1 /*
   2  * Copyright (c) 1999, 2015, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_GC_SHARED_THREADLOCALALLOCBUFFER_INLINE_HPP
  26 #define SHARE_VM_GC_SHARED_THREADLOCALALLOCBUFFER_INLINE_HPP
  27 
  28 #include "gc/shared/collectedHeap.hpp"
  29 #include "gc/shared/threadLocalAllocBuffer.hpp"
  30 #include "runtime/thread.hpp"
  31 #include "utilities/copy.hpp"
  32 
  33 inline HeapWord* ThreadLocalAllocBuffer::allocate(size_t size) {
  34   invariants();
  35   HeapWord* obj = top();
  36   if (pointer_delta(end(), obj) >= size) {
  37     // successful thread-local allocation
  38 #ifdef ASSERT
  39     // Skip mangling the space corresponding to the object header to
  40     // ensure that the returned space is not considered parsable by
  41     // any concurrent GC thread.
  42     size_t hdr_size = oopDesc::header_size();
  43     Copy::fill_to_words(obj + hdr_size, size - hdr_size, badHeapWordVal);
  44 #endif // ASSERT
  45     // This addition is safe because we know that top is
  46     // at least size below end, so the add can't wrap.
  47     set_top(obj + size);
  48 
  49     invariants();
  50     return obj;
  51   }
  52   return NULL;
  53 }
  54 
  55 inline size_t ThreadLocalAllocBuffer::compute_size(size_t obj_size) {
  56   const size_t aligned_obj_size = align_object_size(obj_size);
  57 
  58   // Compute the size for the new TLAB.
  59   // The "last" tlab may be smaller to reduce fragmentation.
  60   // unsafe_max_tlab_alloc is just a hint.
  61   const size_t available_size = Universe::heap()->unsafe_max_tlab_alloc(myThread()) /
  62                                                   HeapWordSize;
  63   size_t new_tlab_size = MIN2(available_size, desired_size() + aligned_obj_size);
  64 
  65   // Make sure there's enough room for object and filler int[].
  66   const size_t obj_plus_filler_size = aligned_obj_size + alignment_reserve();
  67   if (new_tlab_size < obj_plus_filler_size) {
  68     // If there isn't enough room for the allocation, return failure.
  69     if (PrintTLAB && Verbose) {
  70       gclog_or_tty->print_cr("ThreadLocalAllocBuffer::compute_size(" SIZE_FORMAT ")"
  71                     " returns failure",
  72                     obj_size);
  73     }
  74     return 0;
  75   }
  76   if (PrintTLAB && Verbose) {
  77     gclog_or_tty->print_cr("ThreadLocalAllocBuffer::compute_size(" SIZE_FORMAT ")"
  78                   " returns " SIZE_FORMAT,
  79                   obj_size, new_tlab_size);
  80   }
  81   return new_tlab_size;
  82 }
  83 
  84 
  85 void ThreadLocalAllocBuffer::record_slow_allocation(size_t obj_size) {
  86   // Raise size required to bypass TLAB next time. Why? Else there's
  87   // a risk that a thread that repeatedly allocates objects of one
  88   // size will get stuck on this slow path.
  89 
  90   set_refill_waste_limit(refill_waste_limit() + refill_waste_limit_increment());
  91 
  92   _slow_allocations++;
  93 
  94   if (PrintTLAB && Verbose) {
  95     Thread* thrd = myThread();
  96     gclog_or_tty->print("TLAB: %s thread: " INTPTR_FORMAT " [id: %2d]"
  97                         " obj: " SIZE_FORMAT
  98                         " free: " SIZE_FORMAT
  99                         " waste: " SIZE_FORMAT "\n",
 100                         "slow", p2i(thrd), thrd->osthread()->thread_id(),
 101                         obj_size, free(), refill_waste_limit());
 102   }
 103 }
 104 
 105 #endif // SHARE_VM_GC_SHARED_THREADLOCALALLOCBUFFER_INLINE_HPP