Mercurial > hg > graal-compiler
diff src/share/vm/memory/cardTableModRefBS.cpp @ 208:35ca13d63fe8
6688799: Second fix for Guarantee failure "Unexpected dirty card found"
Summary: Expand cardtable without committing over existing regions.
Reviewed-by: apetrusenko
author | jmasa |
---|---|
date | Tue, 10 Jun 2008 07:26:42 -0700 |
parents | ba764ed4b6f2 |
children | 9c2ecc2ffb12 bb254e57d2f4 |
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--- a/src/share/vm/memory/cardTableModRefBS.cpp Mon Jun 09 07:18:59 2008 -0700 +++ b/src/share/vm/memory/cardTableModRefBS.cpp Tue Jun 10 07:26:42 2008 -0700 @@ -196,6 +196,8 @@ assert(_whole_heap.contains(new_region), "attempt to cover area not in reserved area"); debug_only(verify_guard();) + // collided is true if the expansion would push into another committed region + debug_only(bool collided = false;) int const ind = find_covering_region_by_base(new_region.start()); MemRegion const old_region = _covered[ind]; assert(old_region.start() == new_region.start(), "just checking"); @@ -211,12 +213,36 @@ } // Align the end up to a page size (starts are already aligned). jbyte* const new_end = byte_after(new_region.last()); - HeapWord* const new_end_aligned = + HeapWord* new_end_aligned = (HeapWord*) align_size_up((uintptr_t)new_end, _page_size); assert(new_end_aligned >= (HeapWord*) new_end, "align up, but less"); + int ri = 0; + for (ri = 0; ri < _cur_covered_regions; ri++) { + if (ri != ind) { + if (_committed[ri].contains(new_end_aligned)) { + assert((new_end_aligned >= _committed[ri].start()) && + (_committed[ri].start() > _committed[ind].start()), + "New end of committed region is inconsistent"); + new_end_aligned = _committed[ri].start(); + assert(new_end_aligned > _committed[ind].start(), + "New end of committed region is before start"); + debug_only(collided = true;) + // Should only collide with 1 region + break; + } + } + } +#ifdef ASSERT + for (++ri; ri < _cur_covered_regions; ri++) { + assert(!_committed[ri].contains(new_end_aligned), + "New end of committed region is in a second committed region"); + } +#endif // The guard page is always committed and should not be committed over. - HeapWord* const new_end_for_commit = MIN2(new_end_aligned, _guard_region.start()); + HeapWord* const new_end_for_commit = MIN2(new_end_aligned, + _guard_region.start()); + if (new_end_for_commit > cur_committed.end()) { // Must commit new pages. MemRegion const new_committed = @@ -239,9 +265,11 @@ if (!uncommit_region.is_empty()) { if (!os::uncommit_memory((char*)uncommit_region.start(), uncommit_region.byte_size())) { - // Do better than this for Merlin - vm_exit_out_of_memory(uncommit_region.byte_size(), - "card table contraction"); + assert(false, "Card table contraction failed"); + // The call failed so don't change the end of the + // committed region. This is better than taking the + // VM down. + new_end_aligned = _committed[ind].end(); } } } @@ -257,8 +285,25 @@ } assert(index_for(new_region.last()) < (int) _guard_index, "The guard card will be overwritten"); - jbyte* const end = byte_after(new_region.last()); + // This line commented out cleans the newly expanded region and + // not the aligned up expanded region. + // jbyte* const end = byte_after(new_region.last()); + jbyte* const end = (jbyte*) new_end_for_commit; + assert((end >= byte_after(new_region.last())) || collided, + "Expect to be beyond new region unless impacting another region"); // do nothing if we resized downward. +#ifdef ASSERT + for (int ri = 0; ri < _cur_covered_regions; ri++) { + if (ri != ind) { + // The end of the new committed region should not + // be in any existing region unless it matches + // the start of the next region. + assert(!_committed[ri].contains(end) || + (_committed[ri].start() == (HeapWord*) end), + "Overlapping committed regions"); + } + } +#endif if (entry < end) { memset(entry, clean_card, pointer_delta(end, entry, sizeof(jbyte))); }