Re: [PATCH v2 1/5] pmem, dax: clean up clear_pmem()

From: Ross Zwisler
Date: Tue Oct 27 2015 - 13:31:18 EST

On Thu, Oct 22, 2015 at 01:10:21PM -0400, Dan Williams wrote:
> Both, __dax_pmd_fault, and clear_pmem() were taking special steps to
> clear memory a page at a time to take advantage of non-temporal
> clear_page() implementations. However, x86_64 does not use
> non-temporal instructions for clear_page(), and arch_clear_pmem() was
> always incurring the cost of __arch_wb_cache_pmem().
> Clean up the assumption that doing clear_pmem() a page at a time is more
> performant.
> Cc: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
> Reported-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>

Reviewed-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
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