On Wed, 06 Feb 2008 16:13:58 -0600 Eric Sandeen <[EMAIL PROTECTED]> wrote:
> do_mount() uses a whopping 616 bytes of stack on x86_64 in > 2.6.24-mm1, largely thanks to gcc inlining the various helper > functions. hm, sizeof(nameidata)=136 and I can see about three of them on the stack. Must have missed something. > noinlining these can slim it down a lot; on my box this patch > gets it down to 168, which is mostly the struct nameidata nd; > left on the stack. > > These functions are called only as do_mount() helpers; > none of them should be in any path that would see a performance > benefit from inlining... > 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. > -static int do_change_type(struct nameidata *nd, int flag) > +static noinline int do_change_type(struct nameidata *nd, int flag) There's no way for the reader to work out why this is here, so I do think it should be commented somewhere. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
