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From: Ingo Molnar <mingo@elte.hu>
To: David Howells <dhowells@redhat.com>
Cc: torvalds@osdl.org, akpm@osdl.org, benh@kernel.crashing.org,
	linux-kernel@vger.kernel.org, uclinux-dev@uclinux.org
Subject: Re: [PATCH 2/3] FRV: Permit __do_IRQ() to be dispensed with
Date: Sat, 9 Sep 2006 07:12:11 +0200	[thread overview]
Message-ID: <20060909051211.GA6922@elte.hu> (raw)
In-Reply-To: <20060908153240.21015.67367.stgit@warthog.cambridge.redhat.com>


* David Howells <dhowells@redhat.com> wrote:

> +#ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ

> +#ifdef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ

> +#ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ

I think the myriad of arch switches and the resulting #ifdef noise, just 
to get rid of a _single_ unused global function, is pretty lame. (and 
that's of course not your fault)

The real solution would be to use gcc -ffunction-sections plus ld 
--gc-sections to automatically get rid of unused global functions, at 
link time. I'm wondering how hard it would be to enhance kbuild to do 
that - x86_64 already uses -ffunction-sections (if CONFIG_REORDER), so 
the big question is how usable is ld --gc-sections. Such a feature would 
be quite important for embedded systems (and for RAM footprint in 
general) as it would save a significant amount of .text and .data.

	Ingo

  reply	other threads:[~2006-09-09  5:20 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-09-08 15:32 [PATCH 1/3] FRV: Improve FRV's use of generic IRQ handling David Howells
2006-09-08 15:32 ` [PATCH 2/3] FRV: Permit __do_IRQ() to be dispensed with David Howells
2006-09-09  5:12   ` Ingo Molnar [this message]
2006-09-09  7:26     ` Benjamin Herrenschmidt
2006-09-21 13:12       ` David Howells
2006-09-21 21:59         ` Benjamin Herrenschmidt
2006-09-10 14:34     ` Daniel Walker
2006-09-11  5:33       ` Ingo Molnar
2006-09-11  9:47     ` David Howells
2006-09-11 15:33       ` Daniel Walker
2006-09-08 15:32 ` [PATCH 3/3] FRV: Mark __do_IRQ() deprecated David Howells

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