1 /* 2 * Copyright 2016 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 #ifndef ANDROID_SERVERS_CAMERA3_BUFFER_MANAGER_H 18 #define ANDROID_SERVERS_CAMERA3_BUFFER_MANAGER_H 19 20 #include <list> 21 #include <algorithm> 22 #include <ui/GraphicBuffer.h> 23 #include <utils/RefBase.h> 24 #include <utils/KeyedVector.h> 25 #include "Camera3OutputStream.h" 26 27 namespace android { 28 29 namespace camera3 { 30 31 struct StreamInfo; 32 class Camera3OutputStream; 33 34 /** 35 * A class managing the graphic buffers that is used by camera output streams. It allocates and 36 * hands out Gralloc buffers to the clients (e.g., Camera3OutputStream) based on the requests. 37 * When clients request a buffer, buffer manager will pick a buffer if there are some already 38 * allocated buffer available, will allocate a buffer otherwise. When there are too many allocated 39 * buffer maintained by the buffer manager, it will dynamically deallocate some buffers that are 40 * solely owned by this buffer manager. 41 * In doing so, it reduces the memory footprint unless it is already minimal without impacting 42 * performance. 43 * 44 */ 45 class Camera3BufferManager: public virtual RefBase { 46 public: 47 explicit Camera3BufferManager(); 48 49 virtual ~Camera3BufferManager(); 50 51 /** 52 * This method registers an output stream to this buffer manager by using the provided stream 53 * information. 54 * 55 * The stream info includes the necessary information such as stream size, format, buffer count, 56 * usage flags, etc. for the buffer manager to allocate and hand out buffers for this stream. 57 * 58 * It's illegal to call this method if the stream is not CONFIGURED yet, as some critical 59 * stream properties (e.g., combined usage flags) are only available in this state. It is also 60 * illegal to call this method with an invalid stream set ID (CAMERA3_STREAM_SET_ID_INVALID), 61 * as the invalid stream set ID indicates that this stream doesn't intend to use buffer manager. 62 * 63 * 64 * Once a stream is successfully registered to this buffer manager, the buffer manager takes 65 * over the buffer allocation role and provides buffers to this stream via getBufferForStream(). 66 * The returned buffer can be sent to the camera HAL for image output, and then queued to the 67 * ANativeWindow (Surface) for downstream consumer to acquire. Once the image buffer is released 68 * by the consumer end point, the BufferQueueProducer callback onBufferReleased will call 69 * returnBufferForStream() to return the free buffer to this buffer manager. If the stream 70 * uses buffer manager to manage the stream buffers, it should disable the BufferQueue 71 * allocation via IGraphicBufferProducer::allowAllocation(false). 72 * 73 * Registering an already registered stream has no effect. 74 * 75 * Return values: 76 * 77 * OK: Registration of the new stream was successful. 78 * BAD_VALUE: This stream is not at CONFIGURED state, or the stream ID or stream set 79 * ID are invalid, or attempting to register the same stream to multiple 80 * stream sets, or other stream properties are invalid. 81 * INVALID_OPERATION: This buffer manager doesn't support buffer sharing across this stream 82 * and other streams that were already registered with the same stream set 83 * ID. 84 */ 85 status_t registerStream(wp<Camera3OutputStream>& stream, const StreamInfo &streamInfo); 86 87 /** 88 * This method unregisters a stream from this buffer manager. 89 * 90 * After a stream is unregistered, further getBufferForStream() calls will fail for this stream. 91 * After all streams for a given stream set are unregistered, all the buffers solely owned (for 92 * this stream set) by this buffer manager will be freed; all buffers subsequently returned to 93 * this buffer manager for this stream set will be freed immediately. 94 * 95 * Return values: 96 * 97 * OK: Removal of the a stream from this buffer manager was successful. 98 * BAD_VALUE: stream ID or stream set ID are invalid, or stream ID and stream set ID 99 * combination doesn't match what was registered, or this stream wasn't registered 100 * to this buffer manager before. 101 */ 102 status_t unregisterStream(int streamId, int streamSetId); 103 104 /** 105 * This method obtains a buffer for a stream from this buffer manager. 106 * 107 * This method returns the first free buffer from the free buffer list (associated with this 108 * stream set) if there is any. Otherwise, it will allocate a buffer for this stream, return 109 * it and increment its count of handed-out buffers. When the total number of allocated buffers 110 * is too high, it may deallocate the unused buffers to save memory footprint of this stream 111 * set. 112 * 113 * After this call, the client takes over the ownership of this buffer if it is not freed. 