jit/ExecutableAllocator.cpp

   1 /*
   2  * Copyright (C) 2008 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. ``AS IS'' AND ANY
  14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #include "config.h"
  27
  28 #include "ExecutableAllocator.h"
  29
  30 #if ENABLE(EXECUTABLE_ALLOCATOR_DEMAND)
  31 #include "CodeProfiling.h"
  32 #include <wtf/HashSet.h>
  33 #include <wtf/MetaAllocator.h>
  34 #include <wtf/PageReservation.h>
  35 #if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
  36 #include <wtf/PassOwnPtr.h>
  37 #endif
  38 #include <wtf/ThreadingPrimitives.h>
  39 #include <wtf/VMTags.h>
  40 #endif
  41
  42 // Uncomment to create an artificial executable memory usage limit. This limit
  43 // is imperfect and is primarily useful for testing the VM's ability to handle
  44 // out-of-executable-memory situations.
  45 // #define EXECUTABLE_MEMORY_LIMIT 1000000
  46
  47 #if ENABLE(ASSEMBLER)
  48
  49 using namespace WTF;
  50
  51 namespace JSC {
  52
  53 #if ENABLE(EXECUTABLE_ALLOCATOR_DEMAND)
  54
  55 class DemandExecutableAllocator : public MetaAllocator {
  56 public:
  57     DemandExecutableAllocator()
  58         : MetaAllocator(jitAllocationGranule)
  59     {
  60         MutexLocker lock(allocatorsMutex());
  61         allocators().add(this);
  62         // Don't preallocate any memory here.
  63     }
  64
  65     virtual ~DemandExecutableAllocator()
  66     {
  67         {
  68             MutexLocker lock(allocatorsMutex());
  69             allocators().remove(this);
  70         }
  71         for (unsigned i = 0; i < reservations.size(); ++i)
  72             reservations.at(i).deallocate();
  73     }
  74
  75     static size_t bytesAllocatedByAllAllocators()
  76     {
  77         size_t total = 0;
  78         MutexLocker lock(allocatorsMutex());
  79         for (HashSet<DemandExecutableAllocator*>::const_iterator allocator = allocators().begin(); allocator != allocators().end(); ++allocator)
  80             total += (*allocator)->bytesAllocated();
  81         return total;
  82     }
  83
  84     static size_t bytesCommittedByAllocactors()
  85     {
  86         size_t total = 0;
  87         MutexLocker lock(allocatorsMutex());
  88         for (HashSet<DemandExecutableAllocator*>::const_iterator allocator = allocators().begin(); allocator != allocators().end(); ++allocator)
  89             total += (*allocator)->bytesCommitted();
  90         return total;
  91     }
  92
  93 #if ENABLE(META_ALLOCATOR_PROFILE)
  94     static void dumpProfileFromAllAllocators()
  95     {
  96         MutexLocker lock(allocatorsMutex());
  97         for (HashSet<DemandExecutableAllocator*>::const_iterator allocator = allocators().begin(); allocator != allocators().end(); ++allocator)
  98             (*allocator)->dumpProfile();
  99     }
 100 #endif
 101
 102 protected:
 103     virtual void* allocateNewSpace(size_t& numPages)
 104     {
 105         size_t newNumPages = (((numPages * pageSize() + JIT_ALLOCATOR_LARGE_ALLOC_SIZE - 1) / JIT_ALLOCATOR_LARGE_ALLOC_SIZE * JIT_ALLOCATOR_LARGE_ALLOC_SIZE) + pageSize() - 1) / pageSize();
 106
 107         ASSERT(newNumPages >= numPages);
 108
 109         numPages = newNumPages;
 110
 111 #ifdef EXECUTABLE_MEMORY_LIMIT
 112         if (bytesAllocatedByAllAllocators() >= EXECUTABLE_MEMORY_LIMIT)
 113             return 0;
 114 #endif
 115
 116         PageReservation reservation = PageReservation::reserve(numPages * pageSize(), OSAllocator::JSJITCodePages, EXECUTABLE_POOL_WRITABLE, true);
 117         RELEASE_ASSERT(reservation);
 118
 119         reservations.append(reservation);
 120
 121         return reservation.base();
 122     }
 123
 124     virtual void notifyNeedPage(void* page)
 125     {
 126         OSAllocator::commit(page, pageSize(), EXECUTABLE_POOL_WRITABLE, true);
 127     }
 128
 129     virtual void notifyPageIsFree(void* page)
 130     {
 131         OSAllocator::decommit(page, pageSize());
 132     }
 133
 134 private:
