--- a/hotspot/src/share/vm/memory/barrierSet.inline.hpp Tue Nov 24 15:19:30 2009 -0800
+++ b/hotspot/src/share/vm/memory/barrierSet.inline.hpp Thu Dec 03 15:01:57 2009 -0800
@@ -43,6 +43,8 @@
}
void BarrierSet::write_ref_array(MemRegion mr) {
+ assert((HeapWord*)align_size_down((uintptr_t)mr.start(), HeapWordSize) == mr.start() , "Unaligned start");
+ assert((HeapWord*)align_size_up ((uintptr_t)mr.end(), HeapWordSize) == mr.end(), "Unaligned end" );
if (kind() == CardTableModRef) {
((CardTableModRefBS*)this)->inline_write_ref_array(mr);
} else {
@@ -50,6 +52,34 @@
}
}
+// count is number of array elements being written
+void BarrierSet::write_ref_array(HeapWord* start, size_t count) {
+ assert(count <= (size_t)max_intx, "count too large");
+ HeapWord* end = (HeapWord*)((char*)start + (count*heapOopSize));
+ // In the case of compressed oops, start and end may potentially be misaligned;
+ // so we need to conservatively align the first downward (this is not
+ // strictly necessary for current uses, but a case of good hygiene and,
+ // if you will, aesthetics) and the second upward (this is essential for
+ // current uses) to a HeapWord boundary, so we mark all cards overlapping
+ // this write. In the event that this evolves in the future to calling a
+ // logging barrier of narrow oop granularity, like the pre-barrier for G1
+ // (mentioned here merely by way of example), we will need to change this
+ // interface, much like the pre-barrier one above, so it is "exactly precise"
+ // (if i may be allowed the adverbial redundancy for emphasis) and does not
+ // include narrow oop slots not included in the original write interval.
+ HeapWord* aligned_start = (HeapWord*)align_size_down((uintptr_t)start, HeapWordSize);
+ HeapWord* aligned_end = (HeapWord*)align_size_up ((uintptr_t)end, HeapWordSize);
+ // If compressed oops were not being used, these should already be aligned
+ assert(UseCompressedOops || (aligned_start == start && aligned_end == end),
+ "Expected heap word alignment of start and end");
+#if 0
+ warning("Post:\t" INTPTR_FORMAT "[" SIZE_FORMAT "] : [" INTPTR_FORMAT","INTPTR_FORMAT")\t",
+ start, count, aligned_start, aligned_end);
+#endif
+ write_ref_array_work(MemRegion(aligned_start, aligned_end));
+}
+
+
void BarrierSet::write_region(MemRegion mr) {
if (kind() == CardTableModRef) {
((CardTableModRefBS*)this)->inline_write_region(mr);