Messages in this thread | | | Date | Thu, 24 Sep 2015 17:47:22 +0200 | From | Borislav Petkov <> | Subject | Re: [Patch V1 1/3] x86, mce: MCE log size not enough for high core parts |
| |
On Thu, Sep 24, 2015 at 01:48:38AM -0400, Ashok Raj wrote: > MCE_LOG_LEN appears to be short for high core count parts. Especially when > handling fatal errors, we don't clear MCE banks. Socket level MC banks > are visible to all CPUs that share banks. > > Assuming 18 core part, 2 threads per core 2 banks per thread and couple uncore > MSRs. Rounding to 128 with some fudge to grow in future. > > Signed-off-by: Ashok Raj <ashok.raj@intel.com> > Suggested-by: Tony Luck <tony.luck@intel.com> > --- > arch/x86/include/asm/mce.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/include/asm/mce.h b/arch/x86/include/asm/mce.h > index 2dbc0bf..4293ae7 100644 > --- a/arch/x86/include/asm/mce.h > +++ b/arch/x86/include/asm/mce.h > @@ -88,7 +88,7 @@ > #define MCE_EXTENDED_BANK 128 > #define MCE_THERMAL_BANK (MCE_EXTENDED_BANK + 0) > > -#define MCE_LOG_LEN 32 > +#define MCE_LOG_LEN 128 > #define MCE_LOG_SIGNATURE "MACHINECHECK"
Hmm, I don't think this is what I meant when we talked about it previously. So let me try again:
Now that we have this shiny 2-pages sized lockless gen_pool, why are we still dealing with struct mce_log mcelog? Why can't we rip it out and kill it finally? And switch to the gen_pool?
All code that reads from mcelog - /dev/mcelog chrdev - should switch to the lockless buffer and will iterate through the logged MCEs there.
I think this way we're much better prepared for future machine sizes. We can even use memblock to allocate appropriate memory at boot for the gen_pool if the 2 pages are not enough.
Hmmm?
-- Regards/Gruss, Boris.
ECO tip #101: Trim your mails when you reply.
| |