src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp
Print this page
rev 3986 : 7176479: G1: JVM crashes on T5-8 system with 1.5 TB heap
Summary: Refactor G1's hot card cache and card counts table into their own files. Simplify the card counts table, including removing the encoding of the card index in each entry. The card counts table now has a 1:1 correspondence with the cards spanned by heap. Space for the card counts table is reserved from virtual memory (rather than C heap) during JVM startup and is committed/expanded when the heap is expanded.
Reviewed-by:
@@ -1,7 +1,7 @@
/*
- * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2013, 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
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
@@ -94,11 +94,11 @@
G1RemSet* g1rs,
ConcurrentG1Refine* cg1r) :
_sts(sts), _g1rs(g1rs), _cg1r(cg1r), _concurrent(true)
{}
bool do_card_ptr(jbyte* card_ptr, int worker_i) {
- bool oops_into_cset = _g1rs->concurrentRefineOneCard(card_ptr, worker_i, false);
+ bool oops_into_cset = _g1rs->refine_card(card_ptr, worker_i, false);
// This path is executed by the concurrent refine or mutator threads,
// concurrently, and so we do not care if card_ptr contains references
// that point into the collection set.
assert(!oops_into_cset, "should be");
@@ -1432,13 +1432,14 @@
print_hrs_post_compaction();
_hr_printer.end_gc(true /* full */, (size_t) total_collections());
}
- if (_cg1r->use_cache()) {
- _cg1r->clear_and_record_card_counts();
- _cg1r->clear_hot_cache();
+ G1HotCardCache* hot_card_cache = _cg1r->hot_card_cache();
+ if (hot_card_cache->use_cache()) {
+ hot_card_cache->reset_card_counts();
+ hot_card_cache->reset_hot_cache();
}
// Rebuild remembered sets of all regions.
if (G1CollectedHeap::use_parallel_gc_threads()) {
uint n_workers =
@@ -1741,10 +1742,12 @@
_g1_committed.set_end(new_end);
// Tell the card table about the update.
Universe::heap()->barrier_set()->resize_covered_region(_g1_committed);
// Tell the BOT about the update.
_bot_shared->resize(_g1_committed.word_size());
+ // Tell the hot card cache about the update
+ _cg1r->hot_card_cache()->resize_card_counts(capacity());
}
bool G1CollectedHeap::expand(size_t expand_bytes) {
size_t old_mem_size = _g1_storage.committed_size();
size_t aligned_expand_bytes = ReservedSpace::page_align_size_up(expand_bytes);
@@ -1982,11 +1985,11 @@
// Ensure that the sizes are properly aligned.
Universe::check_alignment(init_byte_size, HeapRegion::GrainBytes, "g1 heap");
Universe::check_alignment(max_byte_size, HeapRegion::GrainBytes, "g1 heap");
- _cg1r = new ConcurrentG1Refine();
+ _cg1r = new ConcurrentG1Refine(this);
// Reserve the maximum.
// When compressed oops are enabled, the preferred heap base
// is calculated by subtracting the requested size from the
@@ -2043,10 +2046,13 @@
_g1_committed = MemRegion((HeapWord*)_g1_storage.low(), (size_t) 0);
_hrs.initialize((HeapWord*) _g1_reserved.start(),
(HeapWord*) _g1_reserved.end(),
_expansion_regions);
+ // Do later initialization work for concurrent refinement.
+ _cg1r->init();
+
// 6843694 - ensure that the maximum region index can fit
// in the remembered set structures.
const uint max_region_idx = (1U << (sizeof(RegionIdx_t)*BitsPerByte-1)) - 1;
guarantee((max_regions() - 1) <= max_region_idx, "too many regions");
@@ -2135,13 +2141,10 @@
// In case we're keeping closure specialization stats, initialize those
// counts and that mechanism.
SpecializationStats::clear();
- // Do later initialization work for concurrent refinement.
- _cg1r->init();
-
// Here we allocate the dummy full region that is required by the
// G1AllocRegion class. If we don't pass an address in the reserved
// space here, lots of asserts fire.
HeapRegion* dummy_region = new_heap_region(0 /* index of bottom region */,
@@ -2296,11 +2299,12 @@
void G1CollectedHeap::iterate_dirty_card_closure(CardTableEntryClosure* cl,
DirtyCardQueue* into_cset_dcq,
bool concurrent,
int worker_i) {
// Clean cards in the hot card cache
- concurrent_g1_refine()->clean_up_cache(worker_i, g1_rem_set(), into_cset_dcq);
+ G1HotCardCache* hot_card_cache = _cg1r->hot_card_cache();
+ hot_card_cache->drain(worker_i, g1_rem_set(), into_cset_dcq);
DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
int n_completed_buffers = 0;
while (dcqs.apply_closure_to_completed_buffer(cl, worker_i, 0, true)) {
n_completed_buffers++;
@@ -5593,12 +5597,15 @@
// Should G1EvacuationFailureALot be in effect for this GC?
NOT_PRODUCT(set_evacuation_failure_alot_for_current_gc();)
g1_rem_set()->prepare_for_oops_into_collection_set_do();
- concurrent_g1_refine()->set_use_cache(false);
- concurrent_g1_refine()->clear_hot_cache_claimed_index();
+
+ // Disable the hot card cache.
+ G1HotCardCache* hot_card_cache = _cg1r->hot_card_cache();
+ hot_card_cache->reset_hot_cache_claimed_index();
+ hot_card_cache->set_use_cache(false);
uint n_workers;
if (G1CollectedHeap::use_parallel_gc_threads()) {
n_workers =
AdaptiveSizePolicy::calc_active_workers(workers()->total_workers(),
@@ -5676,12 +5683,15 @@
}
release_gc_alloc_regions(n_workers);
g1_rem_set()->cleanup_after_oops_into_collection_set_do();
- concurrent_g1_refine()->clear_hot_cache();
- concurrent_g1_refine()->set_use_cache(true);
+ // Reset and re-enable the hot card cache.
+ // Note the counts for the cards in the regions in the
+ // collection set are reset when the collection set is freed.
+ hot_card_cache->reset_hot_cache();
+ hot_card_cache->set_use_cache(true);
finalize_for_evac_failure();
if (evacuation_failed()) {
remove_self_forwarding_pointers();
@@ -5739,10 +5749,16 @@
bool par) {
assert(!hr->isHumongous(), "this is only for non-humongous regions");
assert(!hr->is_empty(), "the region should not be empty");
assert(free_list != NULL, "pre-condition");
+ // Clear the card counts for this region.
+ // Note: we only need to do this if the region is not young
+ // (since we don't refine cards in young regions).
+ if (!hr->is_young()) {
+ _cg1r->hot_card_cache()->reset_card_counts(hr);
+ }
*pre_used += hr->used();
hr->hr_clear(par, true /* clear_space */);
free_list->add_as_head(hr);
}