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6578152: fill_region_with_object has usability and safety issues

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Reviewed-by: apetrusenko, ysr
This commit is contained in:
John Coomes 2008-12-11 12:05:08 -08:00
parent 26f6b1692a
commit 000b184507
25 changed files with 261 additions and 198 deletions
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39
hotspot/src/share/vm/gc_interface/collectedHeap.hpp
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@ -47,6 +47,9 @@ class CollectedHeap : public CHeapObj {
static int _fire_out_of_memory_count;
#endif
// Used for filler objects (static, but initialized in ctor).
static size_t _filler_array_max_size;
protected:
MemRegion _reserved;
BarrierSet* _barrier_set;
@ -119,6 +122,21 @@ class CollectedHeap : public CHeapObj {
// Clears an allocated object.
inline static void init_obj(HeapWord* obj, size_t size);
// Filler object utilities.
static inline size_t filler_array_hdr_size();
static inline size_t filler_array_min_size();
static inline size_t filler_array_max_size();
DEBUG_ONLY(static void fill_args_check(HeapWord* start, size_t words);)
DEBUG_ONLY(static void zap_filler_array(HeapWord* start, size_t words);)
// Fill with a single array; caller must ensure filler_array_min_size() <=
// words <= filler_array_max_size().
static inline void fill_with_array(HeapWord* start, size_t words);
// Fill with a single object (either an int array or a java.lang.Object).
static inline void fill_with_object_impl(HeapWord* start, size_t words);
// Verification functions
virtual void check_for_bad_heap_word_value(HeapWord* addr, size_t size)
PRODUCT_RETURN;
@ -294,6 +312,27 @@ class CollectedHeap : public CHeapObj {
// The boundary between a "large" and "small" array of primitives, in words.
virtual size_t large_typearray_limit() = 0;
// Utilities for turning raw memory into filler objects.
//
// min_fill_size() is the smallest region that can be filled.
// fill_with_objects() can fill arbitrary-sized regions of the heap using
// multiple objects. fill_with_object() is for regions known to be smaller
// than the largest array of integers; it uses a single object to fill the
// region and has slightly less overhead.
static size_t min_fill_size() {
return size_t(align_object_size(oopDesc::header_size()));
}
static void fill_with_objects(HeapWord* start, size_t words);
static void fill_with_object(HeapWord* start, size_t words);
static void fill_with_object(MemRegion region) {
fill_with_object(region.start(), region.word_size());
}
static void fill_with_object(HeapWord* start, HeapWord* end) {
fill_with_object(start, pointer_delta(end, start));
}
// Some heaps may offer a contiguous region for shared non-blocking
// allocation, via inlined code (by exporting the address of the top and
// end fields defining the extent of the contiguous allocation region.)