Messages in this thread | | | From | Andy Lutomirski <> | Date | Tue, 1 Aug 2017 07:17:56 -0700 | Subject | Re: linux-next: manual merge of the rcu tree with the tip tree |
| |
On Tue, Aug 1, 2017 at 7:15 AM, Peter Zijlstra <peterz@infradead.org> wrote: > On Tue, Aug 01, 2017 at 03:58:49PM +0200, Peter Zijlstra wrote: >> On Tue, Aug 01, 2017 at 06:43:14AM -0700, Andy Lutomirski wrote: >> > Anyway, can you document whatever property you require with a comment >> > in switch_mm() or wherever you're finding that property so that future >> > arch changes don't break it? >> >> We need _a_ smp_mb after rq->curr store. x86 has plenty. > > That is, we need it when we change to a different !0 mm. And we have the > mm_cpumask() atomics at the very least, even if loading a new CR3 would > not be serializing.
I'm 99.5% sure that loading a new CR3 is always serializing even if it doesn't flush the TLB.
| |