Re: POSIX.1 semaphores vs message queues

[Masao Uebayashi <uebayasi%gmail.com@localhost>]

On Mon, Nov 9, 2015 at 9:21 AM, Joerg Sonnenberger
<joerg%britannica.bec.de@localhost> wrote:
> On Mon, Nov 09, 2015 at 08:05:43AM +0800, Paul Goyette wrote:
>> Well, both EXEC_SCRIPT and COREDUMP are modularized, and they _are_
>> optional.
>
> See part about modularity masturbation. Making things optional for the
> sake of making them optional is just as wrong.
>
>> Both EXEC_SCRIPT and COREDUMP are also much smaller than the ksem code;
>> these two optional/removeable modules together add up to just about
>> the size of a SEMAPHORE module.  (On amd64 we have exec_script weighing
>> in at 1285 bytes and coredump at 3895 bytes, while ksem tips the scales
>> at 5186 bytes).  There are numerous other modules which are similar in
>> size to the SEMAPHORE module.
>
> Add in the page alignment and the cost becomes even larger. There is
> nothing to be gained.

Please don't (intentionally) confuse module in general and dynamic loading.

For buiit-in modules, the extra size is code added by #ifdef _MODULE.
In the long run, xxx_modcmd() functions are merged into kctors.  If
other metada consume more than expected, it will be addressed and
reconsidered.  But that goes away in !MODULAR kernels.  So virtually
you lose nothing.