randomAccessFile.getChannel().map() java.io.IOException: mmap failed: ENOMEM (Out of memory)

[mozikun]

When I upload 1GB file to android devices by nanohttpd, android devices will OOM.

It maybe that call FileChannel.map() load the 1GB file to ByteBuffer cause out of memory.

How can I fix the problem? Thank you!

ByteBuffer fbuf = null; if (baos != null) { fbuf = ByteBuffer.wrap(baos.toByteArray(), 0, baos.size()); Log.d(TAG, "fbuf1 -- baos != null"); } else {//READ_ONLY fbuf = randomAccessFile.getChannel().map(FileChannel.MapMode.READ_WRITE, 0, randomAccessFile.length()); randomAccessFile.seek(0); Log.d(TAG, "fbuf2 -- baos == null"); // executed }

09-19 14:10:05.056 W/System.err( 1576): java.io.IOException: mmap failed: ENOMEM (Out of memory)

09-19 14:10:05.071 W/System.err( 1576): at java.nio.MemoryBlock.mmap(MemoryBlock.java:125)

09-19 14:10:05.071 W/System.err( 1576): at java.nio.FileChannelImpl.map(FileChannelImpl.java:257)

09-19 14:10:05.071 W/System.err( 1576): at httpserver.NanoHTTPD$HTTPSession.parseBody(NanoHTTPD.java:1080)

[LordFokas]

We probably have to "buffer" files to disk...

[ngochai]

I got the error too, Ubuntu Linux, OpenJDK 32bit 1.7, file uploaded is about 500Mb. System mem is 4G

[kaiv587hh]

I have the same problem too，hope soon...

[GggggitHub]

I have the same problem too.

origin code:

1. fbuf = randomAccessFile.getChannel().map(FileChannel.MapMode.READ_WRITE, 0, randomAccessFile.length());

2. private String saveTmpFile(ByteBuffer b, int offset, int len, String filename_hint) {

       String path = "";
       if (len > 0) {
           FileOutputStream fileOutputStream = null;
   
           try {
               TempFile tempFile = this.tempFileManager.createTempFile(filename_hint);
               ByteBuffer src = b.duplicate();
               fileOutputStream = new FileOutputStream(tempFile.getName());
               FileChannel dest = fileOutputStream.getChannel();
               src.position(offset).limit(offset + len);
               dest.write(src.slice());
               path = tempFile.getName();
           } catch (Exception var13) {
               throw new Error(var13);
           } finally {
               NanoHTTPD.safeClose(fileOutputStream);
           }
       }
   
       return path;
   }

origin code 2 can optimization ？？ or origin code 1 can optimization ？？

[GggggitHub]

I solve this problem ,modify origin code.

    //success  随机读写 + buffer. 成功。1G file memory just used 50mb.
    public void onCopyOTAFile(RandomAccessFile rafi,String destPath,int offset,int len) throws IOException {
        // 2、自己处理Buffer(RandomAccessFile): 0.13s

// String srcFile = "/Users/macpro/Downloads/00111-BXMJ_2G_DVT_2.6.2.63.d.s.d_06240942-ota.zip"; // String destFile = "/Users/macpro/Downloads/copy-BXMJ_2G_DVT_2.6.2.63.d.s.d_06240942-ota.zip"; File file = new File(destPath); if (file.exists())file.delete(); // RandomAccessFile rafi = new RandomAccessFile(srcFile, "r"); RandomAccessFile rafo = new RandomAccessFile(destPath, "rw"); // int len = 1024 1024 1024;//总大小。需要读取的大小 // int offset = 2;//读取的偏移量

        int bufferSize = 1024 * 1024;//
        byte[] buf = new byte[bufferSize];

        long start = System.currentTimeMillis();
        try {
            rafi.seek(0);
            rafi.skipBytes(offset);

            int c = 0;
            //第一次读取，
            if (len <= bufferSize){//读取的总量 < filesize,所以做截取
                c = rafi.read(buf,0,len);
            }else {
                c = rafi.read(buf);
            }

            int count = c;

            while (c > 0) {
                //写入
                if (c == buf.length) {
                    rafo.write(buf);
                } else {
                    rafo.write(buf, 0, c);
                }

                if (count >= len){ //读取，写入完成。
                    break;
                }

                //读取
                if (count + bufferSize >=len){//读取的总量 < filesize,所以做截取
                    int currentlen =  len - count;
                    c = rafi.read(buf,0,currentlen);
                }else {
                    c  = rafi.read(buf);
                }
                count = count+c;
            }
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            rafi.close();
            rafo.close();
        }
        System.out.println("Spend: " + (double) (System.currentTimeMillis() - start) / 1000 + "s");
    }

[GggggitHub]

1个 G file oom

[GggggitHub]

channel().map .this method is for get buffer .this buffer for get boundary and real file position. so ,you gan open little buffer.for get real file position.