Messages in this thread | | | Date | Thu, 21 Jun 2018 15:42:03 -0700 | From | Fenghua Yu <> | Subject | Re: [RFC PATCH 00/16] x86/split_lock: Enable #AC exception for split locked accesses |
| |
On Thu, Jun 21, 2018 at 03:18:19PM -0700, Dave Hansen wrote: > On 06/21/2018 03:08 PM, Peter Zijlstra wrote: > > On Thu, Jun 21, 2018 at 03:00:03PM -0700, Fenghua Yu wrote: > >> The control knob for kernel is to choose re-executing the faulting > >> instruction (default) or kernel panic. Kernel panic may be useful in hard > >> real time which has less tolerant to bad performance. > > The kernel should never trigger this, ever. Any #AC is a plain bug and > > should be fixed. So unconditional WARN+disable is suffient. > > It sounds like we need to start with that functionality and then if > Fenghua wants to do more, we have add-on patches that can be evaluated > by themselves.
For split lock in kernel, by default, I just do warning, disable feature in #AC handler, continue to execute the faulting instruction, and re-enable #AC for split lock after a delay. This is the default behavior in the current patches.
By "WAR+disable", you mean I just do this default behavior and remove the control knob?
Thanks.
-Fenghua
| |