Messages in this thread | | | From | Jeff Moyer <> | Subject | Re: [PATCH v2] libnvdimm: re-enable deep flush for pmem devices | Date | Tue, 13 Feb 2018 08:17:38 -0500 |
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Dan Williams <dan.j.williams@intel.com> writes:
> On Mon, Feb 12, 2018 at 2:53 PM, Jeff Moyer <jmoyer@redhat.com> wrote: >> Dave Jiang <dave.jiang@intel.com> writes: >> >>> Re-enable deep flush so that users always have a way to be sure that a write >>> does make it all the way out to the NVDIMM. The PMEM driver writes always >>> make it "all the way to the NVDIMM", and it relies on the ADR mechanism to >>> flush the write buffers on power failure. Deep flush is there to explicitly >>> flush those write buffers to protect against (rare) ADR failure. >>> This change prevents a regression in deep flush behavior so that applications >>> can continue to depend on fsync() as a mechanism to trigger deep flush in the >>> filesystem-dax case. >> >> That's still very confusing text. Specifically, the part where you say >> that pmem driver writes always make it to the DIMM. I think the >> changelog could start with "Deep flush is there to explicitly flush >> write buffers...." Anyway, the fix looks right to me. > > I ended up changing the commit message to this, let me know if it reads better:
Thanks. It's still unclear to me what the text, "The PMEM driver writes always arrive at the NVDIMM" means. However, it's good enough.
Thanks! Jeff
> > libnvdimm: re-enable deep flush for pmem devices via fsync() > > Re-enable deep flush so that users always have a way to be sure that a > write makes it all the way out to media. The PMEM driver writes always > arrive at the NVDIMM, and it relies on the ADR (Asynchronous DRAM > Refresh) mechanism to flush the write buffers on power failure. Deep > flush is there to explicitly flush those write buffers to protect > against (rare) ADR failure. This change prevents a regression in deep > flush behavior so that applications can continue to depend on fsync() as > a mechanism to trigger deep flush in the filesystem-DAX case. > > Fixes: 06e8ccdab15f4 ("acpi: nfit: Add support for detect platform > CPU cache...") > Signed-off-by: Dave Jiang <dave.jiang@intel.com> > Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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