Folder /tmp/ filled with empty files

Hello,

Every two seconds or so, a file starting with “sess_” is written to the /tmp/ folder at the root of my site. For example : sess_6cit425beljmq547ejq4mlosv0

Almost all the files are empty.

Sometimes a file contains the geolocation information of a real user, but this is only a very small part of the list.

Maybe it’s my cache preload that’s causing this, but how can I avoid these never-ending writes?

Thanks for your help.