1 /* 2 * Copyright (C) 2009 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #define LOG_TAG "MediaBufferGroup" 18 #include <utils/Log.h> 19 20 #include <media/stagefright/foundation/ADebug.h> 21 #include <media/stagefright/MediaBuffer.h> 22 #include <media/stagefright/MediaBufferGroup.h> 23 24 namespace android { 25 26 // std::min is not constexpr in C++11 27 template<typename T> 28 constexpr T MIN(const T &a, const T &b) { return a <= b ? a : b; } 29 30 // MediaBufferGroup may create shared memory buffers at a 31 // smaller threshold than an isolated new MediaBuffer. 32 static const size_t kSharedMemoryThreshold = MIN( 33 (size_t)MediaBuffer::kSharedMemThreshold, (size_t)(4 * 1024)); 34 35 MediaBufferGroup::MediaBufferGroup(size_t growthLimit) : 36 mGrowthLimit(growthLimit) { 37 } 38 39 MediaBufferGroup::MediaBufferGroup(size_t buffers, size_t buffer_size, size_t growthLimit) 40 : mGrowthLimit(growthLimit) { 41 42 if (buffer_size >= kSharedMemoryThreshold) { 43 ALOGD("creating MemoryDealer"); 44 // Using a single MemoryDealer is efficient for a group of shared memory objects. 45 // This loop guarantees that we use shared memory (no fallback to malloc). 46 47 size_t alignment = MemoryDealer::getAllocationAlignment(); 48 size_t augmented_size = buffer_size + sizeof(MediaBuffer::SharedControl); 49 size_t total = (augmented_size + alignment - 1) / alignment * alignment * buffers; 50 sp<MemoryDealer> memoryDealer = new MemoryDealer(total, "MediaBufferGroup"); 51 52 for (size_t i = 0; i < buffers; ++i) { 53 sp<IMemory> mem = memoryDealer->allocate(augmented_size); 54 if (mem.get() == nullptr || mem->pointer() == nullptr) { 55 ALOGW("Only allocated %zu shared buffers of size %zu", i, buffer_size); 56 break; 57 } 58 MediaBuffer *buffer = new MediaBuffer(mem); 59 buffer->getSharedControl()->clear(); 60 add_buffer(buffer); 61 } 62 return; 63 } 64 65 // Non-shared memory allocation. 66 for (size_t i = 0; i < buffers; ++i) { 67 MediaBuffer *buffer = new MediaBuffer(buffer_size); 68 if (buffer->data() == nullptr) { 69 delete buffer; // don't call release, it's not properly formed 70 ALOGW("Only allocated %zu malloc buffers of size %zu", i, buffer_size); 71 break; 72 } 73 add_buffer(buffer); 74 } 75 } 76 77 MediaBufferGroup::~MediaBufferGroup() { 78 for (MediaBuffer *buffer : mBuffers) { 79 if (buffer->refcount() != 0) { 80 const int localRefcount = buffer->localRefcount(); 81 const int remoteRefcount = buffer->remoteRefcount(); 82 83 // Fatal if we have a local refcount. 84 LOG_ALWAYS_FATAL_IF(localRefcount != 0, 85 "buffer(%p) localRefcount %d != 0, remoteRefcount %d", 86 buffer, localRefcount, remoteRefcount); 87 88 // Log an error if we have a remaining remote refcount, 89 // as the remote process may have died or may have inappropriate behavior. 90 // The shared memory associated with the MediaBuffer will 91 // automatically be reclaimed when there are no remaining fds 92 // associated with it. 93 ALOGE("buffer(%p) has residual remoteRefcount %d", 94 buffer, remoteRefcount); 95 } 96 // gracefully delete. 97 buffer->setObserver(nullptr); 98 buffer->release(); 99 } 100 } 101 102 void MediaBufferGroup::add_buffer(MediaBuffer *buffer) { 103 Mutex::Autolock autoLock(mLock); 104 105 buffer->setObserver(this); 106 mBuffers.emplace_back(buffer); 107 // optionally: mGrowthLimit = max(mGrowthLimit, mBuffers.size()); 108 } 109 110 bool MediaBufferGroup::has_buffers() { 111 if (mBuffers.size() < mGrowthLimit) { 112 return true; // We can add more buffers internally. 113 } 114 for (MediaBuffer *buffer : mBuffers) { 115 if (buffer->refcount() == 0) { 116 return true; 117 } 118 } 119 return false; 120 } 121 122 status_t MediaBufferGroup::acquire_buffer( 123 MediaBuffer **out, bool nonBlocking, size_t requestedSize) { 124 Mutex::Autolock autoLock(mLock); 125 for (;;) { 126 size_t smallest = requestedSize; 127 MediaBuffer *buffer = nullptr; 128 auto free = mBuffers.end(); 129 for (auto it = mBuffers.begin(); it != mBuffers.end(); ++it) { 130 if ((*it)->refcount() == 0) { 131 const size_t size = (*it)->size(); 132 if (size >= requestedSize) { 133 buffer = *it; 134 break; 135 } 136 if (size < smallest) { 137 smallest = size; // always free the smallest buf 138 free = it; 139 } 140 } 141 } 142 if (buffer == nullptr 143 && (free != mBuffers.end() || mBuffers.size() < mGrowthLimit)) { 144 // We alloc before we free so failure leaves group unchanged. 145 const size_t allocateSize = requestedSize < SIZE_MAX / 3 * 2 /* NB: ordering */ ? 146 requestedSize * 3 / 2 : requestedSize; 147 buffer = new MediaBuffer(allocateSize); 148 if (buffer->data() == nullptr) { 149 ALOGE("Allocation failure for size %zu", allocateSize); 150 delete buffer; // Invalid alloc, prefer not to call release. 151 buffer = nullptr; 152 } else { 153 buffer->setObserver(this); 154 if (free != mBuffers.end()) { 155 ALOGV("reallocate buffer, requested size %zu vs available %zu", 156 requestedSize, (*free)->size()); 157 (*free)->setObserver(nullptr); 158 (*free)->release(); 159 *free = buffer; // in-place replace 160 } else { 161 ALOGV("allocate buffer, requested size %zu", requestedSize); 162 mBuffers.emplace_back(buffer); 163 } 164 } 165 } 166 if (buffer != nullptr) { 167 buffer->add_ref(); 168 buffer->reset(); 169 *out = buffer; 170 return OK; 171 } 172 if (nonBlocking) { 173 *out = nullptr; 174 return WOULD_BLOCK; 175 } 176 // All buffers are in use, block until one of them is returned. 177 mCondition.wait(mLock); 178 } 179 // Never gets here. 180 } 181 182 void MediaBufferGroup::signalBufferReturned(MediaBuffer *) { 183 mCondition.signal(); 184 } 185 186 } // namespace android 187