heap/SuperRegion.cpp

   1 /*
   2  * Copyright (C) 2013 Apple Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
  14  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  15  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
  17  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  18  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  19  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  20  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  21  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  22  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  23  * THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #include "config.h"
  27 #include "SuperRegion.h"
  28
  29 #include "JSCInlines.h"
  30 #include "Region.h"
  31
  32 namespace JSC {
  33
  34 const uint64_t SuperRegion::s_fixedHeapMemoryPoolSize = 4 * 1024 * static_cast<uint64_t>(MB);
  35
  36 SuperRegion::SuperRegion()
  37     : MetaAllocator(Region::s_regionSize, Region::s_regionSize)
  38     , m_reservationBase(0)
  39 {
  40 #if ENABLE(SUPER_REGION)
  41     // Over-allocate so that we can make sure that we're aligned to the size of Regions.
  42     m_reservation = PageReservation::reserve(s_fixedHeapMemoryPoolSize + Region::s_regionSize, OSAllocator::JSGCHeapPages);
  43     m_reservationBase = getAlignedBase(m_reservation);
  44     addFreshFreeSpace(m_reservationBase, s_fixedHeapMemoryPoolSize);
  45 #else
  46     UNUSED_PARAM(m_reservation);
  47     UNUSED_PARAM(m_reservationBase);
  48 #endif
  49 }
  50
  51 SuperRegion::~SuperRegion()
  52 {
  53 #if ENABLE(SUPER_REGION)
  54     m_reservation.deallocate();
  55 #endif
  56 }
  57
  58 void* SuperRegion::getAlignedBase(PageReservation& reservation)
  59 {
  60     for (char* current = static_cast<char*>(reservation.base()); current < static_cast<char*>(reservation.base()) + Region::s_regionSize; current += pageSize()) {
  61         if (!(reinterpret_cast<size_t>(current) & ~Region::s_regionMask))
  62             return current;
  63     }
  64     ASSERT_NOT_REACHED();
  65     return 0;
  66 }
  67
  68 void* SuperRegion::allocateNewSpace(size_t&)
  69 {
  70     return 0;
  71 }
  72
  73 void SuperRegion::notifyNeedPage(void* page)
  74 {
  75     m_reservation.commit(page, Region::s_regionSize);
  76 }
  77
  78 void SuperRegion::notifyPageIsFree(void* page)
  79 {
  80     m_reservation.decommit(page, Region::s_regionSize);
  81 }
  82
  83 } // namespace JSC