FPM pool manager

Description

FPM allows creating multiple pools which except other things provides some sort of separation between processes. There is still however lots of shared resources because MINIT happens in master process which is common for all pools. That's problematic for extension like opcache that creates shared memory between all pools. This gets even more problematic if pools have different users / groups configured due to potential permission errors when accessing shared resources.

The proposed solution for this problem is to create extra layer between master and children processes. It would be a pool manager process that would handle creation of children, logs, MINIT and other things currently handled by master process. Master process would then become very thin and just supervise pool manager(s) as well as some other common things (e.g. loading configuration). This would be also beneficial for improving graceful reload and extending of status and access logging for resource information related to the whole pool like for example request for adding utime and stime.

ファイルやテストは指定されていません。まず、PHP-FPM における現在の master プロセスと child プロセスの責務を、pool の作成、ロギング、MINIT の処理を含めて追跡し、その後、pool-manager 層によって共有リソースをどのように分離できるかを判断してください。提案されたプロセスの責務と pool の分離を対象とする合意済みの設計と実装が揃えば、完了とします。