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From: Hugh LaMaster <lamaster@nas.nasa.gov>
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Mbone/vic shared memory problems (was Re: non-present SYSVSHM?)
Date: Wed, 11 Jun 1997 12:34:42 -0700
Organization: NASA Ames Research Center
Lines: 113
Message-ID: <339EFDD2.3359@nas.nasa.gov>
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<Pine.BSF.3.95.970605214717.20031A-100000@public.ug.cs.sunysb.edu> <5n8mak$20d@ui-gate.utell.co.uk>
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Xref: euryale.cc.adfa.oz.au comp.unix.bsd.freebsd.misc:42783
Brian Somers wrote:
>
> In article <Pine.BSF.3.95.970605214717.20031A-100000@public.ug.cs.sunysb.edu>,
> xiang xia <xiax@public.ug.cs.sunysb.edu> writes:
> >
> > On Thu, 29 May 1997, Richard Tsai wrote:
> >
> >> Hi,
> >> I just installed FreeBSD 2.2.1 on my machine. I found this following
> >> message under X-window often:
> >> cmd XF86 pid 2784 tried to use non-present SYSVSHM
> >> And ppp connection would be cut afterward.
> >> Does anyone know what causes this? and how to fix it?
------------ From the Manual
--------------------------------------------------------
7.5. Does FreeBSD support System V IPC primitives?
Yes, FreeBSD supports System V-style IPC. This includes shared memory,
messages and semaphores. You need to add the
following lines to your kernel config to enable them.
options SYSVSHM
options "SHMMAXPGS=64" # 256Kb of sharable memory
options SYSVSEM # enable for semaphores
options SYSVMSG # enable for messaging
Recompile and install.
NOTE: You may need to increase SHMMAXPGS to some ridiculous number like
4096 (16M!) if you want to run GIMP.
256Kb is plenty for X11R6 shared memory.
----------------------------------------------------------------------------------
> > I got the same message on my PC. Is there anybody can help us?
> > Thanks.
>
> Yes. Brian Clapper helped 6 days before your posting by pointing
> at the docs :)
Of course, when I had the problem, I read the manual
(notice the halo glowing over my head right now?),
recompiled, and everything worked fine. Sort of.
Then, I went back to the manual, but couldn't find
anything more than the section "7.5" above.
For some reason, vic2.8 doesn't work perfectly.
(It worked fine before, actually, just using X straight,
but now it uses shared memory and has a problem. Yes,
I can force the X server to not use shared memory, but
I would like to use it, so, here is the problem.)
For some reason, vic apparently wants to open a fresh
shared-memory segment for each window. (Not all
versions of vic do this: e.g. on Irix, I think I only
see one segment when I do an ipcs, but on FreeBSD 2.2.1,
I think I see one for every expanded video window).
When I try to open four such windows from one process,
(e.g. for Mbone users: "places around the world" when
4 or more people are broadcasting), I get the following
message:
shmat: too many open files
Also, when I have more than about ten segments total open,
(this may be a red herring) I get
X Error of failed request: BadAccess (attempt to access
private resource denied)
And, then the vic which tried to create the next window
dies completely.
So, really, I have three questions:
1) How can I increase the number of possible shared memory
segments available
2) How can I increase the number of files memory-mapped files
a particular process may open
3) Why is vic on FreeBSD (is this an XFree86 question, or,
related to some other issue?) trying to open a new segment
for every video window? When I do an "ipcs" on, e.g., Irix6.2,
I only see *one* segment open no matter how many video windows
are going...
[The environment is FreeBSD 2.2.1/XFree86
with either of the following two systems.
I get exactly the same errors on both systems:]
Pent 166/16 MB/SCSI/ATI Graphics Xpression/3Com3C595
PPro 200/64 MB/SCSI/#9Motion771/SMC DEC tulip 10/100
I realize that the *problem* may be between vic and XFree86,
but, a brute force solution [just increase shared-memory
resources] may work just fine, especially on the 64 MB system.
--
Hugh LaMaster, M/S 258-5, ASCII Email:
hlamaster@mail.arc.nasa.gov
NASA Ames Research Center Or: lamaster@nas.nasa.gov
Moffett Field, CA 94035-1000 No Junkmail: USC 18 section 2701
Phone: 415/604-1056 Disclaimer: Unofficial, personal
*opinion*.