272 // caller must do the necessary locking.
273 virtual HeapWord* allocation_limit_reached(Space* space, HeapWord* top,
274 size_t word_size) {
275 return NULL;
276 }
277
278 // Some generation may offer a region for shared, contiguous allocation,
279 // via inlined code (by exporting the address of the top and end fields
280 // defining the extent of the contiguous allocation region.)
281
282 // This function returns "true" iff the heap supports this kind of
283 // allocation. (More precisely, this means the style of allocation that
284 // increments *top_addr()" with a CAS.) (Default is "no".)
285 // A generation that supports this allocation style must use lock-free
286 // allocation for *all* allocation, since there are times when lock free
287 // allocation will be concurrent with plain "allocate" calls.
288 virtual bool supports_inline_contig_alloc() const { return false; }
289
290 // These functions return the addresses of the fields that define the
291 // boundaries of the contiguous allocation area. (These fields should be
292 // physicall near to one another.)
293 virtual HeapWord** top_addr() const { return NULL; }
294 virtual HeapWord** end_addr() const { return NULL; }
295
296 // Thread-local allocation buffers
297 virtual bool supports_tlab_allocation() const { return false; }
298 virtual size_t tlab_capacity() const {
299 guarantee(false, "Generation doesn't support thread local allocation buffers");
300 return 0;
301 }
302 virtual size_t unsafe_max_tlab_alloc() const {
303 guarantee(false, "Generation doesn't support thread local allocation buffers");
304 return 0;
305 }
306
307 // "obj" is the address of an object in a younger generation. Allocate space
308 // for "obj" in the current (or some higher) generation, and copy "obj" into
309 // the newly allocated space, if possible, returning the result (or NULL if
310 // the allocation failed).
311 //
312 // The "obj_size" argument is just obj->size(), passed along so the caller can
468 // beginning allocation point post-collection, which might allow some later
469 // operations to be optimized.
470 virtual void save_marks() {}
471
472 // This function allows generations to initialize any "saved marks". That
473 // is, should only be called when the generation is empty.
474 virtual void reset_saved_marks() {}
475
476 // This function is "true" iff any no allocations have occurred in the
477 // generation since the last call to "save_marks".
478 virtual bool no_allocs_since_save_marks() = 0;
479
480 // Apply "cl->apply" to (the addresses of) all reference fields in objects
481 // allocated in the current generation since the last call to "save_marks".
482 // If more objects are allocated in this generation as a result of applying
483 // the closure, iterates over reference fields in those objects as well.
484 // Calls "save_marks" at the end of the iteration.
485 // General signature...
486 virtual void oop_since_save_marks_iterate_v(OopsInGenClosure* cl) = 0;
487 // ...and specializations for de-virtualization. (The general
488 // implemention of the _nv versions call the virtual version.
489 // Note that the _nv suffix is not really semantically necessary,
490 // but it avoids some not-so-useful warnings on Solaris.)
491 #define Generation_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \
492 virtual void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl) { \
493 oop_since_save_marks_iterate_v((OopsInGenClosure*)cl); \
494 }
495 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(Generation_SINCE_SAVE_MARKS_DECL)
496
497 #undef Generation_SINCE_SAVE_MARKS_DECL
498
499 // The "requestor" generation is performing some garbage collection
500 // action for which it would be useful to have scratch space. If
501 // the target is not the requestor, no gc actions will be required
502 // of the target. The requestor promises to allocate no more than
503 // "max_alloc_words" in the target generation (via promotion say,
504 // if the requestor is a young generation and the target is older).
505 // If the target generation can provide any scratch space, it adds
506 // it to "list", leaving "list" pointing to the head of the
507 // augmented list. The default is to offer no space.
508 virtual void contribute_scratch(ScratchBlock*& list, Generation* requestor,
|
272 // caller must do the necessary locking.
273 virtual HeapWord* allocation_limit_reached(Space* space, HeapWord* top,
274 size_t word_size) {
275 return NULL;
276 }
277
278 // Some generation may offer a region for shared, contiguous allocation,
279 // via inlined code (by exporting the address of the top and end fields
280 // defining the extent of the contiguous allocation region.)
281
282 // This function returns "true" iff the heap supports this kind of
283 // allocation. (More precisely, this means the style of allocation that
284 // increments *top_addr()" with a CAS.) (Default is "no".)
285 // A generation that supports this allocation style must use lock-free
286 // allocation for *all* allocation, since there are times when lock free
287 // allocation will be concurrent with plain "allocate" calls.
288 virtual bool supports_inline_contig_alloc() const { return false; }
289
290 // These functions return the addresses of the fields that define the
291 // boundaries of the contiguous allocation area. (These fields should be
292 // physically near to one another.)
293 virtual HeapWord** top_addr() const { return NULL; }
294 virtual HeapWord** end_addr() const { return NULL; }
295
296 // Thread-local allocation buffers
297 virtual bool supports_tlab_allocation() const { return false; }
298 virtual size_t tlab_capacity() const {
299 guarantee(false, "Generation doesn't support thread local allocation buffers");
300 return 0;
301 }
302 virtual size_t unsafe_max_tlab_alloc() const {
303 guarantee(false, "Generation doesn't support thread local allocation buffers");
304 return 0;
305 }
306
307 // "obj" is the address of an object in a younger generation. Allocate space
308 // for "obj" in the current (or some higher) generation, and copy "obj" into
309 // the newly allocated space, if possible, returning the result (or NULL if
310 // the allocation failed).
311 //
312 // The "obj_size" argument is just obj->size(), passed along so the caller can
468 // beginning allocation point post-collection, which might allow some later
469 // operations to be optimized.
470 virtual void save_marks() {}
471
472 // This function allows generations to initialize any "saved marks". That
473 // is, should only be called when the generation is empty.
474 virtual void reset_saved_marks() {}
475
476 // This function is "true" iff any no allocations have occurred in the
477 // generation since the last call to "save_marks".
478 virtual bool no_allocs_since_save_marks() = 0;
479
480 // Apply "cl->apply" to (the addresses of) all reference fields in objects
481 // allocated in the current generation since the last call to "save_marks".
482 // If more objects are allocated in this generation as a result of applying
483 // the closure, iterates over reference fields in those objects as well.
484 // Calls "save_marks" at the end of the iteration.
485 // General signature...
486 virtual void oop_since_save_marks_iterate_v(OopsInGenClosure* cl) = 0;
487 // ...and specializations for de-virtualization. (The general
488 // implementation of the _nv versions call the virtual version.
489 // Note that the _nv suffix is not really semantically necessary,
490 // but it avoids some not-so-useful warnings on Solaris.)
491 #define Generation_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \
492 virtual void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl) { \
493 oop_since_save_marks_iterate_v((OopsInGenClosure*)cl); \
494 }
495 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(Generation_SINCE_SAVE_MARKS_DECL)
496
497 #undef Generation_SINCE_SAVE_MARKS_DECL
498
499 // The "requestor" generation is performing some garbage collection
500 // action for which it would be useful to have scratch space. If
501 // the target is not the requestor, no gc actions will be required
502 // of the target. The requestor promises to allocate no more than
503 // "max_alloc_words" in the target generation (via promotion say,
504 // if the requestor is a young generation and the target is older).
505 // If the target generation can provide any scratch space, it adds
506 // it to "list", leaving "list" pointing to the head of the
507 // augmented list. The default is to offer no space.
508 virtual void contribute_scratch(ScratchBlock*& list, Generation* requestor,
|