Re: [PATCH 0/2] Fix BTT data corruptions after crash

[Dan Williams]

On Thu, Jan 28, 2016 at 12:43 PM, Toshi Kani <toshi.kani@xxxxxxx> wrote:
> On Thu, 2016-01-28 at 12:12 -0800, Dan Williams wrote:
[..]
>> I'm wondering if we should just document that this routine does not
>> support unaligned transfers?  Maybe backed by a debug mode that does
>> the alignment check.
>
> Yes, I agree.  For this debug mode, do you have something in mind?  Or
> should we add a new CONFIG option like CONFIG_PMEM_DEBUG?
>

I hesitated to say yes to this since some simple alignment checks
seems like a thin reason to add a new Kconfig symbol.  However, one
way we can test that memcpy_to_pmem() properly bypasses the cache is
to invalidate the cache contents that it touches.  This would have
caught this bug without needing to do a power cycle test.  In
otherwords in debug mode run an 'invd' loop after the copy.