Re: [patch] SMP alternatives

[Eric W. Biederman]

Andi Kleen <ak@xxxxxxx> writes:

>> 2. Uncached mappings are unworkable for this because we must never have
>> a page mapped with conflicting cache types - thats ugly, and plain
>> horrific on SMP.
>
> For kernel mapping change_page_attr() takes care of it,
> and for user space memory following all mappings is the only
> reliable way to find out which process needs to be killed
> anyways - and when you do that you can as well unmap
> or just kill.

I think I see the source of the confusion.  Scrubbing is the
process of taking data that is correctable and writing it back to
memory so that if a second correctable error occurs the net is still
corrected.

Directed killing of processes is something that must be done
inside a synchronous exception (like a machine check) because otherwise
it is so racy you don't know who has seen the bad data.  

Eric
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