jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/heapRegionSet.hpp@0fa27f37d4d4 (annotated)

src/share/vm/gc_implementation/g1/heapRegionSet.hpp@0fa27f37d4d4 (annotated)

src/share/vm/gc_implementation/g1/heapRegionSet.hpp

Wed, 19 Jan 2011 19:30:42 -0500

author: tonyp
date: Wed, 19 Jan 2011 19:30:42 -0500
changeset 2472: 0fa27f37d4d4
child 2643: 1216415d8e35
permissions: -rw-r--r--

6977804: G1: remove the zero-filling thread
Summary: This changeset removes the zero-filling thread from G1 and collapses the two free region lists we had before (the "free" and "unclean" lists) into one. The new free list uses the new heap region sets / lists abstractions that we'll ultimately use it to keep track of all regions in the heap. A heap region set was also introduced for the humongous regions. Finally, this change increases the concurrency between the thread that completes freeing regions (after a cleanup pause) and the rest of the system (before we'd have to wait for said thread to complete before allocating a new region). The changest also includes a lot of refactoring and code simplification.
Reviewed-by: jcoomes, johnc

 /*
  * copyright (c) 2011, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */
 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSET_HPP
 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSET_HPP
 #include "gc_implementation/g1/heapRegion.hpp"
 // Large buffer for some cases where the output might be larger than normal.
 #define HRL_ERR_MSG_BUFSZ 512
 typedef FormatBuffer<HRL_ERR_MSG_BUFSZ> hrl_err_msg;
 // Set verification will be forced either if someone defines
 // HEAP_REGION_SET_FORCE_VERIFY to be 1, or in builds in which
 // asserts are compiled in.
 #ifndef HEAP_REGION_SET_FORCE_VERIFY
 #define HEAP_REGION_SET_FORCE_VERIFY defined(ASSERT)
 #endif // HEAP_REGION_SET_FORCE_VERIFY
 //////////////////// HeapRegionSetBase ////////////////////
 // Base class for all the classes that represent heap region sets. It
 // contains the basic attributes that each set needs to maintain
 // (e.g., length, region num, used bytes sum) plus any shared
 // functionality (e.g., verification).
 class hrl_ext_msg;
 class HeapRegionSetBase VALUE_OBJ_CLASS_SPEC {
   friend class hrl_ext_msg;
 protected:
   static size_t calculate_region_num(HeapRegion* hr);
   static size_t _unrealistically_long_length;
   // The number of regions added to the set. If the set contains
   // only humongous regions, this reflects only 'starts humongous'
   // regions and does not include 'continues humongous' ones.
   size_t _length;
   // The total number of regions represented by the set. If the set
   // does not contain humongous regions, this should be the same as
   // _length. If the set contains only humongous regions, this will
   // include the 'continues humongous' regions.
   size_t _region_num;
   // We don't keep track of the total capacity explicitly, we instead
   // recalculate it based on _region_num and the heap region size.
   // The sum of used bytes in the all the regions in the set.
   size_t _total_used_bytes;
   const char* _name;
   bool        _verify_in_progress;
   size_t      _calc_length;
   size_t      _calc_region_num;
   size_t      _calc_total_capacity_bytes;
   size_t      _calc_total_used_bytes;
   // verify_region() is used to ensure that the contents of a region
   // added to / removed from a set are consistent. Different sets
   // make different assumptions about the regions added to them. So
   // each set can override verify_region_extra(), which is called
   // from verify_region(), and do any extra verification it needs to
   // perform in that.
   virtual const char* verify_region_extra(HeapRegion* hr) { return NULL; }
   bool verify_region(HeapRegion* hr,
                      HeapRegionSetBase* expected_containing_set);
   // Indicates whether all regions in the set should be humongous or
   // not. Only used during verification.
   virtual bool regions_humongous() = 0;
   // Indicates whether all regions in the set should be empty or
   // not. Only used during verification.
   virtual bool regions_empty() = 0;
   // Subclasses can optionally override this to do MT safety protocol
   // checks. It is called in an assert from all methods that perform
   // updates on the set (and subclasses should also call it too).
