Re: [RESEND PATCH 0/7] Add FOLL_LONGTERM to GUP fast and use it

[Ira Weiny]

On Tue, Mar 19, 2019 at 03:19:30PM -0700, Andrew Morton wrote:
> On Sun, 17 Mar 2019 11:34:31 -0700 ira.weiny@xxxxxxxxx wrote:
> 
> > Resending after rebasing to the latest mm tree.
> > 
> > HFI1, qib, and mthca, use get_user_pages_fast() due to it performance
> > advantages.  These pages can be held for a significant time.  But
> > get_user_pages_fast() does not protect against mapping FS DAX pages.
> > 
> > Introduce FOLL_LONGTERM and use this flag in get_user_pages_fast() which
> > retains the performance while also adding the FS DAX checks.  XDP has also
> > shown interest in using this functionality.[1]
> > 
> > In addition we change get_user_pages() to use the new FOLL_LONGTERM flag and
> > remove the specialized get_user_pages_longterm call.
> 
> It would be helpful to include your response to Christoph's question
> (http://lkml.kernel.org/r/20190220180255.GA12020@xxxxxxxxxxxxxxxxxxxxxxxxx)
> in the changelog.  Because if one person was wondering about this,
> others will likely do so.
> 
> We have no record of acks or reviewed-by's.  At least one was missed
> (http://lkml.kernel.org/r/CAOg9mSTTcD-9bCSDfC0WRYqfVrNB4TwOzL0c4+6QXi-N_Y43Vw@xxxxxxxxxxxxxx),
> but that is very very partial.

That is my bad.  Sorry to Mike.  And I have added him.

> 
> This patchset is fairly DAX-centered, but Dan wasn't cc'ed!

Agreed, I'm new to changing things which affect this many sub-systems and I
struggled with who should be CC'ed (get_maintainer.pl returned a very large
list  :-(.

I fear I may have cc'ed too many people, and the wrong people apparently, so
that may be affecting the review...

So again my apologies.  I don't know if Dan is going to get a chance to put a
reviewed-by on them this week but I thought I would send this note to let you
know I'm not ignoring your feedback.  Just waiting a bit before resending to
hopefully get some more acks/reviewed bys.

Thanks,
Ira

> 
> So ho hum.  I'll scoop them up and shall make the above changes to the
> [1/n] changelog, but we still have some work to do.
>