Messages in this thread |  | | | Date | Mon, 21 Mar 2011 20:19:09 +0300 | | From | Cyrill Gorcunov <> | | Subject | Re: [PATCH] x86, UV: Fix NMI handler for UV platforms |
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On 03/21/2011 08:08 PM, Jack Steiner wrote: > On Mon, Mar 21, 2011 at 08:00:53PM +0300, Cyrill Gorcunov wrote: >> On 03/21/2011 07:43 PM, Cyrill Gorcunov wrote: >> ... >>> >>> I think Jack might need to setup priority for his notifier, like >>> >>> static struct notifier_block uv_dump_stack_nmi_nb = { >>> .notifier_call = uv_handle_nmi, >>> .priority = NMI_LOCAL_HIGH_PRIOR+1, >>> }; >>> >>> so it would be called before perf nmi. Don, am I right? >>> >>> Since for perf nmis we do have >>> >>> static __read_mostly struct notifier_block perf_event_nmi_notifier = { >>> .notifier_call = perf_event_nmi_handler, >>> .next = NULL, >>> .priority = NMI_LOCAL_LOW_PRIOR, >>> }; >>> >> >> I must admit I've missed the fact that Jack has tried NMIs priorities, right? >> x86_platform_ops seems to be a cleaner indeed (btw I think p4 pmu kgdb issue >> is exactly the same problem) but same time this might end up in over-swelled >> ideas behind this small code snippet. Dunno. Probably we need some per-cpu >> system status for nmi reasons other than unknown nmis... > > We use KDB internally, and yes, it has the same issue. The version of the > patch that uses KDB OR's the "handled" status for both KDB & the UV NMI handler. > If either KDB or the UV NMI handler returns "handled", the code in traps.c exits > after the call to the first die notifier. > > Not particularily pretty but I could not find a better way to do it. > > --- jack
Another option might be to add pre-nmi notifier chain, which of course not much differ from platform ops but I guess platform ops stands mostly for one-shot events while chain might be more flexible. Ie I mean something like
if (notify_pre_die(DIE_NMI, "nmi", regs, 0, 2, SIGINT) == NOTIFY_STOP) return; -- Cyrill
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