   virtual bool check_mt_safety() { return true; }
   // fill_in_ext_msg() writes the the values of the set's attributes
   // in the custom err_msg (hrl_ext_msg). fill_in_ext_msg_extra()
   // allows subclasses to append further information.
   virtual void fill_in_ext_msg_extra(hrl_ext_msg* msg) { }
   void fill_in_ext_msg(hrl_ext_msg* msg, const char* message);
   // It updates the fields of the set to reflect hr being added to
   // the set.
   inline void update_for_addition(HeapRegion* hr);
   // It updates the fields of the set to reflect hr being added to
   // the set and tags the region appropriately.
   inline void add_internal(HeapRegion* hr);
   // It updates the fields of the set to reflect hr being removed
   // from the set.
   inline void update_for_removal(HeapRegion* hr);
   // It updates the fields of the set to reflect hr being removed
   // from the set and tags the region appropriately.
   inline void remove_internal(HeapRegion* hr);
   // It clears all the fields of the sets. Note: it will not iterate
   // over the set and remove regions from it. It assumes that the
   // caller has already done so. It will literally just clear the fields.
   virtual void clear();
   HeapRegionSetBase(const char* name);
 public:
   static void set_unrealistically_long_length(size_t len);
   const char* name() { return _name; }
   size_t length() { return _length; }
   bool is_empty() { return _length == 0; }
   size_t region_num() { return _region_num; }
   size_t total_capacity_bytes() {
     return region_num() << HeapRegion::LogOfHRGrainBytes;
   }
   size_t total_used_bytes() { return _total_used_bytes; }
   virtual void verify();
   void verify_start();
   void verify_next_region(HeapRegion* hr);
   void verify_end();
 #if HEAP_REGION_SET_FORCE_VERIFY
   void verify_optional() {
     verify();
   }
 #else // HEAP_REGION_SET_FORCE_VERIFY
   void verify_optional() { }
 #endif // HEAP_REGION_SET_FORCE_VERIFY
   virtual void print_on(outputStream* out, bool print_contents = false);
 };
 // Customized err_msg for heap region sets. Apart from a
 // assert/guarantee-specific message it also prints out the values of
 // the fields of the associated set. This can be very helpful in
 // diagnosing failures.
 class hrl_ext_msg : public hrl_err_msg {
 public:
   hrl_ext_msg(HeapRegionSetBase* set, const char* message) : hrl_err_msg("") {
     set->fill_in_ext_msg(this, message);
   }
 };
 // These two macros are provided for convenience, to keep the uses of
 // these two asserts a bit more concise.
 #define hrl_assert_mt_safety_ok(_set_)                                        \
   do {                                                                        \
     assert((_set_)->check_mt_safety(), hrl_ext_msg((_set_), "MT safety"));    \
   } while (0)
 #define hrl_assert_region_ok(_set_, _hr_, _expected_)                         \
   do {                                                                        \
     assert((_set_)->verify_region((_hr_), (_expected_)),                      \
            hrl_ext_msg((_set_), "region verification"));                      \
   } while (0)
 //////////////////// HeapRegionSet ////////////////////
 #define hrl_assert_sets_match(_set1_, _set2_)                                 \
   do {                                                                        \
     assert(((_set1_)->regions_humongous() ==                                  \
                                             (_set2_)->regions_humongous()) && \
            ((_set1_)->regions_empty() == (_set2_)->regions_empty()),          \
            hrl_err_msg("the contents of set %s and set %s should match",      \
                        (_set1_)->name(), (_set2_)->name()));                  \
   } while (0)
 // This class represents heap region sets whose members are not
 // explicitly tracked. It's helpful to group regions using such sets
 // so that we can reason about all the region groups in the heap using
 // the same interface (namely, the HeapRegionSetBase API).
 class HeapRegionSet : public HeapRegionSetBase {
 protected:
   virtual const char* verify_region_extra(HeapRegion* hr) {
     if (hr->next() != NULL) {
       return "next() should always be NULL as we do not link the regions";
     }
     return HeapRegionSetBase::verify_region_extra(hr);
   }
