Messages in this thread | | | From | Thomas Gleixner <> | Subject | Re: [patch V6 04/37] x86: Make hardware latency tracing explicit | Date | Thu, 21 May 2020 00:20:07 +0200 |
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Andy Lutomirski <luto@amacapital.net> writes: >> On May 20, 2020, at 1:10 PM, Thomas Gleixner <tglx@linutronix.de> wrote: >> Peter Zijlstra <peterz@infradead.org> writes: >>> We probably have to anyway. But I can do that later I suppose. >> >> Second thoughts. For #DB and #INT3 we can just keep nmi_enter(), needs >> just annotation in nmi_enter() around that trace muck. >> >> For #NMI and #MCE I rather avoid the early trace call and do it once we >> have reached "stable" state, i.e. avoid it in the whole nested NMI mess. > > What’s the issue? The actual meat is mostly in the asm for NMI, and > for MCE it’s just the sync-all-the-cores thing. The actual > simultaneous NMI-and-MCE case is utterly busted regardless, and I’ve > been thinking about how to fix it. It won’t be pretty, but nmi_enter() > will have nothing to do with it.
The issue is that I want to avoid anything which is not essential just for pure paranoia reasons.
I can drop that and just move the trace muck after RCU is safe and annotate it properly.
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