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From: Rusty Russell <rusty@rustcorp.com.au>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Brandon Philips <brandon@ifup.org>,
	"Rafael J. Wysocki" <rjw@sisk.pl>,
	LKML <linux-kernel@vger.kernel.org>,
	Jon Masters <jonathan@jonmasters.org>,
	Tejun Heo <htejun@gmail.com>,
	Masami Hiramatsu <mhiramat@redhat.com>,
	Kay Sievers <kay.sievers@vrfy.org>
Subject: Re: [PATCH 2/2] module: fix bne2 "gave up waiting for init of module libcrc32c"
Date: Wed, 2 Jun 2010 12:45:57 +0930	[thread overview]
Message-ID: <201006021245.59076.rusty@rustcorp.com.au> (raw)
In-Reply-To: <201006011449.51587.rusty@rustcorp.com.au>

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.

  reply	other threads:[~2010-06-02  3:16 UTC|newest]

Thread overview: 71+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-05-25 21:00 [Regression] Crash in load_module() while freeing args Rafael J. Wysocki
2010-05-25 22:54 ` Rafael J. Wysocki
2010-05-25 23:47   ` Linus Torvalds
2010-05-26  8:00     ` Rusty Russell
2010-05-26 11:57       ` Rusty Russell
2010-05-26 22:56         ` Rafael J. Wysocki
2010-05-26 23:07           ` Linus Torvalds
2010-05-27  5:26           ` Rusty Russell
2010-05-27 18:46             ` Brandon Philips
2010-05-31  9:40               ` Rusty Russell
2010-05-31 12:00                 ` [PATCH 0/2] kernel/module.c locking changes Rusty Russell
2010-05-31 12:01                   ` [PATCH 1/2] module: make locking more fine-grained Rusty Russell
2010-05-31 12:02                     ` [PATCH 2/2] module: fix bne2 "gave up waiting for init of module libcrc32c" Rusty Russell
2010-05-31 16:48                       ` Andrew Morton
2010-05-31 18:19                         ` Linus Torvalds
2010-05-31 20:15                           ` Linus Torvalds
2010-05-31 20:16                             ` [PATCH 1/2] Make the module 'usage' lists be two-way Linus Torvalds
2010-05-31 20:17                               ` [PATCH 2/2] module: wait for other modules after dropping the module_mutex Linus Torvalds
2010-06-01  1:37                               ` [PATCH 1/2] Make the module 'usage' lists be two-way Rusty Russell
2010-06-01  3:42                                 ` Rusty Russell
2010-06-01  4:00                                   ` Linus Torvalds
2010-06-01  4:05                                     ` Linus Torvalds
2010-06-01  2:44                               ` Américo Wang
2010-06-01  3:51                                 ` Linus Torvalds
2010-06-01  1:57                             ` [PATCH 2/2] module: fix bne2 "gave up waiting for init of module libcrc32c" Rusty Russell
2010-06-01  3:40                               ` Linus Torvalds
2010-06-01  4:27                                 ` Linus Torvalds
2010-06-01  5:19                                 ` Rusty Russell
2010-06-02  3:15                                   ` Rusty Russell [this message]
2010-06-01  1:21                           ` Rusty Russell
2010-06-01  3:24                             ` Linus Torvalds
2010-06-01  5:22                               ` Rusty Russell
2010-06-01 14:58                                 ` Linus Torvalds
2010-06-01 17:53                                   ` Linus Torvalds
2010-06-01 23:24                                     ` Brandon Philips
2010-06-01 23:51                                       ` Linus Torvalds
2010-06-02  2:10                                         ` Brandon Philips
2010-06-02  3:03                                           ` Rusty Russell
2010-06-02  4:35                                           ` Linus Torvalds
2010-06-02  4:44                                             ` Linus Torvalds
2010-06-02  6:35                                               ` Rusty Russell
2010-06-02  7:45                                                 ` Linus Torvalds
2010-06-02  8:12                                                   ` Linus Torvalds
2010-06-02  9:07                                                     ` Rusty Russell
2010-06-02  5:52                                             ` Rusty Russell
2010-06-02  7:21                                               ` Linus Torvalds
2010-06-02 14:06                                                 ` Rusty Russell
2010-06-02 14:50                                                   ` Linus Torvalds
2010-06-03 13:06                                                     ` Rusty Russell
2010-06-02 16:53                                                   ` Brandon Philips
2010-06-02 18:01                                                   ` Linus Torvalds
2010-06-03  5:20                                                     ` Rusty Russell
2010-06-03 16:24                                                       ` Linus Torvalds
2010-06-04  1:02                                                         ` Rusty Russell
2010-06-04  1:55                                                           ` Linus Torvalds
2010-06-04  5:20                                                             ` Rusty Russell
2010-06-04 22:48                                                               ` Linus Torvalds
2010-06-05  1:49                                                                 ` Rusty Russell
2010-06-02  3:09                                   ` Rusty Russell
2010-06-02  4:32                                     ` Linus Torvalds
2010-06-02  4:56                                     ` Linus Torvalds
2010-06-02  5:52                                       ` Rusty Russell
2010-06-02  6:59                                         ` Linus Torvalds
2010-06-01  1:04                         ` Rusty Russell
2010-06-01  5:38                     ` [PATCH 1/2] module: make locking more fine-grained Américo Wang
2010-06-01  5:55                       ` Rusty Russell
2010-05-27 21:57             ` [Regression] Crash in load_module() while freeing args Rafael J. Wysocki
2010-05-31  7:54               ` Rusty Russell
2010-05-31 10:23               ` [PATCH] module: fix reference to mod->percpu after freeing module Rusty Russell
2010-05-31 10:25                 ` Tejun Heo
2010-05-26 15:41       ` [Regression] Crash in load_module() while freeing args Linus Torvalds

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