On Mon, 18 Jan 2021 05:15:55 +0000 HORIGUCHI NAOYA(堀口 直也) <naoya.horiguchi@xxxxxxx> wrote: > Hi Aili, > > On Fri, Jan 15, 2021 at 05:26:22PM +0800, Aili Yao wrote: > > On Fri, 15 Jan 2021 09:49:24 +0100 > > Oscar Salvador <osalvador@xxxxxxx> wrote: > > > > > I am having a hard time trying to grasp what are you trying to achieve here. > > > Could you elaborate some more? Ideally stating what is the problem you are > > > fixing here. > > > > > Sorry for confusion, example: there are four process A,B,C,D,which map the same file into > > there process space, which set there PF_MCE_KILL_EARLY flag to TRUE, if process A trigger one > > UE with MF_ACTION_REQUIRED set, in current code, only process A will be killed, B,C,D remain > > alive, but for the PF_MCE_KILL_EARLY we set, we want B,C,D also be killed. > > This behavior seems not to me what PF_MCE_KILL_EARLY intends. This flag > controls whether memory error handler kills processes immediately or not, > and it only affects action optional cases (i.e. called without > MF_ACTION_REQUIRED). In MF_ACTION_REQUIRED case, we have no such choice > and affected processes should be always killed immediately. > > We may also need to consider the difference in context of these two cases. > Action optional case is called asynchronously by background process like > memory scrubbing, so all processes mapping the error memory are the affected > ones. Action required event is more synchronous, and is called when a > process experiences memory access errors on data load and instruction fetch > instructions. So the affected process in this case is only the process. > So I still think the this background justifies the current behavior. > > But my knowledge might be old, if you have newer hardwares which define > other type of memory error and that doesn't fit with current implementation, > I'd like to extend code to support the new cases, so please let me know. > Sorry, I don't fully get your concern. For Action optional cases, It's may from CE storm or patrol scrub, when the process want to process this condition, it will set PF_MCE_KILL_EARLY, and it will be signaled for such case. For Action Required cases,we must do something, I think it's more urgent and serious, In the current code, the process triggered the Error Should be signaled. but the process with PF_MCE_KILL_EARLY won't get signaled, just because PF_MCE_KILL_EARLY is for action optional case? Action Required is for current we must handle, the same Action Required issue is Action optional for non-current processes, Right? I don't think Action Required is for all processes, For current processes , it may be AR, for other process, it may be AO, and they should also be signaled, I think this behavior its reasonable. And we can't determine which error will be triggered, the PF_MCE_KILL_EARLY fLAG is meant to handle memory error gracefully and won't be restricted to explicitly declared AO errors. Thanks! -- Best Regards! Aili Yao
