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7026932: G1: No need to abort VM when card count cache expansion fails

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Manage allocation/freeing of the card cache counts and epochs arrays directly so that an allocation failure while attempting to expand these arrays does not abort the JVM. Failure to expand these arrays is not fatal.

Reviewed-by: iveresov, tonyp
This commit is contained in:
John Cuthbertson 2011-03-28 10:58:54 -07:00
parent 4fd9f5071f
commit c2275649b7
3 changed files with 170 additions and 52 deletions
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40
hotspot/src/share/vm/gc_implementation/g1/concurrentG1Refine.hpp
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@ -1,5 +1,5 @@
/*
* Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2001, 2011, 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
@ -94,7 +94,7 @@ class ConcurrentG1Refine: public CHeapObj {
} CardEpochCacheEntry;
julong make_epoch_entry(unsigned int card_num, unsigned int epoch) {
assert(0 <= card_num && card_num < _max_n_card_counts, "Bounds");
assert(0 <= card_num && card_num < _max_cards, "Bounds");
assert(0 <= epoch && epoch <= _n_periods, "must be");
return ((julong) card_num << card_num_shift) | epoch;
@ -117,15 +117,24 @@ class ConcurrentG1Refine: public CHeapObj {
CardEpochCacheEntry* _card_epochs;
// The current number of buckets in the card count cache
unsigned _n_card_counts;
size_t _n_card_counts;
// The max number of buckets required for the number of
// cards for the entire reserved heap
unsigned _max_n_card_counts;
// The number of cards for the entire reserved heap
size_t _max_cards;
// The max number of buckets for the card counts and epochs caches.
// This is the maximum that the counts and epochs will grow to.
// It is specified as a fraction or percentage of _max_cards using
// G1MaxHotCardCountSizePercent.
size_t _max_n_card_counts;
// Possible sizes of the cache: odd primes that roughly double in size.
// (See jvmtiTagMap.cpp).
static int _cc_cache_sizes[];
enum {
MAX_CC_CACHE_INDEX = 15 // maximum index into the cache size array.
};
static size_t _cc_cache_sizes[MAX_CC_CACHE_INDEX];
// The index in _cc_cache_sizes corresponding to the size of
// _card_counts.
@ -147,11 +156,22 @@ class ConcurrentG1Refine: public CHeapObj {
CardTableModRefBS* _ct_bs;
G1CollectedHeap* _g1h;
// Expands the array that holds the card counts to the next size up
void expand_card_count_cache();
// Helper routine for expand_card_count_cache().
// The arrays used to hold the card counts and the epochs must have
// a 1:1 correspondence. Hence they are allocated and freed together.
// Returns true if the allocations of both the counts and epochs
// were successful; false otherwise.
bool allocate_card_count_cache(size_t n,
CardCountCacheEntry** counts,
CardEpochCacheEntry** epochs);
// Expands the arrays that hold the card counts and epochs
// to the cache size at index. Returns true if the expansion/
// allocation was successful; false otherwise.
bool expand_card_count_cache(int index);
// hash a given key (index of card_ptr) with the specified size
static unsigned int hash(size_t key, int size) {
static unsigned int hash(size_t key, size_t size) {
return (unsigned int) key % size;
}