hotspot/src/share/vm/gc_implementation/g1/heapRegionSet.hpp - platform/libcore - Git at Google

 /*
  * 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
	/*
	* 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