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hotspot/src/share/vm/gc_implementation/shared/mutableNUMASpace.hpp

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+/*
+ * Copyright 2006-2007 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+/*
+ *    The NUMA-aware allocator (MutableNUMASpace) is basically a modification
+ * of MutableSpace which preserves interfaces but implements different
+ * functionality. The space is split into chunks for each locality group
+ * (resizing for adaptive size policy is also supported). For each thread
+ * allocations are performed in the chunk corresponding to the home locality
+ * group of the thread. Whenever any chunk fills-in the young generation
+ * collection occurs.
+ *   The chunks can be also be adaptively resized. The idea behind the adaptive
+ * sizing is to reduce the loss of the space in the eden due to fragmentation.
+ * The main cause of fragmentation is uneven allocation rates of threads.
+ * The allocation rate difference between locality groups may be caused either by
+ * application specifics or by uneven LWP distribution by the OS. Besides,
+ * application can have less threads then the number of locality groups.
+ * In order to resize the chunk we measure the allocation rate of the
+ * application between collections. After that we reshape the chunks to reflect
+ * the allocation rate pattern. The AdaptiveWeightedAverage exponentially
+ * decaying average is used to smooth the measurements. The NUMASpaceResizeRate
+ * parameter is used to control the adaptation speed by restricting the number of
+ * bytes that can be moved during the adaptation phase.
+ *   Chunks may contain pages from a wrong locality group. The page-scanner has
+ * been introduced to address the problem. Remote pages typically appear due to
+ * the memory shortage in the target locality group. Besides Solaris would
+ * allocate a large page from the remote locality group even if there are small
+ * local pages available. The page-scanner scans the pages right after the
+ * collection and frees remote pages in hope that subsequent reallocation would
+ * be more successful. This approach proved to be useful on systems with high
+ * load where multiple processes are competing for the memory.
+ */
+
+class MutableNUMASpace : public MutableSpace {
+  friend class VMStructs;
+
+  class LGRPSpace : public CHeapObj {
+    int _lgrp_id;
+    MutableSpace* _space;
+    MemRegion _invalid_region;
+    AdaptiveWeightedAverage *_alloc_rate;
+
+    struct SpaceStats {
+      size_t _local_space, _remote_space, _unbiased_space, _uncommited_space;
+      size_t _large_pages, _small_pages;
+
+      SpaceStats() {
+        _local_space = 0;
+        _remote_space = 0;
+        _unbiased_space = 0;
+        _uncommited_space = 0;
+        _large_pages = 0;
+        _small_pages = 0;
+      }
+    };
+
+    SpaceStats _space_stats;
+
+    char* _last_page_scanned;
+    char* last_page_scanned()            { return _last_page_scanned; }
+    void set_last_page_scanned(char* p)  { _last_page_scanned = p;    }
+   public:
+    LGRPSpace(int l) : _lgrp_id(l), _last_page_scanned(NULL) {
+      _space = new MutableSpace();
+      _alloc_rate = new AdaptiveWeightedAverage(NUMAChunkResizeWeight);
+    }
+    ~LGRPSpace() {
+      delete _space;
+      delete _alloc_rate;
+    }
+
+    void add_invalid_region(MemRegion r) {
+      if (!_invalid_region.is_empty()) {
+      _invalid_region.set_start(MIN2(_invalid_region.start(), r.start()));
+      _invalid_region.set_end(MAX2(_invalid_region.end(), r.end()));
+      } else {
+      _invalid_region = r;
+      }
+    }
+
+    static bool equals(void* lgrp_id_value, LGRPSpace* p) {
+      return *(int*)lgrp_id_value == p->lgrp_id();
+    }
+
+    void sample() {
+      alloc_rate()->sample(space()->used_in_bytes());
+    }
+
+    MemRegion invalid_region() const                { return _invalid_region;      }
+    void set_invalid_region(MemRegion r)            { _invalid_region = r;         }
+    int lgrp_id() const                             { return _lgrp_id;             }
