Re: Slow DOWN, please!!!

From: Ingo Molnar
Date: Wed Apr 30 2008 - 21:41:41 EST



* David Miller <davem@xxxxxxxxxxxxx> wrote:

> Ingo, let me know what I need to do to change your behavior in
> situations like the one I'm about to describe, ok?
>
> Today, you merged in this bogus "regression fix".

the motivation of that fix wasnt UML - that was just an (indeed
incorrect) after-thought when i wrote up the commit log. The fix is
obviously right - although it doesnt fix UML.

btw., did you see my stream of fixes about UML?

> To an arbitrary person reading the commit logs, the above looks like
> you fixed something, when you actually didn't fix anything.

it is wrong that it "doesnt fix anything". Look at the change itself:

- * Force always-inline if the user requests it so via the .config:
+ * Force always-inline if the user requests it so via the .config,
+ * or if gcc is too old:
*/
#if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \
- !defined(CONFIG_OPTIMIZE_INLINING) && (__GNUC__ >= 4)
+ !defined(CONFIG_OPTIMIZE_INLINING) || (__GNUC__ < 4)

before the change it was only possible to disable the optimization on
gcc 4 and above. The intended (and now implemented) condition is to only
change anything on gcc 4 and above. I.e. on gcc3x the config option has
no effect at all - and that's what we want.

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