Re: POSIX.1 semaphores vs message queues

[Paul Goyette <paul%vps1.whooppee.com@localhost>]

On Fri, 13 Nov 2015, David Holland wrote:

> On Fri, Nov 13, 2015 at 04:41:18PM +0000, David Holland wrote:
> > On Fri, Nov 13, 2015 at 08:05:25PM +0800, Paul Goyette wrote:
> >  > One final attempt to summarize the objections that have been made:
> >  > [snip]
> >
> > One other thing: posix semaphores used to be a module. That code was
> > made the victim^W showpiece for demonstrating how the New World Order
> > was going to be. When the New World Order turned out to be broken,
> > that and other things were rolled back after a lengthy political
> > squabble.
> >
> > Part of the resistance you're seeing is the legacy of that squabble,
> > even though people probably don't really want to say so.
>
> One other point: the changes add mechanism, and that mechanism has a
> cost (in maintenance if nothing else) -- if the changes are more or
> less pointless as a number of people think, then we'd be paying that
> cost for zero or negligible benefit. That does seem like a valid
> reason to oppose such changes.

The mechanisms are currently still included.  When the ksem module was
removed, the only thing that was done was removal of the modular variant
from the build.  All of the "module mechanisms" still remain.  The
current ksem_modcmd() even continues to use syscall_establish() to
"install" the syscalls, and those syscalls are still listed in the table
of autoload-able syscalls (in sys/kern/syscalls_autoload.c) and are
marked as such in syscalls.master.


> for my part during the above-mentioned squabble I made it pretty clear
> that I think aggressive use of kernel modules is at best tilting at
> windmills; I stand by that position, but I'm not really interested in
> fighting about it at the moment so I won't stick my oar in any
> further.

:)


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