403 // * All allocation requests for new TLABs should go to
404 // allocate_new_tlab().
405 //
406 // * All non-TLAB allocation requests should go to mem_allocate().
407 //
408 // * If either call cannot satisfy the allocation request using the
409 // current allocating region, they will try to get a new one. If
410 // this fails, they will attempt to do an evacuation pause and
411 // retry the allocation.
412 //
413 // * If all allocation attempts fail, even after trying to schedule
414 // an evacuation pause, allocate_new_tlab() will return NULL,
415 // whereas mem_allocate() will attempt a heap expansion and/or
416 // schedule a Full GC.
417 //
418 // * We do not allow humongous-sized TLABs. So, allocate_new_tlab
419 // should never be called with word_size being humongous. All
420 // humongous allocation requests should go to mem_allocate() which
421 // will satisfy them with a special path.
422
423 virtual HeapWord* allocate_new_tlab(size_t word_size);
424
425 virtual HeapWord* mem_allocate(size_t word_size,
426 bool* gc_overhead_limit_was_exceeded);
427
428 // First-level mutator allocation attempt: try to allocate out of
429 // the mutator alloc region without taking the Heap_lock. This
430 // should only be used for non-humongous allocations.
431 inline HeapWord* attempt_allocation(size_t word_size);
432
433 // Second-level mutator allocation attempt: take the Heap_lock and
434 // retry the allocation attempt, potentially scheduling a GC
435 // pause. This should only be used for non-humongous allocations.
436 HeapWord* attempt_allocation_slow(size_t word_size);
437
438 // Takes the Heap_lock and attempts a humongous allocation. It can
439 // potentially schedule a GC pause.
440 HeapWord* attempt_allocation_humongous(size_t word_size);
441
442 // Allocation attempt that should be called during safepoints (e.g.,
443 // at the end of a successful GC). expect_null_mutator_alloc_region
444 // specifies whether the mutator alloc region is expected to be NULL
445 // or not.
446 HeapWord* attempt_allocation_at_safepoint(size_t word_size,
447 bool expect_null_mutator_alloc_region);
448
449 // These methods are the "callbacks" from the G1AllocRegion class.
450
451 // For mutator alloc regions.
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403 // * All allocation requests for new TLABs should go to
404 // allocate_new_tlab().
405 //
406 // * All non-TLAB allocation requests should go to mem_allocate().
407 //
408 // * If either call cannot satisfy the allocation request using the
409 // current allocating region, they will try to get a new one. If
410 // this fails, they will attempt to do an evacuation pause and
411 // retry the allocation.
412 //
413 // * If all allocation attempts fail, even after trying to schedule
414 // an evacuation pause, allocate_new_tlab() will return NULL,
415 // whereas mem_allocate() will attempt a heap expansion and/or
416 // schedule a Full GC.
417 //
418 // * We do not allow humongous-sized TLABs. So, allocate_new_tlab
419 // should never be called with word_size being humongous. All
420 // humongous allocation requests should go to mem_allocate() which
421 // will satisfy them with a special path.
422
423 virtual HeapWord* allocate_new_tlab(size_t min_size,
424 size_t requested_size,
425 size_t* actual_size);
426
427 virtual HeapWord* mem_allocate(size_t word_size,
428 bool* gc_overhead_limit_was_exceeded);
429
430 // First-level mutator allocation attempt: try to allocate out of
431 // the mutator alloc region without taking the Heap_lock. This
432 // should only be used for non-humongous allocations.
433 inline HeapWord* attempt_allocation(size_t min_word_size,
434 size_t desired_word_size,
435 size_t* actual_word_size);
436
437 // Second-level mutator allocation attempt: take the Heap_lock and
438 // retry the allocation attempt, potentially scheduling a GC
439 // pause. This should only be used for non-humongous allocations.
440 HeapWord* attempt_allocation_slow(size_t word_size);
441
442 // Takes the Heap_lock and attempts a humongous allocation. It can
443 // potentially schedule a GC pause.
444 HeapWord* attempt_allocation_humongous(size_t word_size);
445
446 // Allocation attempt that should be called during safepoints (e.g.,
447 // at the end of a successful GC). expect_null_mutator_alloc_region
448 // specifies whether the mutator alloc region is expected to be NULL
449 // or not.
450 HeapWord* attempt_allocation_at_safepoint(size_t word_size,
451 bool expect_null_mutator_alloc_region);
452
453 // These methods are the "callbacks" from the G1AllocRegion class.
454
455 // For mutator alloc regions.
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