Re: [patch 1/2] i386: use asm() like the other atomic operations already do.

[Chris Snook <csnook@redhat.com>]

Herbert Xu wrote:
> Andi Kleen <ak@suse.de> wrote:
> > > My config with march=pentium-m and gcc (GCC) 4.1.2 (Gentoo 4.1.2):
> > >   text    data     bss     dec     hex filename
> > > 3434150  249176  176128 3859454  3ae3fe atomic_normal/vmlinux
> > > 3435308  249176  176128 3860612  3ae884 atomic_inlineasm/vmlinux
> > What is the difference between atomic_normal and atomic_inlineasm? 
>
> The inline asm stops certain optimisations from occuring.
>
> I'm still unconvinced why we need this because nobody has
> brought up any examples of kernel code that legitimately
> need this.

There's plenty of kernel code that *wants* this though.  If we can 
reduce the need for register-clobbering barriers, shrink our binaries, 
shrink our code, improve performance, and avoid heisenbugs, I think it's 
a win, whether or not we *need* it.

	-- Chris
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/