On Fri, Aug 11, 2017 at 09:16:29AM -0700, Linus Torvalds wrote: > On Fri, Aug 11, 2017 at 2:03 AM, Peter Zijlstra <[email protected]> wrote: > > > > I'm sure we talked about using HAVE_RCU_TABLE_FREE for x86 (and yes that > > would make it work again), but this was some years ago and I cannot > > readily find those emails. > > I think the only time we really talked about HAVE_RCU_TABLE_FREE for > x86 (at least that I was cc'd on) was not because of RCU freeing, but > because we just wanted to use the generic page table lookup code on > x86 *despite* not using RCU freeing. > > And we just ended up renaming HAVE_GENERIC_RCU_GUP as HAVE_GENERIC_GUP. > > There was only passing mention of maybe making x86 use RCU, but the > discussion was really about why the IF flag meant that x86 didn't need > to, iirc. > > I don't recall us ever discussing *really* making x86 use RCU.
Google finds me this: https://lwn.net/Articles/500188/ Which includes: http://www.mail-archive.com/[email protected]/msg72918.html which does as was suggested here, selects HAVE_RCU_TABLE_FREE for PARAVIRT_TLB_FLUSH. But yes, this is very much virt specific nonsense, native would never need this.
