linux-kernel - Re: [PATCH 2/2] module: fix bne2 "gave up waiting for init of module libcrc32c"

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

Message-Id: <201006021245.59076.rusty@rustcorp.com.au>
Date:	Wed, 2 Jun 2010 12:45:57 +0930
From:	Rusty Russell <rusty@...tcorp.com.au>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Brandon Philips <brandon@...p.org>,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	LKML <linux-kernel@...r.kernel.org>,
	Jon Masters <jonathan@...masters.org>,
	Tejun Heo <htejun@...il.com>,
	Masami Hiramatsu <mhiramat@...hat.com>,
	Kay Sievers <kay.sievers@...y.org>
Subject: Re: [PATCH 2/2] module: fix bne2 "gave up waiting for init of module libcrc32c"

On Tue, 1 Jun 2010 02:49:50 pm Rusty Russell wrote:
> I wonder if we should just get rid of !CONFIG_UNLOAD then?  I have a soft spot
> for it because it keeps us honest and shows how much shit is there simply for
> our poor man's pagable kernel.
> 
> Let me compile up a kernel with and without and see what it's really doing
> to us...

With a distro-style config (copied Ubuntu then held down Enter on oldconfig)
it's:
		Vmlinux	module.o (text/data)	Total module size (text/data)
With unload	8976331	24144/1036		47255565/3298004
Without unload	8962022	20551/732		47176064/3222068
Without modules 8723931

So, we pay 14k for module unload support, or 0.2%, and 0.3% across the
modules themselves.  There's real runtime costs, too, but someone would need
to annotate and see how often we do inc/dec in a real system.

Not sure that last one is exactly comparable, but it looks like module
support is a significant cost...

Cheers,
Rusty.
--
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/