Mon, 12 Mar 2012 14:59:00 -0700
7147724: G1: hang in SurrogateLockerThread::manipulatePLL
Summary: Attempting to initiate a marking cycle when allocating a humongous object can, if a marking cycle is successfully initiated by another thread, result in the allocating thread spinning until the marking cycle is complete. Eliminate a deadlock between the main ConcurrentMarkThread, the SurrogateLocker thread, the VM thread, and a mutator thread waiting on the SecondaryFreeList_lock (while free regions are going to become available) by not manipulating the pending list lock during the prologue and epilogue of the cleanup pause.
Reviewed-by: brutisso, jcoomes, tonyp
1 /*
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25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSET_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSET_HPP
28 #include "gc_implementation/g1/heapRegion.hpp"
30 // Large buffer for some cases where the output might be larger than normal.
31 #define HRS_ERR_MSG_BUFSZ 512
32 typedef FormatBuffer<HRS_ERR_MSG_BUFSZ> hrs_err_msg;
34 // Set verification will be forced either if someone defines
35 // HEAP_REGION_SET_FORCE_VERIFY to be 1, or in builds in which
36 // asserts are compiled in.
37 #ifndef HEAP_REGION_SET_FORCE_VERIFY
38 #define HEAP_REGION_SET_FORCE_VERIFY defined(ASSERT)
39 #endif // HEAP_REGION_SET_FORCE_VERIFY
41 //////////////////// HeapRegionSetBase ////////////////////
43 // Base class for all the classes that represent heap region sets. It
44 // contains the basic attributes that each set needs to maintain
45 // (e.g., length, region num, used bytes sum) plus any shared
46 // functionality (e.g., verification).
48 class hrs_ext_msg;
50 typedef enum {
51 HRSPhaseNone,
52 HRSPhaseEvacuation,
53 HRSPhaseCleanup,
54 HRSPhaseFullGC
55 } HRSPhase;
57 class HRSPhaseSetter;
59 class HeapRegionSetBase VALUE_OBJ_CLASS_SPEC {
60 friend class hrs_ext_msg;
61 friend class HRSPhaseSetter;
62 friend class VMStructs;
64 protected:
65 static size_t calculate_region_num(HeapRegion* hr);
67 static size_t _unrealistically_long_length;
69 // The number of regions added to the set. If the set contains
70 // only humongous regions, this reflects only 'starts humongous'
71 // regions and does not include 'continues humongous' ones.
72 size_t _length;
74 // The total number of regions represented by the set. If the set
75 // does not contain humongous regions, this should be the same as
76 // _length. If the set contains only humongous regions, this will
77 // include the 'continues humongous' regions.
78 size_t _region_num;
80 // We don't keep track of the total capacity explicitly, we instead
81 // recalculate it based on _region_num and the heap region size.
83 // The sum of used bytes in the all the regions in the set.
84 size_t _total_used_bytes;
86 const char* _name;
88 bool _verify_in_progress;
89 size_t _calc_length;
90 size_t _calc_region_num;
91 size_t _calc_total_capacity_bytes;
92 size_t _calc_total_used_bytes;
94 // This is here so that it can be used in the subclasses to assert
95 // something different depending on which phase the GC is in. This
96 // can be particularly helpful in the check_mt_safety() methods.
97 static HRSPhase _phase;
99 // Only used by HRSPhaseSetter.
100 static void clear_phase();
101 static void set_phase(HRSPhase phase);
103 // verify_region() is used to ensure that the contents of a region
104 // added to / removed from a set are consistent. Different sets
105 // make different assumptions about the regions added to them. So
106 // each set can override verify_region_extra(), which is called
107 // from verify_region(), and do any extra verification it needs to
108 // perform in that.
109 virtual const char* verify_region_extra(HeapRegion* hr) { return NULL; }
110 bool verify_region(HeapRegion* hr,
111 HeapRegionSetBase* expected_containing_set);
113 // Indicates whether all regions in the set should be humongous or
114 // not. Only used during verification.
115 virtual bool regions_humongous() = 0;
117 // Indicates whether all regions in the set should be empty or
118 // not. Only used during verification.
119 virtual bool regions_empty() = 0;
121 // Subclasses can optionally override this to do MT safety protocol
122 // checks. It is called in an assert from all methods that perform
123 // updates on the set (and subclasses should also call it too).
