Re: [PATCH] reduce large do_mount stack usage with noinlines

Arjan van de Ven
2008-02-06T22:55:34Z

On Wed, 6 Feb 2008 14:34:57 -0800
Andrew Morton <akpm@linux-foundation.org> wrote:

>
> Does the patch actually help? I mean, if a() calls b() and both use N
> bytes of locals, our worst-case stack usage remains ~2N whether or
> not b() was inlined in a()? In fact, uninlining makes things a
> little worse due to callframe stuff.

it gets interesting at the three-way..
if a() calls b() and then calls c(), and they all use N,
the total usage is now 3N not 2N.

(although current gcc is already somewhat smarter about this, and 3N might actually be 2N for some cases)