Mon, 12 Jan 2015 15:24:29 +0100
8062063: Usage of UseHugeTLBFS, UseLargePagesInMetaspace and huge SurvivorAlignmentInBytes cause crashes in CMBitMapClosure::do_bit
Summary: Making sure committed memory is cleared when re-committed, even if using large pages.
Reviewed-by: jwilhelm, tschatzl
1.1 --- a/src/share/vm/gc_implementation/g1/g1PageBasedVirtualSpace.cpp Fri Dec 12 09:07:54 2014 +0100 1.2 +++ b/src/share/vm/gc_implementation/g1/g1PageBasedVirtualSpace.cpp Mon Jan 12 15:24:29 2015 +0100 1.3 @@ -45,7 +45,8 @@ 1.4 #include "utilities/bitMap.inline.hpp" 1.5 1.6 G1PageBasedVirtualSpace::G1PageBasedVirtualSpace() : _low_boundary(NULL), 1.7 - _high_boundary(NULL), _committed(), _page_size(0), _special(false), _executable(false) { 1.8 + _high_boundary(NULL), _committed(), _page_size(0), _special(false), 1.9 + _dirty(), _executable(false) { 1.10 } 1.11 1.12 bool G1PageBasedVirtualSpace::initialize_with_granularity(ReservedSpace rs, size_t page_size) { 1.13 @@ -66,6 +67,9 @@ 1.14 assert(_committed.size() == 0, "virtual space initialized more than once"); 1.15 uintx size_in_bits = rs.size() / page_size; 1.16 _committed.resize(size_in_bits, /* in_resource_area */ false); 1.17 + if (_special) { 1.18 + _dirty.resize(size_in_bits, /* in_resource_area */ false); 1.19 + } 1.20 1.21 return true; 1.22 } 1.23 @@ -84,6 +88,7 @@ 1.24 _executable = false; 1.25 _page_size = 0; 1.26 _committed.resize(0, false); 1.27 + _dirty.resize(0, false); 1.28 } 1.29 1.30 size_t G1PageBasedVirtualSpace::committed_size() const { 1.31 @@ -120,31 +125,40 @@ 1.32 return num * _page_size; 1.33 } 1.34 1.35 -MemRegion G1PageBasedVirtualSpace::commit(uintptr_t start, size_t size_in_pages) { 1.36 +bool G1PageBasedVirtualSpace::commit(uintptr_t start, size_t size_in_pages) { 1.37 // We need to make sure to commit all pages covered by the given area. 1.38 guarantee(is_area_uncommitted(start, size_in_pages), "Specified area is not uncommitted"); 1.39 1.40 - if (!_special) { 1.41 + bool zero_filled = true; 1.42 + uintptr_t end = start + size_in_pages; 1.43 + 1.44 + if (_special) { 1.45 + // Check for dirty pages and update zero_filled if any found. 1.46 + if (_dirty.get_next_one_offset(start,end) < end) { 1.47 + zero_filled = false; 1.48 + _dirty.clear_range(start, end); 1.49 + } 1.50 + } else { 1.51 os::commit_memory_or_exit(page_start(start), byte_size_for_pages(size_in_pages), _executable, 1.52 err_msg("Failed to commit pages from "SIZE_FORMAT" of length "SIZE_FORMAT, start, size_in_pages)); 1.53 } 1.54 - _committed.set_range(start, start + size_in_pages); 1.55 + _committed.set_range(start, end); 1.56 1.57 - MemRegion result((HeapWord*)page_start(start), byte_size_for_pages(size_in_pages) / HeapWordSize); 1.58 - return result; 1.59 + return zero_filled; 1.60 } 1.61 1.62 -MemRegion G1PageBasedVirtualSpace::uncommit(uintptr_t start, size_t size_in_pages) { 1.63 +void G1PageBasedVirtualSpace::uncommit(uintptr_t start, size_t size_in_pages) { 1.64 guarantee(is_area_committed(start, size_in_pages), "checking"); 1.65 1.66 - if (!_special) { 1.67 + if (_special) { 1.68 + // Mark that memory is dirty. If committed again the memory might 1.69 + // need to be cleared explicitly. 