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Date:      Wed, 29 Jan 1997 10:11:20 -0600
From:      "Eric L. Hernes" <erich@lodgenet.com>
To:        Meir Dukhan <mdukhan@bis.co.il>
Cc:        Julian Elischer <julian@whistle.com>, hackers@FreeBSD.ORG
Subject:   Re: Sys V IPC 
Message-ID:  <199701291611.KAA19636@jake.lodgenet.com>
In-Reply-To: Your message of "Wed, 29 Jan 1997 17:01:00 GMT." <32EF824C.167EB0E7@bis.co.il> 

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Meir Dukhan writes:
>
>That's was not what I wanted to say. First my GENERIC file has the 
>SYSVSHM, SYSVSEM, SYSVMSG options. and second I work with a kernel that
>has, too, these options enabled. 
>
>By saying that they are not sys call, I mean that maybe they are not
>implemented as system calls, because ktrace doesn't record them . 

The system call is shmsys(); shmget and friends are wrapped up into
this.  It looks like the real syscalls are there too, but aren't used
for whatever reason, binary compats maybe, just left undone maybe.
at any rate look for shmsys in kdump's output.

>
>I don't know how ktrace works, maybe it make its jobs by looking at a
>table of existing system calls, instead of checking if a call is
>actually a system call or a mere function. 

ktrace uses the syscall slot number. kdump gets the syscall names
from /usr/src/sys/kern/syscalls.c, same as the kernel.

>
>> >
>> > - a process can have no more than 8 shared mem segments
>> > (how can I change this ?)
>> 
>> compile in a bigger number?
>
>Where can I specify this number ?

options         SHMMAXPGS=4096
options         "SHMSEG=128"

Although as dyson and others have noted, this is mostly an administrative
limit.  If you're feeling ambitious, you could probably turn them into
a sysctl.

>Tia
>
>-- Meir
>
>ps: cc to mdukhan@bis.co.il, I'm not on hackers@freebsd.org, Thanks to
>all in advance.
>

eric.
-- 
erich@lodgenet.com
http://rrnet.com/~erich erich@rrnet.com






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