ERROR log file size is expanding very fast becose of the " GHOST CLEANUP " command

When I access the root directory LOG folder I have noted that the ERRORLOG file is getting bigger very fast.

I opend the error log(Log file viewer) from the SSMS, and I saw in the Source column the process "spid20s" .

from there I RUN the procedure sp_who2 20 and I saw the command "GHOST CLEANUP"(as you can see from the attached picture).

Can anyone help me to understand what is it ? Why it writes to the error log in such massive counts ?