114 * 115 * Sometimes free buffers are discarded from consumer side and the dequeueBuffer call returns 116 * TIMED_OUT, in this case calling getBufferForStream again with noFreeBufferAtConsumer set to 117 * true will notify buffer manager to update its states and also tries to allocate a new buffer. 118 * 119 * Return values: 120 * 121 * OK: Getting buffer for this stream was successful. 122 * ALREADY_EXISTS: Enough free buffers are already attached to this output buffer queue, 123 * user should just dequeue from the buffer queue. 124 * BAD_VALUE: stream ID or streamSetId are invalid, or stream ID and stream set ID 125 * combination doesn't match what was registered, or this stream wasn't registered 126 * to this buffer manager before. 127 * NO_MEMORY: Unable to allocate a buffer for this stream at this time. 128 */ 129 status_t getBufferForStream( 130 int streamId, int streamSetId, sp<GraphicBuffer>* gb, int* fenceFd, 131 bool noFreeBufferAtConsumer = false); 132 133 /** 134 * This method notifies the manager that a buffer has been released by the consumer. 135 * 136 * The buffer is not returned to the buffer manager, but is available for the stream the buffer 137 * is attached to for dequeuing. 138 * 139 * The notification lets the manager know how many buffers are directly available to the stream. 140 * 141 * If onBufferReleased is called for a given released buffer, 142 * returnBufferForStream may not be called for the same buffer, until the 143 * buffer has been reused. The manager will call detachBuffer on the stream 144 * if it needs the released buffer otherwise. 145 * 146 * When shouldFreeBuffer is set to true, caller must detach and free one buffer from the 147 * buffer queue, and then call notifyBufferRemoved to update the manager. 148 * 149 * Return values: 150 * 151 * OK: Buffer release was processed succesfully 152 * BAD_VALUE: stream ID or streamSetId are invalid, or stream ID and stream set ID 153 * combination doesn't match what was registered, or this stream wasn't registered 154 * to this buffer manager before, or shouldFreeBuffer is null/ 155 */ 156 status_t onBufferReleased(int streamId, int streamSetId, /*out*/bool* shouldFreeBuffer); 157 158 /** 159 * This method notifies the manager that certain buffers has been removed from the 160 * buffer queue by detachBuffer from the consumer. 161 * 162 * The notification lets the manager update its internal handout buffer count and 163 * attached buffer counts accordingly. When buffers are detached from 164 * consumer, both handout and attached counts are decremented. 165 * 166 * Return values: 167 * 168 * OK: Buffer removal was processed succesfully 169 * BAD_VALUE: stream ID or streamSetId are invalid, or stream ID and stream set ID 170 * combination doesn't match what was registered, or this stream wasn't registered 171 * to this buffer manager before, or the removed buffer count is larger than 172 * current total handoutCount or attachedCount. 173 */ 174 status_t onBuffersRemoved(int streamId, int streamSetId, size_t count); 175 176 /** 177 * This method notifiers the manager that a buffer is freed from the buffer queue, usually 178 * because onBufferReleased signals the caller to free a buffer via the shouldFreeBuffer flag. 179 */ 180 void notifyBufferRemoved(int streamId, int streamSetId); 181 182 /** 183 * Dump the buffer manager statistics. 184 */ 185 void dump(int fd, const Vector<String16> &args) const; 186 187 private: 188 // allocatedBufferWaterMark will be decreased when: 189 // numAllocatedBuffersThisSet > numHandoutBuffersThisSet + BUFFER_WATERMARK_DEC_THRESHOLD 190 // This allows the watermark go back down after a burst of buffer requests 191 static const int BUFFER_WATERMARK_DEC_THRESHOLD = 3; 192 193 // onBufferReleased will set shouldFreeBuffer to true when: 194 // numAllocatedBuffersThisSet > allocatedBufferWaterMark AND 195 // numAllocatedBuffersThisStream > numHandoutBuffersThisStream + BUFFER_FREE_THRESHOLD 196 // So after a burst of buffer requests and back to steady state, the buffer queue should have 197 // (BUFFER_FREE_THRESHOLD + steady state handout buffer count) buffers. 198 static const int BUFFER_FREE_THRESHOLD = 3; 199 200 /** 201 * Lock to synchronize the access to the methods of this class. 