OPcache per user

Current default OPcache implementation is in-memory, shared. Some of my users expressed concern for performance as shared memory pool can be usurped by other users on the system.
To solve such problem I can set pool per user:

Code:

php_admin_value[opcache.file_cache] = /var/www/user1/opcache

But is this approach is correct? Where should I store opcache generated files and does open_basedir directive also must be modified?

 

If open_basedir allows access to user's tmp, will it allow to access sub-folders in that tmp also?

 

Can confirm, I successfully enabled file cache per user. This mitigates:
* Cache poisoning;
* Problems with proper permission isolation in shared environment as SHM model is not fit for that.