How to recovery the system free memory after I stop the record pipeline

[hzhong]

Hi

How to recovery the system free memory after I stop the record pipeline.

I am using the following step to check the system free memory and create a pipline to record the video stream.
The system free memory will decrease after the pipline running.

But when I stop the pipline, The system memory could not be recovery to the origin memory state. After I delete
the record file, The system memory can be recovery.

1. X86:
(1) Test enviroment:
OS Enviroment: Ubuntu 14.04.4
Gstreamer Version: GStreamer 1.6.3

(2) Check the free memory script(The script name is test.sh) :
#!/bin/sh

while :
do
         cat /proc/meminfo | grep MemFree
         sleep  5
done


(3) Test step
The fist step: Running the test.sh to check the system free memory
The next step: Running the record command as the following:
gst-launch-1.0 videotestsrc ! video/x-raw,format=UYVY,width=640,hight=480 ! videoconvert ! video/x-raw,format=I420 ! x264enc ! avimux ! filesink location=./test.avi

(4) Test Result:
When The pipeline is running, The system free memory will be decreased.
MemFree:          293064 kB
MemFree:          231984 kB
MemFree:          226280 kB
MemFree:          220780 kB
MemFree:          215340 kB
MemFree:          222788 kB
MemFree:          217228 kB
MemFree:          211908 kB
MemFree:          206048 kB
MemFree:          200344 kB
MemFree:          194796 kB
MemFree:          188904 kB
MemFree:          183448 kB
MemFree:          177868 kB
MemFree:          172072 kB
MemFree:          166212 kB
MemFree:          160756 kB
MemFree:          166684 kB
MemFree:          161036 kB
MemFree:          159176 kB
MemFree:          145444 kB

After I stop the pipeline(Using ctrl + c), the free memory will increase something. But it could not to recovery it.
MemFree:          200084 kB
MemFree:          199804 kB
MemFree:          203276 kB
MemFree:          199844 kB
MemFree:          200084 kB
MemFree:          200044 kB


After I delete the record file(test.avi), The system free memory can be recovery.
MemFree:          199968 kB
MemFree:          312332 kB
MemFree:          312288 kB


2. For ARM platform
Freescale imx6q:
gst-launch-1.0 videotestsrc ! video/x-raw,format=UYVY,width=640,hight=480 ! videoconvert ! video/x-raw,format=I420 ! imxvpuenc_h264 ! avimux ! filesink location=./test.avi

Test Result:
When the pipeline is running, The system free memory state:
MemFree:          744920 kB
MemFree:          744600 kB
MemFree:          736352 kB
MemFree:          731656 kB
MemFree:          726316 kB
MemFree:          721024 kB
MemFree:          715908 kB
MemFree:          711088 kB
MemFree:          705872 kB
MemFree:          700204 kB
MemFree:          695028 kB
MemFree:          689984 kB
MemFree:          684784 kB
MemFree:          683872 kB
MemFree:          683772 kB
MemFree:          678640 kB
MemFree:          673712 kB
MemFree:          668380 kB
MemFree:          663100 kB
MemFree:          657808 kB
MemFree:          652732 kB
MemFree:          647516 kB
MemFree:          642316 kB
MemFree:          641476 kB
... ... ... ... ... ...
MemFree:          252860 kB
MemFree:          252812 kB
MemFree:          252860 kB
MemFree:          252844 kB
MemFree:          252796 kB
MemFree:          252876 kB
MemFree:          252876 kB
MemFree:          252876 kB
MemFree:          252868 kB
MemFree:          252836 kB
MemFree:          252884 kB
MemFree:          252744 kB
MemFree:          252812 kB
MemFree:          252736 kB
MemFree:          252736 kB
MemFree:          252624 kB
MemFree:          252672 kB
MemFree:          252704 kB
MemFree:          252516 kB
MemFree:          575392 kB

After I delete the record file(test.avi), The free memory can be recovery to the original state.
MemFree:          743300 kB
MemFree:          743416 kB
MemFree:          743408 kB
MemFree:          743220 kB
MemFree:          743284 kB

Thanks,
Hongbo