What is this OPcache and what of its tools show me what to do next if full and how to fix it- increase opcache?

So i stumblin around ip:22222 found ip:22222/cache/

Memcache somekind tool shows all ok with memory, yes? Shows hits and some misses. Now googling turns out misses is when would have been able to cache but couldnt do cache page?

And in opcache folder is more somekinda caches opcache stats.

Its was full and i pressed some button to clear and in 1minute it was like this fast full.
So What to do? Is somewhere some guides what to do or with theese tools i can manage something better and what needs to be done when something is full?

Here

i understand written that in fpm folder php.ini to change BUT

i found 5 php ini and not in php7 folders as i understood was installed 7 also.

But only these 2 first has opcache.memory_consumption=
So witch to change and how correctly?
/etc/php/5.6/cli/php.ini
/etc/php/5.6/cgi/php.ini

Theese 2 php.ini dont have opcache.memory_consumtion=
/etc/php/5.6/fpm/php.ini
/etc/hhvm/php.ini

Also found
/etc/php/5.6/mods-available/opcache.ini

And how to use PHP7 as written here to use 7 to increase opcache