src/share/vm/gc_implementation/g1/g1PageBasedVirtualSpace.cpp

rev 7618 : 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:

*** 41,53 ****
  #endif
  #ifdef TARGET_OS_FAMILY_bsd
  # include "os_bsd.inline.hpp"
  #endif
  #include "utilities/bitMap.inline.hpp"
  
  G1PageBasedVirtualSpace::G1PageBasedVirtualSpace() : _low_boundary(NULL),
!   _high_boundary(NULL), _committed(), _page_size(0), _special(false), _executable(false) {
  }
  
  bool G1PageBasedVirtualSpace::initialize_with_granularity(ReservedSpace rs, size_t page_size) {
    if (!rs.is_reserved()) {
      return false;  // Allocation failed.
--- 41,55 ----
  #endif
  #ifdef TARGET_OS_FAMILY_bsd
  # include "os_bsd.inline.hpp"
  #endif
  #include "utilities/bitMap.inline.hpp"
+ #include "utilities/copy.hpp"
  
  G1PageBasedVirtualSpace::G1PageBasedVirtualSpace() : _low_boundary(NULL),
!   _high_boundary(NULL), _committed(), _page_size(0), _special(false),
!   _needs_clear_on_commit(), _executable(false) {
  }
  
  bool G1PageBasedVirtualSpace::initialize_with_granularity(ReservedSpace rs, size_t page_size) {
    if (!rs.is_reserved()) {
      return false;  // Allocation failed.
*** 64,73 ****
--- 66,78 ----
    _page_size = page_size;
  
    assert(_committed.size() == 0, "virtual space initialized more than once");
    uintx size_in_bits = rs.size() / page_size;
    _committed.resize(size_in_bits, /* in_resource_area */ false);
+   if (_special) {
+     _needs_clear_on_commit.resize(size_in_bits, /* in_resource_area */ false);
+   }
  
    return true;
  }
  
  
*** 82,91 ****
--- 87,97 ----
    _high_boundary          = NULL;
    _special                = false;
    _executable             = false;
    _page_size              = 0;
    _committed.resize(0, false);
+   _needs_clear_on_commit.resize(0, false);
  }
  
  size_t G1PageBasedVirtualSpace::committed_size() const {
    return _committed.count_one_bits() * _page_size;
  }
*** 122,132 ****
  
  MemRegion G1PageBasedVirtualSpace::commit(uintptr_t start, size_t size_in_pages) {
    // We need to make sure to commit all pages covered by the given area.
    guarantee(is_area_uncommitted(start, size_in_pages), "Specified area is not uncommitted");
  
!   if (!_special) {
      os::commit_memory_or_exit(page_start(start), byte_size_for_pages(size_in_pages), _executable,
                                err_msg("Failed to commit pages from "SIZE_FORMAT" of length "SIZE_FORMAT, start, size_in_pages));
    }
    _committed.set_range(start, start + size_in_pages);
  
--- 128,148 ----
  
  MemRegion G1PageBasedVirtualSpace::commit(uintptr_t start, size_t size_in_pages) {
    // We need to make sure to commit all pages covered by the given area.
    guarantee(is_area_uncommitted(start, size_in_pages), "Specified area is not uncommitted");
  
!   if (_special) {
!     // When the memory is _special it is not really uncommitted. _needs_clear_on_commit
!     // is used to communicate that the memory needs to be cleared because it is seen by
!     // others as uncommitted.
!     for (uintptr_t page_index = start; page_index < start + size_in_pages; page_index++) {
!       if (_needs_clear_on_commit.at(page_index)) {
!         Copy::zero_to_bytes((HeapWord*)page_start(page_index), _page_size);
!         _needs_clear_on_commit.clear_bit(page_index);
!       }
!     }
!   } else {
      os::commit_memory_or_exit(page_start(start), byte_size_for_pages(size_in_pages), _executable,
                                err_msg("Failed to commit pages from "SIZE_FORMAT" of length "SIZE_FORMAT, start, size_in_pages));
    }
    _committed.set_range(start, start + size_in_pages);
  
*** 138,148 ****
  }
  
  MemRegion G1PageBasedVirtualSpace::uncommit(uintptr_t start, size_t size_in_pages) {
    guarantee(is_area_committed(start, size_in_pages), "checking");
  
!   if (!_special) {
      os::uncommit_memory(page_start(start), byte_size_for_pages(size_in_pages));
    }
  
    _committed.clear_range(start, start + size_in_pages);
  
--- 154,167 ----
  }
  
  MemRegion G1PageBasedVirtualSpace::uncommit(uintptr_t start, size_t size_in_pages) {
    guarantee(is_area_committed(start, size_in_pages), "checking");
  
!   if (_special) {
!     // Mark that memory needs to be cleared if committed again.
!     _needs_clear_on_commit.set_range(start, start + size_in_pages);
!   } else {
      os::uncommit_memory(page_start(start), byte_size_for_pages(size_in_pages));
    }
  
    _committed.clear_range(start, start + size_in_pages);