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6962589: remove breadth first scanning code from parallel gc

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Remove the breadth-first copying order from ParallelScavenge and use depth-first by default.

Reviewed-by: jcoomes, ysr, johnc
This commit is contained in:
Antonios Printezis 2010-07-22 10:27:41 -04:00
parent 3a2b2b4fd8
commit 38ab95c64b
30 changed files with 63 additions and 541 deletions
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55
hotspot/src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.inline.hpp
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@ -45,33 +45,8 @@ inline void PSPromotionManager::claim_or_forward_internal_depth(T* p) {
}
}
template <class T>
inline void PSPromotionManager::claim_or_forward_internal_breadth(T* p) {
if (p != NULL) { // XXX: error if p != NULL here
oop o = oopDesc::load_decode_heap_oop_not_null(p);
if (o->is_forwarded()) {
o = o->forwardee();
} else {
o = copy_to_survivor_space(o, false);
}
// Card mark
if (PSScavenge::is_obj_in_young((HeapWord*) o)) {
PSScavenge::card_table()->inline_write_ref_field_gc(p, o);
}
oopDesc::encode_store_heap_oop_not_null(p, o);
}
}
inline void PSPromotionManager::flush_prefetch_queue() {
assert(!depth_first(), "invariant");
for (int i = 0; i < _prefetch_queue.length(); i++) {
claim_or_forward_internal_breadth((oop*)_prefetch_queue.pop());
}
}
template <class T>
inline void PSPromotionManager::claim_or_forward_depth(T* p) {
assert(depth_first(), "invariant");
assert(PSScavenge::should_scavenge(p, true), "revisiting object?");
assert(Universe::heap()->kind() == CollectedHeap::ParallelScavengeHeap,
"Sanity");
@ -80,36 +55,6 @@ inline void PSPromotionManager::claim_or_forward_depth(T* p) {
claim_or_forward_internal_depth(p);
}
template <class T>
inline void PSPromotionManager::claim_or_forward_breadth(T* p) {
assert(!depth_first(), "invariant");
assert(PSScavenge::should_scavenge(p, true), "revisiting object?");
assert(Universe::heap()->kind() == CollectedHeap::ParallelScavengeHeap,
"Sanity");
assert(Universe::heap()->is_in(p), "pointer outside heap");
if (UsePrefetchQueue) {
claim_or_forward_internal_breadth((T*)_prefetch_queue.push_and_pop(p));
} else {
// This option is used for testing. The use of the prefetch
// queue can delay the processing of the objects and thus
// change the order of object scans. For example, remembered
// set updates are typically the clearing of the remembered
// set (the cards) followed by updates of the remembered set
// for young-to-old pointers. In a situation where there
// is an error in the sequence of clearing and updating
// (e.g. clear card A, update card A, erroneously clear
// card A again) the error can be obscured by a delay
// in the update due to the use of the prefetch queue
// (e.g., clear card A, erroneously clear card A again,
// update card A that was pushed into the prefetch queue
// and thus delayed until after the erronous clear). The
// length of the delay is random depending on the objects
// in the queue and the delay can be zero.
claim_or_forward_internal_breadth(p);
}
}
inline void PSPromotionManager::process_popped_location_depth(StarTask p) {
if (is_oop_masked(p)) {
assert(PSChunkLargeArrays, "invariant");