发现标准库也有内存不回收的问题

写了一个从视频中截取预览图的工具, 使用 go 1.7 用这个库: github.com/opennota/screengen 测试时发现内存一直涨,根本就停不下来,最后能服机器搞死,而且无论等多久内存占用也不会降下来 开始以为是第三方库的问题,最后测试发现了点不一样的东西, 具体如下: ``` top (pprof) top 18412.15MB of 18506.45MB total (99.49%) Dropped 21 nodes (cum <= 92.53MB) flat flat% sum% cum cum% 18411.15MB 99.49% 99.49% 18411.65MB 99.49% github.com/opennota/screengen.(*Generator).ImageWxH 1MB 0.0054% 99.49% 18505.45MB 100% main.(*Thumbsrv).thumbtt 0 0% 99.49% 18411.65MB 99.49% github.com/opennota/screengen.(*Generator).Image 0 0% 99.49% 18505.45MB 100% main.main 0 0% 99.49% 18505.45MB 100% main.testrun 0 0% 99.49% 18505.95MB 100% runtime.goexit 0 0% 99.49% 18505.95MB 100% runtime.main (pprof) ``` 细节: ``` 17.98GB 17.98GB (flat, cum) 99.49% of Total . . 196: } . . 197: } . . 198: . . 199: rec := image.Rect(0, 0, width, height) . . 200: 17.96GB 17.96GB 201: img := image.NewRGBA(rec) . . 202: . . 203: . . 204: //w, h := imm.Dx(), imm.Dy() . . 205: //buf := make([]uint8, 4*w*h) . . 206: //img := &image.RGBA{buf, 4 * w, imm} . . 207: . . 208: frame := C.av_frame_alloc() . . 209: defer C.av_frame_free(&frame) . . 210: C.avcodec_flush_buffers(g.avcContext) 1.50MB 1.50MB 211: var pkt C.struct_AVPacket ``` 原因是这个地方: ``` img := image.NewRGBA(rec) ``` 但最根本原因是NewRGBA方法里的这个地方: ``` buf := make([]uint8, 4*w*h) ``` 这可是标准库里的呀, 那么问题来了, 该怎么解决此问题?