   HeapRegionSet(const char* name) : HeapRegionSetBase(name) {
     clear();
   }
 public:
   // It adds hr to the set. The region should not be a member of
   // another set.
   inline void add(HeapRegion* hr);
   // It removes hr from the set. The region should be a member of
   // this set.
   inline void remove(HeapRegion* hr);
   // It removes a region from the set. Instead of updating the fields
   // of the set to reflect this removal, it accumulates the updates
   // in proxy_set. The idea is that proxy_set is thread-local to
   // avoid multiple threads updating the fields of the set
   // concurrently and having to synchronize. The method
   // update_from_proxy() will update the fields of the set from the
   // proxy_set.
   inline void remove_with_proxy(HeapRegion* hr, HeapRegionSet* proxy_set);
   // After multiple calls to remove_with_proxy() the updates to the
   // fields of the set are accumulated in proxy_set. This call
   // updates the fields of the set from proxy_set.
   void update_from_proxy(HeapRegionSet* proxy_set);
 };
 //////////////////// HeapRegionLinkedList ////////////////////
 // A set that links all the regions added to it in a singly-linked
 // list. We should try to avoid doing operations that iterate over
 // such lists in performance critical paths. Typically we should
 // add / remove one region at a time or concatenate two lists. All
 // those operations are done in constant time.
 class HeapRegionLinkedListIterator;
 class HeapRegionLinkedList : public HeapRegionSetBase {
   friend class HeapRegionLinkedListIterator;
 private:
   HeapRegion* _head;
   HeapRegion* _tail;
   // These are provided for use by the friend classes.
   HeapRegion* head() { return _head; }
   HeapRegion* tail() { return _tail; }
 protected:
   virtual void fill_in_ext_msg_extra(hrl_ext_msg* msg);
   // See the comment for HeapRegionSetBase::clear()
   virtual void clear();
   HeapRegionLinkedList(const char* name) : HeapRegionSetBase(name) {
     clear();
   }
 public:
   // It adds hr to the list as the new tail. The region should not be
   // a member of another set.
   inline void add_as_tail(HeapRegion* hr);
   // It removes and returns the head of the list. It assumes that the
   // list is not empty so it will return a non-NULL value.
   inline HeapRegion* remove_head();
   // Convenience method.
   inline HeapRegion* remove_head_or_null();
   // It moves the regions from from_list to this list and empties
   // from_list. The new regions will appear in the same order as they
   // were in from_list and be linked in the end of this list.
   void add_as_tail(HeapRegionLinkedList* from_list);
   // It empties the list by removing all regions from it.
   void remove_all();
   // It removes all regions in the list that are pending for removal
   // (i.e., they have been tagged with "pending_removal"). The list
   // must not be empty, target_count should reflect the exact number
   // of regions that are pending for removal in the list, and
   // target_count should be > 1 (currently, we never need to remove a
   // single region using this).
   void remove_all_pending(size_t target_count);
   virtual void verify();
   virtual void print_on(outputStream* out, bool print_contents = false);
 };
 //////////////////// HeapRegionLinkedList ////////////////////
 // Iterator class that provides a convenient way to iterator over the
 // regions in a HeapRegionLinkedList instance.
 class HeapRegionLinkedListIterator : public StackObj {
 private:
   HeapRegionLinkedList* _list;
   HeapRegion*           _curr;
 public:
   bool more_available() {
     return _curr != NULL;
   }
   HeapRegion* get_next() {
     assert(more_available(),
            "get_next() should be called when more regions are available");
     // If we are going to introduce a count in the iterator we should
     // do the "cycle" check.
     HeapRegion* hr = _curr;
     assert(_list->verify_region(hr, _list), "region verification");
     _curr = hr->next();
     return hr;
   }
   HeapRegionLinkedListIterator(HeapRegionLinkedList* list)
     : _curr(NULL), _list(list) {
     _curr = list->head();
   }
 };
 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSET_HPP

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/g1/heapRegionSet.hpp@0fa27f37d4d4 (annotated)

src/share/vm/gc_implementation/g1/heapRegionSet.hpp