 135     Vector<PageReservation, 16> reservations;
 136     static HashSet<DemandExecutableAllocator*>& allocators()
 137     {
 138         DEFINE_STATIC_LOCAL(HashSet<DemandExecutableAllocator*>, sAllocators, ());
 139         return sAllocators;
 140     }
 141     static Mutex& allocatorsMutex()
 142     {
 143         DEFINE_STATIC_LOCAL(Mutex, mutex, ());
 144         return mutex;
 145     }
 146 };
 147
 148 #if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
 149 void ExecutableAllocator::initializeAllocator()
 150 {
 151 }
 152 #else
 153 static DemandExecutableAllocator* gAllocator;
 154
 155 namespace {
 156 static inline DemandExecutableAllocator* allocator()
 157 {
 158     return gAllocator;
 159 }
 160 }
 161
 162 void ExecutableAllocator::initializeAllocator()
 163 {
 164     ASSERT(!gAllocator);
 165     gAllocator = new DemandExecutableAllocator();
 166     CodeProfiling::notifyAllocator(gAllocator);
 167 }
 168 #endif
 169
 170 ExecutableAllocator::ExecutableAllocator(VM&)
 171 #if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
 172     : m_allocator(adoptPtr(new  DemandExecutableAllocator()))
 173 #endif
 174 {
 175     ASSERT(allocator());
 176 }
 177
 178 ExecutableAllocator::~ExecutableAllocator()
 179 {
 180 }
 181
 182 bool ExecutableAllocator::isValid() const
 183 {
 184     return true;
 185 }
 186
 187 bool ExecutableAllocator::underMemoryPressure()
 188 {
 189 #ifdef EXECUTABLE_MEMORY_LIMIT
 190     return DemandExecutableAllocator::bytesAllocatedByAllAllocators() > EXECUTABLE_MEMORY_LIMIT / 2;
 191 #else
 192     return false;
 193 #endif
 194 }
 195
 196 double ExecutableAllocator::memoryPressureMultiplier(size_t addedMemoryUsage)
 197 {
 198     double result;
 199 #ifdef EXECUTABLE_MEMORY_LIMIT
 200     size_t bytesAllocated = DemandExecutableAllocator::bytesAllocatedByAllAllocators() + addedMemoryUsage;
 201     if (bytesAllocated >= EXECUTABLE_MEMORY_LIMIT)
 202         bytesAllocated = EXECUTABLE_MEMORY_LIMIT;
 203     result = static_cast<double>(EXECUTABLE_MEMORY_LIMIT) /
 204         (EXECUTABLE_MEMORY_LIMIT - bytesAllocated);
 205 #else
 206     UNUSED_PARAM(addedMemoryUsage);
 207     result = 1.0;
 208 #endif
 209     if (result < 1.0)
 210         result = 1.0;
 211     return result;
 212
 213 }
 214
 215 PassRefPtr<ExecutableMemoryHandle> ExecutableAllocator::allocate(VM&, size_t sizeInBytes, void* ownerUID, JITCompilationEffort effort)
 216 {
 217     RefPtr<ExecutableMemoryHandle> result = allocator()->allocate(sizeInBytes, ownerUID);
 218     RELEASE_ASSERT(result || effort != JITCompilationMustSucceed);
 219     return result.release();
 220 }
 221
 222 size_t ExecutableAllocator::committedByteCount()
 223 {
 224     return DemandExecutableAllocator::bytesCommittedByAllocactors();
 225 }
 226
 227 #if ENABLE(META_ALLOCATOR_PROFILE)
 228 void ExecutableAllocator::dumpProfile()
 229 {
 230     DemandExecutableAllocator::dumpProfileFromAllAllocators();
 231 }
 232 #endif
 233
 234 #endif // ENABLE(EXECUTABLE_ALLOCATOR_DEMAND)
 235
 236 #if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
 237
 238 #if OS(WINDOWS)
 239 #error "ASSEMBLER_WX_EXCLUSIVE not yet suported on this platform."
 240 #endif
 241
 242 void ExecutableAllocator::reprotectRegion(void* start, size_t size, ProtectionSetting setting)
 243 {
 244     size_t pageSize = WTF::pageSize();
 245
 246     // Calculate the start of the page containing this region,
 247     // and account for this extra memory within size.
 248     intptr_t startPtr = reinterpret_cast<intptr_t>(start);
 249     intptr_t pageStartPtr = startPtr & ~(pageSize - 1);
 250     void* pageStart = reinterpret_cast<void*>(pageStartPtr);
 251     size += (startPtr - pageStartPtr);
 252
 253     // Round size up
 254     size += (pageSize - 1);
 255     size &= ~(pageSize - 1);
 256
 257     mprotect(pageStart, size, (setting == Writable) ? PROTECTION_FLAGS_RW : PROTECTION_FLAGS_RX);
 258 }
 259
 260 #endif
 261
 262 }
 263
 264 #endif // HAVE(ASSEMBLER)