Re: [PATCH v3 13/14] filesystem-dax: gate calls to dax_flush() on QUEUE_FLAG_WC

From	Dan Williams <dan.j.williams@intel.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v3 13/14] filesystem-dax: gate calls to dax_flush() on QUEUE_FLAG_WC
Date	2017-06-19 04:10 +0200
Message-ID	<tTUiB-4Mk-7@gated-at.bofh.it> (permalink)
References	<tQyRj-6b1-3@gated-at.bofh.it> <tQyRk-6b1-21@gated-at.bofh.it> <tTE4a-2Q6-11@gated-at.bofh.it>
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On Sun, Jun 18, 2017 at 1:45 AM, Christoph Hellwig <hch@lst.de> wrote:
> On Fri, Jun 09, 2017 at 01:24:56PM -0700, Dan Williams wrote:
>> Some platforms arrange for cpu caches to be flushed on power-fail. On
>> those platforms there is no requirement that the kernel track and flush
>> potentially dirty cache lines. Given that we still insert entries into
>> the radix for locking purposes this patch only disables the cache flush
>> loop, not the dirty tracking.
>>
>> Userspace can override the default cache setting via the block device
>> queue "write_cache" attribute in sysfs.
>
> NAK.  Please stop using the block infrastructure for dax values.  Have
> your own flag and sysfs file in the dax infrastructure and only propagate
> it to the block layer for the block devices using dax.

Ok, that makes sense.

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[PATCH v3 13/14] filesystem-dax: gate calls to dax_flush() on  QUEUE_FLAG_WC Dan Williams <dan.j.williams@intel.com> - 2017-06-09 22:40 +0200
  Re: [PATCH v3 13/14] filesystem-dax: gate calls to dax_flush() on  QUEUE_FLAG_WC Jan Kara <jack@suse.cz> - 2017-06-14 12:50 +0200
    Re: [PATCH v3 13/14] filesystem-dax: gate calls to dax_flush() on QUEUE_FLAG_WC Dan Williams <dan.j.williams@intel.com> - 2017-06-14 18:50 +0200
  [PATCH v4 13/14] libnvdimm,  pmem: gate cache management on QUEUE_FLAG_WC in pmem_dax_flush() Dan Williams <dan.j.williams@intel.com> - 2017-06-15 01:20 +0200
    Re: [PATCH v4 13/14] libnvdimm, pmem: gate cache management on  QUEUE_FLAG_WC in pmem_dax_flush() Jan Kara <jack@suse.cz> - 2017-06-15 10:10 +0200
  Re: [PATCH v3 13/14] filesystem-dax: gate calls to dax_flush() on         QUEUE_FLAG_WC Christoph Hellwig <hch@lst.de> - 2017-06-18 10:50 +0200
    Re: [PATCH v3 13/14] filesystem-dax: gate calls to dax_flush() on QUEUE_FLAG_WC Dan Williams <dan.j.williams@intel.com> - 2017-06-19 04:10 +0200

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