Subject: Re: [PATCH] Fake NUMA emulation for PowerPC

From: Olof Johansson <[email-masked]>
Date: Fri, 7 Dec 2007 15:28:17 -0600

Hi,

On Sat, Dec 08, 2007 at 02:44:25AM +0530, Balbir Singh wrote:

> Comments are as always welcome!

Care to explain what this is useful for? (Not saying it's a stupid idea,
just wondering what the reason for doing it is).

> diff -puN arch/powerpc/mm/numa.c~ppc-fake-numa-easy arch/powerpc/mm/numa.c
> --- linux-2.6.24-rc4-mm1/arch/powerpc/mm/numa.c~ppc-fake-numa-easy	2007-12-07 21:25:55.000000000 +0530
> +++ linux-2.6.24-rc4-mm1-balbir/arch/powerpc/mm/numa.c	2007-12-08 02:36:02.000000000 +0530
> @@ -24,6 +24,8 @@
>  
>  static int numa_enabled = 1;
>  
> +char *cmdline __initdata;
> +

Looks like this should be static.

> @@ -702,6 +744,9 @@ static int __init early_numa(char *p)
>  	if (strstr(p, "debug"))
>  		numa_debug = 1;
>  
> +	if (strstr(p, "fake="))
> +		cmdline = p + 5;	/* 5 is faster than strlen("fake=") */

This doesn't look right.

You check if it contains fake=, not if it starts with it. So if someone
did: "numa=foo,fake=bar", or even "numa=debug,fake=", things wouldn't
work right.

-Olof