Date: Wed, 18 Feb 2009 08:18:03 +0000 From: Bruce Simpson <bms@incunabulum.net> To: John Baldwin <jhb@FreeBSD.org> Cc: svn-src-stable@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org, svn-src-stable-7@freebsd.org Subject: Re: 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 Message-ID: <499BC43B.6030701@incunabulum.net> In-Reply-To: <200902171957.n1HJvqk8026145@svn.freebsd.org> References: <200902171957.n1HJvqk8026145@svn.freebsd.org>
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John Baldwin wrote: > Author: jhb > Date: Tue Feb 17 19:57:52 2009 > New Revision: 188727 > URL: http://svn.freebsd.org/changeset/base/188727 > > Log: > MFC: Rework the lifetime management of the kernel implementation of POSIX > 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. cheers BMS
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