Re: About 4k kernel stack size....

[Nikita Danilov <nikita@clusterfs.com>]

linux-os \(Dick Johnson\) writes:
 > 

[...]

 > See, isn't rule-making fun? This whole 4k stack-
 > thing is really dumb. Other operating systems
 > use paged virtual memory for stacks, except
 > for the interrupt stack. If Linux used paged
 > virtual memory for stacks, 

... then spin-locks couldn't be held across function calls.

 >                            the pages would not
 > have to be contiguous so dynamic stack allocation
 > would practically never fail. But Linux doesn't
 > use paged virtual memory for stacks. So, there
 > needs to be some rule to control the amount
 > of kernel stack allocated to each task when it
 > executes a system call.
 > 
 > This means, in the limit, that there are two
 > possibilities:
 > 
 > (1)	Implement paged virtual memory for stack.

As an exercise: subscribe to NT kernel development mailing list, and see
the fun they have when page-in code trips over paged out kernel text
page. As a rule, even code cannot pageable without very involving and
fragile analysis. Not to say about stack.

Nikita.
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