Re: [PATCH v2 1/5] pmem, dax: clean up clear_pmem()
From: Dan Williams
Date: Thu Oct 22 2015 - 18:29:38 EST
On Thu, Oct 22, 2015 at 1:48 PM, Jeff Moyer <jmoyer@xxxxxxxxxx> wrote:
> Dan Williams <dan.j.williams@xxxxxxxxx> writes:
>
>> 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.
>
> Wouldn't another solution be to actually use non-temporal stores?
Sure.
> Why did you choose to punt?
Just a priority call at this point. Patches welcome of course ;-).
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