Re: [PATCH v8 1/1] f2fs: dax: implement direct access

From	Christoph Hellwig <hch@infradead.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH v8 1/1] f2fs: dax: implement direct access
Date	2017-07-26 22:20 +0200
Message-ID	<u7AWJ-4Xd-1@gated-at.bofh.it> (permalink)
References	(3 earlier) <u7xPc-2P1-25@gated-at.bofh.it> <u7xYU-37A-55@gated-at.bofh.it> <u7y8z-3b6-41@gated-at.bofh.it> <u7yig-3eE-63@gated-at.bofh.it> <u7A0F-4lW-9@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

On Wed, Jul 26, 2017 at 12:16:11PM -0700, Dan Williams wrote:
> Silently turn on DAX if HMAT says its ok?

Yes, absolutely.  I want my system to do the right thing by default,
and if HMAT says bypassing the page cache is a clear advatange it
should be the default.

> I think we would instead
> want a "-o autodax" for that case and then "-o dax" and "-o nodax" for
> the force cases.

Why?

> I think it's easier to administer than the dax mount option. If
> someone wants dax on only in a sub-tree they can set the flag on that
> parent directory and have a policy in dax filesystems that children
> inherit the dax policy from the parent. That seems a better
> administrative model than trying to get it all right globally at mount
> time.

And why exactly? If DAX is faster for file a in directory X it will
be just as fast for a file b in directory Y.

Thread

[PATCH v8 1/1] f2fs: dax: implement direct access sunqiuyang <sunqiuyang@huawei.com> - 2017-07-20 14:10 +0200
  Re: [PATCH v8 1/1] f2fs: dax: implement direct access Jaegeuk Kim <jaegeuk@kernel.org> - 2017-07-22 02:40 +0200
    Re: [PATCH v8 1/1] f2fs: dax: implement direct access Sun Qiuyang <sunqiuyang@huawei.com> - 2017-07-24 14:10 +0200
  Re: [PATCH v8 1/1] f2fs: dax: implement direct access Dan Williams <dan.j.williams@gmail.com> - 2017-07-26 02:20 +0200
    Re: [PATCH v8 1/1] f2fs: dax: implement direct access Jaegeuk Kim <jaegeuk@kernel.org> - 2017-07-26 04:20 +0200
      RE: [PATCH v8 1/1] f2fs: dax: implement direct access sunqiuyang <sunqiuyang@huawei.com> - 2017-07-26 08:50 +0200
    Re: [PATCH v8 1/1] f2fs: dax: implement direct access Christoph Hellwig <hch@infradead.org> - 2017-07-26 09:30 +0200
      Re: [PATCH v8 1/1] f2fs: dax: implement direct access Dan Williams <dan.j.williams@intel.com> - 2017-07-26 19:00 +0200
        Re: [PATCH v8 1/1] f2fs: dax: implement direct access Christoph Hellwig <hch@infradead.org> - 2017-07-26 19:10 +0200
          Re: [PATCH v8 1/1] f2fs: dax: implement direct access Dan Williams <dan.j.williams@intel.com> - 2017-07-26 19:20 +0200
            Re: [PATCH v8 1/1] f2fs: dax: implement direct access Christoph Hellwig <hch@infradead.org> - 2017-07-26 19:30 +0200
              Re: [PATCH v8 1/1] f2fs: dax: implement direct access Dan Williams <dan.j.williams@intel.com> - 2017-07-26 21:20 +0200
                Re: [PATCH v8 1/1] f2fs: dax: implement direct access Christoph Hellwig <hch@infradead.org> - 2017-07-26 22:20 +0200
                Re: [PATCH v8 1/1] f2fs: dax: implement direct access Dan Williams <dan.j.williams@intel.com> - 2017-07-26 22:30 +0200

csiph-web