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 * Return values: 116 * 117 * OK: Getting buffer for this stream was successful. 118 * ALREADY_EXISTS: Enough free buffers are already attached to this output buffer queue, 119 * user should just dequeue from the buffer queue. 120 * BAD_VALUE: stream ID or streamSetId are invalid, or stream ID and stream set ID 121 * combination doesn't match what was registered, or this stream wasn't registered 122 * to this buffer manager before. 123 * NO_MEMORY: Unable to allocate a buffer for this stream at this time. 124 */ 125 status_t getBufferForStream(int streamId, int streamSetId, sp<GraphicBuffer>* gb, int* fenceFd); 126 127 /** 128 * This method notifies the manager that a buffer has been released by the consumer. 129 * 130 * The buffer is not returned to the buffer manager, but is available for the stream the buffer 131 * is attached to for dequeuing. 132 * 133 * The notification lets the manager know how many buffers are directly available to the stream. 134 * 135 * If onBufferReleased is called for a given released buffer, 136 * returnBufferForStream may not be called for the same buffer, until the 137 * buffer has been reused. The manager will call detachBuffer on the stream 138 * if it needs the released buffer otherwise. 139 * 140 * When shouldFreeBuffer is set to true, caller must detach and free one buffer from the 141 * buffer queue, and then call notifyBufferRemoved to update the manager. 142 * 143 * Return values: 144 * 145 * OK: Buffer release was processed succesfully 146 * BAD_VALUE: stream ID or streamSetId are invalid, or stream ID and stream set ID 147 * combination doesn't match what was registered, or this stream wasn't registered 148 * to this buffer manager before, or shouldFreeBuffer is null/ 149 */ 150 status_t onBufferReleased(int streamId, int streamSetId, /*out*/bool* shouldFreeBuffer); 151 152 /** 153 * This method notifies the manager that certain buffers has been removed from the 154 * buffer queue by detachBuffer from the consumer. 155 * 156 * The notification lets the manager update its internal handout buffer count and 157 * attached buffer counts accordingly. When buffers are detached from 158 * consumer, both handout and attached counts are decremented. 159 * 160 * Return values: 161 * 162 * OK: Buffer removal was processed succesfully 163 * BAD_VALUE: stream ID or streamSetId are invalid, or stream ID and stream set ID 164 * combination doesn't match what was registered, or this stream wasn't registered 165 * to this buffer manager before, or the removed buffer count is larger than 166 * current total handoutCount or attachedCount. 167 */ 168 status_t onBuffersRemoved(int streamId, int streamSetId, size_t count); 169 170 /** 171 * This method notifiers the manager that a buffer is freed from the buffer queue, usually 172 * because onBufferReleased signals the caller to free a buffer via the shouldFreeBuffer flag. 173 */ 174 void notifyBufferRemoved(int streamId, int streamSetId); 175 176 /** 177 * Dump the buffer manager statistics. 178 */ 179 void dump(int fd, const Vector<String16> &args) const; 180 181 private: 182 // allocatedBufferWaterMark will be decreased when: 183 // numAllocatedBuffersThisSet > numHandoutBuffersThisSet + BUFFER_WATERMARK_DEC_THRESHOLD 184 // This allows the watermark go back down after a burst of buffer requests 185 static const int BUFFER_WATERMARK_DEC_THRESHOLD = 3; 186 187 // onBufferReleased will set shouldFreeBuffer to true when: 188 // numAllocatedBuffersThisSet > allocatedBufferWaterMark AND 189 // numAllocatedBuffersThisStream > numHandoutBuffersThisStream + BUFFER_FREE_THRESHOLD 190 // So after a burst of buffer requests and back to steady state, the buffer queue should have 191 // (BUFFER_FREE_THRESHOLD + steady state handout buffer count) buffers. 192 static const int BUFFER_FREE_THRESHOLD = 3; 193 194 /** 195 * Lock to synchronize the access to the methods of this class. 