292 // Thread "thread_num" (0 <= i < ParalleGCThreads) wants to promote
293 // object "obj", whose original mark word was "m", and whose size is
294 // "word_sz". If possible, allocate space for "obj", copy obj into it
295 // (taking care to copy "m" into the mark word when done, since the mark
296 // word of "obj" may have been overwritten with a forwarding pointer, and
297 // also taking care to copy the klass pointer *last*. Returns the new
298 // object if successful, or else NULL.
299 virtual oop par_promote(int thread_num, oop obj, markOop m, size_t word_sz);
300
301 // Informs the current generation that all par_promote_alloc's in the
302 // collection have been completed; any supporting data structures can be
303 // reset. Default is to do nothing.
304 virtual void par_promote_alloc_done(int thread_num) {}
305
306 // Informs the current generation that all oop_since_save_marks_iterates
307 // performed by "thread_num" in the current collection, if any, have been
308 // completed; any supporting data structures can be reset. Default is to
309 // do nothing.
310 virtual void par_oop_since_save_marks_iterate_done(int thread_num) {}
311
312 // This generation does in-place marking, meaning that mark words
313 // are mutated during the marking phase and presumably reinitialized
314 // to a canonical value after the GC. This is currently used by the
315 // biased locking implementation to determine whether additional
316 // work is required during the GC prologue and epilogue.
317 virtual bool performs_in_place_marking() const { return true; }
318
319 // Returns "true" iff collect() should subsequently be called on this
320 // this generation. See comment below.
321 // This is a generic implementation which can be overridden.
322 //
323 // Note: in the current (1.4) implementation, when genCollectedHeap's
324 // incremental_collection_will_fail flag is set, all allocations are
325 // slow path (the only fast-path place to allocate is DefNew, which
326 // will be full if the flag is set).
327 // Thus, older generations which collect younger generations should
328 // test this flag and collect if it is set.
329 virtual bool should_collect(bool full,
330 size_t word_size,
331 bool is_tlab) {
332 return (full || should_allocate(word_size, is_tlab));
333 }
334
335 // Returns true if the collection is likely to be safely
336 // completed. Even if this method returns true, a collection
337 // may not be guaranteed to succeed, and the system should be
338 // able to safely unwind and recover from that failure, albeit
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292 // Thread "thread_num" (0 <= i < ParalleGCThreads) wants to promote
293 // object "obj", whose original mark word was "m", and whose size is
294 // "word_sz". If possible, allocate space for "obj", copy obj into it
295 // (taking care to copy "m" into the mark word when done, since the mark
296 // word of "obj" may have been overwritten with a forwarding pointer, and
297 // also taking care to copy the klass pointer *last*. Returns the new
298 // object if successful, or else NULL.
299 virtual oop par_promote(int thread_num, oop obj, markOop m, size_t word_sz);
300
301 // Informs the current generation that all par_promote_alloc's in the
302 // collection have been completed; any supporting data structures can be
303 // reset. Default is to do nothing.
304 virtual void par_promote_alloc_done(int thread_num) {}
305
306 // Informs the current generation that all oop_since_save_marks_iterates
307 // performed by "thread_num" in the current collection, if any, have been
308 // completed; any supporting data structures can be reset. Default is to
309 // do nothing.
310 virtual void par_oop_since_save_marks_iterate_done(int thread_num) {}
311
312 // Returns "true" iff collect() should subsequently be called on this
313 // this generation. See comment below.
314 // This is a generic implementation which can be overridden.
315 //
316 // Note: in the current (1.4) implementation, when genCollectedHeap's
317 // incremental_collection_will_fail flag is set, all allocations are
318 // slow path (the only fast-path place to allocate is DefNew, which
319 // will be full if the flag is set).
320 // Thus, older generations which collect younger generations should
321 // test this flag and collect if it is set.
322 virtual bool should_collect(bool full,
323 size_t word_size,
324 bool is_tlab) {
325 return (full || should_allocate(word_size, is_tlab));
326 }
327
328 // Returns true if the collection is likely to be safely
329 // completed. Even if this method returns true, a collection
330 // may not be guaranteed to succeed, and the system should be
331 // able to safely unwind and recover from that failure, albeit
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