Re: [RFC 1/3] Unified NMI delayed call mechanism

Ingo Molnar
2010-06-12T10:26:14Z

* Huang Ying <ying.huang@intel.com> wrote:

> NMI can be triggered even when IRQ is masked. So it is not safe for NMI
> handler to call some functions. One solution is to delay the call via self
> interrupt, so that the delayed call can be done once the interrupt is
> enabled again. This has been implemented in MCE and perf event. This patch
> provides a unified version and make it easier for other NMI semantic handler
> to take use of the delayed call.
>
> Signed-off-by: Huang Ying <ying.huang@intel.com>
> ---
> arch/x86/include/asm/entry_arch.h | 1
> arch/x86/include/asm/hw_irq.h | 1
> arch/x86/include/asm/irq_vectors.h | 5 +
> arch/x86/include/asm/nmi.h | 7 ++
> arch/x86/kernel/entry_64.S | 3 +
> arch/x86/kernel/irqinit.c | 3 +
> arch/x86/kernel/traps.c | 104 +++++++++++++++++++++++++++++++++++++
> 7 files changed, 124 insertions(+)

Instead of introducing this extra intermediate facility please use the same
approach the unified NMI watchdog is using (see latest -tip): a perf event
callback gives all the extra functionality needed.

The MCE code needs to be updated to use that - and then it will be integrated
into the events framework.

Thanks,

Ingo