124 virtual bool check_mt_safety() { return true; }
126 // fill_in_ext_msg() writes the the values of the set's attributes
127 // in the custom err_msg (hrs_ext_msg). fill_in_ext_msg_extra()
128 // allows subclasses to append further information.
129 virtual void fill_in_ext_msg_extra(hrs_ext_msg* msg) { }
130 void fill_in_ext_msg(hrs_ext_msg* msg, const char* message);
132 // It updates the fields of the set to reflect hr being added to
133 // the set.
134 inline void update_for_addition(HeapRegion* hr);
136 // It updates the fields of the set to reflect hr being added to
137 // the set and tags the region appropriately.
138 inline void add_internal(HeapRegion* hr);
140 // It updates the fields of the set to reflect hr being removed
141 // from the set.
142 inline void update_for_removal(HeapRegion* hr);
144 // It updates the fields of the set to reflect hr being removed
145 // from the set and tags the region appropriately.
146 inline void remove_internal(HeapRegion* hr);
148 // It clears all the fields of the sets. Note: it will not iterate
149 // over the set and remove regions from it. It assumes that the
150 // caller has already done so. It will literally just clear the fields.
151 virtual void clear();
153 HeapRegionSetBase(const char* name);
155 public:
156 static void set_unrealistically_long_length(size_t len);
158 const char* name() { return _name; }
160 size_t length() { return _length; }
162 bool is_empty() { return _length == 0; }
164 size_t region_num() { return _region_num; }
166 size_t total_capacity_bytes() {
167 return region_num() << HeapRegion::LogOfHRGrainBytes;
168 }
170 size_t total_used_bytes() { return _total_used_bytes; }
172 virtual void verify();
173 void verify_start();
174 void verify_next_region(HeapRegion* hr);
175 void verify_end();
177 #if HEAP_REGION_SET_FORCE_VERIFY
178 void verify_optional() {
179 verify();
180 }
181 #else // HEAP_REGION_SET_FORCE_VERIFY
182 void verify_optional() { }
183 #endif // HEAP_REGION_SET_FORCE_VERIFY
185 virtual void print_on(outputStream* out, bool print_contents = false);
186 };
188 // Customized err_msg for heap region sets. Apart from a
189 // assert/guarantee-specific message it also prints out the values of
190 // the fields of the associated set. This can be very helpful in
191 // diagnosing failures.
193 class hrs_ext_msg : public hrs_err_msg {
194 public:
195 hrs_ext_msg(HeapRegionSetBase* set, const char* message) : hrs_err_msg("") {
196 set->fill_in_ext_msg(this, message);
197 }
198 };
200 class HRSPhaseSetter {
201 public:
202 HRSPhaseSetter(HRSPhase phase) {
203 HeapRegionSetBase::set_phase(phase);
204 }
205 ~HRSPhaseSetter() {
206 HeapRegionSetBase::clear_phase();
207 }
208 };
210 // These two macros are provided for convenience, to keep the uses of
211 // these two asserts a bit more concise.
213 #define hrs_assert_mt_safety_ok(_set_) \
214 do { \
215 assert((_set_)->check_mt_safety(), hrs_ext_msg((_set_), "MT safety")); \
216 } while (0)
218 #define hrs_assert_region_ok(_set_, _hr_, _expected_) \
219 do { \
220 assert((_set_)->verify_region((_hr_), (_expected_)), \
221 hrs_ext_msg((_set_), "region verification")); \
222 } while (0)
224 //////////////////// HeapRegionSet ////////////////////
226 #define hrs_assert_sets_match(_set1_, _set2_) \
227 do { \
228 assert(((_set1_)->regions_humongous() == \
229 (_set2_)->regions_humongous()) && \
230 ((_set1_)->regions_empty() == (_set2_)->regions_empty()), \
231 hrs_err_msg("the contents of set %s and set %s should match", \
232 (_set1_)->name(), (_set2_)->name())); \
233 } while (0)
235 // This class represents heap region sets whose members are not
236 // explicitly tracked. It's helpful to group regions using such sets
237 // so that we can reason about all the region groups in the heap using
238 // the same interface (namely, the HeapRegionSetBase API).
240 class HeapRegionSet : public HeapRegionSetBase {
241 protected:
242 virtual const char* verify_region_extra(HeapRegion* hr) {
243 if (hr->next() != NULL) {
244 return "next() should always be NULL as we do not link the regions";
245 }
247 return HeapRegionSetBase::verify_region_extra(hr);
248 }
250 HeapRegionSet(const char* name) : HeapRegionSetBase(name) {
251 clear();
252 }
254 public:
255 // It adds hr to the set. The region should not be a member of
256 // another set.