196 */ 197 mutable Mutex mLock; 198 199 static const size_t kMaxBufferCount = BufferQueueDefs::NUM_BUFFER_SLOTS; 200 201 struct GraphicBufferEntry { 202 sp<GraphicBuffer> graphicBuffer; 203 int fenceFd; 204 explicit GraphicBufferEntry(const sp<GraphicBuffer>& gb = 0, int fd = -1) : graphicBufferGraphicBufferEntry205 graphicBuffer(gb), 206 fenceFd(fd) {} 207 }; 208 209 /** 210 * A buffer entry (indexed by stream ID) represents a single physically allocated buffer. For 211 * Gralloc V0, since each physical buffer is associated with one stream, this is 212 * a single entry map. For Gralloc V1, one physical buffer can be shared between different 213 * streams in one stream set, so this entry may include multiple entries, where the different 214 * graphic buffers have the same common Gralloc backing store. 215 */ 216 typedef int StreamId; 217 typedef KeyedVector<StreamId, GraphicBufferEntry> BufferEntry; 218 219 typedef std::list<BufferEntry> BufferList; 220 221 /** 222 * Stream info map (indexed by stream ID) tracks all the streams registered to a particular 223 * stream set. 224 */ 225 typedef KeyedVector<StreamId, StreamInfo> InfoMap; 226 227 /** 228 * Stream set buffer count map (indexed by stream ID) tracks all buffer counts of the streams 229 * registered to a particular stream set. 230 */ 231 typedef KeyedVector<StreamId, size_t> BufferCountMap; 232 233 /** 234 * StreamSet keeps track of the stream info, free buffer list and hand-out buffer counts for 235 * each stream set. 236 */ 237 struct StreamSet { 238 /** 239 * Stream set buffer count water mark representing the max number of allocated buffers 240 * (hand-out buffers + free buffers) count for each stream set. For a given stream set, when 241 * getBufferForStream() is called on this buffer manager, if the total allocated buffer 242 * count exceeds this water mark, the buffer manager will attempt to reduce it as follows: 243 * 244 * In getBufferForStream(), find a buffer associated with other streams (inside the same 245 * stream set) on the free buffer list and free it. For Gralloc V1, can just free the top 246 * of the free buffer list if the physical buffer sharing in this stream is supported. 247 * 248 * For a particular stream set, a larger allocatedBufferWaterMark increases the memory 249 * footprint of the stream set, but reduces the chance that getBufferForStream() will have 250 * to allocate a new buffer. We assume that the streams in one stream set are not streaming 251 * simultaneously, the max allocated buffer count water mark for a stream set will the max 252 * of all streams' total buffer counts. This will avoid new buffer allocation in steady 253 * streaming state. 254 * 255 * This water mark can be dynamically changed, and will grow when the hand-out buffer count 256 * of each stream increases, until it reaches the maxAllowedBufferCount. 257 */ 258 size_t allocatedBufferWaterMark; 259 260 /** 261 * The max allowed buffer count for this stream set. It is the max of total number of 262 * buffers for each stream. This is the upper bound of the allocatedBufferWaterMark. 263 */ 264 size_t maxAllowedBufferCount; 265 266 /** 267 * The stream info for all streams in this set 268 */ 269 InfoMap streamInfoMap; 270 /** 271 * The count of the buffers that were handed out to the streams of this set. 272 */ 273 BufferCountMap handoutBufferCountMap; 274 /** 275 * The count of the buffers that are attached to the streams of this set. 276 * An attached buffer may be free or handed out 277 */ 278 BufferCountMap attachedBufferCountMap; 279 StreamSetStreamSet280 StreamSet() { 281 allocatedBufferWaterMark = 0; 282 maxAllowedBufferCount = 0; 283 } 284 }; 285 286 /** 287 * Stream set map managed by this buffer manager. 288 */ 289 typedef int StreamSetId; 290 KeyedVector<StreamSetId, StreamSet> mStreamSetMap; 291 KeyedVector<StreamId, wp<Camera3OutputStream>> mStreamMap; 292 293 // TODO: There is no easy way to query the Gralloc version in this code yet, we have different 294 // code paths for different Gralloc versions, hardcode something here for now. 295 const uint32_t mGrallocVersion = GRALLOC_DEVICE_API_VERSION_0_1; 296 297 /** 298 * Check if this stream was successfully registered already. This method needs to be called with 299 * mLock held. 300 */ 301 bool checkIfStreamRegisteredLocked(int streamId, int streamSetId) const; 302 303 /** 304 * Check if other streams in the stream set has extra buffer available to be freed, and 305 * free one if so. 306 */ 307 status_t checkAndFreeBufferOnOtherStreamsLocked(int streamId, int streamSetId); 308 }; 309 310 } // namespace camera3 311 } // namespace android 312 313 #endif // ANDROID_SERVERS_CAMERA3_BUFFER_MANAGER_H 314