[libbsd 00/22] Remove FreeBSD file descriptors and avoid VFS

[Sebastian Huber]

On 21/10/2022 16:16, Sebastian Huber wrote:
> On 21/10/2022 16:07, Joel Sherrill wrote:
>> On Thu, Oct 20, 2022 at 7:30 PM Chris Johns <chrisj at rtems.org 
>> <mailto:chrisj at rtems.org>> wrote:
>>
>>     On 20/10/2022 7:01 pm, Sebastian Huber wrote:
>>      > On 29/08/2022 10:27, Sebastian Huber wrote:
>>      >> Hello Chris,
>>      >>
>>      >> On 25/07/2022 08:12, Sebastian Huber wrote:
>>      >>> On 11/07/2022 15:04, Sebastian Huber wrote:
>>      >>>> On 24/06/2022 08:33, Sebastian Huber wrote:
>>      >>>>> This patch set removes the FreeBSD file descriptors.  The VFS
>>     is no longer
>>      >>>>> used
>>      >>>>> if only the USB, SD/MMC, network, PCI, and NVMe support is
>>     used by the
>>      >>>>> application.  This change significantly reduce the memory
>>     usage of LibBSD for
>>      >>>>> these applications.  Using the media01 test case for the
>>     arm/lpc32xx BSP as a
>>      >>>>> benchmark, the heap usage dropped from 14.3MiB to 10.2MiB. 
>>     The "_BSD
>>      >>>>> bufdaemon", "_BSD vnlru", "_BSD syncer", and "_BSD
>>     bufspacedaemon-" tasks are
>>      >>>>> no longer present in media01.  The code size is reduced by
>>     about 8KiB.  The
>>      >>>>> data size is reduced by about 30KiB.  The throughput with a
>>     simple FTP test
>>      >>>>> increased by about 1%.
>>
>>
>> Only the decrease in heap size is significant enough to discuss. The 
>> others are noise
>> when considered in light of the source transparency we aimed for.
>>
>> https://freebsdfoundation.org/wp-content/uploads/2016/08/FreeBSD-and-RTEMS-Unix-in-a-Real-Time-Operating-System.pdf <https://freebsdfoundation.org/wp-content/uploads/2016/08/FreeBSD-and-RTEMS-Unix-in-a-Real-Time-Operating-System.pdf>
>>
>> This guideline which is intended to increase compatibility and lower 
>> long-term
>> maintenance is at odds with this set of patches.
> 
> It would be really nice if you could review the patch set in detail 
> before you write something like this. Did you ever update a FreeBSD 
> baseline in one of the libbsd branches? It is also a nice exercise to 
> step through for example sendto() from the file descriptor until you get 
> the socket object.

I will definitely not ship the FreeBSD file descriptors to our 
customers. As I said before, the current state prevents an update of the 
FreeBSD baseline from my side. Since you are so concerned about the 
long-term maintenance, what are your plans for a FreeBSD baseline update 
of the 6-freebsd-12 branch? The last update was:

commit 46b3858b27d78e14a220f8d251fd7ab28a5244f4
Author: Sebastian Huber <sebastian.huber at embedded-brains.de>
Date:   Mon Feb 10 15:34:55 2020 +0100

     Update to FreeBSD stable/12 2020-02-10

     Git mirror commit 0d1c391321b34b3025cf0e72f2231d836ff76da8.

This is now more than two years ago and there are a couple of security 
fixes available in the FreeBSD 12 release branch which we do not provide 
in libbsd.

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