Messages in this thread | | | Date | Mon, 21 Mar 2011 17:14:25 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH] x86, UV: Fix NMI handler for UV platforms |
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* Jack Steiner <steiner@sgi.com> wrote:
> This fixes a problem seen on UV systems handling NMIs from the node controller. > The original code used the DIE notifier as the hook to get to the UV NMI > handler. This does not work if performance counters are active - the hw_perf > code consumes the NMI and the UV handler is not called.
Sigh:
> --- linux.orig/arch/x86/kernel/traps.c 2011-03-21 09:05:43.000000000 -0500 > +++ linux/arch/x86/kernel/traps.c 2011-03-21 09:13:01.306555675 -0500 > @@ -57,6 +57,7 @@ > #include <asm/mce.h> > > #include <asm/mach_traps.h> > +#include <asm/uv/uv.h> > > #ifdef CONFIG_X86_64 > #include <asm/x86_init.h> > @@ -397,13 +398,16 @@ unknown_nmi_error(unsigned char reason, > static notrace __kprobes void default_do_nmi(struct pt_regs *regs) > { > unsigned char reason = 0; > + int handled; > > /* > * CPU-specific NMI must be processed before non-CPU-specific > * NMI, otherwise we may lose it, because the CPU-specific > * NMI can not be detected/processed on other CPUs. > */ > - if (notify_die(DIE_NMI, "nmi", regs, 0, 2, SIGINT) == NOTIFY_STOP) > + handled = uv_handle_nmi(regs, reason); > + if (notify_die(DIE_NMI, "nmi", regs, 0, 2, SIGINT) == NOTIFY_STOP || > + handled) > return;
Such code is extremely ugly. Please *reduce* the number of is_uv_system() type of hacks in core x86 code, not increase it!
Any reason why a higher priority for the UV NMI handler cannot solve the 'perf eats the NMI' problem?
Thanks,
Ingo
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