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Date: Sun, 21 Jan 2018 11:00:47 +0100
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Subject: OPCache: invalidate vs unlink
From: php@fleshgrinder.com (Fleshgrinder)

`zend_accel_invalidate` is exposed to userland as `opcache_invalidate`
and marks a script as wasted, however, it does not remove that script
from the OPCache.

There is also the `zend_accel_hash_unlink` that actually does that, it's
there since the beginning of time but without a single call to it in the
entire codebase. It actually removes a script from OPCache, yielding the
desired result of freeing up some space without requiring a complete
restart of OPCache.

What are the reasons that this function is not used and not exposed?
What side-effects does it have if we actually selectively remove scripts
from OPCache?

We replaced the `zend_accel_invalidate` call with
`zend_accel_hash_unlink` in the `opcache_invalidate` implementation and
it worked flawlessly. However, it could be that there are some things
that we are simply overlooking.

-- 
Richard "Fleshgrinder" Fussenegger