257 inline void add(HeapRegion* hr);
259 // It removes hr from the set. The region should be a member of
260 // this set.
261 inline void remove(HeapRegion* hr);
263 // It removes a region from the set. Instead of updating the fields
264 // of the set to reflect this removal, it accumulates the updates
265 // in proxy_set. The idea is that proxy_set is thread-local to
266 // avoid multiple threads updating the fields of the set
267 // concurrently and having to synchronize. The method
268 // update_from_proxy() will update the fields of the set from the
269 // proxy_set.
270 inline void remove_with_proxy(HeapRegion* hr, HeapRegionSet* proxy_set);
272 // After multiple calls to remove_with_proxy() the updates to the
273 // fields of the set are accumulated in proxy_set. This call
274 // updates the fields of the set from proxy_set.
275 void update_from_proxy(HeapRegionSet* proxy_set);
276 };
278 //////////////////// HeapRegionLinkedList ////////////////////
280 // A set that links all the regions added to it in a singly-linked
281 // list. We should try to avoid doing operations that iterate over
282 // such lists in performance critical paths. Typically we should
283 // add / remove one region at a time or concatenate two lists. All
284 // those operations are done in constant time.
286 class HeapRegionLinkedListIterator;
288 class HeapRegionLinkedList : public HeapRegionSetBase {
289 friend class HeapRegionLinkedListIterator;
291 private:
292 HeapRegion* _head;
293 HeapRegion* _tail;
295 // These are provided for use by the friend classes.
296 HeapRegion* head() { return _head; }
297 HeapRegion* tail() { return _tail; }
299 protected:
300 virtual void fill_in_ext_msg_extra(hrs_ext_msg* msg);
302 // See the comment for HeapRegionSetBase::clear()
303 virtual void clear();
305 HeapRegionLinkedList(const char* name) : HeapRegionSetBase(name) {
306 clear();
307 }
309 public:
310 // It adds hr to the list as the new head. The region should not be
311 // a member of another set.
312 inline void add_as_head(HeapRegion* hr);
314 // It adds hr to the list as the new tail. The region should not be
315 // a member of another set.
316 inline void add_as_tail(HeapRegion* hr);
318 // It removes and returns the head of the list. It assumes that the
319 // list is not empty so it will return a non-NULL value.
320 inline HeapRegion* remove_head();
322 // Convenience method.
323 inline HeapRegion* remove_head_or_null();
325 // It moves the regions from from_list to this list and empties
326 // from_list. The new regions will appear in the same order as they
327 // were in from_list and be linked in the beginning of this list.
328 void add_as_head(HeapRegionLinkedList* from_list);
330 // It moves the regions from from_list to this list and empties
331 // from_list. The new regions will appear in the same order as they
332 // were in from_list and be linked in the end of this list.
333 void add_as_tail(HeapRegionLinkedList* from_list);
335 // It empties the list by removing all regions from it.
336 void remove_all();
338 // It removes all regions in the list that are pending for removal
339 // (i.e., they have been tagged with "pending_removal"). The list
340 // must not be empty, target_count should reflect the exact number
341 // of regions that are pending for removal in the list, and
342 // target_count should be > 1 (currently, we never need to remove a
343 // single region using this).
344 void remove_all_pending(size_t target_count);
346 virtual void verify();
348 virtual void print_on(outputStream* out, bool print_contents = false);
349 };
351 //////////////////// HeapRegionLinkedListIterator ////////////////////
353 // Iterator class that provides a convenient way to iterate over the
354 // regions of a HeapRegionLinkedList instance.
356 class HeapRegionLinkedListIterator : public StackObj {
357 private:
358 HeapRegionLinkedList* _list;
359 HeapRegion* _curr;
361 public:
362 bool more_available() {
363 return _curr != NULL;
364 }
366 HeapRegion* get_next() {
367 assert(more_available(),
368 "get_next() should be called when more regions are available");
370 // If we are going to introduce a count in the iterator we should
371 // do the "cycle" check.
373 HeapRegion* hr = _curr;
374 assert(_list->verify_region(hr, _list), "region verification");
375 _curr = hr->next();
376 return hr;
377 }
379 HeapRegionLinkedListIterator(HeapRegionLinkedList* list)
380 : _curr(NULL), _list(list) {
381 _curr = list->head();
382 }
383 };
385 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSET_HPP