I have been asked in an interview why the message queues are in kernel address space and same has been suggested in following link.
http://stork.sourceforge.net/thesis/node49.html
Which says "Message queue can be best described as an internal linked list within the kernel's addressing space".
I answered telling interviewer kernel logical addresses can't be swapped out and hence make message queue more robust in a situation where we have to retrieve some data from message queue after any process crash.
I am not sure this is right answer.
Also interviewer then asked why shared memory is not part of kernel address space ?
I couldn't really think of it why is it so.
Can anyone please address these two questions?
