Fast sigblock (AKA rtld speedup)

[John-Mark Gurney]

David Xu wrote this message on Tue, Jan 08, 2013 at 13:09 +0800:
> and can not be freed until process is exited, the page is doubly
> mapped into in kernel and userland, accessing the shared data
> in kernel has zero overhead though.

Don't forget that there are arches out there w/ VIVT caches which will
probably eliminate most of the performance benifits if we have the same
page mapped writable in two different virtual addresses..

-- 
  John-Mark Gurney				Voice: +1 415 225 5579

     "All that I will do, has been done, All that I have, has not."