[Cluster-devel] [PATCH v7 05/19] iov_iter: Introduce fault_in_iov_iter_writeable
tony.luck at intel.com
Mon Aug 30 15:41:45 UTC 2021
>> No #MC on stores. Just on loads. Note that you can't clear poison
>> state with a series of small writes to the cache line. But a single
>> 64-byte store might do it (architects didn't want to guarantee that
>> it would work when I asked about avx512 stores to clear poison
>> many years ago).
> Dave Jiang thinks MOVDIR64B clears poison.
MOVDIR64B has some explicit guarantees (does a write-back invalidate if the target is already
in the cache) that a 64-byte avx512 write doesn't.
Of course it would stop working if some future CPU were to have a longer than 64 bytes cache line.
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