original submission:

> The problem is in fact, that the Make probably uses:
> ```
> cat /proc/cpuinfo
> ```
>
> mechanism to detect the number of CPUs available to Make.
>
>
> However this way will not always work correctly inside of Docker container which was started using limited set of cores, for example:
> ```
> docker run -it --cpuset-cpus=0,1 ubuntu
> ```
>
> Following way of detection for available CPUs should be used instead:
> ```
> cat /sys/fs/cgroup/cpuset/cpuset.cpus
> ```

There is no issue in "make" utility.

The problem is in how it was used inside of Docker container by me.

I've used:
```
NUM_CPUS=$(grep -c ^processor /proc/cpuinfo)
make -j$(NUM_CPUS)
```

inside of Docker container, but this was my mistake.

There is no problem when using simply:
```
make -j
```

Dear admins, feel free to close this bug report.