Re: [PATCH] drm/i915: Minimize uaccess exposure in i915_gem_execbuffer2_ioctl()

[Al Viro]

On Fri, Feb 28, 2020 at 07:04:41PM +0100, Peter Zijlstra wrote:
> On Thu, Feb 27, 2020 at 07:03:42PM -0600, Josh Poimboeuf wrote:
> > > And why not mark gen8_canonical_addr() __always_inline?
> > 
> > Right, marking those two functions as __always_inline is the other
> > option.  The problem is, if you keep doing it, eventually you end up
> > with __always_inline-itis spreading all over the place.  And it affects
> > all the other callers, at least in the CONFIG_CC_OPTIMIZE_FOR_SIZE case.
> > At least this fix is localized.
> 
> I'm all for __always_inline in this case, the compiler not inlining sign
> extention is just retarded,

FWIW, in this case it's
        salq    $8, %rax
        sarq    $8, %rax
i.e. 8 bytes.  Sure, that's 3 bytes longer than call, but really, WTF?