+    MutableSpace* space() const                     { return _space;               }
+    AdaptiveWeightedAverage* alloc_rate() const     { return _alloc_rate;          }
+    SpaceStats* space_stats()                       { return &_space_stats;        }
+    void clear_space_stats()                        { _space_stats = SpaceStats(); }
+
+    void accumulate_statistics(size_t page_size);
+    void scan_pages(size_t page_size, size_t page_count);
+  };
+
+  GrowableArray<LGRPSpace*>* _lgrp_spaces;
+  size_t _page_size;
+  unsigned _adaptation_cycles, _samples_count;
+
+  void set_page_size(size_t psz)                     { _page_size = psz;          }
+  size_t page_size() const                           { return _page_size;         }
+
+  unsigned adaptation_cycles()                       { return _adaptation_cycles; }
+  void set_adaptation_cycles(int v)                  { _adaptation_cycles = v;    }
+
+  unsigned samples_count()                           { return _samples_count;     }
+  void increment_samples_count()                     { ++_samples_count;          }
+
+  size_t _base_space_size;
+  void set_base_space_size(size_t v)                 { _base_space_size = v;      }
+  size_t base_space_size() const                     { return _base_space_size;   }
+
+  // Check if the NUMA topology has changed. Add and remove spaces if needed.
+  // The update can be forced by setting the force parameter equal to true.
+  bool update_layout(bool force);
+  // Bias region towards the first-touching lgrp.
+  void bias_region(MemRegion mr);
+  // Free pages in a given region.
+  void free_region(MemRegion mr);
+  // Get current chunk size.
+  size_t current_chunk_size(int i);
+  // Get default chunk size (equally divide the space).
+  size_t default_chunk_size();
+  // Adapt the chunk size to follow the allocation rate.
+  size_t adaptive_chunk_size(int i, size_t limit);
+  // Scan and free invalid pages.
+  void scan_pages(size_t page_count);
+  // Return the bottom_region and the top_region. Align them to page_size() boundary.
+  // |------------------new_region---------------------------------|
+  // |----bottom_region--|---intersection---|------top_region------|
+  void select_tails(MemRegion new_region, MemRegion intersection,
+                    MemRegion* bottom_region, MemRegion *top_region);
+  // Try to merge the invalid region with the bottom or top region by decreasing
+  // the intersection area. Return the invalid_region aligned to the page_size()
+  // boundary if it's inside the intersection. Return non-empty invalid_region
+  // if it lies inside the intersection (also page-aligned).
+  // |------------------new_region---------------------------------|
+  // |----------------|-------invalid---|--------------------------|
+  // |----bottom_region--|---intersection---|------top_region------|
+  void merge_regions(MemRegion new_region, MemRegion* intersection,
+                     MemRegion *invalid_region);
+
+ public:
+  GrowableArray<LGRPSpace*>* lgrp_spaces() const     { return _lgrp_spaces;       }
+  MutableNUMASpace();
+  virtual ~MutableNUMASpace();
+  // Space initialization.
+  virtual void initialize(MemRegion mr, bool clear_space);
+  // Update space layout if necessary. Do all adaptive resizing job.
+  virtual void update();
+  // Update allocation rate averages.
+  virtual void accumulate_statistics();
+
+  virtual void clear();
+  virtual void mangle_unused_area();
+  virtual void ensure_parsability();
+  virtual size_t used_in_words() const;
+  virtual size_t free_in_words() const;
+  virtual size_t tlab_capacity(Thread* thr) const;
+  virtual size_t unsafe_max_tlab_alloc(Thread* thr) const;
+
+  // Allocation (return NULL if full)
+  virtual HeapWord* allocate(size_t word_size);
+  virtual HeapWord* cas_allocate(size_t word_size);
+
+  // Debugging
+  virtual void print_on(outputStream* st) const;
+  virtual void print_short_on(outputStream* st) const;
+  virtual void verify(bool allow_dirty) const;
+
+  virtual void set_top(HeapWord* value);
+};