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7144296: PS: Optimize nmethods processing

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Prunes scavenge roots in code list every young GC, promote objects directly pointed by the code immediately

Reviewed-by: johnc, jcoomes
This commit is contained in:
Igor Veresov 2012-02-10 17:40:20 -08:00
parent 01ee621b40
commit 47d1b9ee33
7 changed files with 193 additions and 180 deletions
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163
hotspot/src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.cpp
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@ -1,5 +1,5 @@
/*
* Copyright (c) 2002, 2011, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2002, 2012, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -247,167 +247,6 @@ void PSPromotionManager::flush_labs() {
}
}
//
// This method is pretty bulky. It would be nice to split it up
// into smaller submethods, but we need to be careful not to hurt
// performance.
//
oop PSPromotionManager::copy_to_survivor_space(oop o) {
assert(PSScavenge::should_scavenge(&o), "Sanity");
oop new_obj = NULL;
// NOTE! We must be very careful with any methods that access the mark
// in o. There may be multiple threads racing on it, and it may be forwarded
// at any time. Do not use oop methods for accessing the mark!
markOop test_mark = o->mark();
// The same test as "o->is_forwarded()"
if (!test_mark->is_marked()) {
bool new_obj_is_tenured = false;
size_t new_obj_size = o->size();
// Find the objects age, MT safe.
int age = (test_mark->has_displaced_mark_helper() /* o->has_displaced_mark() */) ?
test_mark->displaced_mark_helper()->age() : test_mark->age();
// Try allocating obj in to-space (unless too old)
if (age < PSScavenge::tenuring_threshold()) {
new_obj = (oop) _young_lab.allocate(new_obj_size);
if (new_obj == NULL && !_young_gen_is_full) {
// Do we allocate directly, or flush and refill?
if (new_obj_size > (YoungPLABSize / 2)) {
// Allocate this object directly
new_obj = (oop)young_space()->cas_allocate(new_obj_size);
} else {
// Flush and fill
_young_lab.flush();
HeapWord* lab_base = young_space()->cas_allocate(YoungPLABSize);
if (lab_base != NULL) {
_young_lab.initialize(MemRegion(lab_base, YoungPLABSize));
// Try the young lab allocation again.
new_obj = (oop) _young_lab.allocate(new_obj_size);
} else {
_young_gen_is_full = true;
}
}
}
}
// Otherwise try allocating obj tenured
if (new_obj == NULL) {
#ifndef PRODUCT
if (Universe::heap()->promotion_should_fail()) {
return oop_promotion_failed(o, test_mark);
}
#endif // #ifndef PRODUCT
new_obj = (oop) _old_lab.allocate(new_obj_size);
new_obj_is_tenured = true;
if (new_obj == NULL) {
if (!_old_gen_is_full) {
// Do we allocate directly, or flush and refill?
if (new_obj_size > (OldPLABSize / 2)) {
// Allocate this object directly
new_obj = (oop)old_gen()->cas_allocate(new_obj_size);
} else {
// Flush and fill
_old_lab.flush();
HeapWord* lab_base = old_gen()->cas_allocate(OldPLABSize);
if(lab_base != NULL) {
_old_lab.initialize(MemRegion(lab_base, OldPLABSize));
// Try the old lab allocation again.
new_obj = (oop) _old_lab.allocate(new_obj_size);
}
}
}
// This is the promotion failed test, and code handling.
// The code belongs here for two reasons. It is slightly
// different thatn the code below, and cannot share the
// CAS testing code. Keeping the code here also minimizes
// the impact on the common case fast path code.
if (new_obj == NULL) {
_old_gen_is_full = true;
return oop_promotion_failed(o, test_mark);
}
}
}
assert(new_obj != NULL, "allocation should have succeeded");
// Copy obj
Copy::aligned_disjoint_words((HeapWord*)o, (HeapWord*)new_obj, new_obj_size);
// Now we have to CAS in the header.
if (o->cas_forward_to(new_obj, test_mark)) {
// We won any races, we "own" this object.
assert(new_obj == o->forwardee(), "Sanity");
// Increment age if obj still in new generation. Now that
// we're dealing with a markOop that cannot change, it is
// okay to use the non mt safe oop methods.
if (!new_obj_is_tenured) {
new_obj->incr_age();
assert(young_space()->contains(new_obj), "Attempt to push non-promoted obj");
}
// Do the size comparison first with new_obj_size, which we
// already have. Hopefully, only a few objects are larger than
// _min_array_size_for_chunking, and most of them will be arrays.
// So, the is->objArray() test would be very infrequent.
if (new_obj_size > _min_array_size_for_chunking &&
new_obj->is_objArray() &&
PSChunkLargeArrays) {
// we'll chunk it
oop* const masked_o = mask_chunked_array_oop(o);
push_depth(masked_o);
TASKQUEUE_STATS_ONLY(++_arrays_chunked; ++_masked_pushes);
} else {
// we'll just push its contents
new_obj->push_contents(this);
}
} else {
// We lost, someone else "owns" this object
guarantee(o->is_forwarded(), "Object must be forwarded if the cas failed.");
// Try to deallocate the space. If it was directly allocated we cannot
// deallocate it, so we have to test. If the deallocation fails,
// overwrite with a filler object.
if (new_obj_is_tenured) {
if (!_old_lab.unallocate_object((HeapWord*) new_obj, new_obj_size)) {
CollectedHeap::fill_with_object((HeapWord*) new_obj, new_obj_size);
}
} else if (!_young_lab.unallocate_object((HeapWord*) new_obj, new_obj_size)) {
CollectedHeap::fill_with_object((HeapWord*) new_obj, new_obj_size);
}
// don't update this before the unallocation!
new_obj = o->forwardee();
}
} else {
assert(o->is_forwarded(), "Sanity");
new_obj = o->forwardee();
}
#ifdef DEBUG
// This code must come after the CAS test, or it will print incorrect
// information.
if (TraceScavenge) {
gclog_or_tty->print_cr("{%s %s " PTR_FORMAT " -> " PTR_FORMAT " (" SIZE_FORMAT ")}",
PSScavenge::should_scavenge(&new_obj) ? "copying" : "tenuring",
new_obj->blueprint()->internal_name(), o, new_obj, new_obj->size());
}
#endif
return new_obj;
}
template <class T> void PSPromotionManager::process_array_chunk_work(
oop obj,
int start, int end) {