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

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rev 7192 : [mq]: 8058354-fix

@@ -51,12 +51,12 @@
 }
 
 void G1PageBasedVirtualSpace::initialize_with_page_size(ReservedSpace rs, size_t used_size, size_t page_size) {
   guarantee(rs.is_reserved(), "Given reserved space must have been reserved already.");
 
-  vmassert(_low_boundary == NULL, "VirtualSpace already initialized");
-  vmassert(page_size > 0, "Page size must be non-zero.");
+  assert(_low_boundary == NULL, "VirtualSpace already initialized");
+  assert(page_size > 0, "Page size must be non-zero.");
 
   guarantee(is_ptr_aligned(rs.base(), page_size),
             err_msg("Reserved space base " PTR_FORMAT " is not aligned to requested page size " SIZE_FORMAT, p2i(rs.base()), page_size));
   guarantee(is_size_aligned(used_size, os::vm_page_size()),
             err_msg("Given used reserved space size needs to be OS page size aligned (%d bytes) but is " SIZE_FORMAT, os::vm_page_size(), used_size));

@@ -71,11 +71,11 @@
   _special = rs.special();
   _executable = rs.executable();
 
   _page_size = page_size;
 
-  vmassert(_committed.size() == 0, "virtual space initialized more than once");
+  assert(_committed.size() == 0, "virtual space initialized more than once");
   BitMap::idx_t size_in_pages = rs.size() / page_size;
   _committed.resize(size_in_pages, /* in_resource_area */ false);
   if (_special) {
     _dirty.resize(size_in_pages, /* in_resource_area */ false);
   }

@@ -115,69 +115,138 @@
 
 size_t G1PageBasedVirtualSpace::uncommitted_size()  const {
   return reserved_size() - committed_size();
 }
 
-uintptr_t G1PageBasedVirtualSpace::addr_to_page_index(char* addr) const {
+size_t G1PageBasedVirtualSpace::addr_to_page_index(char* addr) const {
   return (addr - _low_boundary) / _page_size;
 }
 
-bool G1PageBasedVirtualSpace::is_area_committed(uintptr_t start, size_t size_in_pages) const {
-  uintptr_t end = start + size_in_pages;
-  return _committed.get_next_zero_offset(start, end) >= end;
+bool G1PageBasedVirtualSpace::is_area_committed(size_t start_page, size_t size_in_pages) const {
+  size_t end_page = start_page + size_in_pages;
+  return _committed.get_next_zero_offset(start_page, end_page) >= end_page;
 }
 
-bool G1PageBasedVirtualSpace::is_area_uncommitted(uintptr_t start, size_t size_in_pages) const {
-  uintptr_t end = start + size_in_pages;
-  return _committed.get_next_one_offset(start, end) >= end;
+bool G1PageBasedVirtualSpace::is_area_uncommitted(size_t start_page, size_t size_in_pages) const {
+  size_t end_page = start_page + size_in_pages;
+  return _committed.get_next_one_offset(start_page, end_page) >= end_page;
 }
 
-char* G1PageBasedVirtualSpace::page_start(uintptr_t index) {
+char* G1PageBasedVirtualSpace::page_start(size_t index) const {
   return _low_boundary + index * _page_size;
 }
 
-size_t G1PageBasedVirtualSpace::byte_size_for_pages(size_t num) {
-  return num * _page_size;
+bool G1PageBasedVirtualSpace::is_after_last_page(size_t index) const {
+  guarantee(index <= _committed.size(),
+            err_msg("Given boundary page " SIZE_FORMAT " is beyond managed page count " SIZE_FORMAT, index, _committed.size()));
+  return index == _committed.size();
 }
 
