linux-kernel - Re: [PATCH] [RFC] remove (more or less) unnecessary cacheline_aligned from module

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-Id: <200901122138.49092.rusty@rustcorp.com.au>
Date:	Mon, 12 Jan 2009 21:38:48 +1030
From:	Rusty Russell <rusty@...tcorp.com.au>
To:	Kyle McMartin <kyle@...radead.org>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] [RFC] remove (more or less) unnecessary cacheline_aligned from module_ref

On Monday 12 January 2009 13:48:41 Kyle McMartin wrote:
> On x86_64 systems with CONFIG_MAXSMP set, NR_CPUS is exploded to 4096
> cpus. This cacheline_aligned attribute on the local_t in module_ref
> results in struct module bloating to over 512KB in size on x86_64, which
> tends to, er, add up. This results in insane disk usage on distro
> kernel configs (1GB+ on Fedora.)
> 
> Killing cacheline_aligned reduces the size of struct module to somewhat
> more sane levels.
> 
> Signed-off-by: Kyle McMartin <kyle@...hat.com>

Yep, I've applied this.

> I'll followup with a patch to make mod->ref dynamically allocated, but
> that needs a bit more thinking because module_unload_init currently
> doesn't have a failure path.

Thanks, that'd be good.  And it'll be even nicer when the new per-cpu
allocator goes in.

Thanks,
Rusty.


It really needs the per-cpu alloc patches which are pending to make it

> 
> Of course, reducing NR_CPUS to something sane was an easy way to patch
> over the problem.
> 
> diff --git a/include/linux/module.h b/include/linux/module.h
> index 4f7ea12..32b0bda 100644
> --- a/include/linux/module.h
> +++ b/include/linux/module.h
> @@ -222,7 +222,7 @@ void *__symbol_get_gpl(const char *symbol);
>  struct module_ref
>  {
>  	local_t count;
> -} ____cacheline_aligned;
> +};
>  
>  enum module_state
>  {
> 
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/