Re: mprotect() api overhead.

[Benjamin LaHaise]

On Sat, Mar 23, 2002 at 02:20:37AM +0000, Alan Cox wrote:
> > As for SMP case, for my application, it is less an issue, since
> > when user call my API in the .so, the mprotect (or that HP=20
> > 7 instructions) will open access to the share memory for them
> > regardless which CPU they are coming from.  If other thread
> 
> That still requires cross processor synchronization - so it will still
> take the same hit

It's actually an instruction on ia64, so the overhead is fairly low 
(similar to a cache miss).  That said, Linux doesn't have the ability 
to share portions of page tables between processes at present, so it 
doesn't matter.

		-ben