_end = readwrite_bottom;
readonly_bottom =
readonly_end - heap_word_size(spec()->read_only_size());
shared_bottom = readonly_bottom;
unshared_end = shared_bottom;
assert((char*)shared_bottom == shared_rs.base(), "shared space mismatch");
} else {
shared_end = (HeapWord*)(rs.base() + rs.size());
misccode_end = shared_end;
misccode_bottom = shared_end;
miscdata_end = shared_end;
miscdata_bottom = shared_end;
readwrite_end = shared_end;
readwrite_bottom = shared_end;
readonly_end = shared_end;
readonly_bottom = shared_end;
shared_bottom = shared_end;
unshared_end = shared_bottom;
}
unshared_bottom = (HeapWord*) rs.base();
// Verify shared and unshared spaces adjacent.
assert((char*)shared_bottom == rs.base()+rs.size(), "shared space mismatch");
assert(unshared_end > unshared_bottom, "shared space mismatch");
// Split reserved memory into pieces.
ReservedSpace ro_rs = shared_rs.first_part(spec()->read_only_size(),
UseSharedSpaces);
ReservedSpace tmp_rs1 = shared_rs.last_part(spec()->read_only_size());
ReservedSpace rw_rs = tmp_rs1.first_part(spec()->read_write_size(),
UseSharedSpaces);
ReservedSpace tmp_rs2 = tmp_rs1.last_part(spec()->read_write_size());
ReservedSpace md_rs = tmp_rs2.first_part(spec()->misc_data_size(),
UseSharedSpaces);
ReservedSpace mc_rs = tmp_rs2.last_part(spec()->misc_data_size());
_shared_space_size = spec()->read_only_size()
+ spec()->read_write_size()
+ spec()->misc_data_size()
+ spec()->misc_code_size();
// Allocate the unshared (default) space.
_the_space = new ContigPermSpace(_bts,
MemRegion(unshared_bottom, heap_word_size(initial_byte_size)));
if (_the_space == NULL)
vm_exit_during_initialization("Could not allocate an unshared"
" CompactingPermGen Space");
// Allocate shared spaces
if (spec()->enable_shared_spaces()) {
// If mapping a shared file, the space is not committed, don't
// mangle.
NOT_PRODUCT(bool old_ZapUnusedHeapArea = ZapUnusedHeapArea;)
static int size(int length) {
size_t sz = heap_word_size(sizeof(SymbolBase) + (length > 0 ? length : 0));
return align_object_size(sz);
}
// Return true if
// The allocation won't fit into the maximum young gen heap
// jvmpi_slow_allocation
bool TwoGenerationCollectorPolicy::should_try_older_generation_allocation(
size_t word_size) const {
return (word_size > heap_word_size(_max_gen0_size)) ||
Universe::jvmpi_slow_allocation();
}