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From: Toshi Kani <toshi.kani@hpe.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
	Borislav Petkov <bp@suse.de>,
	Ross Zwisler <ross.zwisler@linux.intel.com>,
	Vishal L Verma <vishal.l.verma@intel.com>,
	micah.parrish@hpe.com, brian.boylston@hpe.com,
	X86 ML <x86@kernel.org>,
	"linux-nvdimm@lists.01.org" <linux-nvdimm@ml01.01.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/2] Fix BTT data corruptions after crash
Date: Mon, 01 Feb 2016 12:50:35 -0700	[thread overview]
Message-ID: <1454356235.7165.5.camel@hpe.com> (raw)
In-Reply-To: <CAPcyv4hsa-DCYO-YxMCKat5y-dDvGMMgJ5D-cib2TjhyNan4NA@mail.gmail.com>

On Sat, 2016-01-30 at 09:44 -0800, Dan Williams wrote:
> On Thu, Jan 28, 2016 at 12:43 PM, Toshi Kani <toshi.kani@hpe.com> 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.

That sounds like a good idea to try out.  Since this approach no longer
depends on patch 1/2, I will separate this change from patch 1/2.

Thanks,
-Toshi  

      reply	other threads:[~2016-02-01 19:51 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-28 18:12 [PATCH 0/2] Fix BTT data corruptions after crash Toshi Kani
2016-01-28 18:12 ` [PATCH 1/2] x86/lib/copy_user_64.S: Handle 4-byte uncached copy Toshi Kani
2016-01-29  8:27   ` Ingo Molnar
2016-01-29 14:56     ` Toshi Kani
2016-01-28 18:12 ` [PATCH 2/2] pmem: Flush cache on unaligned request Toshi Kani
2016-01-28 20:12 ` [PATCH 0/2] Fix BTT data corruptions after crash Dan Williams
2016-01-28 20:43   ` Toshi Kani
2016-01-30 17:44     ` Dan Williams
2016-02-01 19:50       ` Toshi Kani [this message]

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