On Tuesday, November 19, 2002, at 01:51 PM, <[EMAIL PROTECTED]> wrote:
apr_proc_mutex_child_init() Depending on mutex type, the cleanup should be killed or not. In general, file-based mutex will be killed, but semaphores will not.
I don't understand this, why does the app treat the different types differently, or are you saying that the cleanup killing does or doesn't happen depending on the implementation?
2) We aren't calling apr_proc_mutex_child_init, which is what makes the
mutex available to the child process. We were relying on inheritance to
get the mutex to the child process. If we had been calling this function
(and the function was fixed to kill the cleanup if appropriate), then we
would have masked the previous bug.
Child init on almost all of the proc mutex implementations is a no-op [on
unix, where this bug exists].
At the end of the day, the test was bogus, and it wasn't good APR code,
which is what was causing the problem. There is one change that should be
made to the underlying APR code to help hide this from the user, but the
real problem is in the test.
I don't think anyone disagrees that there are problems in the test, but I do strongly believe that the interface is also broken.
But the latter is MUCH worse when it comes to locks. You only have so
many semaphores available to you. A resource leak can be a real PITA to
track down, and I suspect that this general bug is biting Apache in a
couple of places because we do leak semaphores. I currently have 12
semaphores in use by Apache. When I stop the currently running server, I
have 9 in use (all by the web server).
Resource leaks suck, and they are just as hard to diagnose as doing something too often.
This is not a valid reason, since these kinds of errors are due to
bugs in the application, NOT due to bad APR interfaces or implementations.
I don't think we should complicate the heck out of APR just to hold the hands of poor app authors.
The real fix for this problem is to fix the test code as I have stated
above so that it is a valid example of how to write APR code, and to fix
the library so that we register cleanups with a public function, and so
that apr_proc_mutex_child_init does the right thing in all cases. I will
do the work later tonight (assuming my wife doesn't go into labor before
then) unless somebody beats me to it.
I'd much rather just have APR not do any automatic cleanups on any of the mutex types, and to leave it up to the app author to decide if they want to register a cleanup or would rather just call the destroy() methods themselves.
-aaron
p.s. Give Kelly my best. :)
