1 /* 2 * Copyright (c) 1999, 2009, 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 inline HeapWord* ThreadLocalAllocBuffer::allocate(size_t size) { 26 invariants(); 27 HeapWord* obj = top(); 28 if (pointer_delta(end(), obj) >= size) { 29 // successful thread-local allocation 30 #ifdef ASSERT 31 // Skip mangling the space corresponding to the object header to 32 // ensure that the returned space is not considered parsable by 33 // any concurrent GC thread. 34 size_t hdr_size = oopDesc::header_size(); 35 Copy::fill_to_words(obj + hdr_size, size - hdr_size, badHeapWordVal); 36 #endif // ASSERT 37 // This addition is safe because we know that top is 38 // at least size below end, so the add can't wrap. 39 set_top(obj + size); 40 41 invariants(); 42 return obj; 43 } 44 return NULL; 45 } 46 47 inline size_t ThreadLocalAllocBuffer::compute_size(size_t obj_size) { 48 const size_t aligned_obj_size = align_object_size(obj_size); 49 50 // Compute the size for the new TLAB. 51 // The "last" tlab may be smaller to reduce fragmentation. 52 // unsafe_max_tlab_alloc is just a hint. 53 const size_t available_size = Universe::heap()->unsafe_max_tlab_alloc(myThread()) / 54 HeapWordSize; 55 size_t new_tlab_size = MIN2(available_size, desired_size() + aligned_obj_size); 56 57 // Make sure there's enough room for object and filler int[]. 58 const size_t obj_plus_filler_size = aligned_obj_size + alignment_reserve(); 59 if (new_tlab_size < obj_plus_filler_size) { 60 // If there isn't enough room for the allocation, return failure. 61 if (PrintTLAB && Verbose) { 62 gclog_or_tty->print_cr("ThreadLocalAllocBuffer::compute_size(" SIZE_FORMAT ")" 63 " returns failure", 64 obj_size); 65 } 66 return 0; 67 } 68 if (PrintTLAB && Verbose) { 69 gclog_or_tty->print_cr("ThreadLocalAllocBuffer::compute_size(" SIZE_FORMAT ")" 70 " returns " SIZE_FORMAT, 71 obj_size, new_tlab_size); 72 } 73 return new_tlab_size; 74 } 75 76 77 void ThreadLocalAllocBuffer::record_slow_allocation(size_t obj_size) { 78 // Raise size required to bypass TLAB next time. Why? Else there's 79 // a risk that a thread that repeatedly allocates objects of one 80 // size will get stuck on this slow path. 81 82 set_refill_waste_limit(refill_waste_limit() + refill_waste_limit_increment()); 83 84 _slow_allocations++; 85 86 if (PrintTLAB && Verbose) { 87 Thread* thrd = myThread(); 88 gclog_or_tty->print("TLAB: %s thread: "INTPTR_FORMAT" [id: %2d]" 89 " obj: "SIZE_FORMAT 90 " free: "SIZE_FORMAT 91 " waste: "SIZE_FORMAT"\n", 92 "slow", thrd, thrd->osthread()->thread_id(), 93 obj_size, free(), refill_waste_limit()); 94 } 95 }