1/*
2 * Copyright (C) 2009 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_FIXED)
31
32#include "CodeProfiling.h"
33#include <errno.h>
34#include <unistd.h>
35#include <wtf/MetaAllocator.h>
36#include <wtf/PageReservation.h>
37#include <wtf/VMTags.h>
38
39#if OS(DARWIN)
40#include <sys/mman.h>
41#endif
42
43#if OS(LINUX)
44#include <stdio.h>
45#endif
46
47#if !PLATFORM(IOS) && PLATFORM(MAC) && __MAC_OS_X_VERSION_MIN_REQUIRED < 1090
48// MADV_FREE_REUSABLE does not work for JIT memory on older OSes so use MADV_FREE in that case.
49#define WTF_USE_MADV_FREE_FOR_JIT_MEMORY 1
50#endif
51
52using namespace WTF;
53
54namespace JSC {
55
56uintptr_t startOfFixedExecutableMemoryPool;
57
58class FixedVMPoolExecutableAllocator : public MetaAllocator {
59    WTF_MAKE_FAST_ALLOCATED;
60public:
61    FixedVMPoolExecutableAllocator()
62        : MetaAllocator(jitAllocationGranule) // round up all allocations to 32 bytes
63    {
64        m_reservation = PageReservation::reserveWithGuardPages(fixedExecutableMemoryPoolSize, OSAllocator::JSJITCodePages, EXECUTABLE_POOL_WRITABLE, true);
65#if !ENABLE(LLINT)
66        RELEASE_ASSERT(m_reservation);
67#endif
68        if (m_reservation) {
69            ASSERT(m_reservation.size() == fixedExecutableMemoryPoolSize);
70            addFreshFreeSpace(m_reservation.base(), m_reservation.size());
71
72            startOfFixedExecutableMemoryPool = reinterpret_cast<uintptr_t>(m_reservation.base());
73        }
74    }
75
76    virtual ~FixedVMPoolExecutableAllocator();
77
78protected:
79    virtual void* allocateNewSpace(size_t&)
80    {
81        // We're operating in a fixed pool, so new allocation is always prohibited.
82        return 0;
83    }
84
85    virtual void notifyNeedPage(void* page)
86    {
87#if USE(MADV_FREE_FOR_JIT_MEMORY)
88        UNUSED_PARAM(page);
89#else
90        m_reservation.commit(page, pageSize());
91#endif
92    }
93
94    virtual void notifyPageIsFree(void* page)
95    {
96#if USE(MADV_FREE_FOR_JIT_MEMORY)
97        for (;;) {
98            int result = madvise(page, pageSize(), MADV_FREE);
99            if (!result)
100                return;
101            ASSERT(result == -1);
102            if (errno != EAGAIN) {
103                RELEASE_ASSERT_NOT_REACHED(); // In debug mode, this should be a hard failure.
104                break; // In release mode, we should just ignore the error - not returning memory to the OS is better than crashing, especially since we _will_ be able to reuse the memory internally anyway.
105            }
106        }
107#else
108        m_reservation.decommit(page, pageSize());
109#endif
110    }
111
112private:
113    PageReservation m_reservation;
114};
115
116static FixedVMPoolExecutableAllocator* allocator;
117
118void ExecutableAllocator::initializeAllocator()
119{
120    ASSERT(!allocator);
121    allocator = new FixedVMPoolExecutableAllocator();
122    CodeProfiling::notifyAllocator(allocator);
123}
124
125ExecutableAllocator::ExecutableAllocator(VM&)
126{
127    ASSERT(allocator);
128}
129
130ExecutableAllocator::~ExecutableAllocator()
131{
132}
133
134FixedVMPoolExecutableAllocator::~FixedVMPoolExecutableAllocator()
135{
136    m_reservation.deallocate();
137}
138
139bool ExecutableAllocator::isValid() const
140{
141    return !!allocator->bytesReserved();
142}
143
144bool ExecutableAllocator::underMemoryPressure()
145{
146    MetaAllocator::Statistics statistics = allocator->currentStatistics();
147    return statistics.bytesAllocated > statistics.bytesReserved / 2;
148}
149
150double ExecutableAllocator::memoryPressureMultiplier(size_t addedMemoryUsage)
151{
152    MetaAllocator::Statistics statistics = allocator->currentStatistics();
153    ASSERT(statistics.bytesAllocated <= statistics.bytesReserved);
154    size_t bytesAllocated = statistics.bytesAllocated + addedMemoryUsage;
155    if (bytesAllocated >= statistics.bytesReserved)
156        bytesAllocated = statistics.bytesReserved;
157    double result = 1.0;
158    size_t divisor = statistics.bytesReserved - bytesAllocated;
159    if (divisor)
160        result = static_cast<double>(statistics.bytesReserved) / divisor;
161    if (result < 1.0)
162        result = 1.0;
163    return result;
164}
165
166PassRefPtr<ExecutableMemoryHandle> ExecutableAllocator::allocate(VM& vm, size_t sizeInBytes, void* ownerUID, JITCompilationEffort effort)
167{
168    RefPtr<ExecutableMemoryHandle> result = allocator->allocate(sizeInBytes, ownerUID);
169    if (!result) {
170        if (effort == JITCompilationCanFail)
171            return result;
172        releaseExecutableMemory(vm);
173        result = allocator->allocate(sizeInBytes, ownerUID);
174        RELEASE_ASSERT(result);
175    }
176    return result.release();
177}
178
179size_t ExecutableAllocator::committedByteCount()
180{
181    return allocator->bytesCommitted();
182}
183
184#if ENABLE(META_ALLOCATOR_PROFILE)
185void ExecutableAllocator::dumpProfile()
186{
187    allocator->dumpProfile();
188}
189#endif
190
191}
192
193
194#endif // ENABLE(EXECUTABLE_ALLOCATOR_FIXED)
195