Subject: Re: Increasing SHMMAXPGS
To: Ignatios Souvatzis <>
From: Jaromir Dolecek <>
List: tech-kern
Date: 05/17/2002 11:25:20
Any guess on how hard it would be to make the SHM/SEM/MSG
constants dynamically settable? Brief scan through
sysv_shm.c seems to suggest the code treats those numbers
constant, but perhaps it wouldn't be too hard to change?

It would be nice if these would be settable custom kernel or reboot.


Ignatios Souvatzis wrote:
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> On Fri, May 17, 2002 at 09:34:43AM +0100, David Brownlee wrote:
> > 	We default to SHMMAXPGS=1024, which seems rather small given this
> > 	is the maximum limit and changes to it shouldn't affect the amount
> > 	of memory in use unless an application takes advantage of a higher
> > 	limit.
> > 
> > 	Ogle (to give an example) likes a SHMMAXPGS of 16384.
> > 
> > 	Would anyone object to increasing the default to 16384 for all
> > 	platforms?
> yes.
> Thats 128 MB of virtual space on Amiga (and similiar PMAPs), and its pmap
> module is known to be unhappy when the virtual address space of a process
> is too big.
> 	-is
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Jaromir Dolecek <>
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