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 /*

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  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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  * 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

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 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_INLINE_HPP

 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_INLINE_HPP

 #include "gc_implementation/g1/g1BlockOffsetTable.inline.hpp"

 #include "gc_implementation/g1/g1CollectedHeap.hpp"

 #include "gc_implementation/g1/heapRegion.hpp"

 #include "memory/space.hpp"

 #include "runtime/atomic.inline.hpp"

 // This version requires locking.

 inline HeapWord* G1OffsetTableContigSpace::allocate_impl(size_t size,

                                                 HeapWord* const end_value) {

   HeapWord* obj = top();

   if (pointer_delta(end_value, obj) >= size) {

     HeapWord* new_top = obj + size;

     set_top(new_top);

     assert(is_aligned(obj) && is_aligned(new_top), "checking alignment");

     return obj;

   } else {

     return NULL;

   }

 }

 // This version is lock-free.

 inline HeapWord* G1OffsetTableContigSpace::par_allocate_impl(size_t size,

                                                     HeapWord* const end_value) {

   do {

     HeapWord* obj = top();

     if (pointer_delta(end_value, obj) >= size) {

       HeapWord* new_top = obj + size;

       HeapWord* result = (HeapWord*)Atomic::cmpxchg_ptr(new_top, top_addr(), obj);

       // result can be one of two:

       //  the old top value: the exchange succeeded

       //  otherwise: the new value of the top is returned.

       if (result == obj) {

         assert(is_aligned(obj) && is_aligned(new_top), "checking alignment");

         return obj;

       }

     } else {

       return NULL;

     }

   } while (true);

 }

 inline HeapWord* G1OffsetTableContigSpace::allocate(size_t size) {

   HeapWord* res = allocate_impl(size, end());

   if (res != NULL) {

     _offsets.alloc_block(res, size);

   }

   return res;

 }

 // Because of the requirement of keeping "_offsets" up to date with the

 // allocations, we sequentialize these with a lock.  Therefore, best if

 // this is used for larger LAB allocations only.

 inline HeapWord* G1OffsetTableContigSpace::par_allocate(size_t size) {

   MutexLocker x(&_par_alloc_lock);

   return allocate(size);

 }

 inline HeapWord* G1OffsetTableContigSpace::block_start(const void* p) {

   return _offsets.block_start(p);

 }

 inline HeapWord*

 G1OffsetTableContigSpace::block_start_const(const void* p) const {

   return _offsets.block_start_const(p);

 }

 inline bool

 HeapRegion::block_is_obj(const HeapWord* p) const {

   G1CollectedHeap* g1h = G1CollectedHeap::heap();

   return !g1h->is_obj_dead(oop(p), this);

 }

 inline size_t

 HeapRegion::block_size(const HeapWord *addr) const {

   // Old regions' dead objects may have dead classes

   // We need to find the next live object in some other

   // manner than getting the oop size

   G1CollectedHeap* g1h = G1CollectedHeap::heap();

   if (g1h->is_obj_dead(oop(addr), this)) {

     HeapWord* next = g1h->concurrent_mark()->prevMarkBitMap()->

         getNextMarkedWordAddress(addr, prev_top_at_mark_start());

     assert(next > addr, "must get the next live object");

     return pointer_delta(next, addr);

   } else if (addr == top()) {

     return pointer_delta(end(), addr);

   }

   return oop(addr)->size();

 }

 inline HeapWord* HeapRegion::par_allocate_no_bot_updates(size_t word_size) {

   assert(is_young(), "we can only skip BOT updates on young regions");

   return par_allocate_impl(word_size, end());

 }

 inline HeapWord* HeapRegion::allocate_no_bot_updates(size_t word_size) {

   assert(is_young(), "we can only skip BOT updates on young regions");

   return allocate_impl(word_size, end());

 }

 inline void HeapRegion::note_start_of_marking() {

   _next_marked_bytes = 0;

   _next_top_at_mark_start = top();

 }

 inline void HeapRegion::note_end_of_marking() {

   _prev_top_at_mark_start = _next_top_at_mark_start;

   _prev_marked_bytes = _next_marked_bytes;

   _next_marked_bytes = 0;

   assert(_prev_marked_bytes <=

          (size_t) pointer_delta(prev_top_at_mark_start(), bottom()) *

          HeapWordSize, "invariant");

 }

 inline void HeapRegion::note_start_of_copying(bool during_initial_mark) {

   if (is_survivor()) {

     // This is how we always allocate survivors.

     assert(_next_top_at_mark_start == bottom(), "invariant");

   } else {

     if (during_initial_mark) {

       // During initial-mark we'll explicitly mark any objects on old

       // regions that are pointed to by roots. Given that explicit

       // marks only make sense under NTAMS it'd be nice if we could

       // check that condition if we wanted to. Given that we don't

       // know where the top of this region will end up, we simply set

       // NTAMS to the end of the region so all marks will be below

       // NTAMS. We'll set it to the actual top when we retire this region.

       _next_top_at_mark_start = end();

     } else {

       // We could have re-used this old region as to-space over a

       // couple of GCs since the start of the concurrent marking

       // cycle. This means that [bottom,NTAMS) will contain objects

       // copied up to and including initial-mark and [NTAMS, top)

       // will contain objects copied during the concurrent marking cycle.

       assert(top() >= _next_top_at_mark_start, "invariant");

     }

   }

 }

 inline void HeapRegion::note_end_of_copying(bool during_initial_mark) {

   if (is_survivor()) {

     // This is how we always allocate survivors.

     assert(_next_top_at_mark_start == bottom(), "invariant");

   } else {

     if (during_initial_mark) {

       // See the comment for note_start_of_copying() for the details

       // on this.

       assert(_next_top_at_mark_start == end(), "pre-condition");

       _next_top_at_mark_start = top();

     } else {

       // See the comment for note_start_of_copying() for the details

       // on this.

       assert(top() >= _next_top_at_mark_start, "invariant");

     }

   }

 }

 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_INLINE_HPP