Even after rebooting the machine, there is >95% of GPU Memory used by python3 process (system-wide interpreter).
Note that memory consumption keeps even if there are no running training scripts, and I've never used keras/tensorflow in the system environment, only with venv or in docker container.
UPDATED: The last activity was the execution of NN test script with the following configurations:
tensorflow==1.14.0
Keras==2.0.3
tf.autograph.set_verbosity(1)
tf.set_random_seed(1)
session_conf = tf.ConfigProto(intra_op_parallelism_threads=8, inter_op_parallelism_threads=8)
session_conf.gpu_options.allow_growth = True
sess = tf.Session(graph=tf.get_default_graph(), config=session_conf)
K.set_session(sess)
$ nvidia-smi
+-----------------------------------------------------------------------------+
| NVIDIA-SMI 440.26       Driver Version: 440.26       CUDA Version: 10.2     |
|-------------------------------+----------------------+----------------------+
| GPU  Name        Persistence-M| Bus-Id        Disp.A | Volatile Uncorr. ECC |
| Fan  Temp  Perf  Pwr:Usage/Cap|         Memory-Usage | GPU-Util  Compute M. |
|===============================+======================+======================|
|   0  GeForce GTX 105...  Off  | 00000000:01:00.0 Off |                  N/A |
| N/A   53C    P3    N/A /  N/A |   3981MiB /  4042MiB |      1%      Default |
+-------------------------------+----------------------+----------------------+
                                                                               
+-----------------------------------------------------------------------------+
| Processes:                                                       GPU Memory |
|  GPU       PID   Type   Process name                             Usage      |
|=============================================================================|
|    0      4105      G   /usr/lib/xorg/Xorg                           145MiB |
|    0      4762      C   /usr/bin/python3                            3631MiB |
|    0      4764      G   /usr/bin/gnome-shell                          88MiB |
|    0      5344      G   ...quest-channel-token=8947774662807822104    61MiB |
|    0      6470      G   ...Charm-P/ch-0/191.6605.12/jre64/bin/java     5MiB |
|    0      7200      C   python                                        45MiB |
+-----------------------------------------------------------------------------+
After rebooting in recovery mode, I've tried to run nvidia-smi -r but It didn't solve the issue.
 
    