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From Jeff Trawick <>
Subject create a pool associated with the MPM generation?
Date Mon, 22 Nov 2010 12:45:15 GMT
The purpose of the pool would be the allocation in the parent of
resources which must live as long as any child processes from a
certain generation are still running.  It helps bridge the gap between
pconf and the process pool when dealing with graceful restart.

Each MPM would be responsible for destroying the pool once the last
child of the corresponding generation has exited.  Since graceful
restart can be invoked again before all the children of older
generations have exited, there could be an arbitrary number of
generation pools at a given time.

It might not be trivial to implement, but it would be a huge help for
modules faced with this issue; it is not practical for modules to try
to solve this lifetime issue.

main() owns the generation ("for (;;) {") and would create the pool.
The natural place to access the pool would be an additional parameter
to hooks which take pconf currently, but that would be disruptive to
almost every module.   The mpm hook (implemented by modules which must
be modified anyway) would take a pointer to pgeneration, and an API
call would be provided for other modules to use; the API would only
support access of the current pgeneration; only the MPM would know
about the pool for earlier generations.  Each instance of the pool
would be a child of the process pool, created by main(), and destroyed
by the MPM at some arbitrary point later.

Problem worth solving?
Simpler solution available?

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