Where opcache stores the cache?

Please tell me, where in the default scheme (mmap) stores the cached data?
The fact that the memory footprint of the apache processes does not change even when the cache is already more than 500 MB of data.
When shm is clear, it is possible to view the segments and their filling, but mmap is not clear.
PS php is running as an apache module.
July 4th 19 at 23:25
2 answers
July 4th 19 at 23:27
mmap - what kind of file memory (memory-mapped files) here is the source code

Please tell me, where in the default scheme (mmap) stores the cached data?

In memory.

The fact that the memory footprint of the apache processes does not change even when the cache is already more than 500 MB of data.

Memory is allocated in one big chunk when php starts up. You have used 500MB of the available volume.
July 4th 19 at 23:29
In programming, alas, is not strong.
Ie all the apache processes have to keep this cache if PHP as a module?
The master (the one from root) when you start eating 33 MB of physical memory, all worker (spare) from www-date of about 17 MB.
The process started directly when executing a script that consumes memory proportional to the heaviness of the script, and hit in the cache is counted (i.e., the data is taken from somewhere).
Actually, as you can still see this cache at the system level, not using shm?

Reviewed the processes with pmap, there is a segment equal in size to the cache size.
On the master:
Kbytes RSS Dirty Mode Mapping
524288 6012 6012 rw-s - zero

On worker all empty:
524288 0 0 rw-s - zero

In the statistics shows that opcache busy all 512 MB.

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