Messages in this thread | | | From | Rusty Russell <> | Subject | Re: regarding the x86_64 zero-based percpu patches | Date | Thu, 15 Jan 2009 12:17:53 +1030 |
| |
On Wednesday 14 January 2009 14:28:56 Tejun Heo wrote: > The main problem is that the area needs to be congruent which > basically mandates them to be contiguous.
I want to explore this assumption a little. Logically, yes, if 50% of pages are free and we have 4096 cpus, the chance that a page is free on all CPUs is 1 in 2^4095. But maybe such systems are fine with 2M pages for per-cpu areas at boot? And can page mobility tricks help us make the odds reasonable here? Only allowing movable pages in our expansion-of-percpu area?
Thanks, Rusty.
| |