Re: [RFC][CFT][PATCHSET v1] uaccess unification

[Al Viro]

On Wed, Mar 29, 2017 at 01:08:12PM -0700, Vineet Gupta wrote:

> Hi Al,
> 
> Thx for taking this up. It seems ARC was missing INLINE_COPY* switch likely due to
> existing 2 variants (inline/out-of-line) we already have.
> I've added a patch for that (attached too) - boot tested the series on ARC.

BTW, I wonder if inlining all of the copy_{to,from}_user() is actually a win.
It's probably arch-dependent and it would be nice if somebody compared
performance with and without inlining those...  ARC, in particular, has
__arc_copy_{to,from}_user() inlining a whole lot, even in case of non-constant
size and your patch, AFAICS, will inline all of it in *all* cases.  It might
end up being a win, but that's not apriori obvious...  Do you have any
profiling results in that area?