1.70 + _dirty.set_range(start, start + size_in_pages); 1.71 + } else { 1.72 os::uncommit_memory(page_start(start), byte_size_for_pages(size_in_pages)); 1.73 } 1.74 1.75 _committed.clear_range(start, start + size_in_pages); 1.76 - 1.77 - MemRegion result((HeapWord*)page_start(start), byte_size_for_pages(size_in_pages) / HeapWordSize); 1.78 - return result; 1.79 } 1.80 1.81 bool G1PageBasedVirtualSpace::contains(const void* p) const { 1.82 @@ -154,7 +168,7 @@ 1.83 #ifndef PRODUCT 1.84 void G1PageBasedVirtualSpace::print_on(outputStream* out) { 1.85 out->print ("Virtual space:"); 1.86 - if (special()) out->print(" (pinned in memory)"); 1.87 + if (_special) out->print(" (pinned in memory)"); 1.88 out->cr(); 1.89 out->print_cr(" - committed: " SIZE_FORMAT, committed_size()); 1.90 out->print_cr(" - reserved: " SIZE_FORMAT, reserved_size());
2.1 --- a/src/share/vm/gc_implementation/g1/g1PageBasedVirtualSpace.hpp Fri Dec 12 09:07:54 2014 +0100 2.2 +++ b/src/share/vm/gc_implementation/g1/g1PageBasedVirtualSpace.hpp Mon Jan 12 15:24:29 2015 +0100 2.3 @@ -49,6 +49,12 @@ 2.4 // Bitmap used for verification of commit/uncommit operations. 2.5 BitMap _committed; 2.6 2.7 + // Bitmap used to keep track of which pages are dirty or not for _special 2.8 + // spaces. This is needed because for those spaces the underlying memory 2.9 + // will only be zero filled the first time it is committed. Calls to commit 2.10 + // will use this bitmap and return whether or not the memory is zero filled. 2.11 + BitMap _dirty; 2.12 + 2.13 // Indicates that the entire space has been committed and pinned in memory, 2.14 // os::commit_memory() or os::uncommit_memory() have no function. 2.15 bool _special; 2.16 @@ -71,12 +77,11 @@ 2.17 public: 2.18 2.19 // Commit the given area of pages starting at start being size_in_pages large. 2.20 - MemRegion commit(uintptr_t start, size_t size_in_pages); 2.21 + // Returns true if the given area is zero filled upon completion. 2.22 + bool commit(uintptr_t start, size_t size_in_pages); 2.23 2.24 // Uncommit the given area of pages starting at start being size_in_pages large. 2.25 - MemRegion uncommit(uintptr_t start, size_t size_in_pages); 2.26 - 2.27 - bool special() const { return _special; } 2.28 + void uncommit(uintptr_t start, size_t size_in_pages); 2.29 2.30 // Initialization 2.31 G1PageBasedVirtualSpace();
3.1 --- a/src/share/vm/gc_implementation/g1/g1RegionToSpaceMapper.cpp Fri Dec 12 09:07:54 2014 +0100 3.2 +++ b/src/share/vm/gc_implementation/g1/g1RegionToSpaceMapper.cpp Mon Jan 12 15:24:29 2015 +0100 3.3 @@ -67,9 +67,9 @@ 3.4 } 3.5 3.6 virtual void commit_regions(uintptr_t start_idx, size_t num_regions) { 3.7 - _storage.commit(start_idx * _pages_per_region, num_regions * _pages_per_region); 3.8 + bool zero_filled = _storage.commit(start_idx * _pages_per_region, num_regions * _pages_per_region); 3.9 _commit_map.set_range(start_idx, start_idx + num_regions); 3.10 - fire_on_commit(start_idx, num_regions, true); 3.11 + fire_on_commit(start_idx, num_regions, zero_filled); 3.12 } 3.13 3.14 virtual void uncommit_regions(uintptr_t start_idx, size_t num_regions) { 3.15 @@ -117,8 +117,7 @@ 3.16 uint old_refcount = _refcounts.get_by_index(idx); 3.17 bool zero_filled = false; 3.18 if (old_refcount == 0) { 3.19 - _storage.commit(idx, 1); 3.20 - zero_filled = true; 3.21 + zero_filled = _storage.commit(idx, 1); 3.22 } 3.23 _refcounts.set_by_index(idx, old_refcount + 1); 3.24 _commit_map.set_bit(i);