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Date: Tue, 24 Sep 2019 17:41:25 +0100
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To: Peter Stalman <sarkedev@gmail.com>
Cc: "internals@lists.php.net" <internals@lists.php.net>
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Subject: Re: [PHP-DEV] Shutdown Memory Allowance (aka Soft Memory Limit)
From: Danack@basereality.com (Dan Ackroyd)

On Tue, 24 Sep 2019 at 07:26, Peter Stalman <sarkedev@gmail.com> wrote:
>
> So I would like to suggest an option for setting a shutdown memory allowance,
> which would be the amount of additional memory allowed to be used by any
> registered error handlers or shutdown functions.

I can see the need, and what problem you're trying to solve. I think
focusing on 'memory to be used by shutdown handlers' is slightly more
specific than a solution needs to be.

Just expressing it as, when PHP fails to allocate some memory due to
reaching the limit then:

* Increase the memory limit by an ini setting defined amount. This
only happens once per request/process.
* Throw an EngineException.

should cover what you want to do, without tying the solution to where
that memory can be used.

One of the reasons I haven't submitted an RFC for that already is that
I'm not sure what would be involved in making sure it was safe to
throw an exception from places where the memory allocation could fail.

FYI possibly of interest, I did some investigation of a related
feature a while ago, allowing people to trigger callbacks when the
memory limit was reached:
https://github.com/Danack/MemTrigger which is terribly out of date and
a bad approach anyway, due to the performance hit, and people only
really caring about hitting the memory limit.

cheers
Dan
Ack