Messages in this thread | | | Date | Fri, 23 May 2014 14:50:41 -0700 | Subject | Re: [PATCH v2] x86/mce: Distirbute the clear operation of mces_seen to Per-CPU rather than only monarch CPU | From | Tony Luck <> |
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On Thu, May 22, 2014 at 6:32 PM, Chen Yucong <slaoub@gmail.com> wrote: > As Naoya Horiguchi says, this patch also have a small benefit that it > can reduce the processing time of monarch CPU.
This is indeed a benefit - but I'm not super worried about performance of machine check handler.
> /* > * Now clear the mces_seen of current CPU -*final - so that it > does not > * reappear on the next mce. > */ > memset(final, 0, sizeof(struct mce)); > mce_wrmsrl(MSR_IA32_MCG_STATUS, 0);
But if the monarch hasn't managed to clean mces_seen, then it certainly hasn't cleared MCG_STATUS ... so there can't be a "next" mce that would see these old values. Any extra MCE will result in system reset.
So we are not arguing that your patch is wrong - it just doesn't seem to be any better that what we have now (except for an unimportant small performance improvement).
-Tony
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