202 */ 203 mutable Mutex mLock; 204 205 static const size_t kMaxBufferCount = BufferQueueDefs::NUM_BUFFER_SLOTS; 206 207 struct GraphicBufferEntry { 208 sp<GraphicBuffer> graphicBuffer; 209 int fenceFd; 210 explicit GraphicBufferEntry(const sp<GraphicBuffer>& gb = 0, int fd = -1) : graphicBufferGraphicBufferEntry211 graphicBuffer(gb), 212 fenceFd(fd) {} 213 }; 214 215 /** 216 * A buffer entry (indexed by stream ID) represents a single physically allocated buffer. For 217 * Gralloc V0, since each physical buffer is associated with one stream, this is 218 * a single entry map. For Gralloc V1, one physical buffer can be shared between different 219 * streams in one stream set, so this entry may include multiple entries, where the different 220 * graphic buffers have the same common Gralloc backing store. 221 */ 222 typedef int StreamId; 223 typedef KeyedVector<StreamId, GraphicBufferEntry> BufferEntry; 224 225 typedef std::list<BufferEntry> BufferList; 226 227 /** 228 * Stream info map (indexed by stream ID) tracks all the streams registered to a particular 229 * stream set. 230 */ 231 typedef KeyedVector<StreamId, StreamInfo> InfoMap; 232 233 /** 234 * Stream set buffer count map (indexed by stream ID) tracks all buffer counts of the streams 235 * registered to a particular stream set. 236 */ 237 typedef KeyedVector<StreamId, size_t> BufferCountMap; 238 239 /** 240 * StreamSet keeps track of the stream info, free buffer list and hand-out buffer counts for 241 * each stream set. 242 */ 243 struct StreamSet { 244 /** 245 * Stream set buffer count water mark representing the max number of allocated buffers 246 * (hand-out buffers + free buffers) count for each stream set. For a given stream set, when 247 * getBufferForStream() is called on this buffer manager, if the total allocated buffer 248 * count exceeds this water mark, the buffer manager will attempt to reduce it as follows: 249 * 250 * In getBufferForStream(), find a buffer associated with other streams (inside the same 251 * stream set) on the free buffer list and free it. For Gralloc V1, can just free the top 252 * of the free buffer list if the physical buffer sharing in this stream is supported. 253 * 254 * For a particular stream set, a larger allocatedBufferWaterMark increases the memory 255 * footprint of the stream set, but reduces the chance that getBufferForStream() will have 256 * to allocate a new buffer. We assume that the streams in one stream set are not streaming 257 * simultaneously, the max allocated buffer count water mark for a stream set will the max 258 * of all streams' total buffer counts. This will avoid new buffer allocation in steady 259 * streaming state. 260 * 261 * This water mark can be dynamically changed, and will grow when the hand-out buffer count 262 * of each stream increases, until it reaches the maxAllowedBufferCount. 263 */ 264 size_t allocatedBufferWaterMark; 265 266 /** 267 * The max allowed buffer count for this stream set. It is the max of total number of 268 * buffers for each stream. This is the upper bound of the allocatedBufferWaterMark. 269 */ 270 size_t maxAllowedBufferCount; 271 272 /** 273 * The stream info for all streams in this set 274 */ 275 InfoMap streamInfoMap; 276 /** 277 * The count of the buffers that were handed out to the streams of this set. 278 */ 279 BufferCountMap handoutBufferCountMap; 280 /** 281 * The count of the buffers that are attached to the streams of this set. 282 * An attached buffer may be free or handed out 283 */ 284 BufferCountMap attachedBufferCountMap; 285 StreamSetStreamSet286 StreamSet() { 287 allocatedBufferWaterMark = 0; 288 maxAllowedBufferCount = 0; 289 } 290 }; 291 292 /** 293 * Stream set map managed by this buffer manager. 294 */ 295 typedef int StreamSetId; 296 KeyedVector<StreamSetId, StreamSet> mStreamSetMap; 297 KeyedVector<StreamId, wp<Camera3OutputStream>> mStreamMap; 298 299 // TODO: There is no easy way to query the Gralloc version in this code yet, we have different 300 // code paths for different Gralloc versions, hardcode something here for now. 301 const uint32_t mGrallocVersion = GRALLOC_DEVICE_API_VERSION_0_1; 302 303 /** 304 * Check if this stream was successfully registered already. This method needs to be called with 305 * mLock held. 306 */ 307 bool checkIfStreamRegisteredLocked(int streamId, int streamSetId) const; 308 309 /** 310 * Check if other streams in the stream set has extra buffer available to be freed, and 311 * free one if so. 312 */ 313 status_t checkAndFreeBufferOnOtherStreamsLocked(int streamId, int streamSetId); 314 }; 315 316 } // namespace camera3 317 } // namespace android 318 319 #endif // ANDROID_SERVERS_CAMERA3_BUFFER_MANAGER_H 320