Re: ipc - msg : memory usage too big ?

[Manfred Spraul]

> If it is seen as a problem, a solution might be to add
> the memory overhead usage into the queue size, or add a
> variable that counts the real memory used, and limits it
> to a reasonable amount.
> 

The limit in the number of messages was added a few years ago, older 
linux kernels [2.0, early 2.2] contain no limit at all :-(

The implementation was choosen to avoid breaking apps that relied on the 
old behaviour: by default send x-byte messages, but if the queue is 
full, send a 0-byte, msgtype > 0 message that notifies a supervisor 
process that the queue is full.

SUS permits a global system imposed limit on the number of messages, but 
IMHO 9 MB is not excessive [actually, 16*9MB, once for each queue] - 
root can reduce the limit further, if users abuse it.

--
	Manfred