Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1631717

Re: [PATCH v3] libnvdimm, region: sysfs trigger for nvdimm_flush()

Show all headers | View raw

Dan Williams <dan.j.williams@intel.com> writes:

> The nvdimm_flush() mechanism helps to reduce the impact of an ADR
> (asynchronous-dimm-refresh) failure. The ADR mechanism handles flushing
> platform WPQ (write-pending-queue) buffers when power is removed. The
> nvdimm_flush() mechanism performs that same function on-demand.
>
> When a pmem namespace is associated with a block device, an
> nvdimm_flush() is triggered with every block-layer REQ_FUA, or REQ_FLUSH
> request. These requests are typically associated with filesystem
> metadata updates. However, when a namespace is in device-dax mode,
> userspace (think database metadata) needs another path to perform the
> same flushing. In other words this is not required to make data
> persistent, but in the case of metadata it allows for a smaller failure
> domain in the unlikely event of an ADR failure.
>
> The new 'flush' attribute is visible when the individual DIMMs backing a
> given interleave-set are described by platform firmware. In ACPI terms
> this is "NVDIMM Region Mapping Structures" and associated "Flush Hint
> Address Structures". Reads return "1" if the region supports triggering
> WPQ flushes on all DIMMs. Reads return "0" the flush operation is a
> platform nop, and in that case the attribute is read-only.

I can make peace with exposing this to userspace, though I am mostly
against its use.  However, sysfs feels like the wrong interface.
Believe it or not, I'd rather see this implemented as an ioctl.

This isn't a NACK, it's me giving my opinion.  Do with it what you will.

Cheers,
Jeff

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH v2 2/2] libnvdimm, region: sysfs trigger for nvdimm_flush() Dan Williams <dan.j.williams@intel.com> - 2017-04-25 02:00 +0200
  Re: [PATCH v2 2/2] libnvdimm, region: sysfs trigger for  nvdimm_flush() Ross Zwisler <ross.zwisler@linux.intel.com> - 2017-04-25 18:40 +0200
    Re: [PATCH v2 2/2] libnvdimm, region: sysfs trigger for nvdimm_flush() Dan Williams <dan.j.williams@intel.com> - 2017-04-25 18:40 +0200
  [PATCH v3] libnvdimm, region: sysfs trigger for nvdimm_flush() Dan Williams <dan.j.williams@intel.com> - 2017-04-25 22:30 +0200
    Re: [PATCH v3] libnvdimm, region: sysfs trigger for nvdimm_flush() Jeff Moyer <jmoyer@redhat.com> - 2017-04-26 22:40 +0200
      Re: [PATCH v3] libnvdimm, region: sysfs trigger for nvdimm_flush() Dan Williams <dan.j.williams@intel.com> - 2017-04-27 01:10 +0200
        Re: [PATCH v3] libnvdimm, region: sysfs trigger for nvdimm_flush() Jeff Moyer <jmoyer@redhat.com> - 2017-04-27 15:50 +0200
          Re: [PATCH v3] libnvdimm, region: sysfs trigger for nvdimm_flush() Dan Williams <dan.j.williams@intel.com> - 2017-04-27 19:00 +0200
            Re: [PATCH v3] libnvdimm, region: sysfs trigger for nvdimm_flush() Jeff Moyer <jmoyer@redhat.com> - 2017-04-27 20:50 +0200
              Re: [PATCH v3] libnvdimm, region: sysfs trigger for nvdimm_flush() Dan Williams <dan.j.williams@intel.com> - 2017-04-27 21:20 +0200
                Re: [PATCH v3] libnvdimm, region: sysfs trigger for nvdimm_flush() Dan Williams <dan.j.williams@intel.com> - 2017-04-27 21:30 +0200
                Re: [PATCH v3] libnvdimm, region: sysfs trigger for nvdimm_flush() Jeff Moyer <jmoyer@redhat.com> - 2017-04-27 21:50 +0200
                Re: [PATCH v3] libnvdimm, region: sysfs trigger for nvdimm_flush() Jeff Moyer <jmoyer@redhat.com> - 2017-04-27 21:50 +0200
                Re: [PATCH v3] libnvdimm, region: sysfs trigger for nvdimm_flush() Dan Williams <dan.j.williams@intel.com> - 2017-04-27 22:10 +0200
                Re: [PATCH v3] libnvdimm, region: sysfs trigger for nvdimm_flush() Dan Williams <dan.j.williams@intel.com> - 2017-04-27 23:40 +0200
      [PATCH v4] libnvdimm, region: sysfs trigger for nvdimm_flush() Dan Williams <dan.j.williams@intel.com> - 2017-04-27 01:50 +0200
        [PATCH v5] libnvdimm, region: sysfs trigger for nvdimm_flush() Dan Williams <dan.j.williams@intel.com> - 2017-04-28 00:30 +0200

csiph-web