src/hotspot/share/memory/metaspace/metachunk.cpp

rev 53600 : imported patch autouncommit-metachunks

*** 21,30 ****
--- 21,31 ----
   * questions.
   *
   */
  
  #include "precompiled.hpp"
+ #include "logging/log.hpp"
  #include "memory/allocation.hpp"
  #include "memory/metaspace/metachunk.hpp"
  #include "memory/metaspace/occupancyMap.hpp"
  #include "memory/metaspace/virtualSpaceNode.hpp"
  #include "utilities/align.hpp"
*** 132,141 ****
--- 133,182 ----
           p2i(this), word_size() * sizeof(MetaWord), required_alignment);
  }
  
  #endif // ASSERT
  
+ bool Metachunk::calc_uncommit_range(address* start, size_t* len) const {
+   // All but the first page (which contains the header) can be uncommitted
+   if (size() * sizeof(MetaWord) > (size_t)os::vm_page_size()) {
+     address from = align_up((address)initial_top(), os::vm_page_size());
+     address to = align_down((address)end(), os::vm_page_size());
+     if (from < to) {
+       *start = from;
+       *len = to - from;
+       return true;
+     }
+   }
+   return false;
+ }
+ 
+ bool Metachunk::commit() {
+   bool rc = false;
+   address p = NULL; size_t len = 0;
+   if (calc_uncommit_range(&p, &len)) {
+     rc = os::commit_memory((char*)p, len, false);
+     if (rc) {
+       log_info(gc, metaspace)("Committed chunk " PTR_FORMAT " (payload area from " PTR_FORMAT " to " PTR_FORMAT ")",
+                               p2i(this), p2i(p), p2i(p + len));
+     }
+   }
+   return rc;
+ }
+ 
+ bool Metachunk::uncommit() {
+   bool rc = false;
+   address p = NULL; size_t len = 0;
+   if (calc_uncommit_range(&p, &len)) {
+     rc = os::uncommit_memory((char*)p, len);
+     if (rc) {
+       log_info(gc, metaspace)("Uncommitted chunk " PTR_FORMAT " (payload area from " PTR_FORMAT " to " PTR_FORMAT ")",
+                               p2i(this), p2i(p), p2i(p + len));
+     }
+   }
+   return rc;
+ }
+ 
  // Helper, returns a descriptive name for the given index.
  const char* chunk_size_name(ChunkIndex index) {
    switch (index) {
      case SpecializedIndex:
        return "specialized";