svn commit: r188727 - in stable/7: sys sys/contrib/pf sys/dev/ath/ath_hal sys/dev/cxgb sys/kern sys/modules/sem sys/sys tools/regression/posixsem usr.bin/procstat

Kris Kennaway kris at
Sat Feb 21 04:56:24 PST 2009

John Baldwin wrote:
> On Wednesday 18 February 2009 3:18:03 am Bruce Simpson wrote:
>> John Baldwin wrote:
>>> Author: jhb
>>> Date: Tue Feb 17 19:57:52 2009
>>> New Revision: 188727
>>> URL:
>>> Log:
>>>   MFC: Rework the lifetime management of the kernel implementation of 
>>>   semaphores.  Specifically, semaphores are now represented as new file
>>>   descriptor type that is set to close on exec.  This removes the need for
>>>   all of the manual process reference counting (and fork, exec, and exit
>>>   event handlers) as the normal file descriptor operations handle all of
>>>   that for us nicely.  It is also suggested as one possible implementation
>>>   in the spec and at least one other OS (OS X) uses this approach.
>> FYI:
>> This change *may* fix Python 2.6's 'multiprocessing' module on FreeBSD 
>> 7-STABLE, which is known to have problems there; it depends on POSIX 
>> semaphores to synchronize its IPC between different fork()'s of the 
>> Python interpreter.
>> If anyone else has an interest in ths they may wish to test, if not, I 
>> will try to get around to it eventually.
> When Kris tested it, it made things significantly better.  I'm not sure if it 
> resolved all the issues though.

Some of the self-tests still failed, but there was confusion about 
whether the tests were broken or the kernel.


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