-bool G1PageBasedVirtualSpace::commit(uintptr_t start, size_t size_in_pages) {
+void G1PageBasedVirtualSpace::commit_preferred_pages(size_t start, size_t num_pages) {
+  assert(num_pages > 0, "No full pages to commit");
+  assert(start + num_pages <= _committed.size(),
+           err_msg("Tried to commit area from page " SIZE_FORMAT " to page " SIZE_FORMAT " "
+                   "that is outside of managed space of " SIZE_FORMAT " pages",
+                   start, start + num_pages, _committed.size()));
+
+  char* start_addr = page_start(start);
+  size_t size = num_pages * _page_size;
+
+  os::commit_memory_or_exit(start_addr, size, _page_size, _executable,
+                            err_msg("Failed to commit area from " PTR_FORMAT " to " PTR_FORMAT " of length " SIZE_FORMAT ".",
+                                    p2i(start_addr), p2i(start_addr + size), size));
+}
+
+void G1PageBasedVirtualSpace::commit_tail() {
+  assert(_tail_size > 0, "The size of the tail area must be > 0 when reaching here");
+
+  char* const aligned_end_address = (char*)align_ptr_down(_high_boundary, _page_size);
+  os::commit_memory_or_exit(aligned_end_address, _tail_size, os::vm_page_size(), _executable,
+                            err_msg("Failed to commit tail area from " PTR_FORMAT " to " PTR_FORMAT " of length " SIZE_FORMAT ".",
+                                    p2i(aligned_end_address), p2i(_high_boundary), _tail_size));
+}
+
+void G1PageBasedVirtualSpace::commit_internal(size_t start_page, size_t end_page) {
+  guarantee(start_page < end_page,
+            err_msg("Given start page " SIZE_FORMAT " is larger or equal to end page " SIZE_FORMAT, start_page, end_page));
+  guarantee(end_page <= _committed.size(),
+            err_msg("Given end page " SIZE_FORMAT " is beyond end of managed page amount of " SIZE_FORMAT, end_page, _committed.size()));
+
+  size_t pages = end_page - start_page;
+  bool need_to_commit_tail = is_after_last_page(end_page) && is_last_page_partial();
+
+  // If we have to commit some (partial) tail area, decrease the amount of pages to avoid
+  // committing that in the full-page commit code.
+  if (need_to_commit_tail) {
+    pages--;
+  }
+
+  if (pages > 0) {
+    commit_preferred_pages(start_page, pages);
+  }
+
+  if (need_to_commit_tail) {
+    commit_tail();
+  }
+}
+
+char* G1PageBasedVirtualSpace::bounded_end_addr(size_t end_page) const {
+  return MIN2(_high_boundary, page_start(end_page));
+}
+
+void G1PageBasedVirtualSpace::pretouch_internal(size_t start_page, size_t end_page) {
+  guarantee(start_page < end_page,
+            err_msg("Given start page " SIZE_FORMAT " is larger or equal to end page " SIZE_FORMAT, start_page, end_page));
+
+  os::pretouch_memory(page_start(start_page), bounded_end_addr(end_page));
+}
+
+bool G1PageBasedVirtualSpace::commit(size_t start_page, 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");
+  guarantee(is_area_uncommitted(start_page, size_in_pages), "Specified area is not uncommitted");
 
   bool zero_filled = true;
-  uintptr_t end = start + size_in_pages;
+  size_t end_page = start_page + size_in_pages;
 
   if (_special) {
     // Check for dirty pages and update zero_filled if any found.
-    if (_dirty.get_next_one_offset(start,end) < end) {
+    if (_dirty.get_next_one_offset(start_page, end_page) < end_page) {
       zero_filled = false;
-      _dirty.clear_range(start, end);
+      _dirty.clear_range(start_page, end_page);
     }
   } 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));
+    commit_internal(start_page, end_page);
   }
-  _committed.set_range(start, end);
+  _committed.set_range(start_page, end_page);
 
   if (AlwaysPreTouch) {
-    os::pretouch_memory(page_start(start), page_start(start) + byte_size_for_pages(size_in_pages));
+    pretouch_internal(start_page, end_page);
   }
   return zero_filled;
 }
 
-void G1PageBasedVirtualSpace::uncommit(uintptr_t start, size_t size_in_pages) {
-  guarantee(is_area_committed(start, size_in_pages), "checking");
+void G1PageBasedVirtualSpace::uncommit_internal(size_t start_page, size_t end_page) {
+  guarantee(start_page < end_page,
+            err_msg("Given start page " SIZE_FORMAT " is larger or equal to end page " SIZE_FORMAT, start_page, end_page));
+
+  char* start_addr = page_start(start_page);
+  os::uncommit_memory(start_addr, pointer_delta(bounded_end_addr(end_page), start_addr, sizeof(char)));
+}
+
+void G1PageBasedVirtualSpace::uncommit(size_t start_page, size_t size_in_pages) {
+  guarantee(is_area_committed(start_page, size_in_pages), "checking");
 
+  size_t end_page = start_page + size_in_pages;
   if (_special) {
     // Mark that memory is dirty. If committed again the memory might
     // need to be cleared explicitly.
-    _dirty.set_range(start, start + size_in_pages);
+    _dirty.set_range(start_page, end_page);
   } else {
-    os::uncommit_memory(page_start(start), byte_size_for_pages(size_in_pages));
+    uncommit_internal(start_page, end_page);
   }
 
-  _committed.clear_range(start, start + size_in_pages);
+  _committed.clear_range(start_page, end_page);
 }
 
 bool G1PageBasedVirtualSpace::contains(const void* p) const {
   return _low_boundary <= (const char*) p && (const char*) p < _high_boundary;
 }
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